Thrips In Cotton

Author : Jonathan A. Janis
Publisher : ProQuest
ISBN 13 : 9780549926924
Total Pages : pages
Book Rating : 4.9/5 (269 download)

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Download or read book Lethal and Sub-lethal Effects of Selected Synthetic Insecticides on Two Cotton Thrips Pests written by Jonathan A. Janis and published by ProQuest. This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Early season thrips damage to cotton can reduce yield and kill plant terminals. Control measures and the compounds used to control thrips vary widely. Thrips species, such as onion thrips, Thrips tabaci Lindman and western flower thrips, Frankliniella occidentalis (Pergande), are major contributors to the agricultural crop pest spectrum on numerous crops. The persistence of these two species as crop pests has led to the delineation of species-specific tactics for insecticidal control measures. The primary objective of this research was to characterize and compare attributes of five insecticides in different classes: anthranilic diamide (352-DPX), microcyclic lactone (spinosad, Tracer® 4 SC), neonicotinoid (thiomethoxam, Cruiser® 40 WG), carbamate (oxamyl, Vydate® L) and organophosphate (acephate, Orthene® 90 S) with thrips activity. Insecticidal potency, feeding/oviposition preference, reproductive effects and feeding damage were studied on T. tabaci and F. occidentalis . Adult potency data (LC50 or dose response mortality of each compound) showed that all compounds were more potent on T. tabaci than F. occidentalis . 352-DPX was 3823X less potent on F. occidentalis, followed by Orthene (411X), Vydate L (11X), and Tracer and Centric both with 6X lower potency on F. occidentalis . Results from the feeding and oviposition preference and reproductive effects bioassay indicated that adult T. tabaci and F. occidentalis tended to be equally distributed between treated and untreated leaves. Some exceptions are discussed where significantly more adults thrips were found on the untreated than treated leaves. The feeding and oviposition preference results indicate that in spite of the significantly lower potency on F. occidentalis, leaves treated with all compounds were less preferred over untreated leaves for feeding and oviposition, resulting in significantly lower larvae and feeding damage. Interestingly, only 352-DPX, Tracer and Vydate had this same effect on T. tabaci . Additional results indicate that sublethal concentrations (e.g. LC10 and LC50) had an effect on feeding and progeny reduction. Finally, treated leaves resulted in lower percent plant damage, caused feeding cessation, and subsequently influenced larval populations. An improved population assessment for thrips management and plant protection was developed based on these findings.