农作物因农药使用不当而产生药害的情况时有发生,受害植株常出现斑点、黄化、畸形、枯萎、生长停滞、不孕、脱落、劣果等症状。如玉米受到二甲四氯药害时表现为心叶纵卷倒立生长;波尔多液可引起苹果落花落果等。但有时农作物患某种病害,也会表现相类似的症状,如何区别?斑点型药害与生理性病害斑点型药害在植株上分布往往无规律,全田亦表现有轻有重;而生理性病害通常发生普遍,植株出现症状的部位 Crops due to improper use of pesticides produce phytotoxicity often occur, the victim plants often appear spots, yellowing, deformity, withered, stagnant growth, infertility, shedding, bad fruit and other symptoms. Such as corn by dimethyl tetrazolium injury manifested as heart leaf vertical roll upside down growth; Bordeaux mixture can cause apples fall and fall fruit. But sometimes a crop disease, will also show similar symptoms, how to distinguish? Spot type phytotoxicity and physiological diseases Spot type phytotoxicity in plants often irregular, the whole field also showed light weight; and physiology Sexually transmitted diseases commonly occur in parts of the plant where symptoms develop