Analysis of the Causes of Peanut Rust Occurrence and Spread
What are the causes of peanut rust occurrence and spread? First, peanut rust is a fungal disease caused by Puccinia arachidis. The urediniospores are yellow, round or nearly round, with minute spines on the surface, and each urediniospore has one germination pore on each side of its middle section. Most urediniospores produce only one germ tube, and an appressorium forms at the tip of the germ tube, from which an infection hypha penetrates the peanut. Urediniospores can germinate only in the presence of water droplets or a water film. They have strong tolerance to low temperatures and poor tolerance to high temperatures. Under normal conditions, the germ tube penetrates the internal tissue after 65 hours, the hyphae continue to grow and produce haustoria, and after 7 days, pinpoint-sized white spots appear and begin to produce urediniospores; after 8 days, the white spots turn yellow-brown and form uredinia; after 10 days, the epidermis of the uredinia ruptures and releases urediniospores to continue infection. During the peanut growing period, the expansion and spread of peanut rust are mainly from local inoculum sources, but in the northern peanut regions, there is also the issue of external inoculum sources for the pathogen in early spring. The main factors affecting the occurrence and spread of peanut rust: First, the amount of overwintering inoculum. If the amount of overwintering inoculum is large, peanut rust may occur severely the following year.
What are the causes of peanut rust occurrence and spread?
First, peanut rust is a fungal disease caused by Puccinia arachidis. The urediniospores are yellow, round or nearly round, with minute spines on the surface, and each urediniospore has one germination pore on each side of its middle section. Most urediniospores produce only one germ tube, and an appressorium forms at the tip of the germ tube, from which an infection hypha penetrates the peanut. Urediniospores can germinate only in the presence of water droplets or a water film. They have strong tolerance to low temperatures and poor tolerance to high temperatures. Under normal conditions, the germ tube penetrates the internal tissue after 65 hours, the hyphae continue to grow and produce haustoria, and after 7 days, pinpoint-sized white spots appear and begin to produce urediniospores; after 8 days, the white spots turn yellow-brown and form uredinia; after 10 days, the epidermis of the uredinia ruptures and releases urediniospores to continue infection. During the peanut growing period, the expansion and spread of peanut rust are mainly from local inoculum sources, but in the northern peanut regions, there is also the issue of external inoculum sources for the pathogen in early spring. The main factors affecting the occurrence and spread of peanut rust: First, the amount of overwintering inoculum. If the amount of overwintering inoculum is large, peanut rust may occur severely the following year.
Second, climatic conditions. Under normal circumstances, temperature is not a limiting factor. The dominant factors affecting the spread of rust are rain and fog/dew; the more days of rain and fog/dew, the more severe the occurrence of rust.
Third, cultivation management. For spring peanuts, early sowing results in mild disease and late sowing results in severe disease; for autumn peanuts, early sowing results in severe disease and late sowing results in mild disease; continuous cropping fields have severe disease, while rotation fields have mild disease; paddy fields have severe occurrence, while dry fields have mild occurrence. Fields with excessive nitrogen fertilizer application have severe disease incidence.