What is the cause of apple leaf spot

summary

It is one of the most important leaf diseases in apple orchards in Bohai Bay, ancient Yellow River and Northwest Plateau. It is also the main disease causing early defoliation and affecting fruit yield and quality in Red Fuji apple orchards during rainy summer in 2004. Let's talk about the cause of apple leaf spot.

What is the cause of apple leaf spot

First, the pathogen overwinters mainly in the fallen leaves on the ground. In the second year, it spread through the wind and rain, mainly from the back of the leaf into the leaf.

Second, the most favorite infected leaves are mature functional leaves and weak old leaves. (the main parts of the disease are the crown bore and the lower part, and the young leaves have disease resistance.)

Thirdly, the main infection period of Apple brown spot is from spring to autumn. (the peak of the disease was from late July to September. In the field, the number of fallen leaves is the most in August, and in September, the leaves are all light. New conidia were produced from the diseased leaves and infected repeatedly, resulting in repeated disease

matters needing attention

In rainy season, 43% tebuconazole · fuliku 5000 times or oxime ester · tebuconazole 6000 times, mancozeb 800 times or propanzeb · antaison 800 times, and jiexiaoli 4000 times solution were used alternately for 1-2 times, which could basically control the occurrence of Apple brown spot.