Panonychus ulmi

Resistance to organotin acaricides has been reported in several populations of spider mites. After cyhexatin and fenbutatin oxide were used for 10 to 17 years on pears and apples to control mites, populations of McDaniel spider mite (Tetranychus mcdanieli), two-spotted spider mite (T. urticae), and European red mite (Panonychus ulmi) slowly began to develop strains that were resistant to these chemicals (Croft et al. 1987). 

Coleoptera Cleridae Thanasimus dubius Tetranychidae) Panonychus ulmi (Acari Tetranychidae) Ips pini (Coleoptera Scolytidae) Pine Takabayashi et al., 1991a Aukema et al., 2000... 

Sabelis, M. W. and van de baan, H. E. (1983). Location of distant spider-mite colonies by phytoseiid predators demonstration of specific kairomones emitted by Tetranychus urticae and Panonychus ulmi. Entomologia Experimentalis etApplicata 33 303-314. 

Fig. 5.23. Life cycle of red spider mite (Panonychus ulmi).

Leptinotarsa decemlineata) (Tetranychus urticae) (Panonychus ulmi)... 

Though subjectively defined, and often not intensively investigated with the necessary field and laboratory studies, the phenomenon of instability has been noted for TEPP resistance 22.), the organotin acaricides (24-26), propargite (fi.), dicofol (see below), and formetanate hydrochloride. Noteworthy contradictions regarding resistance stability exist. Welty et al. (22) found resistance to cyhexatin in Panonychus ulmi to be stable in two field... 

Materials and Methods. Records of acaricide use in 50 Western New York apple orchards (ca. 1-10 ha in size), from 1982-87, were obtained from the Cornell University Apple IPM Program. Totals of 0-3 applications of the acaricides petroleum oil, dicofol, cyhexatin, and propargite were applied annually to each orchard. No dicofol treatments were made in any of these orchards in either 1986 or 1987. Estimates of susceptibility to dicofol were derived for a total of 30 of these orchard for Panonychus ulmi and from 15 orchard populations of Tetranychusurticae. Spider mites to be bioassayed were collected from mid-July to mid-September, 1987. Collections were made by clipping 100 terminal ends, ca. 30 cm in length, from apple branches within a nine-tree sampling unit in each orchard. 

Figure 2. Regression of mean mortality observed in 1987 dicofol bioassays of 30 populations of Panonychus ulmi versus the number of dicofol treatments applied to orchards during 1982-85. No dicofol applications were made in 1986-87. Solid circles denote 22 orchard populations that received 1, 2, or 3 dicofol applications. N = the number of locations sampled in each treatment category.

European red mite, Panonychus ulmi, 824 McDaniel spider mite, Tetranychus mcdanieli, 824... 

Panonychus ulmi (European red mite) Pome fmits ... 

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