Occurrence and Control Methods of Pinellia Virus Disease

After sowing Pinellia (Pinellia ternata), due to various factors, uneven seedling emergence occurs, with some emerging early and some late; throughout the entire growth stage, seedlings also emerge and die back intermittently.

Newly emerged Pinellia seedlings have small and tender leaves with poor resistance to external conditions; in addition, the period just after sowing and emergence coincides with the peak outbreak of aphids and small brown planthoppers. In Pinellia planting areas, large numbers of aphids and small brown planthoppers fly through the air. As soon as Pinellia seedlings emerge from the soil, aphids and small brown planthoppers immediately fly onto the leaves of the seedlings, sucking nutrients while transmitting various pathogens and viruses carried in their bodies to the Pinellia seedlings. After infection, yellow irregular spots appear on the leaves initially, gradually the leaves become mosaic-patterned, shrunken and distorted, with upward curling, and the plants become stunted and deformed with poor growth, seriously affecting the yield and quality of Pinellia. This disease is called virus disease, also known as leaf curl disease. The root cause of virus disease is mainly transmission by aphids and small brown planthoppers: aphids can transmit yellow dwarf virus, and small brown planthoppers can transmit bunchy dwarf virus. Pinellia plots near roadsides, ditches, riverbanks, wheat fields, cotton fields and vegetable gardens are most susceptible to virus disease infection. Therefore, controlling aphids and small brown planthoppers in advance, and promptly spraying fungicides after consecutive rainy days to prevent diseases, are effective technical measures to fundamentally eliminate the occurrence and spread of virus disease.

Control methods:

1. Choose disease-free plots and areas for planting; medium loam soil is preferred, with a pH of 6.5-7.5.

2. Strictly select high-quality Pinellia seed tubers for planting; Pinellia tubers produced from plots where disease occurred in the previous year and wild Pinellia tubers must not be used as seed tubers. To ensure that Pinellia seed tubers do not carry viruses, disinfect the seed tubers with chemicals before sowing.

3. Apply more fermented and decomposed organic fertilizer, and appropriately apply additional phosphorus and potassium fertilizer.

4. After Pinellia seedlings emerge, promptly and thoroughly eliminate the occurrence and spread of aphids, small brown planthoppers and other pests.

(1) Aphid control: you can use 40% dimethoate or 2.5% deltamethrin or 10% cypermethrin emulsifiable concentrate at 2500 times dilution, once every 7-10 days, alternating spray control.

(2) Small brown planthopper control: you can use conventional pesticides such as chlorpyrifos, pymetrozine and dichlorvos, alternating spray control.

5. From 2 days after discovering aphids and small brown planthoppers on Pinellia seedlings, small yellow spots will appear on the Pinellia leaves; this is the early stage of virus disease. You can use new-type low-toxicity and low-residue agents such as Bingduqing, Keduwei and Duba for treatment, once every 3 days, alternating the above agents for 3 consecutive treatments.