[Show abstract][Hide abstract] ABSTRACT: Bifenazate is a novel carbazate acaricide discovered by Uniroyal Chemical (now Chemtura Corporation) for the control of phytophagous mites infesting agricultural and ornamental crops. Its acaricidal activity and that of its principal active metabolite, diazene, were characterized. Bifenazate and diazene had high toxicity and specificity both orally and topically to all life stages of Tetranychus urticae and Panonychus citri. Acute poisoning was observed with no temperature dependency. No cross-resistance was found to mites resistant to several other classes of acaricides, such as tebufenpyrad, etoxazole, fenbutatin oxide and dicofol. Bifenazate remained effective for a long time with only about a 10% loss of efficacy on T. urticae after 1 month of application in the field. All stages of development of the predatory mites, Phytoseiulus persimilis and Neoseiulus californicus, survived treatment by both bifenazate and diazene. When adult females of the two predatory mite species were treated with either bifenazate or diazene, they showed a normal level of fecundity and predatory activity in the laboratory, effectively suppressing spider mite population growth. Even when the predators were fed spider mite eggs that had been treated previously with bifenazate, they survived. These findings indicate that bifenazate is a very useful acaricide giving high efficacy, long-lasting activity and excellent selectivity for spider mites. It is, therefore, concluded that bifenazate is an ideal compound for controlling these pest mites.
[Show abstract][Hide abstract] ABSTRACT: The life history characteristics and predation of the Japanese Neoseiulus californicus (McGregor) strain on the two-spotted spider mite, Tetranychus urticae Koch, were studied in the laboratory under 60–70% RH and 16L: 8D conditions. Developmental time from egg to adult emergence decreased when temperature increased. Total development period of immature stages was longest at 15°C and shortest at 35°C for both male and female. Sex ratio favored females and temperature did not exert a critical effect on sex determination. The total degree-days required from egg to adult female were 71.43 degree-days with thermal constant of 10.64°C. At 25°C, female laid a total of 34.73 eggs during 17.91 days of oviposition period. The net reproductive rate (R o) was highest at 25°C (22.92 females/female) and lowest at 30°C (16.74 females/female). The mean generation time (T) decreased from 20.61 to 16.79 days with increasing temperature up to 30°C. The intrinsic rate of natural increase (r m) ranged from 0.162 to 0.285, and was maximal at 25°C. A gravid N. californicus female consumed more eggs, larvae and nymphs than adult male or female of T. urticae. As T. urticae density increased, prey consumption likewise increased. However, increasing the number of adult male or female preys did not increase the number of eggs laid by a female predator. The results were used to assess the effectiveness of the Japanese N. californicus strain as an important biological control agent against T. urticae.