Causes of Black Bottom in Persimmons and Control Methods

Persimmon is a berry-type fruit of the Ebenaceae family. The ripening season is around October. The fruits come in many shapes, such as spherical, oblate, nearly conical' square, etc. Different cultivars range in color from light orange-yellow to deep orange-red, in size from 2 cm to 10 cm, and in weight from 100 g to 350 g. It originated in China and has been cultivated for more than a thousand years. Persimmon is the fruit produced by an important widely planted fruit tree. The main growing areas are the mountainous regions of Henan, Shanxi, Shaanxi, Hebei and other places. Persimmons were introduced to France and the Mediterranean countries in the 19th century, and later to the United States. The fruit of the persimmon tree is about 5 to 8 cm in diameter, yellow to red. Persimmons contain vitamin A and a small amount of vitamin C.

When the persimmon fruit is nearly ripe, the tail end of the fruit (commonly called the bottom) becomes diseased, forms a lump and turns black, then releases ethylene and rapidly turns red, softens, rots and drops off, while the leaves basically show no symptoms. The symptoms of this disease are similar to those of anthracnose and scab, so some people consider it acute anthracnose.

Integrated control methods

In view of the pathogenesis of this disease, over the past three years the author carried out integrated control trials on his own orchard and the production base of Guilin Gaoyoumei Center, with remarkable control efficacy. The methods are as follows:

1. Apply more farmyard manure and potassium fertilizer, and less chemical nitrogen fertilizer. For mature fruit trees, 1 month before the fruit swelling stage, apply 2~10 kg of chicken manure and 0.1~0.2 kg each of potassium sulfate fertilizer and calcium magnesium phosphate fertilizer per persimmon tree.

2. During the young fruit stage of persimmons, broadcast 100 kg of lime powder and 20 kg of sulfur per mu to improve the soil and promote the absorption of trace elements. This method can also control anthracnose.

3. Spray on the leaves or apply to the roots trace element fertilizers such as calcium, molybdenum, magnesium and iron. Apply 10~20 kg per mu of trace element fertilizers such as zinc, molybdenum, calcium, magnesium and iron to the roots. Spray on the leaves the special leaf fertilizer formulated by Guilin Gaoyou Agricultural Center for the control of persimmon black bottom disease, starting before the persimmon blooms, once a month for 3~4 consecutive sprays.