Currently, as the second wave of the novel coronavirus disease (COVID-19) continues across India, the tomato virus is back, wreaking havoc in Ahmednagar, Satara, Nashik, and Pune districts of Maharashtra. Farmers have alleged their otherwise red, juicy tomatoes have turned into yellow and spongy, plastic-textured fruits. This, despite their adopting the recommended guidelines of testing seeds and pest control provided by the public and private sectors, write G.K. Mahapatro, K. Chandrashekar, and Rahul Ghadge on downtoearth.org.
In June last year, multiple viruses had attacked tomato crops in this region. Samples examined from Satara and Ahmednagar were found to be infected with Cucumber Mosaic Virus (CMV), Groundnut Bud Necrosis Virus (GBNV), and Tomato Chlorosis Virus. “One of the factors for the extensive spread could be a change in climate and cultivation time,” the Indian Institute of Horticultural Research-Bengaluru had maintained.
Maharashtra farmers start growing the summer tomato crop in February and the first harvest commences from late April and continues to cater to the market demand till July. Last year, farmers in the Pune, Satara, Ahmednagar, and Nashik districts complained of early ripening and substantial yield loss.
Many of the viruses transmitted by aphids stay in stylets (mouthparts) of the insects for a short span and their short probe/feeding is sufficient to spread the disease. This makes most of the insecticidal treatments useless. However, though private companies conduct several training programs for tomato farmers in affected areas, they seldom cite this cause. Their primary motto is maximizing business. It is high time farmers recognize this hard fact.
The reason behind the suggestion of planting tall barrier crops like maize around the tomato crop is based on some science. The aphid vectors landing on barrier plants lose their viral load from their stylets before they move on to target the tomato crop. IARI-RS, Pune, Pune as well as IIHR-Bengaluru advocate barrier crops.
Maharashtra is witnessing emerging threats in the form of the Solanum whitefly (Aleurothrixus trachoides) in tomatoes, potatoes and bell peppers and exotic whitefly (Paraleyrodes minei) infestation in several fruit tree crops. Clearly, climate change is causing the shifting of the pest spectrum. This demands more research.
There is no cure for viral diseases. Hence, prevention is the best policy. Seed-borne viruses must be given due attention. Quality seeds from reputed sources must be procured. Resistant/tolerant varieties must be adopted if available.
Read the complete article at www.downtoearth.org.in.