(A23) APPLE: Malus domestica Borkhausen, 'Red Delicious' John C. Wise Department of Entomology Michigan State University East Lansing, MI 48824-1115 Phone: (517) 432-2668 Fax: (517) 353-5598 E-mail: firstname.lastname@example.org Kevin Schoenborn E-mail: email@example.com Larry J. Gut E-mail: firstname.lastname@example.org European red mite (ERM): Panonychus ulmi (Koch) Apple rust mite (ARM): Aculus schlechtendali (Nalepa) This trial was designed to determine the efficacy of different rates and timings for various new miticides. Two-tree plots were established in a 16-yr-old 'Red Delicious' apple block at the Trevor Nichols Research Complex in Fennville, MI and treatments were arranged in a RCB design with four replications. Tree spacing was 18 × 20 ft, with a minimum of one buffer tree and one buffer row separating all plots. Three different timings were tested by initiating applications at petal fall (PF) plus 10 d (2 Jun), ERM action threshold (24 Jun, 2–3 motiles per leaf), or threshold plus 7 d (1 Jul). Only one treatment (Zeal, 2 oz/acre) was applied on 1 Jul to simulate an application 7 d after optimal timing. Note that the BioMite treatments received an extra application on 16 Jul. All treatments were applied with an FMC 1029 tractor-mounted airblast sprayer calibrated to deliver 100 gpa at 2.5 mph. Random leaf samples were collected from four areas of the orchard on a weekly basis to monitor ERM populations for action threshold levels of two to three motile forms per leaf. Evaluations of all plots were conducted on 23 Jun (prior to threshold application), 3 Jul, 8 Jul, 29 Jul, and 12 Aug by picking 50 randomly selected leaves from each replicate for a total of 200 leaves per treatment. Mites and eggs were removed with a mite-brushing machine and counted under a stereomicroscope. The number of ERM and ARM motiles was recorded, and data are reported as the mean number of mites or eggs per leaf. Data were analyzed using ANOVA and means were separation by LSD at (P ≤ 0.05.) Among the PF + 10 d applications, Agri-Mek, Envidor and Mesa all provided excellent ERM control through the 12 Aug evaluation (Table 1). The BioMite treatments did not show significant ERM activity until the 8 Jul rating date. Agri-Mek, Envidor and Mesa all had activity on ARM (Table 3), as well as BioMite (low rate) at the 8 Jul evaluation. Among the threshold applications, all treatments provided excellent control of ERM at 14 DAT (Table 4), while Zeal and Envidor provided the best control at 35 DAT (29 Jul rating). Control of ERM motile forms with Pyramite, Acramite and Kanemite began to break at the 35 DAT count, whereas Zeal and Envidor continued to hold the populations through the 49 day count. Envidor, Pyramite and Zeal gave the best levels of control numerically of ARM at the 29 Jul evaluation (Table 6), with Envidor significantly better than all other treatments on this date.
Arthropod Management Tests – Oxford University Press
Published: Jan 1, 2004