Incidence characteristics and Control of Vertical Blight of planting Cotton

The characteristics of cotton vertical blight: the cotton seedlings were damaged after being unearthed, and at the initial stage, the yellow-brown disease spot appeared near the base of the soil, the disease spot gradually expanded and surrounded the whole base with obvious constriction, and the diseased seedlings wilted and fell and died. After the damage of cotyledons, yellowish-brown irregular disease spots are often produced in the middle of cotyledons, and often fall off and perforate. The disease often leads to the death of cotton seedlings. White and sparse mycelium are often seen at and around the stem base of diseased and dead seedlings and on the soil surface.

Prevention and control methods:

1. Strengthen the management of Tian Wen. It should be ploughed early after emergence, and generally about 70% of the seedlings should be ploughed to loosen the soil, so as to increase the soil temperature, reduce the soil moisture, make the soil loose and well ventilated, which is beneficial to the root development of cotton seedlings and inhibit the root disease. Strengthen pest control, timely seedlings, diseased seedlings, dead seedlings centralized burning, in order to reduce the field infection of germs.

2. Chemical control. Cotton seedlings are prone to diseases under the condition of low temperature and heavy rain, so spraying in time before cold spell and overcast and rain should be carried out at about 80% of seedling emergence, and the times of spraying and the type and concentration of agents should be determined according to the disease. Usage: ① spray. At the initial stage of the disease, 10 ml of 30% Metalaxyl or Metalaxyl + 5 ml of Magic Immortalion or 15 ml of Shenzinmycin + 15 ml of chlorpromaxime was sprayed into a bucket of water (15 kg), the main stem of cotton seedlings was sprayed, and the solution was dropped into the soil along the main stem, with an interval of 10: 15 days, which had a special effect on the control of cotton seedling blight; ② irrigation. At the initial stage of the disease, a bucket of water was irrigated with 15ml of Shenzimycin + 15ml of carbendazim + 15ml of 38% cuproloxil. The root was irrigated 2 times for 3 times with an interval of 5 days. ③ brushing. With 10 ml magical immortal or Shimadan + 5 ml Aidoushou or 15 ml Shenzimycin + 15 ml 38% cuproloxil, for 0.5 kg of water, peel off the soil around the cotton plant to expose the disease spot, brush it with a brush for 2 times in a row, with an interval of 7 days.