Potato (Solanum tuberosum L.) is one of the most popular crops in the world. About 40 phytopathogenic viruses have been identified on potato in various countries and regions with various natural and climatic conditions. The situation is compounded by the fact that many viral infections persist and accumulate in wild and weedy plants. The viruses spread speed depends on the transmission method, the quickest virus transmission method being flying insects. We have identified 27 species of wild weeds from 13 botanical families. PLRV potato virus (potato leaf roll virus) and PVY (potato virus Y) were detected on the perennial sow thistle (Sonchus arvensis). On the wild camomile (Tripleurospermum inodorum) - PVS (potato virus S), belonging to the Flexiviriadae family, genus Carlavirus. The PVY virus was found on meadow clover (Trifolium pratense typus L.), wild spin (Chenopodium album L.), dooryard plantain (Plantago major L.), upland cress (Barbarea vulgaris W.T.Aiton), ragweed (Ambrosia artemisiifolia L). Potato mosaic group viruses were detected by PCR method in Lygus pratensis and Henosepilachna vigintioctomaculata. Thus, it was identified a pathobiocenosis that includes pathogens – PVY, PVS, PLRV, vectors – Lygus pratensis and Henosepilachna vigintioctomaculata and susceptible to infection organisms, which are wild weeds – Sonchus arvensis and Tripleurospermum inodorum, Trifolium pratense typus, Chenopodium album, Plantago major, Barbarea vulgaris, ambrosia artemisiifolia are virus reservoirs.

Relevance. Late blight (Phytophthora infestans Mont. de Bary) is one of the most harmful, rapidly spreading potato fungal diseases, which dramatically reduces its yield and affects tubers during storage. The quantitative manifestation of partial resistance within the same potato variety depends on meteorological conditions and the infectious load. Therefore, its objective assessment is obtained when testing varieties in regions that are stably favorable for the development of pathogens (Sakhalin Island and central Mexico), or in standard laboratory conditions using climatic chambers and molecular genetic methods. The aim of this work was a laboratory assessment of the potato varieties and hybrids resistance to late blight.Methods. Data on laboratory assessment of the potato varieties and hybrids resistance to late blight are presented. The experiment was carried out using generally accepted methods for the study and assessment of the potato varieties resistance to phytopathogens with minor modifications.Results. It was established that the varieties Smak, Yantar, Dachny and Kazachok are medium susceptible to late blight, as shown in the Catalog of varieties. In the variety specimen Pri-12-35-4, with a low degree of necrosis and sporulation development, slices showed damage to 50% of the tubers surface with active sporulation and maturation of double-flagellated zoospores. Hybrids Pri-11-12-5, Pri-12-18-7 showed a high score for the development of necrosis and sporulation with a slight excess to these indicators for tubers (1.17-1.05 times). Among hybrids and varieties of potatoes, a sample of Pri-11-31-24 stood out, with an average score for sporulation and slice necrosis of 1.44 and 1,42, respectively, for tuber damage - 1,72.

Relevance. Garden strawberry (Fragaria x ananassa Duch.) is one of the most popular and widespread berry crops in the world. One of the reasons for the strawberries low yields is the loss of production from fungal diseases. Especially harmful is pathogens complex affect. One of the fusariosis distinctive features is a specific etiology – the participation of a different types complex of the genus Fusarium fungi in the pathogenic process, which differ in biological properties and are adapted to certain environmental conditions. The pathogen of Botrytis cinerea gray rot parasitizes the culture year-round. Various forms of strawberry root rot caused by pathogens of the genus Phytophthora are poorly studied diseases. Oomycetes of the genus Phytophthora are sources of transient forms of apparently healthy plants withering, associated with the appearance of horns necrosis. These processes occurrence is primarily due to the high harmfulness of these pathogens, that can cause death from 40 to 78% of strawberry plants during the growing season. The object of this work was to establish the species composition of the garden strawberries diseases in the Primorsky Territory and to develop recommendations on measures to control them.Methods. The determination of pathogens was carried out by microscopy and passage of pure culture on differential media (Hella medium, carrot-sucrose agar) according to E. Blagoveshchenskaya (2015).Results. It has been established that in the Primorsky Territory, gray rot, late blight and fusariosis received the highest prevalence among diseases of under coverage strawberry. The causative agent of late blight was previously defined as Phythophtora cactorum (Lebert &. Cohn) Schröd, of the gray rot as Botrytis cinerea, of the fusariosis as Fusarium oxisporum Schlecht. ex Fr. f. sp. fragariae Winks et Williams. Gumat K, Agat-25K, Switch 62.5 WG, Teldor 50 WG are effective drugs to contain its harmfulness and spread. As a result of the measures taken, the spread of the disease decreased to 40%, productivity increased by 1.5 times.

The data on influence of temperature on the duration of egg development and nymphal ages of the field bug Lygus pratensis (Linnaeus, 1758), which is a potato virus vector, are provided. The development of eggs and nymphs of L. pratensis was studied under various combinations of relative humidity and temperature with a constant photoperiod of 16 hours. The thermal constant for the development of bug larvae was found to be 389.1 °C, 394.2 °C, and 445.9 °C, with an average of 410 °C. The optimal temperature range for the field bug is 20-25 °C, with 65% humidity. Within these limits, there was minimal mortality and the most successful ontogenesis.