Effects of Interspecific Competition and Narrow-spectrum Insecticides on the Survival and Development of Diaeretiella rapae in Oklahoma Winter Canola
Başlık:
Effects of Interspecific Competition and Narrow-spectrum Insecticides on the Survival and Development of Diaeretiella rapae in Oklahoma Winter Canola
Yazar:
Jessie, William Paul, author.
ISBN:
9780438066335
Yazar Ek Girişi:
Fiziksel Tanımlama:
1 electronic resource (158 pages)
Genel Not:
Source: Dissertation Abstracts International, Volume: 79-10(E), Section: B.
Advisors: Kristopher Giles Committee members: Norman Elliott; JP Michaud; Mark Payton; Tom Royer.
Özet:
Diaeretiella rapae plays a significant role in aphid suppression across its range. This parasitoid wasp specializes on crucifer-feeding aphids, now common in a rapidly expanding crop (winter canola) in the US Southern Great Plains. Diaeretiella rapae is currently found almost exclusively in winter canola during the spring when aphid intensities are high, yet does not frequently maintain aphid populations below economic thresholds. The minimal role that D. rapae plays in regulating aphids may be influenced by competing natural enemies and/or disruptive management approaches. The abundance and generalist behavior of L. testaceipes may result in frequent competitive interactions between these two parasitoids, either through extrinsic interference (if D. rapae can discriminate parasitized hosts), or intrinsic (i.e., larval) competition inside aphid hosts. Additionally, D. rapae may face significant mortality in the face of frequent applications of broad-spectrum insecticides common in winter canola. This mortality source could be minimized by the use of selective insecticides, such as flonicamid and sulfoxaflor, which have specificity to hemipteran pests and little to no effect on natural enemies. Laboratory experiments were designed to determine the outcomes of competition between D. rapae and L. testaceipes on L. pseudobrassicae and M. persicae hosts on winter canola, and on Rhopalosiphum padi hosts on winter wheat. Separate experiments were conducted in the field and laboratory to determine lethal and sub-lethal effects of flonicamid and sulfoxaflor on preimaginal D. rapae. Results indicate a reduced percentage of canola aphids are parasitized when D. rapae forages simultaneously with L. testaceipes, suggesting the proximity of canola fields to winter wheat may enhance colonization of canola by L. testaceipes and reduce the suppressive effects of D. rapae on aphids in this crop. Results from experiments with selective insecticides revealed application of flonicamid resulted in effective suppression of aphids while retaining higher rates of parasitism post-treatment when compared with other insecticides. Furthermore, the minimal sub-lethal effects of flonicamid on D. rapae suggest this insecticide is compatible with biological control. By using selective insecticides, such as flonicamid, populations of D. rapae in winter canola may be conserved and thus offset the negative effects of competition with L. testaceipes.
Notlar:
School code: 0664
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Yer Numarası | Demirbaş Numarası | Shelf Location | Lokasyon / Statüsü / İade Tarihi |
---|---|---|---|
XX(678082.1) | 678082-1001 | Proquest E-Tez Koleksiyonu | Arıyor... |
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