species of mite predators, called yellow mites, that are very slow 

 and inefficient at locating and capturing red mite prey. These 

 predators were considerably more abundant than A. f allacis , and it 

 is very likely that they were interfering with its performance. 



In the abandoned orchard, two-spotted mites were totally absent, 

 while red mites were always at low levels (Table 1). A. fallacis 

 was largely absent. However, other predacious mites increased to 

 1.70 mites per leaf, which is a rather high level, but still con- 

 siderably lower than predator levels in commercial orchard D. It 

 appears that the fewer numbers of mite predators in the abandoned 

 orchard were able to control red mites better than the larger num- 

 ber of predators in orchard D. This was probably because the dif- 

 ferent predator complex in the abandoned orchard was more efficient 

 in controlling red mites. 



At the Belchertown Research Center, two-spotted mites were in 

 greatest abundance (causing severe leaf injury) and A_^ fallacis in 

 least abundance in the Zolone treated plot (Table 2). However , red 

 mites remained below damaging levels in all plots. In the Guthion 

 and Imidan plots, A_^ fallacis populations were high, keeping two- 

 spotted and red mites well below damaging levels. A. f allacis 

 levels were also high in the Benlate plot but failecPto keep two- 

 spotted mites from reaching damaging levels (Table 2) . This is 

 likely due to certain characteristics of Benlate (see below) which 

 adversely affect Aj_ fallacis populations. Yellow mites were absent 

 from all plots. 



The combined results from the commercial orchards and the 

 Belchertown Research Center show that one or more of the materials 

 Zolone, Benlate, and Glyodin have a toxic and/or other effect on 

 populations of Aj_ fallacis . In addition, our recent laboratory 

 findings confirm results from Michigan (Dr. B.A. Croft's laboratory), 

 showing that Benlate, at orchard concentrations, severely reduces 

 the number of eggs laid by A_^ fallacis . Growers using these mate- 

 rials (Table 1) needed more miticide sprays, principally to control 

 two-spotted mites, than growers spraying only Guthion, Imidan, 

 Captan, and Cyprex. However, red mites can become a problem in some 

 orchards (i.e. in orchard D) using the latter pesticides because 

 the favorable environment may allow less efficient mite predators 

 to increase and interfere with A^ fallacis . 



In the future, we plan further laboratory and field trials 

 aimed at determining which pesticides are safest for A_j_ fallacis 

 populations in our commercial orchards. This predator can be of 

 great assistance in suppressing harmful spider mites if its survival 

 can be guaranteed. In the next issue of Fruit Notes , we will 

 describe results of laboratory tests aimed at determining the 

 toxicity of a large variety of orchard pesticides to A. fallacis . 



