How to control brown spot of lettuce with watery mildew

Lettuce brown spot damage leaves, the disease spot two symptoms: one is initially water-stained, and then gradually expanded into round or irregular brown to dark gray spots, ranging from 2-10 mm in diameter. One is dark brown disease spot, the edge is irregular, the periphery has water stain-like halo. Dark gray mildew grows on the wet spot, and when it is serious, the disease spot fuses and the leaves turn brown and dry.

Brown spot of lettuce

Lettuce brown spot spread, spread and infected through seed disease and wind and rain. Generally warm and humid, rainy and foggy for a long time is conducive to the prevalence of brown spot. In the lack of soil fertility, lettuce growth is poor, or partial application of nitrogen fertilizer, overgrowth, will aggravate the disease.

Measures to control brown spot of lettuce:

(1) before soil preparation, clean the countryside first, and after turning the land deeply, apply appropriate amount of lime and sufficient organic base fertilizer.

(2) during the period of planting management, attention should be paid to rational irrigation, nitrogen, phosphorus and potassium should be rationally matched with topdressing, and foliar fertilizers such as phytoprotegerin and Lufengsu should be sprayed to make lettuce grow healthily and improve its resistance.

(3) before long sealing of lettuce or in the early stage of the disease, pay close attention to spraying. Choice of agents: chlorothalonil or chlorothalonil (40% suspension) 600x, chlorozole (50% polysulfide wettable powder) 1000 times, methyl topazone or promethazol (70% ultrafine compound wettable powder) 1000 # 1500 times, promethazine (50% wettable powder) 1500 times, Xinerpu (65% wettable powder) 400x, Baoning (60% Dofu wettable powder) 600800 times. Spray every 7-10 days for 2-3 times in a row.