Read: more details about this work in Agricultural Research.

Quality Tests for Lab-Raised Beneficial Insects

A few simple tests adapted by the Agricultural Research Service can now help commercial insectaries determine the quality of beneficial insects raised on artificial diets.

In biological control programs, researchers have in hand a variety of predatory insects, including the big-eyed bug, Geocoris punctipes, and the lacewing, Chrysoperla carnea. Beneficial insects such as these are used to check the spread of damaging crop pests like aphids, scale insects and mealybugs.

Instead of feeding the beneficials their natural diets, researchers have developed a variety of artificial ones--mainly composed of cooked chicken eggs, lima bean meal, wheat germ, soy flour, yeast, vitamins and preservatives--that provide the necessary nutrition at a fraction of the cost.

To determine which diet recipe produces the most vigorous insects, researchers have measured differences in the weight, longevity, biomass accumulation and fecundity the insects achieve. Now scientists with ARS’ Biological Control and Mass-Rearing Research Unit in Mississippi State, Miss., led by entomologist Allen C. Cohen, have adapted biochemical and immunological tests that will allow producers to measure the insects’ overall health.

The scientists found a correlation between the artificial diets and an increase in insects’ egg production. Insects reared on a diet made of chicken egg and a plant product--rather than chicken egg and a meat paste--had more yolk proteins in their eggs, which is predictive of a healthier insect. The researchers have also adapted enzyme-linked immunosorbent assays (ELISA)--which are based on the ability of an antibody to recognize and bind to a specific antigen--to identify possible pathogens in the insects.

According to Cohen, these tests will help producers quickly and accurately predict whether a specific diet or rearing condition is good or bad for the insect, saving time and money in the process.

ARS is the U.S. Department of Agriculture’s chief scientific research agency. More details about this work, published in the February issue of Agricultural Research magazine.

Scientific contact: Allen C. Cohen, ARS Biological Control and Mass Rearing Research Unit, Mississippi State, Miss.; phone (662) 320-7380, fax (662) 320-7571, acohen@bcmrru.msstate.edu.