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(BASIC) August 8 & 9 Report
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For All Growers: Trip Report August 8 & 9, 2001

Kern County BASIC Pilot Program

Deke and Francisco Cornejo made and compiled the report.

 

Kevin Antongiovanni Farm – August 8, 2001

Field observations by Francisco:

Pest populations are well down under control. There are signs of good lacewing activity with no visible mites and a very low numbers of whitefly.

Beneficials:

While collecting the pest–beneficial ratio information using the sweep net, I observe several beneficial hover fly species flying near the flowers and feeding on them. The adults about ¼ to ½ inch long, are normally marked on the abdomen with yellow, white or black bands. They fly swiftly and have a characteristic hovering ability. The adults are not predaceous, but feed on pollen, nectar and honeydew. The larvae are blind, slug like in appearance, green brown or purplish, and characteristically tapered toward the anterior end. Hover fly larvae prey on aphids. They are voracious feeders, armed with strong black mouth hooks with which they seize their prey and through which they withdraw the aphid’s body fluids.

Crop setting:

The size of the plant cotton plus the heavy set of bolls, having an average of 18–21 bolls per plant are leading to the crop to fall down, making it difficult to walk through so the samplings were made at the places where plants are still standing erect.

Releases:

We made releases of 150,000 Trichogramma and 1000 Eretmocerus.

Plans:

After meeting with Kevin and his father at their office on Van Horn road, we agree to do the next week releases together including some of his crew in order to show them the different insects that are part of the beneficial insects releases programs

D–Vac analysis by Everett Dietrick:

The big–eyed bug Geocoris pallens has declined, but another species, G. punctipes is reproducing and has replaced it. The numbers of big–eyed bug is increasing and not declining. Whitefly is the most prevalent food source and it appears that lygus and mites are under control and that the whitefly is being suppressed. Spiders, lacewings and ladybugs are increasing

There is an edge of the field increase of whitefly in some spots that we think is caused by Fire ant nesting sites. Fire ants interfere with most natural enemies, in particular the green lacewings.

Psocids are scavengers that feed on dead insects and their exudates. They are beneficial in that they cleanup sooty mold that grows on honeydew from aphids and whitefly.

Monitoring continues with focus on the one potential pest––whitefly.

 

Mr. Banducci’s field – early morning Thursday August 09

The beneficial–pest ratio:

Ration is still overwhelmingly favorable to the first. The sweep net sampling shows abundant numbers of Ladybeetles, Syrphid fly and as always high numbers of lacewing adults and eggs. At the neighboring sweet corn fields were weeds––a very well diversified variety of them.

Hover flies:

I also observed the typical black oily smears of excrement on the cotton plant leaves that are an indication of the presence of recent occurrence of hover fly larvae. The larvae may reach a length of about ½ inch immediately before pupation. The parchment–like puparia (pupal structure), are elliptical or somewhat tear shaped, and may be green, grayish or brownish. The puparia are sometimes formed on cotton leaves but pupation generally occurs in ground litter. Hover flies occur in cotton over much of the growing season, but reproduce most actively in the fall, when the heaviest aphid populations develop.

Pest population:

The aphid population is very well under control by the presence of abundant Ladybeetles adults and larvae. Low populations of whitefly and lygus were observed specially at the edge of the watermelon and sweet corn. There are many looper moths flying over the field, but just a few eggs and low number of looper larvae were found on the cotton plants.

Beneficial insects:

Damsel bugs (Nabis), Six spotted thrips, Minute pirate bug, Orius tristicolor, Collops, Big eyed bug, Geocoris and the assassin bugs, Zelus spp. are present at all the locations where the releases were made.

Boll Count:

There is an average of 14–16 bolls per plant

Releases:

I made the releases of 100,000 Trichogramma and 1000 Eretmocerus at several rows along the field.

D–Vac analysis by Everett Dietrick:

The biodiversity of predators and parasites continue to increase each time the two adjacent alfalfa hay fields to the south and the hay field across the road to the north west are harvested. The trichogramma egg parasites can be readily found in the eggs of the alfalfa butterfly adjacent to the cotton. The adults can be gathered with the D–Vac sampler. The diversity of crops––several plantings of sweet corn, watermelons and alfalfa––insures a diversity of natural enemies.

The weeds along the drive road along the north side is not irrigated and its usefulness as a habitat is gone. The cotton planting and replanting adds to the diversity of insect life.

The aphids provided food for ladybug reproduction increasing the population of natural enemies of aphids useful for suppressing whitefly that are only starting to increase in the younger cotton plants.

 

DeStefani. Farms – August 8, 2001

Field observations by Francisco:
Beneficial insects:

The Beneficial to pest ratio seem to be well under a balance.

I followed the track where I made the ladybeetle releases last week. The canopy of the plants is very high. There are good numbers of Lacewings, Big–eyed bug, Damsel bug, I also find at the sweep net Spiders, Minute pirate bugs.

In general the crop seems to be very clean, with adults and larvae of Lacewing at several locations and also Lacewing eggs. It is easy to observe Dragonflies and Damselflies, Polistes wasps and the black ground beetle, Collosoma spp.

The whitefly population is with low numbers, counting about 5–7 adults every other plant mostly near the outside boundaries of the field. As I walked inside the field, there were not as many.

Boll counts:

The plants are starting to fall down making near impossible to walk through. The crop setting is looking well, with a high ratio between the number of leaves, the size of the plants and the number of bolls per plant, which today has an average of 18–20 per plant

D–Vac analysis by Everett Dietrick:

The natural enemies that controlled the worms are now feeding on the whitefly as well as cotton aphids and mites. There have been no sign of cotton bollworm and lygus remains very low. The alfalfa field has been plowed and all of the alfalfa butterflies are evidence that all of the insects have migrated, most of them into the cotton.

The Fire ants are increasing their activity along the south and west borders where most of the nest openings occur. Fire ants interfere with biological control by protecting aphids and whitefly that provide them with honeydew, a major component of their diet. I am researching possible control action for these nests, should the whitefly and aphids start to increase. Some sort of bait would be least disruptive to biological control.

 

B. Reynolds – August 9, 2001

Field observations by Francisco:

This field was under row irrigation, different from the sprinkler system that was used before. The efficiency on the use of the combination on these systems has given a very good result because the growth of the cotton plants has been very stable and permanent from last few weeks. This particular situation differs from the other cotton fields in that it is the only irrigated field in the immediate area. All the other fields in our project have irrigated crops adjacent to the cotton fields. This situation makes the cotton very attractive to whitefly followed hopefully by beneficials.

This week because the field was under water I took the D–Vac sample at only two locations, only two rows at the center of the field were dry enough to allow me to walk through and take the samples. At the D–Vac samples, the visual observation and the sweep net collecting samples, show that here are high numbers of whiteflies. As I said before, there were only two rows that I could walk through, so this sampling collection may be not representative of the whole field. The field needs to be checked in more spots more frequently than I can check.

Potential pest outbreak:

It is important to point out that there may be a potential outbreak of whitefly population. On the next visit during August 17, I will walk throughout the field that I hope will have been drained of mud and will allow me to scout the field obtaining a more complete sample. As I mentioned before I believe that the high number of whitefly that I found that levels were 30 adults of whitefly per leaf on some of those plants. This may be only a singular spot not necessarily representing the reality on the whole field. Also I want to be cautious to signal a potential problem so more eyes will do a better finding how widespread the whitefly are. This means that I will speak with Mr. Reynolds and his Spanish speaking crew to warn about this potential risk.

D–Vac analysis by Everett Dietrick:

The D–Vac sample picked up a large population of whitefly that surprised me, since we had not observed any previous evidence of such expansion of the whitefly. There are several possible guesses as to what this means. Sampling error in that a single heavily infested plant will affect the sample with large numbers of adult whitefly. The irrigation limited the area that could be sampled. A second guess is that the PIX spray affected the ladybug and other biological controls. I have no experience with PIX and its effect on beneficials. In support of this is the increase in lygus that occurred at the same time. I am concerned about this increase of pest activity and this week's samples will be focused on these pest effects.

It appears that the lygus adults that immigrate into the field cannot find any alternative host plant but cotton and they remain there laying eggs faster than the big–eyed bugs can destroy them. A border strip of alfalfa or some other sacrifice trap crop, attractive to lygus, would give them a haven adjacent to your market crop and protect your cotton.

 

Roger Sanders – August 9, 2001

Field observations by Francisco:

Irrigation at the field and at the habitat

As I mentioned last week, the cotton plants seem to be under water stress at some locations especially at the West Side of the field. As one approached to the north side the growth of the plants seems to be more homogeneous and the growth of the plants a little higher that the average. The growth of the plants at the refuge is very well, even when the irrigation lines of the drip irrigation has too many leaks caused in part by some rodents but also by the farm workers traffic when they move the aluminum irrigation pipes. I spoke about this with Ms. Sandy Sanders and George Long in order to get some collaboration from their crew to keep the lines carrying the water all the way through the end of this refuge plants. Also I asked George about the water supply and he explained about the broken water pump that has limited the water supply.

At the refuge habitat planting:

The Sudan grass is fully developed, flowering as well as the sweet corn, and the sweet alyssum, among some of the other weeds still present even after the two long weeding days, so the pollen availability, plus the attraction of aphids are keeping a high beneficial insects activity at this location.

The boll count:

It is about10/11 bolls per plant with few higher count exceptions especially at the Northwest side where we can find some areas with taller growth.

Pest–beneficial insect population:

Is well under control but there are some areas where the Whitefly count shows some increase from last week. At the sweep net the count shows that Geocoris and Orius are High. With more than 10 counts on 10 samples Nabis, Lady beetles and Zelus are also present with Medium concentration numbers. I also found Spiders, Hover flies, and Lacewing eggs well distributed everywhere I looked.

D–Vac analysis by Everett Dietrick:

The ratio of good bugs to bad bugs remains favorable although whitefly is increasing slowly. The habitat enhancement planting of whitefly attractive perennials and annuals– Sudan, sweet corn, etc.––are growing well. There are also sufficient weeds to add biodiversity and biocomplexity to insure an effective natural enemy complex.

The alfalfa management has attracted the lygus sufficiently that they have not become a problem in the cotton. They may leave but soon return or find other more preferred host plants. A strip of habitat enhancement to attract lygus and protect against dust on the East Side of the field would benefit but would probably not be cost effective.

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