Demographic analysis of sublethal effects of spiromesifen on Neoseiulus californicus (Acari: Phytoseiidae)

Abstract

The sublethal effect of spiromesifen on life table parameters of Neoseiulus californicus McGregor (Acari: Phytoseiidae) was evaluated under laboratory conditions 25±1 °C, 65±5% RH and 16:8 (L:D) h. To take both sexes and the variable developmental rate among individuals into consideration, the raw data were analyzed based on the age stage, two sex life table. The estimated values of LC5, LC10 and LC15 for N. californicus are found to be 5.834, 9.529 and 13.267 ppm, respectively. The total preoviposition period of N. californicus treated with sublethal concentrations of spiromesifen was not significantly longer than for the control treatment. The minimum total fecundity was recorded for the LC15 concentration of spiromesifen (19.37 eggs/female) that was significantly different to the LC5 and control treatments. Compared with the control, the intrinsic rate of increase (r), finite rate of increase (λ), net reproductive rate (R0) and gross reproduction rates (GRR) of mites treated by the dose of the LC15 concentration, decreased significantly but the mean generation time (T) was not affected by this sublethal concentration. Our results indicated that increasing concentrations of spiromesifen had significant negative effects on life table parameters of N. californicus.These quantities should not be used in combination with N. californicus in integrated pest management programs in order to obtain optimal of biological control conclusions.

Side Effects of Pesticides on Population Growth Parameters, Life Table Parameters, and Predation of the Subsequent Generation of Phytoseiid Mites

“…This parameter does not change significantly in offspring of treated females with abamectin [14]. This is in consistence the other study of the effect of spirodiclofen, spiromesifen on predatory mite, A. swirskii, N. colifornicus, respectively [62,65]. T was decreased in the subsequent generation of N. longispinosus treated females with abamectin [56].…”

“…The other studies reported a similar decrease in this parameter due to abamectin application on phytoseiid mites, Notoplites longispinosus and P. persimilis [56,64]. GRR was decreased by other insecticides in the subsequent generation of treated phytoseiid mites [60][61][62]65]. In contrast, in the other study spirodiclofen did not affect the GRR of the subsequent generation of treated predatory mite, A. swirskii [65].…”

“…Several researchers have reported that life-table parameters of predatory mites of family Phytoseiidae were affected by sublethal concentrations of pesticides [10,11,[56][57][58][59][60][61][62][63]]. In the above-mentioned studies, the population parameters of the subsequent generation of a lot of phytoseiid mites were decreased when exposed to sublethal concentrations of pesticides.…”