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theses

Ecological engineering of agricultural ecosystems for enhancement of biological control services provided by natural enemies of target pests holds promise to potentially reduce or replace pesticide use to control pest populations below economic thresholds. The European corn borer Ostrinia nubilalis Hübner is a major insect pest of New Jersey peppers, around which integrated pest management programs are designed. Provision of nectar and pollen resources from intercrops to natural enemies can enhance their biological control of pest species. I tested the effect of intercrop species planted with New Jersey peppers on abundance of anthocorid natural enemies, anthocorid predation on sentinel European corn borer egg masses and crop injury. Three intercrops were studied: coriander, Coriandrum sativum L., dill, Anethum graveolens L., and fennel, Foeniculum vulgare Miller.

The proximity and species composition of the intercrops to NJ peppers was evaluated. No significant results were found for proximity of intercrops to the peppers, apart from one non-intercropped predation treatment, testing within-row plants, planted interspersed among the peppers, one-row and three-row distant from peppers. There were significant results for abundance of Orius insidiosus Say in the inter-row experiment, where peppers were planted in different rows from the intercrop. In 2015, coriander intercrops showed a higher anthocorid abundance than dill, fennel and control, non-intercropped, treatments. In 2016, in one field fennel had a higher anthocorid abundance than dill, mixed and control; whereas, in the other field, dill had a higher anthocorid abundance than fennel and control. There was a trend for higher crop damage in 2015 in the non-intercropped control intra-row treatment and in 2016 in the inter-row treatments.

Quantitative PCR of molecular gut contents of O. insidiosus was conducted to determine dietary preference. There were no significant results for the molecular gut content assays. The results indicated that O. insidiosus forages both in adjacent intercrops and in farther intercrops before entering peppers.

Pollen preference trials were investigated for O. insidiosus to determine whether there is a preference for one pollen over another among coriander, dill and fennel. There was significantly more coriander chosen over fennel. Other tests were non-significant, though there were slight trends shown for non-pollen treatment over coriander and dill, as well as slightly greater choice for dill over coriander.

ETD_10467

Ph.D.

Includes bibliographical references

doi:10.7282/t3-99bb-sx98

ETD doctoral

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