How to prevent and cure tea wheel spot disease?

Tea ring spot disease is a common disease in tea garden, also known as tea shoot blight. The pathogen is Phaeosporium campestris, which is a high-temperature and high-humidity disease. It occurs in all tea-producing provinces across the country, causing a large number of damaged leaves to fall off, causing withered shoots, resulting in a decline in tree potential and a decline in yield. let's take a look at how to control tea ring spot.

Conditions for the occurrence of tea ring spot

Tea ring leaf spot is a high temperature and high humidity disease. The temperature is 25: 28 ℃ and the relative humidity is 85: 87%. It occurs heavily in summer and autumn. In production, tea gardens with many tea pests such as plucking, mechanical tea picking, pruning, summer cutting seedlings and tea pests are easy to occur. The tea garden has poor drainage and the cuttage nursery which is too densely planted is seriously affected. There were significant differences in disease resistance among varieties. Phoenix daffodil, Xiangbo green and Yunnan big leaf species are prone to disease.

Symptoms of tea ring spot disease

The main results are as follows: 1. Tea ring spot is mainly harmful to leaves and new shoots, and young leaves, adult leaves and old leaves are all diseased. Yellow-green small disease spots are first produced on the leaf tip or leaf edge, and then expand into large round to oval or irregular brown disease spots. The disease spots on adult leaves and old leaves have obvious concentric lines, and in the later stage, the disease spots become gray in the middle, and there are small black spots arranged in ribs with high humidity, that is, the fruiting body of the pathogen.

2. When the young leaves get sick, they gradually turn dark brown from the leaf tip to the leaf edge, the disease spot is irregular and scorched, the spot is scattered on the front of the disease spot, there is no wheel pattern on the disease spot, and the disease spot often fuses with each other, so that most of the leaves are covered with brown spots. The tip of the shoot infected with the disease first became sick, then blackened and withered, continued to expand downward, resulting in branch blight, and when it was serious, a large number of leaves fell off or the cuttings died.

Prevention and control of tea ring spot

1. Choose Longjing long leaf, rattan tea, Yinxiang tea, hairy crab and other more disease-resistant or disease-tolerant varieties.

2. Strengthen the management of tea garden, prevent stroking or forced picking, and do everything possible to reduce the wound. After machine picking, pruning and discovering pests, fungicides and insecticides are sprayed in time to prevent the invasion of germs. Timely drainage after rain to prevent moisture retention can reduce the incidence of the disease.

3. Enter the disease period, spray 1500 times of 50% carbendazim wettable powder or 50% carbendazim (carbendazim) wettable powder 1000 times, 25% carbendazim wettable powder 1000 times, 80% carbendazim wettable powder 1500 times, 75% chlorothalonil wettable powder 1500 times, 36% thiophanate suspension 700x, control once every 14 days for 2 consecutive times.