1.僵苗症状植株矮小,生长缓慢,根发黄甚至褐变,新生根少,在苗期和定植前期容易发生。发病原因气温低,土壤温度低,土质黏重,土壤含水量高;定植时伤根过多;整地、定植时操作粗放,根部架空;苗床或定植穴施用未经腐熟的农家肥发热烧根,施用化肥较多,施肥时离根较近,土壤溶液浓度过 1. Stiff Miao symptoms of plant dwarf, slow growth, root yellowing or browning, the new root less prone to early seedling and colonization. The cause of the disease is low temperature, soil temperature is low, soil viscosity, high soil moisture; excessive root injury when planting; site preparation, planting extensive operation, root overhead; seedbed or planting hole without burning rotten roots of farmyard manure, Fertilizer application more fertilizer from the root closer, soil solution concentration too