The comparative study of the potato varieties damage by the click beetles larvae in different agroecological conditions
Some ecology and feeding specialization features of click beetles larvae known as the “wireworms”, with larvae of the field click beetle Agriotes lineatus L. (Coleoptera, Elateridae) as a model object, have been studies. It has been shown that the potato variety peculiarities are among the major factors determining the behavior of wireworms in the food foraging and searching for available water sources. Moreover, the tubers infected by phytopathogens at the early stages of pathogenesis, are more attractive for the wireworms. Among the exogenous natural factors, the plants-precursors and the soil humidity regime in its seasonal dynamics have the most significant influence on the ways of potato plantations colonization by click beetles larvae and on the migrating activity of this species. These factors should be considered for choosing the conditions, methods and the selection criteria for the potato varieties least-damaged by wireworms. In the field conditions, such selection is possible on the experimental plot with the uniform natural colonization by the pests with high or medium density of their population, using the following main criteria for the each variety: 1) a percent of damaged tubers; 2) a total number of tunnels (“worm-holes”); 3) a mean number of tunnels per 1 damaged tuber. For the laboratory evaluation of potato varieties, the non-infected tubers only are suitable. According to the data of annual research of 20-40 potato varieties in 2009-2018 on the experimental fields of VIZR in Pushkin (SPb.) and in Tosno District of the Leningrad Region, the Nayada, Alyi Parus, Liga and Svitanok kievskiy varieties have the group resistance to the wireworms and to the Colorado potato beetle Leptinotarsa decemlineata Say (Coleoptera, Chrysomelidae), whereas the Nevsky variety is among the most intensively damaged by both pests.