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

Abstract

BackgroundSublethal effects of insecticides may negatively affect several biological and behavioral traits of insects. The lethal effects of pirimiphos‐methyl and chlorfenapyr have been previously tested successfully against Trogoderma granarium, but little knowledge is available about their diverse effects at low concentrations on male and female beetles. Herein, the sublethal effects of pirimiphos‐methyl and chlorfenapyr on the mobility of T. granarium males and females were investigated.ResultsLethal concentrations (LC) of pirimiphos‐methyl and chlorfenapyr were lower for T. granarium females than males. LC values on males were LC10 = 0.000788 and 0.00139 mg a.i. cm‐2, LC30 = 0.00350 and 0.00535 mg a.i. cm‐2, and LC50 = 0.00986 and 0.0110 mg a.i. cm‐2 for pirimiphos‐methy and chlorfenapyr respectively. LC on females were LC10 = 0.000704 and 0.00136 mg a.i. cm‐2, LC30 = 0.00323 and 0.00428 mg a.i. cm‐2, and LC50 = 0.00925 and 0.0110 mg a.i. cm‐2 for pirimiphos‐methyl and chlorfenapyr respectively. The walking duration of beetles exposed to LC30 of pirimiphos‐methyl was significantly lower than the individuals exposed to LC10 and LC30 of both insecticides and control ones. LC30‐exposed males remained more time on their back (101.7 s) than females (46.9 s), while the latter stayed immobile longer time than males (381.7 s vs. 371.9 s). The highest speed was recorded for control beetles (14.7 mm/s females vs. 12.44 mm/s males), while the lowest speed was observed in LC30‐treated males (8.36 mm/s) and females (9.66 mm/s).ConclusionsOverall, males and females exposed to low concentrations of pirimiphos‐methyl and chlorfenapyr showed reduced motility. This knowledge can be exploited further to exploit behavioral effects of insecticides for effective pest management programs in warehouses.This article is protected by copyright. All rights reserved.

Sublethal Effects of Chlorantraniliprole on the Mobility Patterns of Sitophilus spp.: Implications for Pest Management

“…R statistical software (version 2.15.1) was used to determine the sublethal concentrations of chlorantraniliprole [50]. Data on the impact of chlorantraniliprole on the walking behavior of S. oryzae and S. zeamais adults were transformed to log(x + 1) format to achieve standard means and normal variances [47,51]. Two-way ANOVA was conducted to assess the impact of chlorantraniliprole on the mobility of both weevil species [52].…”

“…Each adult was allowed a three-minute acclimatization period within the arena. Subsequently, the following traits were visually recorded: (1) “walking (s)”—the duration of locomotion, (2) “stops (s)”—the duration of immobility, (3) “climb up (s)”—the duration of attempts to ascend the arena walls, (4) “upturned (s)”—the duration of time spent on the insect’s back, (5) “short stops (n)”—the number of interruptions in movement followed by resumption, (6) “climb up (n)”—the number of attempts to ascend the arena walls, (7) “upturned (n)”—the number of instances the beetle was found on its back, (8) “flying attempts (n)”—the number of flight attempts into the arena, and (9) “flying”—the duration of flight within the arena [ 47 ]. These observations were conducted for 15 min.…”

“…Separate arenas were utilized for each replication, species, and exposure. The experiments were conducted between 8 a.m. and 8 p.m. at a temperature of 30 °C [ 47 ].…”