Effect of a Foliar Urea Application and Mite Injury on Yield and Fruit Quality of Apple

Abstract

Malus × domestica Borkhauser, ‘Bisbee Delicious’ and ‘Rome Beauty’ apple trees were subjected to varying amounts (range, approximately 20-1,140) of European red mite, Panonychus ulmi (Koch), injury and then treated with a foliar urea to determine if the effects of mite injury could be mitigated. The effects of these treatments were determined on mean fruit weight, soluble solids, fruit firmness, fruit color, leaf nitrogen, and number of actively growing shoots at harvest, as well as return bloom, percentage of fruit set, and crop load the following season. Mean fruit weight, fruit firmness, and percentage of leaf nitrogen in August and September were affected by mite injury on ‘Bisbee Delicious,’ whereas with ‘Rome Beauty’ soluble solids, fruit color, and percentage of leaf nitrogen in August were affected by mite injury. The only effect of the urea application after mite injury was a reduction in red color of ‘Bisbee Delicious.’