Efficacy of Provado and Thiodan for Aphid Control, 1995

The trial was conducted in a 2-acre 5-yr-old mixed ‘Delicious’, ‘Gala‘, and ‘Idared’ orchard with under-tree irrigation. Guthion 50W (2 lb form./acre) was applied for codling moth control on 2 and 16 Jun, 7 Jul, and 1 and 22 Aug with an air blast sprayer. The experimental design was a RCB with 5 single-tree replicates per treatment. There were two or more buffer trees within rows between treated trees. Dilute sprays were applied to runoff with a handgun sprayer operated at 150-200 psi. Per acre rates were based on application of 1 gal of spray per tree or 182 gal/acre. Aphids (alate + apterous) were counted in situ on the three most recently fully expanded leaves (minimum of 1 inch in length and edges completely unfolded) on three terminals per tree. Pre-treatment counts were made on 20 Jun. All aphicide treatments were applied on 21 Jun, except one follow-up Thiodan application on 10 Jul (19 DAT). Post-treatment counts were made 5, 12, 19, 26, and 34 DAT.