Amid reports of dwarfing of paddy plants across the state, the Punjab Agricultural University (PAU) revealed that rice southern black stripe dwarf virus (SRBSDV) was the cause.

This is the first incident of the viral disease, a double-stranded RNA virus that was originally reported in 2001 in southern China, Punjab,

After moderating a lecture with the experts on Friday, UPA (VC) Vice Chancellor Dr. Satbir Singh Gosal shared that SRBSDV is the real cause of stunting in rice. Punjab Department of Agriculture and Farmers Welfare Director Dr. Gurvinder Singh, PAU Research Director Dr. AS Dhatt, other Research Directors Dr. PPS Pannu, Dr. GS Mangat and rice scientists were among those present at the conference.

Dr Dhatt explained that rice cultivation in Punjab has been known to be affected by many bacterial and fungal diseases in recent times, but it was in mid-July this year that UPA started receiving complaints. about stunted rice plants in farmers’ fields. Within a month, complaints were received from almost all parts of Punjab and neighboring states.

Experts said infected plants were stunted with narrow, erect leaves, with plant roots and shoots severely affected. In severely infected rice fields, infected plants showed wilting. The height of stunted plants showed a reduction of 1/2 to 1/3 compared to normal plants. These plants had shallow roots and could be easily uprooted. These plants have been observed in almost all varieties grown in farmers’ fields.

The team of UPA scientists traveled to different districts of the state to systematically decipher the cause of these stunted rice crops. Laboratory analysis revealed the presence of Southern Rice Black-streaked Dwarf Virus (SRBSDV) in the analyzed samples. To further confirm the presence of the virus, the molecular marker amplified DNA fragments from the samples were sequenced. Sequence data analyzed using online genomic databases showed greater than 99% similarity to previously reported/published SRBSDV sequences. Sequence data was also submitted to the National Center for Biotechnology Information (NCBI), an international genomics database.

In the trials conducted by the university, it was observed that the incidence of stunting was associated with the date of transplanting, as it was greater in the transplanted culture between June 15 and June 25 than in the transplanted culture. after June 25. The team observed that the incidence was more pronounced in early-sown rice fields, regardless of the variety. Analysis of soil and plant samples taken from affected fields showed no relationship between stunting and nutrient deficiencies.

According to previous scientific reports published elsewhere, SRBSDV is transmitted by the white-backed leafhopper (WBPH) in a persistent, circulatory and spreading manner. WBPH nymphs can transmit SRBSDV more efficiently than their adults. Long distance transmission of this virus can occur through the migration of WBPH with typhoons and strong convective winds. Viruliferous WBPH nymphs and adults can transmit SRBSDV to rice plants at different growth stages.

Dr. Gosal commended the team of rice farmers, especially the lead plant pathologist, Dr. Mandeep Singh Hunjan, for cracking the mystery of stunting in rice in the shortest possible time.

UPA publishes a notice to farmers

Experts have said that in the absence of remedial measures for viral diseases, the only way out is to adopt preventive measures to manage the vector of this viral disease. In issuing a notice to farmers, experts said farmers should regularly monitor the rice crop for the presence of WBPH. A few plants in the field should be tilted slightly and tapped 2-3 times at the base at weekly intervals. WBPH nymphs/adults, if present, will be seen floating on the water.

Additionally, farmers are advised to spray any of the insecticides by observing the WBPH viz. Pexalon 10 SC (triflumezopyrim) @ 94ml/acre or Osheen/Token 20 SG (dinotefuran) @ 80g/acre or Chess 50 WG (pymetrozine) @ 120g/acre. For best results, direct the spray towards the base of the plants.

The experts further advised to follow the transplanting dates recommended by the UPA as stunting has been observed to be greater in early transplanted crops. This will not only help manage viral disease, but also save water.

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