The latest control methods of grey mold of lettuce

The main diseases protecting lettuce caused by Botrytis cinerea tend to reduce the yield by about 30% after occurrence, especially when the overwintering lettuce occurs in spring, the yield can be reduced by more than 50%. So how to prevent and cure the lettuce gray mold? Come and have a look with the editor.

1. Symptoms

In the disease of the seedlings, the seedlings showed water-immersed decay, and there was a gray mildew layer on it. After planting, the disease began from the leaves close to the ground, and the leaves showed water-immersed disease spots at the beginning, and the diseased parts would rapidly expand brown under the conditions of high temperature and high humidity. the base of the diseased leaves will also turn reddish brown, and finally the stem base of the diseased plant will rot and die, causing the aboveground parts of stems and leaves to die.

2. Morbidity condition

Botrytis cinerea is a fungal disease. the pathogen is also read by mycelium, sclerotia and conidia in the residual body and soil. In the coming year, it spreads with the help of agricultural operation and watering, and causes the disease through wound and young tissue lenticel invasion. The disease can occur between 5 and 31 degrees, but the disease is most serious when the air humidity is more than 90 percent and the temperature is between 20 and 25 degrees. The occurrence of Botrytis cinerea is closely related to the development of vegetables and the external environment. When the plant is underdeveloped or in the alternating season of winter and spring, it is easy to occur under the condition of high temperature and high humidity due to too much watering in the greenhouse.

3. prevention and control measures

1. Agricultural prevention and control

The seedbed and seeds should be strictly disinfected before sowing, strong seedlings should be selected when planting, diseased and weak seedlings should be removed, and the row spacing should be kept at 20 × 20 cm. Too thin is not conducive to yield, and too dense will cause excessive plant growth and thin stems. It affects the yield and is prone to disease. Reasonable crop rotation in production can not only ensure strong crop growth, but also improve disease resistance and reduce disease damage. In winter cultivation, we should pay attention to ventilation and dehumidification, heat up the greenhouse after each watering, and then ventilate to effectively reduce the relative humidity of the air in the shed. Fertilization should be based on organic fertilizer, reasonably increase the application of phosphorus and potassium fertilizer, prevent partial application of nitrogen fertilizer, so as to avoid the vegetable body is too delicate.

2. Chemical control

Methyl topiramate, carbendazim and chlorothalonil can be sprayed in the onset of the disease, once every 7-10 days, 2-3 times in a row, and the effect of several agents is better.

The above is the introduction of the prevention and control methods of lettuce gray mold, hope to help you, want to know more related knowledge, please pay attention to us.