Effects of Interplanting Flowering Plants on the Biological Control of Corn Earworm (Lepidoptera: Noctuidae) and Thrips (Thysanoptera: Thripidae) in Sweet Corn.
Natural enemy exploitation of food resources and alternative hosts in noncrop vegetation has been shown to be an effective means of enhancing natural enemy populations in diversified agro-ecosystem. Field trials were conducted in Hawaii to examine effects of interplanting flowering plants on 1) parasitism of corn earworm, Helicoverpa zea (Boddie) eggs by Trichogramma spp., and 2) abundance of Orius spp. in relation to prey (H. zea eggs and thrips [primarily, Frankliniella occidentalis (Pergande) and Frankliniella williamsi Hood]). Sweet corn (maize), Zea mays L., was interplanted with three flowering plants, buckwheat, Fagopyrum esculentum Moench, cowpea, Vigna unguiculata (L.), and sunn hemp, Crotolaria juncea L., at 2:1 and 4:1 (corn: flowering plant) ratios in 2009 and 2010, respectively. In 2009, the abundance of Orius spp. was significantly greater in the buckwheat-interplanted treatment compared to the monocrop control at similar levels of prey availability, indicating buckwheat flowers might have provided both prey and nectar resources. In 2010, cowpea and sunn hemp flowering plants provided a source of an alternate host insect's eggs for Trichogramma spp. oviposition, resulting in significantly higher parasitism of H. zea eggs in the cowpea- and sunn hemp-interplanted treatments compared to the monocrop control. Despite of differences in pest and natural enemy interactions in two field trials, our findings suggested that provisioning of an alternate host insect's eggs through flowering plants is an effective means for enhancing Trichogramma spp. and provisioning of both nectar and prey resources through flowering plants is important for enhancing predation by Orius spp.
Current address: Lincoln University, Cooperative Research and Extension, 900 Chestnut St., Allen Hall 302, Jefferson City, MO 65101 (manandharr@lincolnu.edu), Department of Plant and Environmental Protection Sciences, University of Hawaii at Manoa, 3050 Maile Way, Gilmore Hall 310, Honolulu, HI 96822 (markwrig@hawaii.edu), and.
Roshan
R
Manandhar
Department of Plant and Environmental Protection Sciences, University of Hawaii at Manoa, 3050 Maile Way, Gilmore Hall 310, Honolulu, HI 96822 (markwrig@hawaii.edu), and markwrig@hawaii.edu.
Mark G
MG
Wright
D000383:Agriculture / Q000379:methods*; D000818:Animals; D029864:Crotalaria / Q000254:growth & development; D007887:Fabaceae / Q000254:growth & development*; D020387:Food Chain; D006254:Hawaii; D020062:Heteroptera / Q000502:physiology*; D007814:Larva / Q000254:growth & development / Q000502:physiology; D009036:Moths / Q000254:growth & development / Q000502:physiology*; D010572:Pest Control, Biological / Q000379:methods*; D061149:Thysanoptera / Q000254:growth & development / Q000502:physiology*; D003313:Zea mays / Q000254:growth & development*
H. zea; Orius spp.; Trichogramma spp.; flowering plant; parasitism