Intercropping For Conservation Biological Control Of European Corn Borer Ostrinia Nubilalis Hubner Lepidoptera Crambidae In Bell Peppers

Author : Elena Marie Larue
Publisher :
ISBN 13 :
Total Pages : 76 pages
Book Rating : 4.:/5 (712 download)

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Download or read book Oviposition Behavior and Larval Development of the European Corn Borer (Ostrinia Nubilatis) on Sweet Versus Hot Peppers (Capsicum Annum) written by Elena Marie Larue and published by . This book was released on 2006 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Peppers (Capsicum annum) are an important crop in Ohio and also worldwide. European corn borer (Ostrinia nubilalis) is a key pest of peppers. More pungent peppers tend to have less infestation by 0. nubilalis than mild peppers. Pungency in peppers is caused by compounds called capsaicinoids, specifically capsaicin and dihydrocapsaicin. The goals of this project were to understand the insect behavior and plant characteristics that affect pepper infestation by the European corn borer. The more specific objectives were to determine whether: 1) 0. nubilalis moths show an ovipositional preference among pepper varieties, 2) larval development is affected by varieties, 3) plant density affects egg laying. Five pepper varieties were tested with a range in hotness from zero to 50,000 Scoville heat units. These varieties were Socrates (bell pepper), Sweet Spot (sweet banana pepper), Hungarian (hot wax pepper), Ixtapa (jalapeflo pepper), and Cayenne Large Thick (cayenne pepper). Oviposition was studied in laboratory cages, small field cages, large field cages, choice field trials, and no-choice field trials. In laboratory and small field cage studies, each pepper variety was paired with another variety. Moths were introduced into the cage and resulting egg masses were counted after five days. No ovipositional preference was detected for any of the varieties in the two-choice assays. The large field cage trial consisted of three pepper varieties (Socrates, Sweet Spot, and Ixtapa) all placed in a cage in which moths were allowed to oviposit. As in the laboratory assay, no ovipositional preference was found. Choice oviposition trials were conducted in the field by planting all five pepper varieties in adjacent plots. No differences in either number of egg masses laid or larval infestation on the different varieties was seen. Finally a no-choice field trial compared egg laying and larval infestation on three varieties (Socrates, Sweet Spot, Ixtapa) planted in plots separated by corn. Once again, there was no preference for oviposition on any pepper variety; however, larval infestation did vary significantly, with Socrates having the highest infestation and Ixtapa the least. Egg-mass sampling consistently underestimated larvae infestation. It can be concluded from these studies that 0. nubilalis females show no ovipositional preference, at least among the pepper varieties tested here. Larval survival and development time was evaluated by placing an individual larva on a fruit of each pepper variety. Each week survival and pupation was monitored. Larval development time was significantly longer on Ixtapa in comparison to any of the other varieties. There was a significant difference between the sweet and pungent varieties in terms of development time, with pungent varieties having a longer development time. Survival was not significantly lower on any variety in comparison with each other. This shows that larvae are able to enter and develop equally in sweet and pungent peppers. Canopy density was evaluated in an outdoor cage trial by placing one, two, or three pepper plants of the same variety together. Egg masses numbers did not differ for any of the varieties at the three densities tested. There was consistently no difference in oviposition or in larval survival among the pepper varieties although larval development time was significantly longer on one variety. Canopy density also had no effect on oviposition. This shows that the difference in infestation must be due to some other factor after egg laying and before larvae enter the fruit. Some other factors might be the increased leaf size and density of some pepper varieties, which would decrease desiccation of the eggs. This would increase the larval hatch and thus increase infestation rates.