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(BASIC) June 21 & 22 Report
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For All Growers: Trip Report June 21 & 22, 2001

Kern County BASIC Pilot Program

Deke and Francisco Cornejo made and compiled the report.

 

Kevin Antongiovanni, Thursday, June 28 & 29, 2001.

Field Observations:

The field was thought to be under the next heaviest looper moth egg laying pressure. Last week, the neighboring cotton field north of our demonstration plot was being sprayed with a ground rig. We assumed that it would be Bt that they were applying. We were concerned about the moth flight and the eggs and small larvae seen last week. There was less concern in this cotton because of the higher and more diverse populations of beneficial predators sampled here in both the cotton, the safflower to the east, the large numbers of Polistes wasps and mud dobbers that gather worms to feed their young and the flocks black birds seen working the cotton for worms. We have seen the Carabid beetle Calosoma affinae in two locations. It is a large black beetle that climbs plants at night feeding on large worms and pupae in the duff/soil interface with above ground plant surfaces.

Surrounding plantscape supports biological control:

This larger more diverse set of natural enemies suggests more effective biological control is taking place. Only Hyposoter exiguae has not been seen nor have we seen several tachinid flies, but the safflower with some weedy areas of Johnson grass and other weeds and the melons are all good habitat for most of the natural enemies known to be in alfalfa hay. Watermelons to the south and alfalfa hay south of the melons are evidence that this plantscape has more biocomplexity and less pesticide interference than either the DeStefani or Banducci plantscape.

Our foresight was more accurate than expected. The leaf feeding damage was much less than was observed at DeStefani. We were able to meet Antongiovanni and discuss our findings that we had taken to date. I think that the level of biological control has proven to be sufficient by the speed with which the large numbers of big–eyed bugs control of lygus and leaf feeding cabbage loopers, Trichoplusia ni. The number of large worms (more than half inch long) that escape the predators is far fewer than at DeStefani’s. The lygus counts have never been higher than a 3 count (all adults) migrating from the safflower as it matures. This cotton was the first to blossom and green lacewings are laying eggs and small lacewing larvae are in the D–Vac vacuum insect net samples. Lacewing adults are seen throughout the field. The only looper worms found today were in the sweep net samples at the NW corner where cotton is planted interfaced to the north and west of our block. All other sides have sources of natural enemies moving into Antongiovanni's cotton block.

Sudan habitat slow to come up:

Antoniogvanni reported that he had planted the Sudan and the next irrigation will make it grow. However, the Treflan/ Round–up herbicide combination may prevent it. The corn and flowering plant insect refuges have not germinated in this block thus far. The same insectary mix of seeds and Sudan are already 6 to 8 inches tall at Roger Sanders, planted and irrigated two weeks ago. The Sudan barrier acts as a wall to inhibit the flow of dust and other possible pesticide residues that interfere with biological control of cotton pests where natural enemies are being fostered. There is another benefit of the Sudan barrier as far as protecting against an invasion of mites that are encouraged by the infrared radiation effects from a hot dusty dirt road. The outside rows of many farms are being lined with growing plants to inhibit dust (along with sprinkling the roads with water) particularly in strawberry and both table and wine grapes. Some vegetable and tree fruit orchards are also using plants to cool down the outside rows of their fields as a control for the spider mites that seem to flourish at this infrared "hot" interface. It is also a small cost for a large benefit to help increase the biodiversity of monoculture agriculture and protect against mite invasions. Green lacewings spend a lot of the daylight hours in these plants and fly throughout the field laying eggs during the night hours.

The progress of biological control advances with each growth cycle of the plants. The weather has been favorable and the good bugs are winning as of now and the prospects for continued control look good.

 

Ray Banducci, Friday, June 22, 2001.

Banducci has the most biocomplexity having seeded staggered sweet corn plantings, melons and several cotton stages of replants. A small plot of shade trees for bird nesting and alfalfa to the south of the cotton all add up to benefit biological control. The ratio of good bugs that control the pests continues to suppress the pests before they cause any significant damage to the cotton plants as well as the other crops of corn and melons. The alfalfa has been cut at near full bloom. The worms and moths have moved into the cotton, but they are being eaten by predators, daily, as fast as the eggs hatch and before the worms get to be half inch long when their feeding scars cause more damage. Such an attack by worms using biological control increases the biological control for the next flight of pests and ultimately for the full season for all cotton pests that enter the cotton fields.

Lygus is not a problem probably because of the large numbers of big–eyed bugs, damsel bugs, and minute pirate bugs that are found in all sections sampled of this cotton planting. Hooded beetles are keeping the thrips and mites from being a problem. Ladybugs can't find enough aphids to eat so they forage on small worms and other insect prey. This field has the most crab spiders and other spiders that eat nothing but insects. This has been a good year for biological control thus far.

The comparison of Banducci cotton with the Roundup Ready cotton of DeStefani across the road (a check field for fields in this area) has been interesting. There are large numbers of predators similar to Banducci but much larger numbers of pests than Banducci. The alfalfa field north of this "check" cotton plot has been cut and irrigated before the alfalfa field west of Banducci was cut, thus staggering the cutting at least one irrigation schedule. The resident biological control insects are increasing in Banducci, keeping pace with the influx of pest species and both fields are under biological control except that the Roundup Ready cotton of DeStefani has slightly more leaf worm feeding holes showing in the leaves. The cotton is growing away from this damage rapidly.

The point of this is to show that biological control can occur at different densities of pest to beneficial ratios. Selective soft pesticides can often lower the pest density threshold without losing all of the beneficials and causing a resurgence of pests without natural enemies. Bt is such a soft pesticide.

 

Bill DeStefani, Thursday, June 21, 2001.

12 AM. Flying Tiger Farms

We met Bill when entering the farm and told him we were concerned about the high populations of cabbage looper "leaf worms" that we had seen hatching last week. Many cotton fields are being sprayed for the first time as a result of harvesting the first alfalfa hay and sending the moths into the cotton. The moths seen flying, particularly in the evening, were mostly Trichoplusia ni, one of the leaf worms in cotton. Other moths seen are, in descending order, armyworms and bollworms. The alfalfa butterfly Coleus eurytheme butterflies are 10 to 20 times more common around Old River than in the lake bottom near Maricopa.

Some insects particularly the lygus, migrated into the cotton and are now moving back into the alfalfa because the plants hardly stopped growing. The populations of big–eyed bugs, Geocoris 3 species, (G. pallens, G. punctipes, and G. atricolor) are found in large numbers along with less than a 3 out of a possible ten, the standard sweep count of lygus threshold rating and no nymphs have been seen in the cotton, this season. The other predators in addition to the big–eyed bugs are the hooded beetles, damsel bugs, minute pirate bugs, ladybugs and an occasional assassin bug. There are very few thrips and no mites.

However the looper eggs are plentiful and many larvae are now half grown. They are escaping the biological control suppressive forces–the set of resident natural enemies––that are eating the eggs and the up–to half–inch worms. We would like to see a system where the natural enemies migrate into the young cotton from the alfalfa field at the same time as the pests.

Beneficial insects need pollen and nectar:

Cotton farmers need to plant flowering and pollen producing plantings around the outside of their fields before the cotton comes up or at least allow for some plants to bloom when the weather warms up to average 70 degrees in the day time. The so–called weed, the wild sunflowers, is often a source except it is called a weed instead of a habitat enhancement food source for overwintering insects. Such small habitats of blooming flowers provide pollen, nectar and other plant exudates and alternate hosts for the natural enemy complex at a very economical cost. These refuges must not receive herbicides or other pesticides to make them work effectively in biological control. Before alfalfa became a market crop and was planted as grazing food for animals, the weeds and alfalfa bloom served as this refuge. As the price increased for alfalfa hay as a market crop, the chemical industry saw an opportunity to sell more pesticide products and the result is that the one and only crop remaining, that sustains the biological control for cotton and nearly all other crops is no longer able to trap and control nearly all of our pest species without the use of any pesticides. This is a small price to pay for sustainable agriculture production with little or no pesticide costs. Unfortunately, new registration for new chemical controls are being sought because the old ones are failing. Farmers should stop buying these products and the companies would quit making them.

Some weeds in the alfalfa would help biological control:

The alfalfa hay field south of the DeStefani cotton plot has been cut and irrigated, with very little time for the stubble to be a hot, dry alfalfa stubble environment. The only weeds appear to be grasses in the alfalfa. The only blossoms appear is when the alfalfa blooms. A very few Johnson grass clumps provide the only pollen that is necessary for green lacewings adults to lay eggs. Hence very few lacewing eggs and larvae are seen. This makes this very important predator ineffective until the cotton starts to flower. The green lacewing Chrysoperla carnea overwinters as adults, and begins laying eggs when pollen is available as a food for adults. Monoculture and herbicides keep this from happening in a timely way for good biological control to occur in this plantscape. It is a true statement of fact when the advocates of conventional chemical control, CCC, state, "Biocontrol is two weeks too late and not enough of it!"

In fact there is evidence that conventional chemical control, CCC, for alfalfa pests interferes with biological control, thus, making alfalfa a major source for many pests migrating into cotton without all of their natural enemies. Weed–free alfalfa probably destroys (pesticide interference) many natural enemies in the alfalfa habitat in ways that limit its function as a refuge for biological control of many vegetable and field crops. When "cheese weed" or Malva is eradicated with herbicides, the overwintering host for the egg parasites, Trichogramma, which is the painted lady butterfly, Vanessa cardui, populations are reduced. The alfalfa butterfly hosts the Trichogramma parasites in summer. Green peach aphid and its parasites Aphidius spp. winter over on Malva. These are only two examples of many that point to the way CCC makes biological control ineffective. When many of the vegetable crops are not growing, the alternate host plants for many of the sets of pests and natural enemies of those crops have no unsprayed refuges, thus enhancing the necessity for CCC and the pesticide treadmill. Pesticide free habitat refuge plantings are a cost–effective way to make biological control work.

Sudan grass habitat:

Our efforts to plant small patches of corn and flowering plants and Sudan grass as a dust barrier around the fields between the interface of cotton and the road, have met with failure. The seeds failed to germinate due to earlier applications of Treflan and Round–up herbicides. The Roundup ready cotton is very clean of weeds except morning glory bindweed and Johnson grass. The D–Vac samples taken last week had a few one–day–old lacewing larvae and eggs in the 40 plant sample taken on the north side of the field away from the alfalfa.

Lacewing adults fly up into the air, with every step, when walking the fields in the evening and morning. This is an army of enormous numbers distributed throughout the cotton. The green lacewing adults are not predators, but the larvae are general predators of aphids, mites and small worms ready to attack all cotton pests when the adults are able to find feed upon pollen. The cotton flowers and the pollen nutrition coupled with nectar from the cotton nectar glands are necessary for egg laying to kicks in. It takes a week to 10 days for any field collected overwintering adults, from habitats like this, to start laying eggs, when tested in the laboratory.

Releases:

The Trichogramma egg parasites, referred to as "trichos", bought from the insectary rearing sources, began their emerging process into tiny adult wasps, swarming within the drinking cup release colonies on June 22. We arrived at the field early and colonized them by walked through from beginning to end, of ten selected rows of the field (spaced across the field). We placed each colony of approximately 1,000 individual parasitic wasps every 25 to 50 steps. this is the most effective way to release trichos. The cups are used to pre–feed the adults with honey and allow for mating to occur before they venture from the cups into the cotton to find and lay their eggs in the pest moth eggs. The life cycle is 10 days and they will increase in numbers exponentially as the season advances. Weekly releases cover all flights of all cotton moths but releasing every two weeks is all that our budget will buy. The cost for this augmentation of biological control for a season is less than the cost of one application of pesticides.

Evidence that biocontrol can return:

The main findings from this walking the fields colonizing the trichos early in the morning is the discovery of identifying the presence of four species of tachinid flies that are known to parasitize cotton worms and two additional species of parasitic wasps that attack large worms and cocoons (pupae) thus preventing the next generation of these pests to resurge one month from now. Tiger beetles were also seen feeding on cotton pests in patches of sandy soil located at the west end of the field where the tail water basins are prepared. This recorded increase in natural enemy diversity is constructive to support the evidence that probably the full natural enemy complex that we recognized in 1950s is still present. These beneficial insects are present in such very low numbers due to the CCC–type IPM practices, but they will return quickly when unsprayed refuges are provided. This gives confidence to the continued progress of biological control for this season if we can care for them.

Food drives all these systems:

Contrary to conventional thought, biological control is a progressive force that reproduces and gathers strength as the cotton grows and is capable of eradication of pests in local "hot–spot" patches of pest activity. All that is needed to turn things around is a few cost effective, small changes in the way we farm. Nurturing the biological control is accomplished by providing the food (prey) and a pesticide free space as a refuge within the farmers' control under their management so the beneficial insects can work effectively. The way to reduce production costs and make farming sustainable is to work with Natures' biological systems instead of killing them with the chemical "war on bugs". Once you experience the success of these biological systems under EBPM, you won't want to mix pesticide programs that no longer work.

 

Bob Reynolds – Thursday, June 22, 2001.

Pima cotton west of Sanders – Maricopa area.

Sampled 12:00 to 1:00 The weekly D–Vac sample taken at the SE near the road. The usual sweep net samples revealed big–eyed bugs and no lygus. The sprinklers are continuing the irrigation process from last week. Replanting has provided a mix of cotton sizes. Some plant destruction has occurred at the north end from rabbits or some other animal. There are no other pests. The Reynolds cotton has good biological control at this time.

Predators are abundant:

The striped collops, Collops vittatus, bluish and orange colors, soft–winged flower beetles MALACHIIDAE family are more common in this cotton field where they are important predators of stinkbug eggs in particular. The wheat field harvested next door is likely the over–wintering source. The larvae are soil predators feeding on cucumber beetle larvae and other soil–inhabiting pests. Ladybugs adults mostly the Coccinella perplexa, the Julian ladybird beetle, is most common. One Exochomus sp. was sampled and Hippodamia convergens, the one that migrates to the Sierra Nevada foothills to spend the winter at the snow line and which flys back to the valley in the spring to meet the increase in aphid populations. This particular year has been favorable for the ladybug control of aphids. Only an occasional adult winged (alate) cotton aphid has been seen in the samples and no colonies yet.

The ladybugs lay eggs best when aphids are common, generating from egg to adults in 30 days. The adults live for at least a year, foraging on many common soft bodied plant feeding pests from small worms to mites. They are said to be generalist predators in cotton. These resident Julian species probably built up feeding on the several aphids that attack grains as in the adjacent wheat field. They do not migrate staying on the farm and laying eggs when enough aphids are present for their main food source for their larvae to develop upon. We have seen very few ladybug larvae so far, but lots of adults.

The ANTHICIDAE family of beetles, ant–like flower beetles Notoxis constrictus are the second most common predator found in all of the fields of cotton. They are predaceous in all stages (larvae feed on soil pests) and the adults are generalists, believed to feed and lay their eggs when feeding on thrips. They are one of five species that are known to reside in alfalfa hay fields. The low level of western flower thrips that we observe is probably their source food. Orius is forth or fifth most common predator after the damsel bug, Nabis spp. The minute pirate bugs, Orius spp. is also attracted to thrips reproducing when thrips are common. They are one of the best mite predators, along with green lacewing larvae.

The assassin bug Zelus renardii is present in this area of low pesticide usage at about one in several hundred sweeps of the net. They are spectacular, particularly when seen feeding on ladybug adults. However, when one considers the large numbers of nymphs 98 out of 100 it takes Nature to produce only two of which reach the adult sexual stage in order to make a population. All of these 98 babies feed on smaller prey than ladybug adults and therefore are a valuable natural enemy. They are important predators on many cotton pests and only occasionally feed on ladybugs.

Biological control is carried over:

The list of potential cotton beneficials is very long when compared to the few potential pest species seen so far. The absence of pests in a new cotton field is a tribute to biological control of these pests in the off season when no cotton is growing and to the low level of these populations remaining after the cotton is harvested. Heavy pest pressure in the fall often provides favorable biological controls in the following year.

Late season pests that are not eaten by predators following cotton harvest and field preparation for winter that are able to overwinter and come back in the spring, as for example, mites, thrips, aphids, cut worms, leaf worms, armyworms stinkbugs, lygus and so forth. Some of these are a bother in other fields in this demonstration. The alfalfa shows the evidence of pesticide interference caused from sprays put on for early season alfalfa weevil and the indiscriminate use of herbicides fighting weeds and other winter insect refuges. The wild area around Reynolds and Sanders cotton is refuge for the full natural enemy complex known for alfalfa and cotton. The pests will have to migrate from the few farms migrating from other crops in this deserted lake bottom plantscape.

Releases:

Trichogramma parasites from insectary sources called "trichos" have been released each of the previous two weeks. However, this week, all "trichos" were released at the DeStefani block because of the heavier density of cabbage loopers' attack that is causing leaf damage. This egg parasite has been sampled in the D–Vac from Sanders alfalfa field earlier this season. This a natural population of Trichogramma and therefore we have not released "trichos" at Sanders. There are so few moths seen flying that only one or two very small worms have been seen this far in both Reynolds and Sanders fields.

 

Roger & Sandy Sanders – Thursday, June 21, 2001

OLD RIVER FARMS – Maricopa, Pima cotton

Sampled 9 – 1:00 AM. The weekly D–Vac sample was taken at the biodiversity habitat planting site in the SW corner of the plot (Drip irrigation line was turned on.) The irrigation of the cotton was completed last week and both the habitat perennial plants that focus on whitefly management, the insectary mix annuals and the cotton show no stress. There are lots of weeds germinating as well. The check cotton field to the west that is being prepared for irrigation shows typical leaf wilt from the heat. Temperatures will reach over 100 degrees each day. The alfalfa hay field has grown back from the cutting that was harvested two weeks ago, is still without irrigation. Irrigation will be completed June 22, in the cotton across to the east from the alfalfa. Sweep samples of the alfalfa and all of the cotton reveal good sets of natural enemies, particularly the big–eyed bugs, the most effective predator control for lygus and many other soft bodied insect pests.

Staggered strip–cutting of the alfalfa planting:

starting from the south end of the field advancing to the north end (leaving 7 strips of standing alfalfa spread evenly from the middle to the north end) caused the mature insects to fly into this standing alfalfa and concentrate in these strips. This concentration of adult insects triggers reproduction of both the plant feeding insects (potential pests) and their sets of natural enemies (beneficial biological controls). The D–Vac samples and sweep–net samples revealed that lygus in particular and the predators (big–eyed bugs, damsel bugs, minute pirate bugs) responded to this concentration of lygus prey (food). They increased their reproduction rate in proportion to this concentration of all insect life present within this small amount of alfalfa plants remaining in these strips.

D–Vac Samples:

Our observations of insect samples showed a crowding of (wingless) immature insect predators in these strips. Only, the adult insects were able to move with the cutting process. The resident immature (wingless) insects were left in the alfalfa stubble where the removal of growing alfalfa plants concentrated the prey (lygus, aphids, mites, thrips etc.) on the stubble. This increased the searching efficiency, resulting from crowding of all flightless stages of insects onto stubble gave the advantage to the beneficial predators, less food for the pest and less searching for the predators, favoring biological control in the battle of good and bad bugs in the whole alfalfa planting.

Small habitat management decision made big difference in beneficial insect ecology:

The combined effects of this slight modification of the alfalfa hay harvest resulted in favoring the reproduction of beneficial insects and reducing the numbers of their prey (all plant feeding species). The process also drove the adult insects (flyers) away from the cotton dispersing them throughout the area. It is documented that the increased reproduction of beneficial predators eventually find their prey. Food drives all of these sets of biological controls and the plant feeders alike.

Thus, this farming process or event demonstrates that small changes in farming practice can be used to increase the effective biological control of all pests of vegetable and field crop pests. Extensive research in ecologically based pest management (EBPM) has proven beyond doubt that cotton can be grown with much less use of pesticides when alfalfa hay production is managed as a resource for beneficial and a trap for potential pests.

This season is unique in that the cotton aphid, thrips and mites as well as less than usual lygus populations reside in all of the cotton blocks. Lygus adults are relatively rare species while all of the cotton worms are high density at the all other farms. We can only guess that the favorable number of big–eyed bugs and the hooded beetles seen in every sample is responsible. Aphid predators are abundant and yet aphids difficult to find. All of these predators overwintered from the large populations that occurred following last season at Sanders Ranch because Silverleaf whitefly was a pest and no pesticides other than sulfur and no herbicides have been used.

Early aphids can be a resource for growing mite predators:

The usual process of biological control systems is for the 60 or more species of predators and parasites of aphids to attract and grow the biological controls that clean up of aphids and then mite control follows soon after. All of the aphid predators are hungry and are forced to clean up the mites or starve or migrate. Most of the aphid predators will feed on mites when they no longer can find aphids. The same is true of thrips and their natural enemies. The western flower thrips, a pollen feeder, will eat mite eggs before it resorts to feeding on plant tissues. Our samples reveal many kinds of mite predators and few if any mites at this time. The lygus populations are also no threat.

Keep predators alive longer with carbohydrate food sources in a habitat:

There is the chance that many of these predators will die of old age or starvation before any new pests arrive, but we know that they can live longer feeding on plant exudates, nectar and pollen when they cannot find their prey that makes them lay their eggs. Each set of predators reproduces rapidly when their particular prey resource becomes abundant. This is the natural rule that is the basis for the biological control process. It is a "density–dependent" response that speeds the reproduction process of predator and parasite species over the prey.

Keep the insect–plant systems functioning:

Successful biological control is based on biodiversity and biocomplexity of both plant and insect species. The principle basis for this demonstration is to find ways to increase polyculture of plants, even non–noxious weeds that provide the food and space (habitat enhancement) to the massive monocultures of agriculture. We must provide non–sprayed patches or crops where "pesticide interference" to biological control systems is prevented. These small unsprayed plantings will keep the full sets of natural enemy complexes breeding in residence and adjacent to the market crops where they can enter the new cotton planting as soon as the first pests arrive. Ways must be found to keep insect–plant systems functioning in between crops. This is the opposite of the present paradigm, the opposite of eradication by broad–spectrum pesticides.

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