The Latest Control Methods for Peanut Stem Rot

Peanut stem rot, commonly known as "rotten neck disease", is distributed in all peanut-producing areas across the country. It generally occurs in the middle and late stages. After infection, the plant quickly wilts and dies, and the pods often rot or the kernels fail to fill, causing serious losses. The general field incidence rate is 20-30%, and in severe cases it reaches 60-70%. Especially in peanut plots with continuous cropping for many years, plants may even die in large patches. Let's take a look at the control methods for peanut stem rot!

Symptoms of Peanut Stem Rot Damage

The pathogen invades the plant from the cotyledons or young roots, producing yellow-brown water-soaked lesions at the root crown, which later turn dark brown and cause rotting of the root tissue. In humid environments, the diseased area produces pycnidia (i.e., small black protrusions), the epidermis of the diseased area easily peels off, and the fibrous tissue is exposed. In dry environments, the epidermis of the diseased area becomes sunken and clings tightly to the stem. After infection at the mature plant stage, the entire plant dies within about 10-30 days. The affected area is mostly at the base of the stem near the ground, and sometimes the main stem and lateral branches die sequentially.

Conditions for Peanut Stem Rot Outbreaks

The pathogen mainly overwinters on seeds and diseased plant residues in the soil, becoming the source of infection for the following year. If diseased plants are used as feed or pod shells to feed livestock, the resulting manure, as well as farmyard manure composted with diseased plant residues, can also spread the disease. In the field, the main means of spread is rainwater runoff, followed by strong wind, though pathogens carried during farming operations can also spread the disease. In rainy and humid years, especially when rain occurs during the harvest season, the harvested seeds have a higher rate of carrying the pathogen. Therefore, they are not only the main spreaders of the disease but can also spread it over long distances through seed introduction.

Agricultural Control of Peanut Stem Rot

1. Select superior varieties: Yuhua No. 7, Yuhua No. 8, Yuhua No. 9, and Luhua No. 11 are all good varieties.

2. Manage seeds well: Peanuts used as seeds should be harvested promptly, dried promptly, and stored in a ventilated and dry place to prevent moisture and mold. Before sowing, carefully select and sun-dry the seeds to promote germination and emergence.

Chemical Control of Peanut Stem Rot

1. Seed soaking with chemicals: Use 50% carbendazim wettable powder plus Xin Gao Zhi Mo at 5% of the seed amount, mix with 1.5-2 kg of fine soil, spray water and scatter the chemical in layers, then mix well, promote germination, and sow. This can repel underground pests and diseases, isolate virus infection, without affecting the germination and imbibition function, strengthen respiration intensity, and improve the seed germination rate.

2. Chemical spraying: During the growing period, use 50% carbendazim wettable powder at 600 times dilution or 70% thiophanate-methyl plus 50% carbendazim powder for spraying. Spray once after full seedling emergence and once before and after flowering, or spray 1-2 times in the early stage of disease onset. Using Previcur at 800-1000 times dilution for spraying can also concurrently control peanut root rot, damping-off, leaf spot, and other diseases.