When can pear trees be sprayed with pesticides to prevent black heart disease?

(1) Select and plant disease-resistant varieties in orchards with serious diseases.

(2) Strengthen plant quarantine. Strictly implement the quarantine system to prevent the introduction of diseased seedlings, scions and fruits from epidemic areas into non-epidemic areas.

(3) eliminate the primary source of infection. In late autumn and early winter, fallen leaves and diseased fruits should be thoroughly removed, burned or buried centrally. Or spray 0.5% dinitro-o-cresol sodium or 4: 4: 100 bordeaux solution on the ground to kill the ascospores in the diseased leaves.

(4) Spray protection. Spray period is the most critical. Before onset, Liang Guoan was diluted and sprayed with 800 times solution once every 15 days. Treatment plan: when the illness is mild, diluted Liangguoan and sprayed with 800 times solution once every 10- 15 days; When the condition is serious, it should be diluted 500 times and sprayed once every 7- 10 days.

Early-maturing varieties (such as Huang Taiping) began to spray 1: 2-3: 160 times Bordeaux mixture at the flowering stage in mid-May; /kloc-once every 0/5 days, spray 5 times. You can also use 77% kesaide wettable powder 500 times or 70% mancozeb wettable powder 500 times, 50% benomyl wettable powder 1500 times, 70% thiophanate-methyl ultrafine wettable powder 1000 times, 64% antiviral alum wettable powder 400-600 times and 50% mixed sulfur suspending agent 5000 times.