owned and operated by Marshall Farms Inc., 

 Fitchburg, MA. Each 1.5-acre plot consisted of 

 three rows of primarily Mcintosh trees 

 approximately 12 feet high, planted on 16 x 24 

 foot spacing with a dilute tree row volume of 

 280 gallons per acre. Treatments were made 

 with a Hardie airblast sprayer calibrated to 

 deliver 150 gal per acre while operating at 2.5 

 miles per hour according to the treatment 

 schedule outlined in Table 1. 



European red mite populations were 

 evaluated by selecting randomly 15 leaves per 

 tree from each of 4 trees per treatment. 

 Composite samples then were brushed unto 

 glass plates and populations estimated using 

 standard leaf-brushing protocol. 



Results & Discussion 



There were no substantial differences 

 between treatments with respect to European 

 red mite control in this study. Both Agri-Mek 

 timings as well as the prebloom Savey 

 application, included for comparison, were 

 successful in suppressing ERM populations 

 below injurious levels through the last week of 

 August. Estimated mite populations in these 



plots ranged from 2.0 - 7.2 per/leaf on August 

 28 (Figure 1) with little or no foliar damage 

 evident. ERM populations in the check plot, 

 which received only a prebloom oil treatment, 

 built rapidly after first-generation egg hatch 

 and exceeded 15.0 mites per/leaf by early July. 

 Moderate foliar damage was noted at this time 

 and rescue treatments of miticide were applied 

 July 7 and July 25 to prevent excessive 

 damage. A third treatment was made on 

 August 9 to suppress late-season build up. 



It is interesting to note that, although both 

 treatments were successful in suppressing 

 ERM populations below injurious levels, trees 

 receiving the later Agri-Mek treatment applied 

 on June 17 had more motile forms consistently 

 throughout the growing season. Pre-treatment 

 counts on June 14 revealed approximately 4.0 

 mites per/leaf, and although our application 

 was successful in reducing that population, 

 there were still significant numbers of motile 

 forms on July 3 when one would expect to see 

 full expression of the treatment. In contrast, 

 the petal-fall treatment applied May 23 

 suppressed ERM numbers to barely detectable 

 levels until early August and final counts on 

 August 28 were less than 50% of the later 



20 



Fruit Notes, Volume 62 (Number 1), Winter, 1997 



