How to prevent and control sclerotinia rot in celtuce? Latest technical method tutorial

Celtuce, also called lettuce, is a popular market crop with a relatively high demand for fertilizer. Many farmers grow it, but during cultivation it is harmed by various pests and diseases, among which sclerotinia rot is one of the more serious ones. Once infected with this disease, it will severely reduce the yield and quality of lettuce, and in severe cases cause total crop failure. So how should lettuce sclerotinia rot be prevented and controlled? Let us learn about it together.

1. Disease symptoms

In the early stage of the disease, the base of the plant stem is affected first. The lesions are initially brown and water-soaked, then gradually expand to the entire stem, causing the stem base to become soft and rotted. The affected parts of the disease are also densely covered with cotton-like white mycelium, and later sclerotia are produced. Sometimes the stem base also shows cracking symptoms. The sclerotia are initially white, then gradually become mouse-dropping-like black granular bodies. The rot caused by sclerotinia rot usually has no foul odor, which distinguishes it from bacterial soft rot. After lettuce is infected, the lower leaves of the plant become soft and brown, and the disease develops upward. The upper leaves wilt in a green-wilted state. When the stem is affected, the plant grows poorly, and in severe cases the whole plant dies or lodges.

2. Disease occurrence pattern

The occurrence of lettuce sclerotinia rot is greatly related to climate and field management level. The pathogen can spread through airflow, rainwater and farming operations. Sclerotinia rot prefers warm and humid environments. A temperature of around 20 degrees and humidity above 80% are favorable for the occurrence of this disease. When the temperature is above 35 degrees, the disease is less likely to occur. In low-lying plots that easily accumulate water, field humidity is high, and the incidence is also relatively high. When planting is too dense, and if old leaves at the base, diseased leaves and weeds are not removed in the middle and late growth stages, this also favors the occurrence of the disease.

3. Prevention and control methods

Diseased fields should be rotated with grass-family crops, or during summer high-temperature fallow, flooding irrigation can be used to soak the field, and greenhouses can be sealed at high temperature, which can reduce field pathogens. Strengthen field drainage, plant at a reasonable density, pay attention to opening ditches for drainage, timely remove diseased leaves and diseased plants, increase air permeability and reduce field humidity. Seeds can be rinsed with salt water or ammonium sulfate aqueous solution, then soaked in 55-degree warm water for 15 minutes for disinfection. In the middle and late growth stages, the disease is very likely to occur. Chemicals can be sprayed on the stem base, old leaves and the ground, and sprayed again after 7 days for better control. However, attention should be paid to rotating pesticides and to the pesticide safety interval.

The above is an introduction to the prevention and control techniques for lettuce sclerotinia rot. We hope it can help you. For more related knowledge, please stay tuned to us.