Sublethal effects of Milbemectin on biological parameters of Amblyseius swirskii (Acari: Phytoseiidae)

Abstract

Pesticides cause serious damage to agricultural and natural ecosystems. Knowing pesticides' side effects on non-target beneficial phytoseiids is crucial for integrated mite management (IMM) programs. One solution is to use biological agents and a low concentration of pesticides together. The present study was conducted to evaluate sublethal effects of acaricide Milbemectin (Milbecnock®) at LC5, LC15 and LC25 levels on development and reproduction parameters of Amblyseius swirskii Athias-Heneroit (Acari: Phytoseiidae) under laboratory conditions [25 ± 1°C, 70 ± 5% RH and 16:8 (L:D) hours]. Our results demonstrated that higher concentrations of Milbemectin (LC15 and LC25) had the most effect on the Longevity and the Total life span of both males and females of a predatory mite. The total life span in females was recorded from 42.67 days (Control) to 23.46 days (LC25 treatment). In an unusual observation, the oviposition period and also the total fecundity of the LC5 treatment have been 21.42 days and 37.31 offspring per individual, respectively. Which is recorded higher than the control treatment. These parameters were recorded in minimum value on the highest concentration treatment. Contrariwise the intrinsic rate of increase (r) and the finite rate of increase (λ) are not affected by sublethal concentrations of Milbemectin. The recommended dose of milbemectin based on the active ingredient is 10 ppm and the concentration obtained for LC5 is 27.92 ppm, which had a positive effect on fecundity and a slight imperceptible effect on the total life span reducing of the predatory mite. Sublethal effects of milbemectin and its impact on A. swirskii are discussed.

The effects of the abamectin and spirodiclofen mixture on life history and population parameters of Amblyseius swirskii

“…Increasing the Envidor speed concentrations, caused a large negative effect on the longevity and the total lifespan, which is the minimum value of these parameters recorded for the greatest concentration, i.e., LC 25 treatment. Similarly, it has been reported that female longevity of A. swiriskii, after treatment with sublethal concentrations of Milbemectin and bifenazate respectively, has reduced significantly (Havasi et al 2021a;Mousavi et al 2022). Pre-ovipositional periods play an important role in the intrinsic rate of increase (Khanamani et al 2017).…”

“…Similarly, it has been reported that female longevity of A. swiriskii , after treatment with sublethal concentrations of Milbemectin and bifenazate respectively, has reduced significantly (Havasi et al . 2021a; Mousavi et al . 2022).…”