Efficacy of diatomaceous earths and their low-dose combinations with spinosad or deltamethrin against three beetle pests of stored-maize

Autor: Honest Machekano, Brighton M. Mvumi, Richard Rwafa, Susan J. Richardson-Kageler, Peter Chinwada
Rok vydání: 2017
Předmět:
Zdroj: Journal of Stored Products Research. 72:128-137
ISSN: 0022-474X
DOI: 10.1016/j.jspr.2017.04.009
Popis: A key element in postharvest IPM is the reduction of chemical residues in food through the use of reduced dosages of less toxic grain protectants. Two laboratory experiments were conducted: Experiment I determined the efficacies of straight diatomaceous earths (DEs) – “Chemutsi” (African raw DE), MN51 (new formulation) and Protect-It® (enhanced DE), and two new food grade DE-based formulations (A2 and A3) against adult Prostephanus truncatus (Horn), Sitophilus zeamais (Motschulsky) and Tribolium castaneum (Herbst) admixed with shelled maize. In Experiment II, Chemutsi and Protect-It® were further tested in varying combinations with low-dose deltamethrin and spinosad. At 21 days post-exposure, MN51 800 ppm and 1000 ppm, Chemutsi 1000 ppm, Protect-It® 600 ppm and food grade A3 150 ppm caused S. zeamais mortalities that were not significantly different from the positive control (Protect-It® 1000 ppm). However, after the same exposure period, all the straight DEs (applied at ≤ 1000 ppm) and the DE-based food grade formulations were not effective on P. truncatus and T. castaneum. In low dose combinations, 7 day mortalities showed high S. zeamais susceptibility to both DE-spinosad and DE-deltamethrin while P. truncatus was more susceptible only to DE-spinosad and T. castaneum to Protect-It®-deltamethrin only. At 21 days, all DE-spinosad and DE-deltamethrin treatments were effective and not significantly different from the commercial grain protectant (fenitrothion 1.0% w/w (10000 ppm) + deltamethrin 0.13% w/w (130 ppm)) on all test species. DE-spinosad and DE-deltamethrin combinations significantly suppressed (P
Databáze: OpenAIRE
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