Causes and control of "black ass" of persimmon

Persimmon is a berry fruit of the persimmon family. The ripening season is around October. The fruit has many shapes, such as spherical, flat, cone-shaped & # 39; square and so on. Different varieties vary in color from light orange to deep orange red, size from 2 cm to 10 cm, and weight from 100 g to 350 g. It is of origin in China and has been cultivated for more than a thousand years. Persimmon is the fruit of a widely planted important fruit tree, mainly planted in Henan, Shanxi, Shaanxi, Hebei and other mountainous areas. Persimmon was introduced into France and Mediterranean countries in the 19th century, and then into the United States. The diameter of persimmon fruit is about 5 to 8 centimeters, yellow to red. Persimmons contain vitamin An and a small amount of vitamin C.

When the persimmon is nearly ripe, the tail of persimmon (commonly known as butt) becomes black, and then releases ethylene to quickly turn red, soften, rot and fall off, while the leaves are basically asymptomatic. The symptoms of the disease are similar to anthrax and scab, so some people think that acute anthrax.

Comprehensive prevention and control method

In view of the pathogenesis of the disease, the author has carried out comprehensive control experiments on his own orchard and Guilin Gaomei center production base in the past three years, and the control effect is remarkable. The methods are as follows:

1. Apply more farm manure and potash fertilizer and less chemical nitrogen fertilizer. One month before the fruit expansion period, each persimmon tree was treated with 2kg chicken manure, 0.1kg potassium sulfate fertilizer and 0.1kg calcium magnesium phosphate fertilizer.

two。 In the young fruit stage of persimmon, 100 kg of lime powder and 20 kg of sulfur were applied per mu to improve the soil to promote the absorption of micro-fertilizer, which can also control anthracnose.

3. Foliar spraying or root application of calcium, molybdenum, magnesium, iron and other trace element fertilizer. Zinc, molybdenum, calcium, magnesium, iron and other trace element fertilizers 10kg / mu were applied to the roots. Foliar application of special leaf fertilizer for prevention and control of black ass disease of persimmon in Guilin Gaoyou Agricultural Center was sprayed once a month for 3 times before flowering.