Lettuce planting: what is lettuce brown spot?

What is lettuce brown spot? What harm does lettuce brown spot have? How to control brown spot of lettuce? Netizens are also invited to help introduce the harm of lettuce brown spot and its control methods as follows (provided by the farming network). The harm of lettuce brown spot: lettuce brown spot mainly harms the leaf; the disease spot on the leaf shows two symptoms, one is water stain at the beginning of the disease, and then gradually expands into round to irregular shape, brown to dark gray spot, 2mm in diameter; the other is dark brown disease spot, the edge is irregular, the periphery has a water stain halo. When the environmental humidity is high, dark gray mildew occurs on the disease spot, and when the disease spot is serious, the disease spot fuses with each other, causing the leaves to turn brown and dry. The first brown spot symptom is caused by Cercospora lutescens in lettuce, while Cercospora brown spot in banana causes the second brown spot symptom. Lettuce brown spot will lead to aggravation of the disease in continuous rainy and snowy weather, poor plant growth or excessive growth caused by partial application of nitrogen fertilizer. Prevention and control methods of lettuce brown spot 1. Clean the countryside: take the diseased remains out of the garden and burn them in time. 2. rational fertilization: adopt the technology of formula fertilization, increase the application of organic fertilizer, phosphorus and potassium fertilizer, avoid partial application of nitrogen fertilizer, make the plant grow healthily and enhance the disease resistance. 3. Chemical control: at the initial stage of the disease, 40% polysulfide suspension can be sprayed 1000 times, or 75% chlorothalonil wettable powder 1000 times plus 70% methyl thiophanate wettable powder 1000 times, or 50% prohydantoin wettable powder 1200-1500 times, or 60% ethyl phosphine aluminum wettable powder 500x, etc., once every 10 days or so for 2 consecutive times. Stop using medicine 5-7 days before harvest. Click for more lettuce planting techniques click to get more vegetable planting techniques