The Effect of European Red Mite Feeding on the Fruit Quality of ‘Miller Sturdeespur’ Apple

Abstract

Abstract Trees of Malus domestica (Borkh.) ‘Miller Sturdeespur’ were hand thinned to achieve light, medium, and heavy fruit loads. A heavy European red mite (ERM), Panonychus ulmi (Koch), infestation was encouraged by mite seeding and predator elimination in half the trees for each fruit load. The effect of these treatments were determined on fruit number, number and percentage of drops, fruit size, color, soluble solids, titratable acidity, pH, firmness, and percentage of foliar concentration for 5 macronutrients. Mite feeding increased the percentage of drop and reduced red pigmentation, soluble solids, and leaf phosphorus and calcium. Deleterious effects of mite feeding increased with increasing fruit load. With light fruit loads, heavy mite feeding had a negligible effect on fruit quality.