The rusty blackhaw bloomed today
Just prior to the month of May
Five stamens nigh five petals rose
Of panicles in white array
The leaves are velvet green beneath
Un-rusted and uneaten yet
Above a longhorn beetle feeds
On pollen covering up its head
The oaks nearby have fully leafed
Though flaccid and lethargic still
With yellow tinting everywhere
Awash in springtime chlorophyll
Sunday, April 26, 2009
Saturday, April 18, 2009
Knowledge and Polestars
In Josephine Johnson’s Pulitzer-winning novel, Now in November, Grant and Marget come across a snake while walking on the farm. Grant can tell that it’s about to shed its skin. Marget then wishes she knew as many things about the world as Grant does. Then Grant makes a remarkable admission. “I have a fool hopeful belief,” he says, “that the more we know, the more we can come to understand.”
For those of us who are hopelessly addicted to learning new things, these are assuring words. In fact we know intuitively that they are true. Those moments in our lives when the light of understanding breaks through our otherwise clouded existence, it often comes piggy-back on what we already know – in contingencies of previously known facts.
And yet the opposite also seems true. Sometimes the more we know, the more confusing things become. In a recent evaluation of how little we know about nitrogen fixation in plants, G.J. Leigh laments that, “the more we know, the less we understand.” (See The World’s Greatest Fix, A History of Nitrogen and Agriculture, Oxford University Press, 2004, p. 178.)
This, of course, is a common theme in science and is more often expressed as, “the more we know, the more we realize that we don’t know.” This has become an aphorism and a call to humility among scientists for a long time, but scientists don’t normally understand it to mean that the more we know, the less we wisdom we have. On the contrary, most scientists believe that the more we are aware of our knowledge gaps, the greater is our understanding, at least to a degree.
So all of this seems to imply that both statements are true. The more we know, the more we do understand - in an absolute sense (our total amount of knowledge does increase). But it is also true that the more we know, the awareness of our ignorance also increases, such that the proportion of our knowledge, compared to all there really is to be known, becomes less. At least it appears less to us.
In Grant’s conversation with Marget, it is apparent that he wants understanding most of all. Knowledge is just a way of getting understanding. This is certainly a commendable use of knowledge. Many have been the abuses of knowledge for less worthy ends - such as power, prestige, or wealth. But understanding by itself is not free of ambiguity. This is because understanding implies a world view.
Knowledge without a polestar is like plowing a field without your eyes fixed on an immoveable object. You begin to wander in many different directions. The wandering may be subtle or not so subtle, but it is wandering nonetheless. This sounds a bit too subjective for most people - who want absolute facts free of value judgments or preconceived theories. The only problem with this kind of thinking is that we humans aren’t made to see the world this way. The need for a polestar is part of our nature.
Grant’s next question could easily be, “why do snakes shed their skin?” followed ultimately by, “why are there even snakes at all?” the answers to these questions can be very different if one’s polestar sees the creation as a product of chance or part of an intended order.
All of our knowledge, ultimately, is informed by our views, whether we realize it or not. Even the certain laws of mathematics will be pointed in different directions in persons of different polestars. They may be grounded immovably in fact, but the direction they are headed makes all the difference in the world.
The remarkable truth to be gained from all of this is that there is only one ordered universe that accounts for all knowledge – and therefore only one polestar that aligns with all of this knowledge. All other polestars will never be able to account for everything – there are simply too many contradictions.
Think of a million ropes (representing a million bits of knowledge) all tied to the ground and measured precisely to hold a giant hot air balloon high above the earth. When working as they were designed to, each rope is securely fastened to the balloon and carries an equal share of the weight. Any other balloon anywhere else in the world would leave many ropes unused, or twisted and out of proportion. Our balloon – that is, our world – is clearly not this way. It is an ordered world.
Instead of a twisted laws, or no apparent laws at all, we experience systems that work with great precision together in ways to foster life. Many of these systems – in fact most of them – we are ignorant of. There is a lot of knowledge that we will never have. We can therefore be forgiven for this ignorance, at least in part. Our choice of polestars, however, is a different thing. Our understanding depends on which one we chose. It seems obvious that we should choose one that is ordered the best. To me it seems obvious that this is a created order.
For those of us who are hopelessly addicted to learning new things, these are assuring words. In fact we know intuitively that they are true. Those moments in our lives when the light of understanding breaks through our otherwise clouded existence, it often comes piggy-back on what we already know – in contingencies of previously known facts.
And yet the opposite also seems true. Sometimes the more we know, the more confusing things become. In a recent evaluation of how little we know about nitrogen fixation in plants, G.J. Leigh laments that, “the more we know, the less we understand.” (See The World’s Greatest Fix, A History of Nitrogen and Agriculture, Oxford University Press, 2004, p. 178.)
This, of course, is a common theme in science and is more often expressed as, “the more we know, the more we realize that we don’t know.” This has become an aphorism and a call to humility among scientists for a long time, but scientists don’t normally understand it to mean that the more we know, the less we wisdom we have. On the contrary, most scientists believe that the more we are aware of our knowledge gaps, the greater is our understanding, at least to a degree.
So all of this seems to imply that both statements are true. The more we know, the more we do understand - in an absolute sense (our total amount of knowledge does increase). But it is also true that the more we know, the awareness of our ignorance also increases, such that the proportion of our knowledge, compared to all there really is to be known, becomes less. At least it appears less to us.
In Grant’s conversation with Marget, it is apparent that he wants understanding most of all. Knowledge is just a way of getting understanding. This is certainly a commendable use of knowledge. Many have been the abuses of knowledge for less worthy ends - such as power, prestige, or wealth. But understanding by itself is not free of ambiguity. This is because understanding implies a world view.
Knowledge without a polestar is like plowing a field without your eyes fixed on an immoveable object. You begin to wander in many different directions. The wandering may be subtle or not so subtle, but it is wandering nonetheless. This sounds a bit too subjective for most people - who want absolute facts free of value judgments or preconceived theories. The only problem with this kind of thinking is that we humans aren’t made to see the world this way. The need for a polestar is part of our nature.
Grant’s next question could easily be, “why do snakes shed their skin?” followed ultimately by, “why are there even snakes at all?” the answers to these questions can be very different if one’s polestar sees the creation as a product of chance or part of an intended order.
All of our knowledge, ultimately, is informed by our views, whether we realize it or not. Even the certain laws of mathematics will be pointed in different directions in persons of different polestars. They may be grounded immovably in fact, but the direction they are headed makes all the difference in the world.
The remarkable truth to be gained from all of this is that there is only one ordered universe that accounts for all knowledge – and therefore only one polestar that aligns with all of this knowledge. All other polestars will never be able to account for everything – there are simply too many contradictions.
Think of a million ropes (representing a million bits of knowledge) all tied to the ground and measured precisely to hold a giant hot air balloon high above the earth. When working as they were designed to, each rope is securely fastened to the balloon and carries an equal share of the weight. Any other balloon anywhere else in the world would leave many ropes unused, or twisted and out of proportion. Our balloon – that is, our world – is clearly not this way. It is an ordered world.
Instead of a twisted laws, or no apparent laws at all, we experience systems that work with great precision together in ways to foster life. Many of these systems – in fact most of them – we are ignorant of. There is a lot of knowledge that we will never have. We can therefore be forgiven for this ignorance, at least in part. Our choice of polestars, however, is a different thing. Our understanding depends on which one we chose. It seems obvious that we should choose one that is ordered the best. To me it seems obvious that this is a created order.
Saturday, April 11, 2009
King's River
This is the best time of the year to visit the foothills of the western Sierra Nevada. Lupines – colored lavender, white, blue, and violet – are covering the hillsides. The grass is actually green and the new oak leaves are small and shiny. Most of the trees have leafed out already or are bursting their buds. Scattered amid the sea of green are a few exceptions clustered in pockets of brilliant magenta. These are the flowers of the western redbud that hold back their leaves until the flowers have had their several days of glory.
We decided to spend a couple of days over Spring Break on the King’s River in the foothills of southern Fresno County, just north of King’s Canyon National Park. We camped at Kirch Flat just upriver from Pine Flat Reservoir.
King’s River is a swift yet fairly flat river. Its banks are sandy and lined with cobbles that have long endured the grinding pressure of the white-water current. There are California sycamores and lupines as big as sagebrush along the shore. A little further upriver the hillsides are covered with California poppies and a host of other wildflowers.
We found a large population of blister beetles (of the genus Lytta) feeding on the poppy petals. They were about half an inch long and were brightly metallic. Some individuals were coppery green while others were blue or just plain green. The young larvae of these beetles (called triungulins) are highly active and are known to jump from flowers onto solitary bees that come to feed. After hitching a ride to their nests, the immature beetles feed on the developing larval bees and grow fat in their underground nests. Once the bee larvae are consumed, the beetle parasitoids pupate in the soil and emerge as adult blister beetles ready for a new generation.
But this doesn’t explain the penchant that these particular beetles have for poppy flowers. It is more than likely that they are acquiring alkaloids or glycosides (both known to occur in California poppies) to protect themselves from predators. They certainly do like the flowers. We found several of them nearly skeletonized, while hanging behind the beetles, like drag lines, were strings of scarlet frass.
We also found a few scorpion flies (Bittacus chlorostigma, also known as the green stigma hangingfly) in the tall grass of the cooler shaded areas. They are similar to the crane flies that are numerous right now and, as a result, we almost overlooked them. One mating pair, however, was oblivious to our presence and let us get close enough to see their pointed mouthparts. They were locked in copula and a plant bug was clasped in their tarsi – apparently a nuptial gift for the female. The delicate yellow patch at the end of the wings matched their yellow legs and is the diagnostic character of this beautiful insect.
But perhaps our most interesting finds were near the river under driftwood. We came across a darkling beetle just under an inch long looking very much like an iron-clad beetle. These beetles are known to be very hard to smash (one has to wonder who first figured this interesting fact out). Their hard exoskeleton can sometimes be stepped-on without breaking. The insect we found was not actually one of these but a related species, Nyctoporis carinata. It is a dull blackish gray and has an intricate sculptured pattern on its back with ridges and grooves that even extend on to its head. It looks a bit like a small tank. Even its antennae look reinforced and armored.
Another interesting beetle under the driftwood was a snail-eating ground beetle (of the genus Scaphinotus, sensu lato). These remarkable insects have elongated mouthparts that they use to eat snails. The wing covers of this particular species were nearly round.
I should mention another curious incident that happened during our trip. Our campsite was spotted with the mounds of the valley pocket gopher (Thomomys bottae). There were piles of moist soil from their recently excavated tunnels and piles of drier soil from older ones. We didn’t think much of them until our dog (a poodle terrier mix) found one outside its tunnel just before sunset. The dog had probably never seen so many wild things in its life before (we were caring for it for a friend who, we expect, had not taken it out much) and so was a bit unsure of itself at times. The gopher, finding itself cornered by the dog, tried to dig a tunnel as fast as it could. Unfortunately it wasn’t fast enough and was forced to confront the small dog (looming as a giant to the poor rodent). It backed into its partially dug hole, confronted the dog and bared its re-curved teeth. If it made a sound I couldn’t hear it. Instead it tried to look as intimidating as it could. I was surprised at how long it managed to bluff the much bigger animal. It wasn’t until it tried to run for cover that the dog quickly grabbed it and then, just as quickly, drop it again. It didn’t have the nerve to finish it off. The gopher, however, had lost the use of one of its front paws and was otherwise unable to move. The dog, deciding either that the furry creature didn’t taste good or that it wasn’t worth the trouble, left the small creature to fend for itself. Knowing that it didn’t have much chance on its own, I put the poor creature out of its misery.
Overhead, the acorn woodpeckers were busy chasing each other from tree to tree and hardly noticed. A pair of kingbirds was perched on a bare branch near the river with their backs to us. They couldn’t have cared less at what we were doing. They were just gloating over the finches that they had scared away – and, no doubt, enjoying the sounding riffles of the river.
We decided to spend a couple of days over Spring Break on the King’s River in the foothills of southern Fresno County, just north of King’s Canyon National Park. We camped at Kirch Flat just upriver from Pine Flat Reservoir.
King’s River is a swift yet fairly flat river. Its banks are sandy and lined with cobbles that have long endured the grinding pressure of the white-water current. There are California sycamores and lupines as big as sagebrush along the shore. A little further upriver the hillsides are covered with California poppies and a host of other wildflowers.
We found a large population of blister beetles (of the genus Lytta) feeding on the poppy petals. They were about half an inch long and were brightly metallic. Some individuals were coppery green while others were blue or just plain green. The young larvae of these beetles (called triungulins) are highly active and are known to jump from flowers onto solitary bees that come to feed. After hitching a ride to their nests, the immature beetles feed on the developing larval bees and grow fat in their underground nests. Once the bee larvae are consumed, the beetle parasitoids pupate in the soil and emerge as adult blister beetles ready for a new generation.
But this doesn’t explain the penchant that these particular beetles have for poppy flowers. It is more than likely that they are acquiring alkaloids or glycosides (both known to occur in California poppies) to protect themselves from predators. They certainly do like the flowers. We found several of them nearly skeletonized, while hanging behind the beetles, like drag lines, were strings of scarlet frass.
We also found a few scorpion flies (Bittacus chlorostigma, also known as the green stigma hangingfly) in the tall grass of the cooler shaded areas. They are similar to the crane flies that are numerous right now and, as a result, we almost overlooked them. One mating pair, however, was oblivious to our presence and let us get close enough to see their pointed mouthparts. They were locked in copula and a plant bug was clasped in their tarsi – apparently a nuptial gift for the female. The delicate yellow patch at the end of the wings matched their yellow legs and is the diagnostic character of this beautiful insect.
But perhaps our most interesting finds were near the river under driftwood. We came across a darkling beetle just under an inch long looking very much like an iron-clad beetle. These beetles are known to be very hard to smash (one has to wonder who first figured this interesting fact out). Their hard exoskeleton can sometimes be stepped-on without breaking. The insect we found was not actually one of these but a related species, Nyctoporis carinata. It is a dull blackish gray and has an intricate sculptured pattern on its back with ridges and grooves that even extend on to its head. It looks a bit like a small tank. Even its antennae look reinforced and armored.
Another interesting beetle under the driftwood was a snail-eating ground beetle (of the genus Scaphinotus, sensu lato). These remarkable insects have elongated mouthparts that they use to eat snails. The wing covers of this particular species were nearly round.
I should mention another curious incident that happened during our trip. Our campsite was spotted with the mounds of the valley pocket gopher (Thomomys bottae). There were piles of moist soil from their recently excavated tunnels and piles of drier soil from older ones. We didn’t think much of them until our dog (a poodle terrier mix) found one outside its tunnel just before sunset. The dog had probably never seen so many wild things in its life before (we were caring for it for a friend who, we expect, had not taken it out much) and so was a bit unsure of itself at times. The gopher, finding itself cornered by the dog, tried to dig a tunnel as fast as it could. Unfortunately it wasn’t fast enough and was forced to confront the small dog (looming as a giant to the poor rodent). It backed into its partially dug hole, confronted the dog and bared its re-curved teeth. If it made a sound I couldn’t hear it. Instead it tried to look as intimidating as it could. I was surprised at how long it managed to bluff the much bigger animal. It wasn’t until it tried to run for cover that the dog quickly grabbed it and then, just as quickly, drop it again. It didn’t have the nerve to finish it off. The gopher, however, had lost the use of one of its front paws and was otherwise unable to move. The dog, deciding either that the furry creature didn’t taste good or that it wasn’t worth the trouble, left the small creature to fend for itself. Knowing that it didn’t have much chance on its own, I put the poor creature out of its misery.
Overhead, the acorn woodpeckers were busy chasing each other from tree to tree and hardly noticed. A pair of kingbirds was perched on a bare branch near the river with their backs to us. They couldn’t have cared less at what we were doing. They were just gloating over the finches that they had scared away – and, no doubt, enjoying the sounding riffles of the river.
Saturday, April 4, 2009
The Asian Citrus Psyllid in California
In May of last year, a small insect about the size of an aphid – but looking more like a miniature cicada – was discovered in California near San Diego. Known as the Asian citrus psyllid, this small creature has caused a large amount of concern.
The reason is that the psyllid is known to carry a disease that is devastating to citrus trees. In Florida, the disease (known as citrus greening) is killing so many trees that some people are predicting the end of the state’s citrus industry within 15 years.
Fortunately for Californians, the disease hasn’t been detected here yet even though the disease’s vector – the psyllid - has. Even so, we’re not taking any chances. In fact, earlier this week, a room full of entomologists and other interested parties met for a full day near Sea World to discuss the issue.
For a day-length symposium, it was surprising how well attended every talk was – even the last ones. It was also surprising how engaged everybody seemed to be throughout. A big feature of the morning session was the presence of scientists from Florida discussing what had been happening in their state – including what successes they had had; and, more importantly, what had not worked well.
Florida’s number one lesson for Californians is that waiting to control the insect (and hoping that the disease doesn’t show up) is a very bad idea. The reason for this is that the disease can remain dormant in trees for over a year. Florida learned this lesson the hard way. The psyllid showed up in 1998 and a bit later the disease was detected. Efforts were made to control the insect but the focus was on those areas were the disease was apparent. As a result an ever-increasing number of trees, infected with the dormant disease, went undetected. Almost over-night, it seemed, when these trees started showing symptoms, it was discovered that much of the state was infected. Not enough attention had been given to the insects.
The bad news for California is that this lesson is more easily understood than acted upon. The psyllids are too mobile and are quite good at remaining undetected. The California Department of Food and Agriculture (CDFA) has acted promptly in putting together a team to deal with this problem, and significant efforts are being made to discover the insects and kill them, but there are two major reasons that their efforts will probably not be successful at completely containing the insect.
The biggest problem is that the psyllid has not only been feeding on citrus trees in San Diego County but it has also been feeding south of the border. In fact there have been many times more captures of the insect in Mexico than there have been in California. We can continue to kill every insect we find but unless something is done to control the pests outside our jurisdiction, our efforts will be no more effective than a fly swatter is for killing mosquitoes in a swamp.
The other major problem is that there are just too many citrus trees in California, and many of them will probably not be sampled or effectively treated no matter how much money we throw at the problem. If we only had to worry about citrus orchards, we might have a chance. It is known that the psyllids prefer feeding on new leaves from trees on the borders of orchards. It is conceivably possible to monitor these places and either treat them with effective insecticides, or else remove the trees so they can’t be reservoirs of the disease. Unfortunately, there are just too many trees in urban areas and even in rural areas outside of orchards. It isn’t possible to find all of these trees even if we had the resources.
In the last several months, despite our significant effort, the psyllid has moved from San Diego County to Imperial County, and it is now in Riverside County too. It seems to be only a matter of time before it jumps over the Transverse Ranges (or skirts them from the east) and enters the Central Valley. We seem to be pretty good at monitoring the critters, but this isn’t enough. We’re just watching them expand their range.
And then there remains the big unknown threat of a yellowing disease on tomatoes and potatoes. A graduate student has recently shown that the bacterium causing this disease is closely related to citrus greening. The bad news is that it can also infect citrus trees. It seems that it isn’t happening very often because the insect that feeds on tomatoes and potatoes doesn’t like to feed on citrus too (thus transferring the disease). The big unknown is whether or not our newly-arrived psyllid – the Asian citrus psyllid - might do a much better job at carrying it around. We might end up with an entirely different citrus greening (or yellowing) disease on our hands.
So what are citrus growers to do? Watch and despair – and pray that the disease doesn’t show up? Well, things probably aren’t that bad yet – although a bit of prayer might not hurt. We do have tools.
For starters, we have good systemic products that kill psyllids and that have been very effective in Florida on young trees – both as a preventative treatment and to already infested plants. It is applied to the roots and is absorbed by the plant - moving into the newer plant tissue. This is where the psyllids are feeding or laying eggs. It would probably work on older trees too but the rate would have to be quite a bit higher than is currently allowed. Putting this large amount on the trees, besides being illegal, might only make for super-resistant bugs. There are a few people looking into higher rates in order to save the more mature trees and this may be an option later on under certain conditions. We’ll have to wait and see.
Another important precaution is to watch your trees - especially the new growth - for signs of the insects. They’re small so you have to pay attention but they tend to like the outside trees of an orchard. If you can catch them early and kill them with a good insecticide, you may be able to keep things under control. The best time for spraying for maximum effect is just prior to the adult flush – to prevent egg-laying and subsequent feeding by the nymphs. In California, this timing isn’t worked out yet as well as it is in Florida, so we’ll have to pay extra careful attention until it is.
And remember, Southern California is now a war zone, and like any effective military effort, we need to anticipate where the enemy is headed. Quite simply, it is headed to any and all unprotected citrus plants. It’s true that citrus growers are the first that need to take precautions, but this is not enough. For every commercial citrus grower there are many more home owners that are not paying attention to the looming crisis. Growers need to make as large of a “no-fly” zone as possible around their trees. This means talking to neighbors and thinking like the enemy. It’s the newly-potted nursery plant sitting on an apartment balcony that’s going to be forgotten. We need snipers everywhere (polite ones, for sure). CDFA, for all their help, will never make this work alone. It’s time to bring out the troops. If we fail, we may lose the citrus industry in the Golden State.
The reason is that the psyllid is known to carry a disease that is devastating to citrus trees. In Florida, the disease (known as citrus greening) is killing so many trees that some people are predicting the end of the state’s citrus industry within 15 years.
Fortunately for Californians, the disease hasn’t been detected here yet even though the disease’s vector – the psyllid - has. Even so, we’re not taking any chances. In fact, earlier this week, a room full of entomologists and other interested parties met for a full day near Sea World to discuss the issue.
For a day-length symposium, it was surprising how well attended every talk was – even the last ones. It was also surprising how engaged everybody seemed to be throughout. A big feature of the morning session was the presence of scientists from Florida discussing what had been happening in their state – including what successes they had had; and, more importantly, what had not worked well.
Florida’s number one lesson for Californians is that waiting to control the insect (and hoping that the disease doesn’t show up) is a very bad idea. The reason for this is that the disease can remain dormant in trees for over a year. Florida learned this lesson the hard way. The psyllid showed up in 1998 and a bit later the disease was detected. Efforts were made to control the insect but the focus was on those areas were the disease was apparent. As a result an ever-increasing number of trees, infected with the dormant disease, went undetected. Almost over-night, it seemed, when these trees started showing symptoms, it was discovered that much of the state was infected. Not enough attention had been given to the insects.
The bad news for California is that this lesson is more easily understood than acted upon. The psyllids are too mobile and are quite good at remaining undetected. The California Department of Food and Agriculture (CDFA) has acted promptly in putting together a team to deal with this problem, and significant efforts are being made to discover the insects and kill them, but there are two major reasons that their efforts will probably not be successful at completely containing the insect.
The biggest problem is that the psyllid has not only been feeding on citrus trees in San Diego County but it has also been feeding south of the border. In fact there have been many times more captures of the insect in Mexico than there have been in California. We can continue to kill every insect we find but unless something is done to control the pests outside our jurisdiction, our efforts will be no more effective than a fly swatter is for killing mosquitoes in a swamp.
The other major problem is that there are just too many citrus trees in California, and many of them will probably not be sampled or effectively treated no matter how much money we throw at the problem. If we only had to worry about citrus orchards, we might have a chance. It is known that the psyllids prefer feeding on new leaves from trees on the borders of orchards. It is conceivably possible to monitor these places and either treat them with effective insecticides, or else remove the trees so they can’t be reservoirs of the disease. Unfortunately, there are just too many trees in urban areas and even in rural areas outside of orchards. It isn’t possible to find all of these trees even if we had the resources.
In the last several months, despite our significant effort, the psyllid has moved from San Diego County to Imperial County, and it is now in Riverside County too. It seems to be only a matter of time before it jumps over the Transverse Ranges (or skirts them from the east) and enters the Central Valley. We seem to be pretty good at monitoring the critters, but this isn’t enough. We’re just watching them expand their range.
And then there remains the big unknown threat of a yellowing disease on tomatoes and potatoes. A graduate student has recently shown that the bacterium causing this disease is closely related to citrus greening. The bad news is that it can also infect citrus trees. It seems that it isn’t happening very often because the insect that feeds on tomatoes and potatoes doesn’t like to feed on citrus too (thus transferring the disease). The big unknown is whether or not our newly-arrived psyllid – the Asian citrus psyllid - might do a much better job at carrying it around. We might end up with an entirely different citrus greening (or yellowing) disease on our hands.
So what are citrus growers to do? Watch and despair – and pray that the disease doesn’t show up? Well, things probably aren’t that bad yet – although a bit of prayer might not hurt. We do have tools.
For starters, we have good systemic products that kill psyllids and that have been very effective in Florida on young trees – both as a preventative treatment and to already infested plants. It is applied to the roots and is absorbed by the plant - moving into the newer plant tissue. This is where the psyllids are feeding or laying eggs. It would probably work on older trees too but the rate would have to be quite a bit higher than is currently allowed. Putting this large amount on the trees, besides being illegal, might only make for super-resistant bugs. There are a few people looking into higher rates in order to save the more mature trees and this may be an option later on under certain conditions. We’ll have to wait and see.
Another important precaution is to watch your trees - especially the new growth - for signs of the insects. They’re small so you have to pay attention but they tend to like the outside trees of an orchard. If you can catch them early and kill them with a good insecticide, you may be able to keep things under control. The best time for spraying for maximum effect is just prior to the adult flush – to prevent egg-laying and subsequent feeding by the nymphs. In California, this timing isn’t worked out yet as well as it is in Florida, so we’ll have to pay extra careful attention until it is.
And remember, Southern California is now a war zone, and like any effective military effort, we need to anticipate where the enemy is headed. Quite simply, it is headed to any and all unprotected citrus plants. It’s true that citrus growers are the first that need to take precautions, but this is not enough. For every commercial citrus grower there are many more home owners that are not paying attention to the looming crisis. Growers need to make as large of a “no-fly” zone as possible around their trees. This means talking to neighbors and thinking like the enemy. It’s the newly-potted nursery plant sitting on an apartment balcony that’s going to be forgotten. We need snipers everywhere (polite ones, for sure). CDFA, for all their help, will never make this work alone. It’s time to bring out the troops. If we fail, we may lose the citrus industry in the Golden State.
Saturday, March 28, 2009
Buzz Off
Else Olsen was upset for days after the car in front of her hit a squirrel. Before dying, the poor rodent thrashed around for longer than Else could see it in her rear view memory. For days afterward she couldn’t eat much of anything. For a frail woman over 60, that was downright dangerous.
This morning, though, she had a different problem. It presented itself in the form of a fly as she sat daintily in her Queen Anne recliner nibbling a chocolate bar. Her thin fingers, just faintly arthritic, held the candy precisely between the outstretched tips of her thumb and forefinger.
Her perfectly even teeth had just removed a semicircular morsel when the insect alighted and began probing the chocolate with its proboscis. Else’s meticulous cleaning habits usually kept pests out. The fly’s abrupt appearance startled her. She thrust her hand over her breast while her heart thumped against her ribs. Her last morsel was left half masticated on her tongue. It was with remarkable control that she avoided dropping the candy bar altogether.
Chocolate was one of the few pleasures this small woman ever allowed herself. Now it would have to be thrown out. The little beast would have to go. So with accustomed delicate precision, Else lowered the candy bar onto a spotless sham and lifted herself from the couch. Her paltry, femininely distributed pounds hardly moved the pillow case as she rose.
Her small slippered feet made no noise as she walked to the front door and opened it wide. Then returning to the couch she found the fly still feeding on a crumb. She waved at it but the insect flew away from her bejeweled hand, buzzed around the lamp shade and promptly landed back on the candy.
“Hmmph.” muttered Else in frustration, whereupon she took a step closer to her antagonist and waved her hand twice as fast and three times as long as she had before.
This time the fly made it straight for the ceiling and waited - well out of reach of the glowering women. “You won’t stay there very long,” said Else, unaware how foolish it was that she fully expected the fly to understand what she was saying.
Fortunately there was a newspaper on the stereo. She picked it up, rolled it into a weapon, and swung at the fly on tiptoes. To her surprise, the insect flew away. In fact it flew over to the front door and landed on the doorknob.
“What luck,” cried Else, “now you’re out the door.” But she was wrong. As soon as she got closer to scare the thing outside, it buzzed into the air and flew back to the candy on the couch. Else then noticed another fly on the front porch. It was looking straight in at her.
“My goodness,” she exclaimed. “I can’t let any more of you in here.” She then wiped the doorknob clean with her skirt and closed the door. Now she was really getting angry. This fly would have to pay for its effrontery with its life.
It had been a long time since Else had been so mad. She had forgotten how much fun it was. Now she was no longer playing a defensive game. She was hunting and so passed without a sound into the laundry room full of revenge. Decades of practice being quiet made tiptoeing easy. The swatter hung on the wall, exactly where she had left it the last time she had used it. At first she wondered if it might need disinfecting. “No matter,” she muttered to herself and then grinned. “It will certainly need cleaning today.”
Back on the couch, the fly buzzed and walked across the candy. Else returned just as one of the creature’s back legs caught a wing and slid over it as if it were a comb.
“How dare you?” she said trying to be intimidating, “cleaning your filthy body on my food.” Her voice was touched with a polite Southern drawl that didn’t faze the fly at all. It merely began wiping its other wing. This apparent apathy only made Else feel half helpless. Ever since her husband Harold died, nobody took her suggestions seriously. Now this noisome insect wouldn’t even flinch at her harshest threat. It was exasperating.
“You’ll regret this,” she warned, then lifted the plastic mesh to within striking range. Then, taking a deep breath, she thrust it at the fly with all the finesse of a manicurist drying her nails. The faceted eyes of the fly saw the attack long before it landed and flew away. The swatter only smashed chocolate all over the pillowcase.
“Ooh,” fumed Else, inspecting the damage. Then, momentarily conceding defeat, she sunk into the upholstery and picked at the candied orts, watching as her antagonist resumed its feast.
A moment passed and a small shadow, no longer than a dime, descended from inside the lampshade beside her. It moved so slow that Else didn’t notice it until it was nearly to the bottom. Then it jumped onto the table and began swinging its front legs back and forth, like a magician casting a spell.
“A spider,” she gasped, as the fly buzzed near her head. “Look how red it is.” Then, almost on cue, the woman and the insect moved closer for a better look. No sooner had the fly approached then the arachnid backed up with short jerky pantomimes. Before long, its eight hairy legs were dancing across the polished glaze of the table. The fly, half hypnotized, followed.
Else, overcoming angst, sat up straight with her hand over her mouth. Then the spider jumped forward and caught the fly. It happened so quickly that Else flinched and nearly fell to the floor.
Soon the buzzing of the fly became muffled and then stopped altogether. The spider, grasping its prey, inched its way backward up the base of the lamp and out of sight.
“My goodness,” managed Else, now carefully placing chocolate pieces onto the fly swatter. I’ve never seen anything like that before, serves the pesky critter right.”
Back at the kitchen, she began running hot water into the sink. Without looking she reached under the counter and retrieved the detergent. She wiped it with the washcloth and squeezed three practiced squirts into the running water then returned it to its proper place.
Just outside the window there was a shuffling of leaves. Else looked up, and into, the stare of a fox squirrel nibbling on an acorn. She was beginning to feel better already.
This morning, though, she had a different problem. It presented itself in the form of a fly as she sat daintily in her Queen Anne recliner nibbling a chocolate bar. Her thin fingers, just faintly arthritic, held the candy precisely between the outstretched tips of her thumb and forefinger.
Her perfectly even teeth had just removed a semicircular morsel when the insect alighted and began probing the chocolate with its proboscis. Else’s meticulous cleaning habits usually kept pests out. The fly’s abrupt appearance startled her. She thrust her hand over her breast while her heart thumped against her ribs. Her last morsel was left half masticated on her tongue. It was with remarkable control that she avoided dropping the candy bar altogether.
Chocolate was one of the few pleasures this small woman ever allowed herself. Now it would have to be thrown out. The little beast would have to go. So with accustomed delicate precision, Else lowered the candy bar onto a spotless sham and lifted herself from the couch. Her paltry, femininely distributed pounds hardly moved the pillow case as she rose.
Her small slippered feet made no noise as she walked to the front door and opened it wide. Then returning to the couch she found the fly still feeding on a crumb. She waved at it but the insect flew away from her bejeweled hand, buzzed around the lamp shade and promptly landed back on the candy.
“Hmmph.” muttered Else in frustration, whereupon she took a step closer to her antagonist and waved her hand twice as fast and three times as long as she had before.
This time the fly made it straight for the ceiling and waited - well out of reach of the glowering women. “You won’t stay there very long,” said Else, unaware how foolish it was that she fully expected the fly to understand what she was saying.
Fortunately there was a newspaper on the stereo. She picked it up, rolled it into a weapon, and swung at the fly on tiptoes. To her surprise, the insect flew away. In fact it flew over to the front door and landed on the doorknob.
“What luck,” cried Else, “now you’re out the door.” But she was wrong. As soon as she got closer to scare the thing outside, it buzzed into the air and flew back to the candy on the couch. Else then noticed another fly on the front porch. It was looking straight in at her.
“My goodness,” she exclaimed. “I can’t let any more of you in here.” She then wiped the doorknob clean with her skirt and closed the door. Now she was really getting angry. This fly would have to pay for its effrontery with its life.
It had been a long time since Else had been so mad. She had forgotten how much fun it was. Now she was no longer playing a defensive game. She was hunting and so passed without a sound into the laundry room full of revenge. Decades of practice being quiet made tiptoeing easy. The swatter hung on the wall, exactly where she had left it the last time she had used it. At first she wondered if it might need disinfecting. “No matter,” she muttered to herself and then grinned. “It will certainly need cleaning today.”
Back on the couch, the fly buzzed and walked across the candy. Else returned just as one of the creature’s back legs caught a wing and slid over it as if it were a comb.
“How dare you?” she said trying to be intimidating, “cleaning your filthy body on my food.” Her voice was touched with a polite Southern drawl that didn’t faze the fly at all. It merely began wiping its other wing. This apparent apathy only made Else feel half helpless. Ever since her husband Harold died, nobody took her suggestions seriously. Now this noisome insect wouldn’t even flinch at her harshest threat. It was exasperating.
“You’ll regret this,” she warned, then lifted the plastic mesh to within striking range. Then, taking a deep breath, she thrust it at the fly with all the finesse of a manicurist drying her nails. The faceted eyes of the fly saw the attack long before it landed and flew away. The swatter only smashed chocolate all over the pillowcase.
“Ooh,” fumed Else, inspecting the damage. Then, momentarily conceding defeat, she sunk into the upholstery and picked at the candied orts, watching as her antagonist resumed its feast.
A moment passed and a small shadow, no longer than a dime, descended from inside the lampshade beside her. It moved so slow that Else didn’t notice it until it was nearly to the bottom. Then it jumped onto the table and began swinging its front legs back and forth, like a magician casting a spell.
“A spider,” she gasped, as the fly buzzed near her head. “Look how red it is.” Then, almost on cue, the woman and the insect moved closer for a better look. No sooner had the fly approached then the arachnid backed up with short jerky pantomimes. Before long, its eight hairy legs were dancing across the polished glaze of the table. The fly, half hypnotized, followed.
Else, overcoming angst, sat up straight with her hand over her mouth. Then the spider jumped forward and caught the fly. It happened so quickly that Else flinched and nearly fell to the floor.
Soon the buzzing of the fly became muffled and then stopped altogether. The spider, grasping its prey, inched its way backward up the base of the lamp and out of sight.
“My goodness,” managed Else, now carefully placing chocolate pieces onto the fly swatter. I’ve never seen anything like that before, serves the pesky critter right.”
Back at the kitchen, she began running hot water into the sink. Without looking she reached under the counter and retrieved the detergent. She wiped it with the washcloth and squeezed three practiced squirts into the running water then returned it to its proper place.
Just outside the window there was a shuffling of leaves. Else looked up, and into, the stare of a fox squirrel nibbling on an acorn. She was beginning to feel better already.
Saturday, March 21, 2009
Richard Weaver and Hugh Nibley on Rhetoric
Richard Weaver was a Southern conservative writer during the middle of the 20th Century (and one of the original Southern Agrarians from Vanderbilt University). Most of what he wrote was motivated by a regard for and an appeal to tradition. He is mostly recognized for Ideas Have Consequences, published in 1948. Liberty Fund has also recently (2000) published many of his shorter writings (In Defense of Tradition) and his essays on the South (The Southern Essays of Richard M. Weaver, 1987).
Weaver taught English at the University of Chicago for many years before his untimely death in 1963. He also taught rhetoric and wrote an important introductory text on the subject (The Ethics of Rhetoric, published in 1953). He is generally recognized as one of the five or six leading rhetorical theorists of the 20th Century (see T. Smith’s introduction to Weaver’s rhetorical essays,in In Defense of Tradition).
Rhetoric was not really a subject that Weaver saw differently from his other research interests. He was deeply concerned about the fracturing of traditional values and saw the demise of rhetoric, from a highly respected role in the humanities to a moribund remnant of prior prestige, as just another example of our current troubles. He followed Cicero in esteeming rhetoric as a significant force in a just society.
Hugh Nibley, by contrast, was a scholar of ancient history and religion at Brigham Young University where he taught throughout the last half of the 20th Century. He was a pathfinder in many areas of Mormon studies and ancient scripture. His influence as a Mormon apologist has been immense. Today a small army of scholars continue the work he began on many subjects. His primary study of rhetoric is the essay, Victoria Loquacitas: The Rise of Rhetoric and the Decline of Everything Else (originally published in Western Speech in 1956) although rhetoric shows up in many of his other writings.
Given Nibley’s understanding of history and the number of comparisons he made between a wayward modernity and the ancient world, one might expect that he would largely agree with a defender of tradition like Weaver. No doubt there would have been many things that they agreed on. Weaver’s address at BYU in May, 1961 (entitled, Reflections of Modernity) certainly met with campus approval and was published later that year in Speeches of the Year. His argument about finding the nature of man in history instead of in science reflected many themes common in Nibley’s work.
But on the subject of rhetoric the two men had very different ideas. They never seemed to have crossed swords on the subject (Weaver may not have even been aware of Nibley’s work) but one certainly comes away from their writings aware of important differences.
Both men, following Quintilian, understood rhetoric to be the art of persuasion. But whereas Weaver saw it as a tool in defense of truth, Nibley saw it’s long historical abuse as one of truth’s greatest enemies. Weaver was certainly aware of the abuses and chose to make distinctions to clarify the difference. His recognition of propaganda as a corrupted rhetoric is an example of this.
Weaver’s interest in rhetoric is an awareness that much has been lost since it’s decline; or rather its transformation, in American life. His examples of rhetorical excellence include “Parson” Weems, Daniel Webster, Tom Paine. These were clearly persuasive and opinionated men, but for the most part, they also stood for virtuous principles.
Weaver sees Weems as part of a “fortunate class of persons whose way of looking at the world makes it impossible for them to be dull.” And, in fact, Weems’ exuberance (verging on hero worship for his subjects such as Washington, Franklin, and others) is sometimes hard to resist. But this flowery expression and hyperbole make him hard for an objective modern reader to believe - and so Weems has been banished from our classrooms. In fact almost nobody has even heard of him anymore.
An example of Weems’ rhetorical style is this comment about religious persecutions: “they were common in those dark and dismal days, when the clergy thought more of creeds than of Christ, and of learning Latin than of learning love.”
There is no doubt that this is writing with a clear motive. But it isn’t writing that pretends to be objective - at least not objective in the sense that one approaches opposing positions equally. Weems’ loyalties are baldly apparent from the start. He accepts that truth exists and uses his craft to defend it. He understands very well that human beings have passions and that they respond to emotional appeals. And Weems is writing for human beings.
But modern readers would be myopic if they ignored the potential for abuse in this sort of writing. A gifted rhetorician, it seems, could easily use his skill to promote many causes that are not worthy - causes that are false. In fact, these abuses have been apparent from the very beginning.
Nibley gives the example of Gorgias, a contemporary of Plato and participant in his dialogues. Gorgias began his career seeking truth and became convinced that it could never be found - at least not in its purity. So he decided on a path of rhetoric which was much more practical. It was also more profitable.
It isn’t difficult to find, even from this early period, individuals who sell their persuasive talents to the highest bidder or otherwise use them for causes other than truth. If Weaver and his sympathizers hold fast to a virtuous rhetorical high-ground, they certainly can’t deny that the history of rhetoric has as many, if not more, bad examples as good ones.
In order to avoid this, Cicero, like Weaver, insisted that rhetoricians be men of honesty and the best examples of virtue. It was their lot to make important, if not subtle, distinctions between apparently contradictory positions. Murder itself could at times be justified, but only by someone with enough understanding to make truthful distinctions.
Much depended on the rhetorician himself. But in the end, more depended on his audience. If the audience were uneducated or lacked understanding, the rhetorician could get by with being lazy. But there was worse, as Nibley quite persuasively shows. It was more common for the rhetorician to use his practiced skill for whatever profitable or desirable argument came his way. If his audience was not well informed, so much the better.
Today’s situation is obviously similar to this degraded form of the art. We seem to be at our rhetorical best when selling something - whether that be items for profit; or ourselves, for promotion. Manifest as blatant advertising we might see how tendentious it all is. But in our school books, newspapers, and much of popular culture, we usually fail to notice.
Another important argument against rhetoric is that it lacks the precision of a scientific algorithm. And in our technologically advanced society, precision is expected. Scientific manuscripts are regularly rejected for publication if an author extrapolates too far from the data. Accuracy is expected and is the measure of excellence. This is, of course, as it should be in the sciences. Many of us owe our lives to this attention to detail. Where we err is on assuming that because such tools serve science so well, they can do the same for our souls. Clearly this is a mistake that we are paying the price for now.
Weaver is convinced that there is an important relationship between the decline of culture and the decline of rhetoric. “Eloquence in disfavor,” he writes, “signifies a crisis of the human spirit.” Nibley, on the other hand, thinks that rhetoric itself is a critical cause of cultural decline. Although he basically ignores the high points of the art - the examples that Weaver wishes to recover. (Yet in fairness, Nibley was certainly not ignorant of or unaffected by classical literature - much of which is rife with rhetoric.)
It’s hard not to appreciate the position of both scholars and I have no intention of taking sides of one against the other. It’s true enough that when words lose their meaning that people lose their liberty. And rhetoric, for sure, has a long history of corrupting the meaning of words. But too much empiricism isn’t good for us either. There is a certain sterility of the spirit that comes from too much science. I, for one, am certainly in favor of a bit more eloquence on this, our overly objective orb. I personally think that Weaver and Nibley were both right - and in that order.
Weaver taught English at the University of Chicago for many years before his untimely death in 1963. He also taught rhetoric and wrote an important introductory text on the subject (The Ethics of Rhetoric, published in 1953). He is generally recognized as one of the five or six leading rhetorical theorists of the 20th Century (see T. Smith’s introduction to Weaver’s rhetorical essays,in In Defense of Tradition).
Rhetoric was not really a subject that Weaver saw differently from his other research interests. He was deeply concerned about the fracturing of traditional values and saw the demise of rhetoric, from a highly respected role in the humanities to a moribund remnant of prior prestige, as just another example of our current troubles. He followed Cicero in esteeming rhetoric as a significant force in a just society.
Hugh Nibley, by contrast, was a scholar of ancient history and religion at Brigham Young University where he taught throughout the last half of the 20th Century. He was a pathfinder in many areas of Mormon studies and ancient scripture. His influence as a Mormon apologist has been immense. Today a small army of scholars continue the work he began on many subjects. His primary study of rhetoric is the essay, Victoria Loquacitas: The Rise of Rhetoric and the Decline of Everything Else (originally published in Western Speech in 1956) although rhetoric shows up in many of his other writings.
Given Nibley’s understanding of history and the number of comparisons he made between a wayward modernity and the ancient world, one might expect that he would largely agree with a defender of tradition like Weaver. No doubt there would have been many things that they agreed on. Weaver’s address at BYU in May, 1961 (entitled, Reflections of Modernity) certainly met with campus approval and was published later that year in Speeches of the Year. His argument about finding the nature of man in history instead of in science reflected many themes common in Nibley’s work.
But on the subject of rhetoric the two men had very different ideas. They never seemed to have crossed swords on the subject (Weaver may not have even been aware of Nibley’s work) but one certainly comes away from their writings aware of important differences.
Both men, following Quintilian, understood rhetoric to be the art of persuasion. But whereas Weaver saw it as a tool in defense of truth, Nibley saw it’s long historical abuse as one of truth’s greatest enemies. Weaver was certainly aware of the abuses and chose to make distinctions to clarify the difference. His recognition of propaganda as a corrupted rhetoric is an example of this.
Weaver’s interest in rhetoric is an awareness that much has been lost since it’s decline; or rather its transformation, in American life. His examples of rhetorical excellence include “Parson” Weems, Daniel Webster, Tom Paine. These were clearly persuasive and opinionated men, but for the most part, they also stood for virtuous principles.
Weaver sees Weems as part of a “fortunate class of persons whose way of looking at the world makes it impossible for them to be dull.” And, in fact, Weems’ exuberance (verging on hero worship for his subjects such as Washington, Franklin, and others) is sometimes hard to resist. But this flowery expression and hyperbole make him hard for an objective modern reader to believe - and so Weems has been banished from our classrooms. In fact almost nobody has even heard of him anymore.
An example of Weems’ rhetorical style is this comment about religious persecutions: “they were common in those dark and dismal days, when the clergy thought more of creeds than of Christ, and of learning Latin than of learning love.”
There is no doubt that this is writing with a clear motive. But it isn’t writing that pretends to be objective - at least not objective in the sense that one approaches opposing positions equally. Weems’ loyalties are baldly apparent from the start. He accepts that truth exists and uses his craft to defend it. He understands very well that human beings have passions and that they respond to emotional appeals. And Weems is writing for human beings.
But modern readers would be myopic if they ignored the potential for abuse in this sort of writing. A gifted rhetorician, it seems, could easily use his skill to promote many causes that are not worthy - causes that are false. In fact, these abuses have been apparent from the very beginning.
Nibley gives the example of Gorgias, a contemporary of Plato and participant in his dialogues. Gorgias began his career seeking truth and became convinced that it could never be found - at least not in its purity. So he decided on a path of rhetoric which was much more practical. It was also more profitable.
It isn’t difficult to find, even from this early period, individuals who sell their persuasive talents to the highest bidder or otherwise use them for causes other than truth. If Weaver and his sympathizers hold fast to a virtuous rhetorical high-ground, they certainly can’t deny that the history of rhetoric has as many, if not more, bad examples as good ones.
In order to avoid this, Cicero, like Weaver, insisted that rhetoricians be men of honesty and the best examples of virtue. It was their lot to make important, if not subtle, distinctions between apparently contradictory positions. Murder itself could at times be justified, but only by someone with enough understanding to make truthful distinctions.
Much depended on the rhetorician himself. But in the end, more depended on his audience. If the audience were uneducated or lacked understanding, the rhetorician could get by with being lazy. But there was worse, as Nibley quite persuasively shows. It was more common for the rhetorician to use his practiced skill for whatever profitable or desirable argument came his way. If his audience was not well informed, so much the better.
Today’s situation is obviously similar to this degraded form of the art. We seem to be at our rhetorical best when selling something - whether that be items for profit; or ourselves, for promotion. Manifest as blatant advertising we might see how tendentious it all is. But in our school books, newspapers, and much of popular culture, we usually fail to notice.
Another important argument against rhetoric is that it lacks the precision of a scientific algorithm. And in our technologically advanced society, precision is expected. Scientific manuscripts are regularly rejected for publication if an author extrapolates too far from the data. Accuracy is expected and is the measure of excellence. This is, of course, as it should be in the sciences. Many of us owe our lives to this attention to detail. Where we err is on assuming that because such tools serve science so well, they can do the same for our souls. Clearly this is a mistake that we are paying the price for now.
Weaver is convinced that there is an important relationship between the decline of culture and the decline of rhetoric. “Eloquence in disfavor,” he writes, “signifies a crisis of the human spirit.” Nibley, on the other hand, thinks that rhetoric itself is a critical cause of cultural decline. Although he basically ignores the high points of the art - the examples that Weaver wishes to recover. (Yet in fairness, Nibley was certainly not ignorant of or unaffected by classical literature - much of which is rife with rhetoric.)
It’s hard not to appreciate the position of both scholars and I have no intention of taking sides of one against the other. It’s true enough that when words lose their meaning that people lose their liberty. And rhetoric, for sure, has a long history of corrupting the meaning of words. But too much empiricism isn’t good for us either. There is a certain sterility of the spirit that comes from too much science. I, for one, am certainly in favor of a bit more eloquence on this, our overly objective orb. I personally think that Weaver and Nibley were both right - and in that order.
Sunday, March 15, 2009
Egyptian Alfalfa Weevil
Right now in the Central Valley of California, alfalfa leaves are being skeletonized by little green worms. They are about a fourth of an inch long and are proportionately plump. Much of the feeding is done at night if it doesn’t get too cold, although they were out in numbers last week (here in Fresno) in the middle of the day when the sky was overcast.
These little worms are larvae of the Egyptian alfalfa weevil, Hypera brunneipennis, and they’ve been in California and Arizona since the spring of 1939. How they got here is anybody’s guess. Originally they’re from the Middle East. But they seem to like America a bit more - at least they‘re a lot more abundant over here.
Lawrence Wehrle was the first to discover them. He was working on a farm at the University of Arizona in early April when he saw feeding damage on the fenugreek (a clover-like legume). He soon discovered the small worms responsible but supposed they were alfalfa weevil (Hypera postica) larvae. Alfalfa weevils were known to cause damage further north (having first appeared in the US near Salt Lake City in 1904) and Wehrle feared that they might have made it all the way to Arizona.
Unfortunately he was wrong. The sample he sent to Washington DC was identified as the Egyptian alfalfa weevil - a related species. This was unfortunate because the Egyptian alfalfa weevil has done a lot more damage than the alfalfa weevil in many parts of the Western US. Seventy years later, we still have a hard time keeping it under control.
That doesn’t mean there aren’t options. Fairly early on, entomologists discovered that if the first alfalfa cutting were done a bit earlier than normal (just before flowering) that some of the weevils (adults and larvae) would die. The larvae didn’t have anything left to eat and they ended up getting cooked in the heat without places to hide. Even some of the vulnerable newly emerging adults died too.
Some creative farmers went a step further and pulled a brush or wire drag through their fields. This not only dislodged any remaining larvae but it also kicked up a lot of dust that killed even more (dust is one of the oldest and most effective ways to kill many kinds of insect pests). Other ways to kill the weevils included spraying with lead arsenate or zinc arsenate. These chemicals, of course, are not available options today but other insecticides often work well. Sometimes it isn’t necessary to treat at all if the infestation is light and if the first cutting can be made soon enough.
The reason for this is that the weevils only go through one generation a year. This is not generally the case with arthropod species that become key pests. Often they become pests because they can go through multiple generations a year and several pesticide applications become necessary. With the Egyptian alfalfa weevil, the damaging larvae only occur in the spring. If they can be controlled then (now) they no longer present a problem.
But there are a few things to watch out for. To start with, it’s not a good idea to let the cut alfalfa sit around for very long. Windrows can hold moisture underneath where the larvae can survive and cause problems to new growth. Many of the little worms will pupate and ensure a healthy pest population the next spring.
Another thing to watch out for are the beneficial insects. They will be building up in the field about the time of the first cutting. If a late insecticide application is made, you might wipe them out and have a big aphid problem later on.
This doesn’t mean that beneficial insects will help you much with your weevil problem. They won’t. There is a little wasp that lays eggs in alfalfa weevil larvae and is pretty good at keeping their numbers down but it has a hard time with Egyptian alfalfa weevil larvae. For some reason, the haemolymph (insect blood) is able to prevent the little parasitoid wasps from developing.
Right now is the time to go take a look at your field. Chances are, you’ll find something out there enjoying a free lunch. Of course, depending on where you live, you might find other things instead. Alfalfa weevils are also active now. So are clover leaf weevils, clover head weevils and the lesser clover weevil. They all look pretty much alike. In fact they like to eat pretty much the same things - clover-like legumes. Let’s face it. This is a weevily time of year. We and our legumes had better get used to the fact.
These little worms are larvae of the Egyptian alfalfa weevil, Hypera brunneipennis, and they’ve been in California and Arizona since the spring of 1939. How they got here is anybody’s guess. Originally they’re from the Middle East. But they seem to like America a bit more - at least they‘re a lot more abundant over here.
Lawrence Wehrle was the first to discover them. He was working on a farm at the University of Arizona in early April when he saw feeding damage on the fenugreek (a clover-like legume). He soon discovered the small worms responsible but supposed they were alfalfa weevil (Hypera postica) larvae. Alfalfa weevils were known to cause damage further north (having first appeared in the US near Salt Lake City in 1904) and Wehrle feared that they might have made it all the way to Arizona.
Unfortunately he was wrong. The sample he sent to Washington DC was identified as the Egyptian alfalfa weevil - a related species. This was unfortunate because the Egyptian alfalfa weevil has done a lot more damage than the alfalfa weevil in many parts of the Western US. Seventy years later, we still have a hard time keeping it under control.
That doesn’t mean there aren’t options. Fairly early on, entomologists discovered that if the first alfalfa cutting were done a bit earlier than normal (just before flowering) that some of the weevils (adults and larvae) would die. The larvae didn’t have anything left to eat and they ended up getting cooked in the heat without places to hide. Even some of the vulnerable newly emerging adults died too.
Some creative farmers went a step further and pulled a brush or wire drag through their fields. This not only dislodged any remaining larvae but it also kicked up a lot of dust that killed even more (dust is one of the oldest and most effective ways to kill many kinds of insect pests). Other ways to kill the weevils included spraying with lead arsenate or zinc arsenate. These chemicals, of course, are not available options today but other insecticides often work well. Sometimes it isn’t necessary to treat at all if the infestation is light and if the first cutting can be made soon enough.
The reason for this is that the weevils only go through one generation a year. This is not generally the case with arthropod species that become key pests. Often they become pests because they can go through multiple generations a year and several pesticide applications become necessary. With the Egyptian alfalfa weevil, the damaging larvae only occur in the spring. If they can be controlled then (now) they no longer present a problem.
But there are a few things to watch out for. To start with, it’s not a good idea to let the cut alfalfa sit around for very long. Windrows can hold moisture underneath where the larvae can survive and cause problems to new growth. Many of the little worms will pupate and ensure a healthy pest population the next spring.
Another thing to watch out for are the beneficial insects. They will be building up in the field about the time of the first cutting. If a late insecticide application is made, you might wipe them out and have a big aphid problem later on.
This doesn’t mean that beneficial insects will help you much with your weevil problem. They won’t. There is a little wasp that lays eggs in alfalfa weevil larvae and is pretty good at keeping their numbers down but it has a hard time with Egyptian alfalfa weevil larvae. For some reason, the haemolymph (insect blood) is able to prevent the little parasitoid wasps from developing.
Right now is the time to go take a look at your field. Chances are, you’ll find something out there enjoying a free lunch. Of course, depending on where you live, you might find other things instead. Alfalfa weevils are also active now. So are clover leaf weevils, clover head weevils and the lesser clover weevil. They all look pretty much alike. In fact they like to eat pretty much the same things - clover-like legumes. Let’s face it. This is a weevily time of year. We and our legumes had better get used to the fact.
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