Preliminary study results on the fruit drop syndrom on the Xuan Van persimmon trees in Tuyen Quang province

Abstract

The fruit drop syndromon of persimmon trees in Xuanvan, Tuyenquang province, has become increasingly

serious in most orchards. Fruit drop occurs at two peaks, the first at the beginning of the season - along with

physiological fruit drop, and the second at the end of the season - about one month before harvesting. The

causative agent has been identified as the fungus Diaporthe sp. based on the combination of the morphological

and molecular characteristics. In vitro, the optimal conditions for the growth of Diaporthe sp. were on PDA

medium at a range of 25 oC - 30oC and pH 5,0 – 7,0. Proactively apply a double sprays of chemical fungicides

containing active ingredient Azoxystrobin of 7 days interval when the leaves of spring shoots reach about

maximum size can effectively to prevent fruit drop on Xuanvan persimmon trees.