The difference between potato early blight and late blight: 1. Judging from the time, early blight occurs in the early stage, late blight occurs in the late stage. 2. Distinguish from the symptoms: potato early blight is mainly caused by Streptomyces australopithecineus, which can occur in the leaves, but also infested with tubers. Leaf staining spot black brown, round or subround, with concentric whorls, size 3 ~ 4mm. humidity, the spot on the black mold signs, that is, the pathogen fungal conidiophores and conidia. Severe leaf drying and shedding, field plants into pieces of yellow. Tubers infected with dark brown slightly sunken round or nearly round spots, the edge is clear, the skin is light brown spongy dry rot. Potato late blight leaf infection first in the leaf tip or leaf edge water-soaked greenish-brown spots, light green halo around the spot, high humidity when the spot quickly expanded, brown, and produce a circle of white mold, namely, sporangium and sporocysts, especially the back of the leaf is most obvious; dry spot brown and dry, brittle and easy to crack, no white mold, and the expansion of the speed is slowed down. Stem or petiole infected with brown spots. The onset of serious leaf drooping, curling, and ultimately lead to the whole plant black rot, the whole field a scorched, emitting a rotten odor. Tubers are infected with brown or purple-brown spots, slightly sunken, the flesh of the potato under the skin of the diseased part is also brown, slowly expanding around or rotting.

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