Apple, Integrated Mite Control Test, 1979

The experiment reported below was designed to test several miticides for midseason control of P. ulmi in an orchard where T. urticae was being controlled by T. occidentalis. The test was performed on a commercial orchard at Batlow, N. S. W. 350 km SW of Sydney. Nine-tree plots (3 × 3) were used with leaf samples taken from the center tree. Each treatment (see Tables) was replicated 4 times in a randomized, complete block design. Test sprays were applied dilute to all trees in each plot by an M.B.P. Airmist drivepast sprayer at 2800 liters/ha on Jan 18. Good coverage was achieved with little run-off. Control plots were sprayed with Plictran 50W (20 g/100 liters) on Jan 31 to prevent damage to trees by P. ulmi. Routine cover sprays applied by the grower to the study block during the test period were: Captan A 83W + Gusathion 50W + CaNO3 (Jan 12), Captan A 83W + Gusathion 50W (Jan 31). Samples of 25 leaves were taken from the inner parts of each study tree (100 leaves/treatment) below a height of 1.5 m at the time intervals shown in the table. The numbers of active stages of the 3 mite species were counted on the leaves using dissecting steromicroscopes.