Year-end Sale % OFF 
Abstract
Residual effects of pyrethrin + methoprene aerosol dispensed at 4 and 16-µm particle sizes and an untreated control, was assessed against late-stage larvae of Trogoderma inclusum (LeConte), the larger cabinet beetle, and T. variabile (Ballion), the warehouse beetle. Treated arenas were stored at 25, 30, 35, and 40 °C and bioassays were conducted at 1, 3, or 6 weeks post-treatment. Larval development was monitored through adult emergence to compare the efficacy of treatments by using both the percentage of normal adult emergence and a developmental index as dependent variables. There was no overall effect of temperature on residual activity as measured using either adult emergence or developmental index values. Both the 4 and 16-µm particle sizes resulted in reduced adult emergence and low developmental index values compared to untreated controls. The insecticide was more effective on T. variabile than on T. inclusum. The impact of particle size varied between species, both particle sizes reduced adult emergence and developmental index in T. variabile, but only the 16-µm particle size resulted in reduction of adult emergence of T. inclusum. Furthermore, there was a reduction in activity of methoprene with residual exposure time. The variations in susceptibility of species to methoprene, differences in efficacy of particle sizes, and decrease in residual persistence at smaller particle sizes highlight the need for attaining optimal particle size to improve overall efficacy of aerosol mixtures containing methoprene.
Highlights
Aerosol insecticides can be vital components in management of stored product insects in mills, processing plants, and food storages
Studies on efficacy of different particle sizes of pyrethrin aerosol dispensed on adults of Tribolium confusum Jacqueline du Val, the confused flour beetle, exposed on treated concrete arenas revealed that the smaller particle size did not kill the adults, while the largest particle size of 16 μm resulted in a significant mortality [8,9]
This study has demonstrated striking variability between late larvae of the two dermestid species viz., D. maculatus and T. variabile in response to methoprene
Summary
Aerosol insecticides can be vital components in management of stored product insects in mills, processing plants, and food storages. A naturally occurring insecticide, is used in the US either alone or in combination with an insect growth regulator (IGR), either methoprene or pyriproxyfen [3,4,5,6,7,8]. Their combined use can accomplish insect population control by direct initial kill of exposed immatures and adults due to immediate contact toxicity of pyrethrin and delayed control of immature stages through exposure to residues of the IGR on treated surfaces. In another study by Arthur et al [7], Insects 2019, 10, 142; doi:10.3390/insects10050142 www.mdpi.com/journal/insects
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
