Author
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Cohen, Allen |
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Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 1/31/2000 Publication Date: N/A Citation: N/A Interpretive Summary: Tarnished plant bugs (TPB) (Lygus hesperus and L. lineolaris) are very destructive pests on a wide variety of crops and have been found to be resistant to many pesticides. These 2 factors make control of TPB increasingly difficult by conventional pesticides. Alternatives such as biological control are being sought, but difficulties in rearing lygus bugs swhich could be used as hosts for parasites, complicate efforts at parasite mass rearing. The information presented here describes a new artificial diet for rearing L. hesperus. It costs less than 1/10 of the production expenses of the only previously formulated L. hesperus diet to be used to successfully rear continuous generations of these important pests. The reduction in rearing costs and the simplicity of producing the diet will be economically advantageous for producers of biological control agents to rear L. hesperus as hosts to rear lygus parasites for mass production. Technical Abstract: A new diet for Lygus hesperus Knight (Heteroptera: Miridae) is described, and results of tests of biological fitness are presented along with preliminary production cost estimates. The new diet was compared to the Debolt diet. The new diet has supported 11 generations of L. hesperus. Adult females weighed 10.7 (+/- S.E. or 0.19) mg, while the Debolt diet yielded 11.6 (+/- S.E. of 0.22) mg females. Adult male weights from the two respective treatments were 7.7 (+/- S.E. of 0.14) and 7.8 (+/- S.E. of 0.15) mg. Average egg production was between 13 and 24 eggs per female per day for both diets. Weights of eggs were equal from adults reared on either diet, and the egg production from the new diet was 82% of those from Debolt diet. Egg hatch was about 85% on both diets. About 55% of the nymphs developed to the adult stage on both diets. However, survival of adults at four weeks post-eclosion was about 30% on the new diet compared to 67% for the Debolt diet. This difference in adult longevity accounts for most of the difference in fecundity. The ingredients in the new diet cost less than 1/8 those used in the Debolt diet and demand less than 1/2 of the time required for that diet's preparation. With the new diet, the total cost for production per 1000 eggs is $0.23 compared to $0.32 for the Debolt diet. The ingredients of the Debolt diet cost about $8/kg compared to about $1/kg for the Cohen diet. The reason for the relatively small difference costs per 1000 eggs is that the predominant expense in rearing L. hesperus is labor in packaging the diet. Automation would be highly beneficial in reducing expenses of mass rearing L. hesperus. |
