Currently, in connection with the outbreak of the tomato yellow curl virus (TYLCV) in South Dagestan, there is an unhealthy hype. Seed companies decided to use it to promote more expensive hybrids with resistance throughout the South of Russia. What is the real biology of the yellow curl virus and the real, not imaginary dangers of the spread of this virus in the South of Russia?
Tomato yellow curl virus belongs to the group of begomoviruses, distributed throughout the southern part of Eurasia, Africa, the Americas, etc. Spread only by the tobacco whitefly Bemisia tabaci and Bemisia argentifolii. Inside the whitefly, the virus remains active for about 30 days. The first cases of this disease were noted back in the “zero” years in the area of the village of Pavlovskaya, where trucks carrying tomatoes from Turkey were aired. However, the disease did not spread in the Krasnodar Territory.
Based on our climatic conditions and the persistence of the virus in the carrier for about 30 days, it should not have created a problem even in South Dagestan. For example, I will cite the situation in India, for example, in the state of Karnataka, where the tomato is grown all year round, this is the most severe disease, and in the state of Maharashtra, where the tomato is grown seasonally, it is not a particular problem. Although, both there and there are approximately the same tropical climate and the whitefly is active throughout the season.
Why then has TYLCV become such a devastating disease in Southern Dagestan? The first is the importation of infected seedlings from Azerbaijan, the second is the low level of agricultural technology and plant protection, and the third is the presence of a transitional turnover. Moreover, the second and third are the defining and main reasons for the spread of TYLCV. It turns out that greenhouse "combines" are the main reservists and distributors of the virus. Accordingly, in those regions where there is no transition turnover, the distribution of TYLCV is impossible. So, in the mountainous regions of Southern Dagestan, who grows seedlings on his own, he does not have problems with this phenomenon. Therefore, Northern Dagestan, Kabardino-Balkaria, the Chechen Republic, the Krasnodar Territory and other regions have nothing to fear.
Last, in regions where TYLCV is not a problem, growing tomato hybrids with resistance to this virus is not economically justified, because these hybrids are more light-demanding and late-ripening, less productive, and seeds are more expensive.