Rainy green plum is prone to black star disease in July. How to control green plum black star disease?

Scab of green plum is a fungal disease. Its pathogen overwinters in ascomycetes or hyphae on diseased leaves or branches, and spores are produced in April of the following year, which are transmitted to leaves or fruits through Rain Water. The fruit began to occur in early May and became prevalent in July. If the disease is more serious in rainy years, we should seize the opportunity and timely prevention and control.

Green plum

Symptoms of the disease

Green plum scab mainly occurs on branches, leaves and fruits, the leaves are infected, the initial reddish brown spots are enlarged into round or shedding; the branches are infected, the spots on the green branches are also reddish brown or dark red, and the central part is gray; the fruit is infected, a dark green to dark brown round spot is formed around the fruit pedicle to the shoulder of the fruit, and the diseased part does not go deep into the pulp, slightly raised, and several disease spots are concentrated into blocks with cracks on the surface. The disease spot gradually shrinks after fruit ripening or harvest.

II. Prevention and control methods

1. Cut off diseased branches, withered branches, shade branches and dense branches and burn them in winter to improve ventilation and light transmission.

2. Spraying stone sulfur mixture or Lishengfu suspension 500 times before flowering.

3. At the initial stage of the onset of green plum scab, 40% Hodeli wettable powder or 25% leaf spot whey EC was sprayed 4000-5000 times, once every 10 days, even 2-3 times; it can also be prevented and treated with 70% topjin wettable powder.