Impact of insecticides on parasitoids of the leafminer, Liriomyza trifolii, in pepper in south Texas
1Department of Entomology, Texas AgriLife Research, Texas A&M University System, 2415 E. Highway 83,
Weslaco, TX 78596-8399, USA
2Department of Entomology, Texas A&M University, 2475 TAMU, College Station, TX 77843-2475, USA
3Current address: Key Laboratory of Applied Entomology, Northwest A&F University, Yangling, Shaanxi, 712100,
China
Abstract
Liriomyza leafminers (Diptera: Agromyzidae) are cosmopolitan, polyphagous pests of horticultural plants and many are resistant to insecticides. Producers in South Texas rely on insecticides as the primary management tool for leafminers, and several compounds are available. The objective of this study is to address the efficacy of these compounds for controlling Liriomyza while minimizing their effects against natural enemies. Research plots were established at Texas AgriLife research center at Weslaco, Texas in fall 2007 and spring 2008 seasons, and peppers were used as a model crop. Plots were sprayed with novaluron, abamectin, spinetoram, lambda-cyhalothrin and water as treatments according to leafminer infestation; insecticide efficacy was monitored by collecting leaves and infested foliage. Plant phenology was also monitored. Novaluron was the most effective insecticide and lambda-cyhalothrin showed resurgence in leafminer density in fall 2007 and no reduction in spring 2008. Other compounds varied in efficacy. Novaluron showed the least number of parasitoids per leafminer larva and the lowest parasitoid diversity index among treatments followed by spinetoram. Liriomyza trifolii (Burgess) was the sole leafminer species on peppers, and 19 parasitoid species were found associated with this leafminer. Application of these insecticides for management of leafminers with conservation of natural enemies is discussed.
Keywords: conservation biological control, Neochrysocharis formosa, Closterocerus cinctipennis, Opius dissitus, Cirrospilus variegates
Correspondence:
a ricahm@gmail.com,
b m-harris@tamu.edu,
c txliu@nwsuaf.edu.cn
Editor: James Ottea was editor of this paper
Received: 21 April 2010 | Accepted: 3 September 2010 | Published: 17 May 2011
Copyright: This is an open access paper. We use the Creative Commons Attribution 3.0 license that permits unrestricted use, provided that the paper is properly attributed.
ISSN: 1536-2442 | Volume 11, Number 61
Hernández R, Harris M, Liu T-X. 2011. Impact of insecticides on parasitoids of the leafminer, Liriomyza trifolii, in pepper in south Texas. Journal of Insect Science 11:61 available online: insectscience.org/11.61
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