What are the latest control methods for peanut scab?
During peanut cultivation, various diseases can be encountered. What I want to talk about now is peanut scab, which mainly damages the aboveground stems and leaves of peanuts. This disease is the main disease that harms the leaves and causes the plants to wither and die, so today let us discuss together why it occurs, how it continues to cause damage, how to eliminate it, and how to prevent it from infecting peanuts.
I. Occurrence and spread
Scab is a disease caused by fungal infection. It mainly overwinters on diseased tissue and spreads through wind and rain. Moisture is a prerequisite for infection. Summer is generally the peak period for the disease. Under high-temperature and high-humidity conditions, it reproduces rapidly through conidia and begins to spread and cause damage over a large area. Because the spores reproduce in large amounts and quickly, and the incubation period of the disease is short, the disease can cause repeated infections.
II. Infection symptoms
This disease mainly infects the leaves and stems of peanuts. After initial infection, yellow-brown spots of irregular shape form on the leaf surface, with sunken centers. The spots formed on the underside of the leaves are also irregular with sunken centers, except that the lesion color is light reddish-brown. When the stems and leaf stalks are affected, nearly circular lesions are produced, and the lesions gradually expand into large lesions, causing the aboveground parts to wither and die.
III. Control methods
1. Crop rotation
Rotation or intercropping with grass-family crops can reduce the source of inoculum and prevent occurrence. Even if you do not rotate crops, try not to continue planting in the same field.
2. Cleaning up
After harvest, all aboveground stems and leaves should be gathered and burned so as not to give the pathogen a chance to overwinter, and to prevent it from continuing to cause damage the following year.
3. Fertilizer and water
In rainy seasons, be sure to prevent water accumulation from causing excessive soil and air humidity, which can promote the spread of the disease. Apply less nitrogen fertilizer and more phosphorus and potassium fertilizer, and supplement trace elements to enhance resistance.
4. Spraying
When preparing the land, spray the corresponding pesticide to sterilize and prevent disease, then expose the field to the sun for a few days before sowing. Seeds should be disinfected to avoid carrying pathogens. After emergence, first spray Syngenta “Amistar” and DuPont “Vertisan” to prevent disease. If disease is found, use a 1500-fold solution of 50% carbendazim wettable powder for control. If the disease is severe, use a 1500-fold solution of 30% difenoconazole·propiconazole for spraying treatment. Preventive spraying can be done only once, but for treatment it must be sprayed three times consecutively at three-day intervals for good results.
With peanut scab, prevention is the priority, so be sure to start prevention at sowing and planting time before it occurs. If prevention is possible, it is best not to use medication first, to reduce residues. However, if the disease occurs, it must be controlled and eliminated quickly. If it cannot be controlled, switch medications and use them alternately, spraying several more times for control.