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(BASIC) August 17 & 18 Report
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For All Growers: Trip Report August 17 & 18, 2001

Kern County BASIC Pilot Program

Deke and Francisco Cornejo made and compiled the report.

 

Antongiovanni Farms

Pest situation:

Whiteflies are increasing their numbers and also there are aphids especially at the cotton plants on the outside boundaries of the field. As we walk inside of the field there are less insect pest and high numbers of lacewings adults eggs. Also there are some places along the dirt road and near the trees and at the machinery lot that it is easy to observe colonies of southern fire ants

Beneficial releases:

We made releases of 2,000 Eretmocerus, 150,000 Trichogramma and 30,000 Lacewings.

Counts at the sweep net:

Beneficial insects observed during walking while doing releases and at the sweep net are Lacewings adults and eggs, Ladybeetles, Syrphid fly adults and some larvae. The Big–eyed bug still present with high counts as well as Spiders. Still observing beneficial wasps and Tachinid fly. I did not find mites but there are a good number of six spotted thrips.

General comments:

I believe that the beneficial insect population still keeping the insect pest under control especially at the inside rows through the fields. I would like to have somebody from this field that can keep an eye on the counts during the early days of the week. (We are there normally on Thursday). During this trip, Kevin allowed us to have one of the employees helping with the releases. It will be easy to explain about numbers of whitefly and mapping the hot spots of the field.

Everett Dietrick’s Comments after Study of Vacuum Samples from Mr. Antongiovanni’s:

The observations concerning the D–Vac sample of insects from your cotton reveal a high density of both good insects and whitefly and fewer cotton aphids. This is not representative of biological control as will occur later in the transition period. Such large populations of insects can be troublesome in that even though there are many predators, the level of pests is higher than desirable. Hot spots of pest density can rise above the damage level before they fluctuate down from predator action. This is particularly the case with highly reproductive species like whitefly, cotton aphids and mites. Mites are in the samples but only very few compared to whitefly. Aphid populations appear to be somewhat a benefit since they attract many kinds of predators that will eat whitefly when aphids are suppressed. The best parasite of the cotton aphid has not appeared, but it is an internal parasite that has not yet emerged as from the host aphid as adult wasps.

Whitefly adults disperse and can migrate on the airstream in the warm evenings and mornings when temperatures start to warm up. The cotton adjacent to your field that was treated could be supplying you with migrations of whitefly adults since the systemic pesticide only kills the nymphs. The sample indicates increasing numbers of adult whitefly (only the adults are harvested by the D–Vac).

It could be sample error in that whitefly populations are very unevenly distributed. Fire ant infested plants have more whitefly due to ant interference that protects immature whitefly from predators.

Ant baits are available in garden shops that will control the colonies very selectively. The only registered pesticides in the UC IPM Pest Management Guidelines are for almonds. The UC Cotton IPM Guidelines have no control listed for ants.

 

Mr. Banducci’s Farm

Pest situation:

At this farm, the biodiversity on the crops keep a very high number of beneficial organisms. Pollen supply is at the very high point since the sweet corn that was planted at different dates is under heavy flowering time. Also there is an increasing number of different weeds producing pollen and creating a good habitat for the insects.

Sweep net counts:

The sampling counts at the sweep net shows that the Lacewings adults still hanging over here with an overwhelmingly high number while the whitefly population is exactly the opposite. There is a good population of Syrphid and Tachinid fly, Ladybeetles, Nabis, Geocoris, and Assassin bugs. Also there are several species of spiders and some parasitic wasps.

Beneficial releases:

We released 150,000 Trichogramma, especially at the boundaries of the sweet corn. There are still some corn earworm at the neighboring cornfield. The Looper moth is visibly reduced in their population and no worms but some eggs were observed. We also released 1500 Eretmocerus.

Deke’s Comments after Study of Vacuum Samples taken from Mr. Banducci’s Cotton:

The cotton is later but has many beneficials and few pests. The Cotton aphid is suppressed very well and the key parasite of the cotton aphid is seen in the D–Vac samples. Whitefly is increasing but is still much less than other fields in the study.

The adjacent alfalfa fields are no longer exporting worms to the cotton. Spider mites have not been a problem. Tolerable levels of lygus nymphs continue in the samples. The adults migrate to other alfalfa more than to the cotton. The few that go to the cotton lay a few eggs that are eaten by big–eyed bugs and others expanding their population density that in turn feed on whitefly rather than starve.

 

Mr. DeStefani Farms

Actual Pest Situation:

So far so good! This farm has a good number of beneficial insects already present at this field. I believe that is the result of discing the adjacent field of alfalfa where all the beneficial insects moved to this dark green tall cotton field.

Sweep net counts At this field it is easy to observe the Tachinid and Syrphid fly. I also observed some of their larvae at the lower part of the plants. Assassin bugs, Geocoris, Nabis, Zelus and Collops. Several species of Spiders and the ground black beetle, Collosoma. Dragonflies and Damselflies are seen in considerably high numbers.

Beneficial insects:

Eretmocerus. and Lacewings were released at two main areas of this farm. I walked from the west side facing east and then going north. Another way was walking from east toward the southeast. The tallest of the plants, many of them lying sideward, make it extremely difficult to walk throughout. At the same time this is the perfect way to see the insect activity on the main part of the field.

Everett Dietrick’s Comments after Study of Vacuum Samples from Mr. DeStefani’s Farm:

The ratio of predators and parasites to pests continues to be favorable. There is no evidence of migrations of whitefly into the cotton.

However, the sample indicates increasing numbers of adult whitefly (only the adults are harvested by the D–Vac). This increase can be from additional generations growing within the field.

Sample error is high for aphids, whitefly and mites. Whitefly populations are very unevenly distributed. One heavily infested plant will affect the total sample a lot. Fire ant infested plants have more whitefly due to "ant interference" that protects immature whitefly from predators.

Ant baits are available in garden shops that will control the colonies very selectively. The only registered pesticides in the UC IPM Pest Management Guidelines are for almonds. The UC Cotton IPM Guidelines have no control listed for ants.

The roads are nesting sites. Ants are mostly active at mornings, evenings and all night resting below ground in the nests when temperatures rise.

 

B. Reynolds Farm:

As we mention last week, this is an unique ecological farmscape because the isolation that is located respect to other cotton fields and the surrounding fields with a typical landscape from a semi desert area in Southern California make this field to be highlighted.

Pest situation:

At the boundaries of the cotton field there are some plants with high numbers of whiteflies and aphids. The irrigation schedule made this week to have one side of the farm under water so the D–Vac and the sweep net samples were made at the half west side of the field. Visual observation at the east side were made at some of the rows through the crop that were drained enough to allowed us to walk few feet inside of the field. The beneficial–pest ratio is increasingly better when approaching to the center of the field and at this particular case, the presence of colonies of Southern fire ants along the interior driveways could mean that ants are helping to keep the beneficial insects away from their target.

Sweep net counts:

Shows a good number of Ladybeetle but very low counts of Lacewings. There are also Syrphid and Tachinid flies, Geocoris, Assassin bug, Nabis, Spined Soldier Bug and some Spiders

Beneficial insect releases:

Eretmocerus and Lacewings were made at the west side of the field. Extra lacewing larvae were released at several of the plants that have the highest counts of a combination of Aphids and Whiteflies.

Everett Dietrick’s Comments after Study of Vacuum Samples from Mr. Reynolds’ Farm:

The whitefly is less in this sample, so prior sampling of the hot spot of whitefly caused the sample to rise and not the whole field. There are still immature lygus nymphs, but they are small and the density does not seem to increase in size sufficiently to indicate a problem. This lygus population is being suppressed by big–eyed bugs and others and the population density is not expanding rapidly like it does when there are no natural enemies. The biological control is occurring at a higher level of pests to beneficials, but is still only a threatening situation and not damaging.

 

Roger and Sandy Sanders’ place
Overview

This farm is showing a good diversification of the beneficial insects–pest populations. The nearby alfalfa field s along with some of the weeds that are present at the cotton fields are helping to keep this ratio large on favor of the beneficial insects.

At the hedge, there is a majority of the plants with a very good growth. I would like to put emphasis on the topic that this is a collective job between us as the Dietrick Institute and the grower. Growing successfully the refuge plants will be achieved if a serious commitment is made in order to keep this area weeded and irrigated. If we had planted in plastic mulch as done at the hedges managed by CDFA, they require less than four hours of weeding every three months.

At some specific locations there still water stress at the plants but for most of the crop, the growth is coming well The best growing area is at the Northwest side of this field. Bermuda grass patches along the East side limit the best development of the plants.

Sweep net counts:

The sweep net was done while walk doing the releases. There are surprisingly high numbers of six spotted thrips, Lacewing adults and eggs. Also easy to observe are Tachinid and Syrphid fly , Assassin bug, Damsel bugs, Geocoris, Orius and Ladybeetle, adults and larvae, were also observed .

Beneficial insects releases:

30,000 Lacewings, 1500 Eretmocerus and 20,000 Trichogrammas were released at a diagonal walk starting at the South side along the habitat plants releasing the Eretmocerus, and the rest of the beneficial insects were released walking northbound and then turned west.

Everett Dietrick’s Comments after Study of Vacuum Samples taken at Sanders cotton:

The D–Vac samples were taken at the three corners East, West and at the North sides. Lygus are staying in the alfalfa and have not increased in the cotton. Spider mites have not been a problem nor has any other potential cotton pests except the whitefly population is increasing. There have been no parasites of whitefly seen in the samples.

The perennial plants have been shown in demonstrations in Texas and in Imperial Valley to attract whitefly and the parasites of whitefly. Charlie Pickett of CDFA has supplied these plants for this demonstration and we want to follow through on the test through next season at least. This week we will finish planting the lavatera plants that we have been holding in your shop. Thank you so much for your cooperation in this demonstration and your leadership in forming this group of farmers. We especially thank you for your hospitality and friendship. We need to find the answer for establishing the parasites of the whitefly, because they are known to take care of this one problem.

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