Black spot disease affects the appearance of pear how to control pear black spot disease

The black spot disease of pear is also called black fart disease. According to the research and identification, the pathogen is the source of black spot disease, and the pathogen enters the pear bag along the pear stalk with rain, fog and medicine solution, and gathers in the calyx depression. After bagging, the humidity in the bag is high and the air permeability is poor, which is suitable for the growth and reproduction of Alternaria. The peak of the disease is in the rainy season from late June to late July. In the early stage of the disease, small black spots with large needles appeared around the calyx depression of the pear. With the development of the symptoms, the diameter of the black spots expanded, and several black spots connected together to form near-round sunken spots around the lenticels. The disease spots only occurred in the pear epidermis and did not cause pear flesh ulceration. In the late growth and storage period of the pear, the black spots enlarged and slightly sunken. Black spot disease mainly occurs on pear trees such as emerald and yellow crown.

Pear black spot disease

I. pathogenic factors

According to the research and investigation, the climatic conditions in June and July of that year are directly related to the severity of pear black spot disease sooner or later. The main causes of black spot disease are too high air humidity and humidity in the fruit bag, more rainy days, heavy precipitation and serious disease. On the contrary, the disease is mild or not easy to occur. Through the investigation, it was found that the worse the air permeability of the fruit bag was, the higher the incidence of black spot disease was, and the higher the incidence of black spot disease was in the pear orchards with high humidity, poor ventilation and light transmission, serious sealing and partial application of nitrogen fertilizer.

II. Prevention and control methods

The prevention of pear black spot disease should be given priority to, and the management of pear orchard should be strengthened.

1. Strengthen pear orchard cleaning, clear pear orchard with broad-spectrum fungicide Mengfuli (80% mancozeb) or pure spot wheel (80% tebuconazole) all pear tree spray; pear orchard diseased branches should be cleaned up.

two。 Pruning the pear orchard well can improve the light and air permeability of the pear orchard and reduce the humidity in the orchard.

3. Supplement calcium in the young fruit stage, spray organic calcium before bagging pears, once every 7-10 days, 2-3 times in a row

4. Do a good job in drug prevention, timely use Mengfuli 600,800 times liquid after pear blossom, before bagging, make efficient fungicide, spray interval less than 10 days before bagging, at this time you can use 1000-1500 times liquid of Ye Huimei (25% pyrimidyl ester), spray quality and quantity, uniform and thoughtful, fruit surface and pear leaves should be sprayed on both sides.

5. Bagging in time, when bagging, choose the fruit bag with good air permeability and light transmittance.