Abstract
The effect of injuries to peach leaves caused by Aculus fockeui on photosynthetic rate, fruit quality, early defoliation and tree vigor were examined. Photosynthetic rates were significantly lower in injured leaves than in healthy leaves. Although no significant relationships between leaf injury levels at fruit harvest (late August) and fruit weights or acidities were detected, the sugar content of fruit was negatively correlated with injury levels. The percentages of defoliation in late September and leaf injury levels at fruit harvest showed a significant positive correlation. Enlargement of the floral bud volume was suppressed in severely damaged trees with 70%-80% defoliation in late September compared to undamaged trees with 5%-10% defoliation. Also damaged trees had significantly smaller ovary size and fruit enlargement was similarly suppressed. Further, weight, sugar content and acidity of next year's fruit in damaged trees were all significantly lower than in undamaged ones. Thus, severe peach leaf injuries caused by A. fockeui reduce the sugar content of fruit in the current year and damaged trees have lower vigor due to postharvest defoliation, resulting in lower fruit quality in the next year.
