(2)Main kinds of pathogens in crops Fungi真菌; bacteria细菌; viruses病毒; viroids类病毒; nematodes线虫 large numbers of insect pests害虫 They are generally called biotic stresses or pests of plants(2)Main kinds of pathogens in crops Fungi 真菌； bacteria 细菌； viruses 病毒； viroids 类病毒； nematodes 线虫 large numbers of insect pests 害虫 They are generally called biotic stresses or pests of plants