Field Crops News

Orius Feeding Habits in Corn

In many cases laboratory feeding trials have been used to determine consumption rates and acceptance of different potential insect prey of predatory insects. Field studies are also needed to determine what actually occurs in the field.

The feeding habits of the hemipteran predator, Orius insidiosus, were studied over a period of several weeks in Northwest Kansas field corn fields using gel electrophoresis, which biochemically identifies different enzymes by the patterns of bands formed in an electrophoresis gel. Banding patterns of the enzyme isocitrate dehydrogenase were characterized for starved Orius insidiosus, and different potential food items (European corn borer eggs and first instar larvae, corn earworm eggs and first instar larvae, corn leaf aphids, thrips, twospotted spider mites, adult and nymphal leafhoppers, and corn pollen, silk, and anthers). An advantage of electrophoresis is its high degree of sensitivity; it can detect whether an insect has fed upon a single corn borer egg or first instar larva within the last 16 hours.

Orius were collected from three different fields once a week for 10 weeks in 1992 and for 8 weeks in 1993. Early in the season (early to mid-June), before tasselling, the predominant food item of O. insidiosus was thrips. During July and early August, Orius fed most commonly on corn pollen. Late in the season (mid-August to early September), another common food item, suspected to be corn kernels, was detected but was not conclusively identified. From late June through early September, corn leaf aphids, leafhoppers, thrips, corn earworms, and eggs and first instar larvae of European corn borer were also commonly feed upon, but at lower levels.

These studies show that Orius insidiosus has a broad food range in field corn, including both insects and plant tissue. These field results are consistent with past laboratory research which demonstrated that O. insidiosus could survive and reproduce on diets of thrips, lepidopteran eggs, and corn pollen, either alone or in combination with each other.

Source:

Corey, D., S. Kambhampati & G. Wilde. 1998. Electrophoretic analysis of Orius insidiosus feeding habits in field corn. J. Kansas Entomol. Soc. 71: 11-17.


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