Occurrence and Control of Pear Blight Rot(Phytophthora cactorum) in Qianxian of Shaanxi Province

[ Objective ] The paper was to investigate the occurrence condition of pear blight rot in pear-producing areas in Qianxian of Shannxi Province, so as to find the main cause of the disease and the effective agents for the disease. [Method] The occurrence condition of pear blight rot was surveyed in field, the inci- dence rate of trees and incidence index of fruits were counted, and the field control test of different agents against pear blight rot was carried out. [ Result] The ma- jor reasons for outbreak of pear blight rot in Ganhe pear-producing areas in Qianxian of Shannxi Province were excessive rainfall and high temperature and humidity in July 2010, poor drainage in orchards and large planting density were also the main factors causing outbreak of pear blight rot. 64% oxadixyl · mancozeb WP, 60% metalaxyl-mancozeb WP and 80% aliette WP had significant control effect on pear blight rot, fruit bagging was also an ideal measure for prevention of the dis- ease. [ Conclusion] Pear production should focus on improving the air and light condition, enhancing the drainage capacity of orchard and promoting bagging culti- vation, and the systemic control agents should be selected to control pear blight rot.

A Review on Research Progress of Pear Ring Rot

The pathogen,pathogenic mechanism and incidence condition of pear ring rot,and its damage on fruits,branches and leaves are summarized in the paper. The control measures including plant quarantine,agricultural control,physical control,biological control,and chemical control against pear ring rot are reviewed.

Isolation and Characterization of Bacillus Amyloliquefaciens L-1 for Biocontrol of Pear Ring Rot

Considering the heavy losses caused by pear ring rot(Botryosphaeria berengeriana) disease, the potential biocontrol agent against B. berengeriana was isolated and characterized in this work. Bacteria, isolated from pear orchard rhizosphere soil, were screened for the biological control of pear ring rot caused by B. berengeriana. Among them, strain L-1 showed noticeable inhibitory activities against B. berengeriana and six other commonly occurring postharvest pathogens. Molecular methods indicated strain L-1 was Bacillus amyloliquefaciens. The potential of strain L-1 as an effective biocontrol agent was further estimated. Results showed strain L-1 could successfully colonize in pear wounds, its colonies reached 142.35 folds on 4 days post inoculation, and maintained at a high level during storage. In addition, strain L-1 caused abnormal hyphae growth of B. berengeriana,and its inhibitory percentage against pear ring rot reached 76.55% in vivo on 11 days post inoculation. Strain L-1 significantly induced the peroxidase(POD) and catalase(CAT) activities and delayed the accumulation of malondialdehyde(MDA) in pears. What's more, strain L-1 did not impair the fruit quality. All these results suggest that B. berengeriana L-1 is a promising agent for the biocontrol of pear ring rot.