Residual efficacy of Deltamethrin against Sitophilus oryzae (L.), Rhyzopertha dominica (F.), Tribolium castaneum (Herbst) and Sitotroga cerealella (Oliv.) in wheat grain

Abstract

Residual efficacy of the insecticide deltamethrin, an EC formulation containing 25 g/L AI + 225 g/L PBO (piperonyl butoxide synergist), against lab populations of Sitophilus oryzae, Rhyzopertha dominica, Tribolium castaneum and Sitotroga cerealella was investigated in the laboratory by applying product water solutions (0.25 mg AI/kg) to wheat grain (at 25±1°C and 60±5% r.h.). Adult mortality on 0, 7, 14 and 30 days old deposits was estimated after 2, 7 and 14 days of exposure to treated wheat grain and additional 7 days of recovery. Progeny reduction (PR, %) was also assessed. After 2 days of exposure to deposits of all ages, deltamethrin caused only 0-10% mortality of coleopterans (up to 37% after the recovery period) and 23-30% of S. cerealella, while mortality before and after recovery from 14 days of exposure was 95-50% for S. oryzae, 97-100% for R. dominica, 99-100% for T. castaneum and 100% for S. cerealella. Progeny production of S. oryzae was highest after parents contacted with 14 days old deposit of deltamethrin (PR, 76%), and lowest after contact with fresh deposit (PR, 95%), while R. dominica and T. castaneum had no progeny on any deltamethrin deposit age in wheat (PR, 100%), and S. cerealella had only a very low progeny (PR, 99%). The results showed that the synergised deltamethrin, applied at 0.25 mg/kg in wheat grain, is a highly effective insecticide for storedproduct insect control, while a higher dose is required for successful residual control of S. oryzae.

Effect of four plant extracts on the mortality, population growth, and fluctuating asymmetry of Sitophilus oryzae

“…Due to their economic importance, the majority of studies on insects of the genus Sitophilus are focused on their eradication and suppression (Batta, 2004; Alleoni & Ferreira, 2006; Adams et al, 2016; Pražić‐Golić et al, 2018; Villegas et al, 2019). However, due to a ban of a number of efficient chemical insecticides, under the Directive 128/2009/EC of the European Parliament, novel ways of controlling the rice weevil are required.…”

Being exposed to low concentrations of pirimiphos‐methyl and chlorfenapyr has detrimental effects on the mobility of Trogoderma granarium

“…The protection of stored commodities against many pests, including T. granarium, has been widely investigated for the acute toxicity of various surface-or kernel-applied chemical formulations 18,[21][22][23][24] as well as botanical insecticides. 25 Applying pirimiphos-methyl at 5 ppm on maize, wheat and barley killed 100% of T. granarium adults after 7 days of exposure, causing complete suppression of offspring.…”