The rice blast fungus is a fungus that reproduces through spores.
Rice blast is one of the important diseases of rice, which can cause a substantial reduction in yield. In severe cases, the yield can be reduced by 40% to 50%, or even no harvest. It occurs evenly in all rice regions of the world. This disease occurs in various places, most of which occur in leaves and nodes. After the occurrence, it can cause varying degrees of yield reduction. Especially when ear neck blast or node blast occurs early and severe, it can cause white ears and even the loss of production.
On September 15, 2020, rice blast was included in the "List of First-Class Crop Diseases and Pests" by the Ministry of Agriculture and Rural Affairs of China.
Pathogenic characteristics:
The pathogenic fungus of M. oryzae belongs to the genus Piriformospora and the family Piriformaceae. The asexual stage of rice blast pathogen (under natural conditions) is Pyricularia cinerea (scientific name: Pyricularia oryzae Cav.), which belongs to the genus Pyricularia of the genus Pyricularia.
The sexual stage (the sexual generation formed after mating with different strains on artificial culture media) is Magnaporthe grisea Barr. The spp.
It has not been found under natural conditions. Conidiophores are unbranched, with 3-5 roots in clusters, protruding from the host epidermis or stomata, size 80-160×4-6 (μm), with 2-8 septa, the base is slightly enlarged, light brown, and colored upward Pale, top curved, with conidia.
The conidia are colorless, pear-shaped or club-shaped, often with 1-3 septa, size 14-40×6-14 (μm), with foot cells at the base, and the cells at both ends stand up when they germinate. The germ tube produces an appressorium at the top of the germ tube, which is nearly spherical, dark brown, and closely attached to the host, producing invading filaments to invade the host tissue. The bacteria can be divided into 7 groups and 128 physiological races.