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(BASIC) General Observations July 26 & 27


D–Vac General Observations July 26 & 27

Kern County BASIC Pilot Program

General observations to all growers:


The list of insects collected in the vacuum insect net is growing as the season advances. At the last grower meeting, we attempted to show the biodiversity of insect life that lives in cotton and alfalfa. We call it the natural enemy complex (NEC)and their prey (food insects and mites). The biocomplexity of interactions and interconnected food webs are nearly impossible to describe in words. Using the microscope and television screen made the pictures large enough so it helped show their many differences in structure. These beneficial insects are no different than many other domesticated animals that have been helping farmers grow food and fiber for generations. We encounter hundreds and even thousands of species. We kill millions of them with broad spectrum pesticides every season because of our lack of understanding.

Weekly sampling using the vacuum insect collector shows the many associations of species of plant feeding pests and some of their sets of beneficial predators and parasites are observed. For instance, when a particular pest species becomes common, it is immediately observable that certain individual predators and parasites appear in the same sample. The association is too obvious to ignore. Food drives all of nature’s systems. We are trying to set tolerable damage thresholds relative to the natural enemies in order to take advantage of their benefits in managing the pest populations without killing the good guys.. Insect populations are selected by the poisons and also the good guys can be managed by providing food and space for them on our farm fields.

Biological control is successful when all of the sets of predators and parasites are present in and adjacent to the cotton field when it is first planted. Alfalfa hay and corn ensilage production, safflower and many weed species and covercrops foster this enhancement of the natural enemy complex (NEC). When or wherever the plantscape lacks these crops that can tolerate diverse insect life without significant damage, it is prudent to provide "habitat enhancement plantings" to overcome the lack of biodiversity of natural enemies for the market crops such as cotton and vegetables. We want to encourage even small plantings of patches of flowering plants that will provide food and shelter for the NEC and overcome the monoculture agriculture that addicts farming to the pesticide treadmill.

Transitioning from monoculture conventional chemical controls is frightening to begin with because we have not experienced it. In the beginning, to overcome some of the fear of insects, we must unlearn the mantra that "the only good bug is a dead one". This is not true! Neither is it right that by simply stopping spraying everything will correct itself. This cotton season, so far, has been a good one for making a transition. The leaf–eating looper worms have not done any damage and have provided food for many beneficial insects that will help the rest of the season. Every time an alfalfa hay field is cut, a corn field is harvested, or a crop matures beyond usefulness, more insects find their way into the cotton. The confidence level for our judgment will grow with time.

Immediate forecast:

The lygus and worm problems have not become pests because of the attack of their sets of predators and parasites that have overwintered in the plantscape––alfalfa hay and weedy areas. However, the whitefly and cotton aphids are increasing. I don't expect bollworms so long as corn continues to be planted. Mites are still being fed upon by a wide variety of general predators and they seem to be suppressing them when we find a few. "Hot spots" of mites have not developed. We still have a high ratio of predators and parasites to pests in all fields. I look for these hungry beneficials to suppress whitefly and aphids as well as mites in the coming weeks.


We will be releasing ladybugs and Eretmocerus this week in some blocks to augment the sets of natural enemies of whitefly that have already taken up residence in some of the cotton.

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