Control methods of brown rot of papaya with long spot or rot or rigidity of fruit

Brown rot of papaya

First, symptoms: Brown rot mainly harms papaya fruits, but also flowers and tender shoots. Fruit disease, the initial brown nearly round disease spot, and then with the development of the disease, continue to expand, when the conditions are appropriate, expand to the whole fruit, and extend to the pulp, serious, the whole papaya rot. After losing water, the diseased fruit turns brown, hangs on the branch and does not fall for a long time. The bacteria on the pedicel or papaya invade the branches, form brown ulcer spots, affect the normal transport of water and nutrients, inhibit the growth of branches, and cause branches to die.

Second, the law of incidence: papaya brown rot is a fungal disease, the pathogen overwinters on the stiff fruit, and the bacteria on the diseased branches can also be infected after overwintering. In the following spring, after the temperature rose, diseased fruit and diseased branch pathogens produced conidia, which were spread by wind and rain. Around the first ten days of May, when the young fruit was formed, the bacteria mostly invaded from the wound of papaya. Therefore, the insect pest is serious, the insect injury is many, the brown rot is also serious.

3. Prevention and control methods:

1. Deal with the sick and disabled body. After papaya harvest, combined with winter pruning, cutting off diseased branches, picking diseased fruit, concentrated burning, can effectively reduce the source of overwintering bacteria.

2. Chemical control. Spray 5 Baomedu stone sulfur mixture once before papaya germination in early spring; from flowering to harvest from March to April, you can spray 50% carbendazim 500 times or 50% methyl topiramate 800 times every 10-15 days, 2-3 times in a row, can also treat leaf diseases.

3. Prevent insect damage. Peach borer is an important pest that harms papaya. In mid-late June, when the fruit of papaya expands, the female moth lays eggs in the cavities and cavities of papaya. After the larvae hatch, they bite through the pericarp and decay into the fruit. Not only eat the flesh, but also cause insect wounds, which is conducive to the invasion of germs. Control methods: during the larval incubation period, spray 1000 times of crystal trichlorfon or 1500 times of fenitrothion emulsion, once every 7 days, for 3 times.