Effect of Constant- and Variable-Humidity and Temperature Regimes on the Survival and Developmental Periods of Oligonychus ununguis (Acarina: Tetranychidae) and Neoseiulus fallacis (Acarina: Phytoseiidae)

Evaluation of Predatory Mite (Acari: Phytoseiidae) Releases to Suppress Spruce Spider Mites, <I>Oligonychus ununguis</I> (Acari: Tetranychidae), on Juniper

“…Type II predators are selective for mites in the Tetranychidae family (McMurtry and Croft 1997), and there are numerous studies documenting type II predators, mainly Neoseiulus and Galendromus species, feeding on Oligonychus species (McMurtry and Croft 1997, Pratt and Croft 2000b. Moreover, Neoseiulus fallacis (Garman) has been reported to feed on and suppress populations of our study herbivore, O. ununguis, in both natural and manipulated ornamental systems (Boyne and Hain 1983;Kramer and Hain 1989;Pratt et al 1999Pratt et al , 2002Pratt and Croft 2000a). In addition, Pratt and Croft (2000c) found higher densities of N. fallacis overwintered on conifers and evergreen shrubs than other plant types.…”

“…This was not surprising because type II phytoseiid mites in the genus Neoseiulus and Galendromus are known to feed on tetranychid spider mites, including those in the genus Oligonychus (McMurtry and Croft 1997. Of the few studies examining the efÞcacy of phytoseiids in suppressing spruce spider mite, N. fallacis was used successfully under controlled laboratory (Boyne and Hain 1983, Kramer and Hain 1989, Pratt et al 1999 and Þeld conditions (Boyne and Hain 1983), further supporting our selection of N. fallacis as a likely candidate for augmentative control of spruce spider mite.…”

“…Therefore, we sought predators that differed somewhat in thermal and humidity requirements for releases of single species and a combination of two species. Pratt and Croft (2000b) examined life history traits of phytoseiids and found that G. occidentalis tolerates relative humidity levels as low as 28% (Pratt and Croft 2000b), whereas others reported that N. fallacis performs best at relative humidities Ͼ70% (Boyne and Hain 1983, Kramer and Hain 1989, Pratt and Croft 2000b. In addition, we thought it best to select predators that differed somewhat in other life history traits.…”

“…Pratt et al (2002) suggested that differences in control levels could be related to foliage density and the associated relative humidities of varying plant canopies. N. fallacis is known to be sensitive to low relative humidity (Kramer andHain 1989, Croft et al 1993).…”

Effect of temperature on the development of Eotetranychus hirsti (Tetranychidae) on fig leaves

“…Some research discusses the relation between the RH and development of tetranychid mites (such as Kramer and Hain, 1989;Bonato et al, 1995;Abou-Awad et al, 2001), but there is no information about the effect of RH on the development of E. hirsti. Additional studies on the effects of relative humidity on the development of E. hirsti can further increase our knowledge to forecast its population dynamics in cropping systems.…”