Insect predators in North America suppress Aphis glycinesMatsumura (Hemiptera: Aphididae) populations; however, insecticides are required when populations reach economically damaging levels. Currently, insecticides used to manage A. glycines are broad-spectrum (pyrethroids and organophosphates), and probably reduce beneficial insect abundance in soybean, Glycine max (L.) Merr. Our goal was to determine whether insecticides considered reduced-risk by the Environmental Protection Agency could protect soybean yield from A. glycines herbivory while having a limited impact on the aphid's natural enemies. We compared three insecticides (imidacloprid, thiamethoxam, and pymetrozine,) to a broad-spectrum insecticide (λ-cyhalothrin) and an untreated control using two application methods. We applied neonicotinoid insecticides to seeds (imidacloprid and thiamethoxam) as well as foliage (imidacloprid); pymetrozine and λ-cyhalothrin were applied only to foliage. Foliage-applied insecticides had lower A. glycines populations and higher yields than the seed-applied insecticides. Among foliage-applied insecticides, pymetrozine and imidacloprid had an intermediate level of A. glycines population and yield protection compared with λ-cyhalothrin and the untreated control. We monitored natural enemies with yellow sticky cards, sweep-nets, and direct observation. Before foliar insecticides were applied (i.e., before aphid populations developed) seed treatments had no observable effect on the abundance of natural enemies. After foliar insecticides were applied, differences in natural enemy abundance were observed when sampled with sweep-nets and direct observation but not with yellow sticky cards. Based on the first two sampling methods, pymetrozine and the foliage-applied imidacloprid had intermediate abundances of natural enemies compared with the untreated control and λ-cyhalothrin. KeywordsGlycine max, biological control, insecticide regulation, conservation, nontarget impacts Disciplines Agriculture | Entomology CommentsThis article is from Journal of Economic Entomology 102 (5) ABSTRACT Insect predators in North America suppress Aphis glycines Matsumura (Hemiptera: Aphididae) populations; however, insecticides are required when populations reach economically damaging levels. Currently, insecticides used to manage A. glycines are broad-spectrum (pyrethroids and organophosphates), and probably reduce beneÞcial insect abundance in soybean, Glycine max (L.) Merr. Our goal was to determine whether insecticides considered reduced-risk by the Environmental Protection Agency could protect soybean yield from A. glycines herbivory while having a limited impact on the aphidÕs natural enemies. We compared three insecticides (imidacloprid, thiamethoxam, and pymetrozine,) to a broad-spectrum insecticide (-cyhalothrin) and an untreated control using two application methods. We applied neonicotinoid insecticides to seeds (imidacloprid and thiamethoxam) as well as foliage (imidacloprid); pymetrozine and -cyhalothrin were applied only to ...

No abstract

No abstract

Chapter 1 General Introduction and Literature Review Thesis Organization This thesis has been organized into 5 chapters. Chapter 1 contains the general introduction and literature review. Chapter 2 contains the experiment conducted with reduced-risk insecticides and their efficacy for soybean aphid management and conservation of natural enemies. Chapter 3 is part of a community assessment of aphids in Iowa prairies prior to the release of an Asian parasitoid. Chapter 4 includes the study of prairies as a source of natural enemies for soybean biological control. Chapter 5 is the general conclusions and summary. Aphis glycines natural enemies Competitors, pathogens, predators, and parasitoids are all types of natural enemies of A. glycines. In North America, A. glycines is the only aphid to successfully colonize soybean and produce economically important populations. Entomopathogenic fungi have been identified to play a role in A. glycines population regulation in New York State (Nielson and Hajek 2005). However, there is little evidence that pathogens play a role in population regulation in the north central region of the United States. Endemic predators can regulate populations of A. glycines (

No abstract