India - After south, ‘dieback’ virus hits neem trees in Vidarbha

Date:11-30-2021

By Vijay Pinjarkar

After playing havoc in Tamil Nadu, Karnataka, Andhra Pradesh and Telangana, the ‘dieback’ disease affecting neem trees has hit Vidarbha region for the first time.

It is a fungus (Phomopsis Azadirachtae) reported on neem causing dieback in 1998 in the southern states. The fungus infects trees of all ages and sizes and the results are devastating.

Though the disease has not been noticed by common man and farmers or must have been treated as a usual phenomenon, progressive farmer Shrikant Deshpande said during his visit to Akola, Amravati, Yavatmal, and other towns in the region during the last 15 days, it has been observed that many neem trees are drying and leaves have turned brown, including the ones in his farm at Dhamangaon.

“Several neem trees planted by the Nagpur Municipal Corporation (NMC) in the city showed similar symptoms but before making any concrete statement facts need to be scientifically studied whether it is a virus or fungus, and why it has chosen only neem trees. We are in touch with experts from PDKV-run College of Agriculture, Nagpur, and plan to send samples to the National Institute of Virology, Pune,” said Amol Chorpagar, garden superintendent, NMC.

Neem (Azadirachta Indica) is a native tree to India. Neem finds very wide application and both wood as well as non-wood products are utilized in many ways. Neem products have antibacterial, antifungal, insecticidal and other versatile biological activities. However, neem is not free from microbial diseases though having biological activity against various microorganisms. Many bacteria and fungi are known to infect neem. The symptoms of the disease are twig blight, inflorescence blight and fruit rot. The disease results in almost 100% loss of fruit production.

According to a research paper by senior scientist Girish K from Karnataka, the ‘dieback disease’ is more pronounced during August-December, though it can be observed throughout the year. The appearance of symptoms starts with the onset of the rainy season and becomes progressively severe in the latter part of the rainy season and early winter season.

“The terminal branches are mainly affected. The disease results in the progressive death of the tree, year after year. Twig blight is the major symptom and the disease also results in inflorescence blight and fruit rot resulting in almost 100% yield loss. The disease spreads through conidia that are disseminated by rain droplets and insects,” says Girish.

PDKV’s Dr Yayati Tayde, associate dean, College of Forestry, Akola, says, “This is for the first time we have been hearing about the ‘dieback disease’. A scientific study needs to be done by collecting samples as there can be other multiple reasons like lack of moisture and water, damage to roots, girdling, etc.”

Dr Sharad Pawar, an emeritus scientist from BARC, and researcher Shrutika Bagul, says, “Neem is one of the most researched trees. The ‘dieback disease’ is caused by the fungus Phomopis. A team effort is needed to control it. Losing these well-grown trees would mean a huge environmental loss to humans. Herbal solutions can be tried to treat the disease.”

Going through the research papers it has been found that the disease may be due to lack of minerals, water and groundwater pollution while another feels the problem can be solved by spraying Bavistin, a fungicide to be used with insecticides and fungicides.

Environmentalist Prachi Mahurkar says, “I too observed neem trees affected by the disease in my farm in Katol. If it is affecting antifungal and antibacterial trees like neem, one can imagine the strong undercurrents of climate change. At a time when it should be wintry, we are facing the heat. The rains too were prolonged this year. Global warming affecting these trees also needs to be studied.”

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