Effects of avermectin B₁and fenvalerate on the survival, reproduction, and egg viability of the twospotted spider mitetetranychus urticaekoch (Acari: Tetranychidae)

Abstract

The effects of avermectin BI (AVMB1) and fenvalerate on the survival, reproduction, and egg viability of the twospotted spider mite, Tetranychus urticae Koch, was assessed in laboratory tests at 16 °, 24 °, and 34°C. AVMBI was as much as 1000 x more effective than fenvalerate in producing adult mortality. The efficacy of AVMBI increased at 34 °C, whereas fenvalerate was slightly less effective at this high temperature. The 10-day residual activity of AVMB1 (1 ppm) increased with increasing temperature. Adult mortality was 4, 65, 9407o at 16 °, 24 °, and 34 °C, respectively. Fenvalerate (200 ppm) displayed a lower residual activity, producing little adult mortality at any temperature after 5 days. At concentrations as high as 50 ppm, AVMB1 showed little toxic effect ( < 1807o mortality) on newly laid eggs at 16 ° and 24°C. At 34°C, AVMB 1 caused 10007o egg mortality at rates as low as 12.5 ppm. The ovicidal effect of fenvalerate did not increase with temperature. At 400 ppm, fenvalerate produced 69, 56, 65°7o egg mortality at 16 °, 24 °, 34 °C, respectively. AVMB1 significantly accelerated egg development at 16 °C, where mean days to hatch was 14.32 for the control treatment, but < 11.98 for treated eggs. AVMB1 was significantly potentiated by emulsifiable oil. At 24 °C, AVMB1 (0.78 ppm):oil (0.12507o) combinations produced 100°70 egg mortality. Egg age also significantly influenced susceptibility to AVMB1, eggs being most susceptible ca. 10 h before hatching.

Effects of fluvalinate on two‐spotted spider mite dispersal, fecundity and feeding

“…Enhancement of fecundity by some pyrethroids has been implicated in causing spider mite outbreaks (Iftner & Hall, 1984;Jones & Parrella, 1984) although there are more reports of decreased fecundity on pyrethroid-treated surfaces (Penman et al, 1981;Riedl & Hoying, 1980Iftner & Hall, 1984;E1-Banhawy & Anderson, 1985;Kasamatsu & Fujita, 1986;McKee et al, 1987;Rasmy & Elsawy, 1988;Donahue & McPherson, 1990). Reductions in fecundity were attributed to reduced feeding (Iftner et al, 1986;Kasamatsu & Fujita, 1986) chronic poisoning (Donahue & McPherson, 1990) and changes in oviposifion behaviour (Iftner & Hall, 1984;.…”

Effect of feeding treated prey with dicofol and avermectin on the survival, reproduction and development of the predacious mite Phytoseius finitimus (Acari, Phytoseiidae)

“…Since the discovery of avermectin as a potent insecticide (PUTTER et al 1981), reports have shown that it was also effective on phytophagous mites at comparatively low doses; less toxic as a direct application on predacious mites (GRAFTON-CARDWELL and HOY 1983;EL-BANHAWY and ANDERSON 1985;EL-BANHAWY and EL-BAGOURY 1985) and hopefully safe to mammals. Dicofol, another potent acaricide, has also shown little toxicity to predacious mites (HERNE and CHANT 1985;JEPPSON et al 1975;EL-BANHAWY 1976).…”

Effect of avermectin and dicofol on the immatures of the predacious miteAmblyseius gossipi with a special reference to the secondary poisoning effect on the adult female [Acari: Phytoseiidae]

“…Recently, growers have been complaining that dicofol showed impotency toward the target acarine pests. It is suggested to replace it w~th avermectin, which is effective on mites at very low dosages (Putter et al, 1981 ;EI-Banhawy & Anderson, 1985) and slightly toxic by contact to predacious mites (Grafton-Cardwell & Hoy, 1983;EI-Banhawy & EI-Bagoury, 1985;Hoy & Cave, 1985). Other selective compounds usually exhibit high toxicity when ingested through the prey [benomyl (Nakashima & Croft, 1974); methoprene (EI-Banhawy, 1977), fentrifanil (EI-Banhawy, 1978)].…”