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. One of the most common diseases of potatoes and other nightshade family species is late blight caused by a pathogenic oomycete of the Phytophthora infestans (Mont.) de Bary. At least 100 species of phytophthora have been described in nature, affecting a wide range of plant species. The phytophthora population is heterogeneous and is represented by races, as well as different types of mating. This leads to a rapid adaptation of the pathogen and the emergence of new, more aggressive, and resistant races. Phytophthora is a parasite, the damage from which cannot be avoided within the organic farming framework. Therefore, it is particularly important to know the pathogenesis and racial composition of phytophthora in each individual region of Solanaceae cultivation.Research methodology. Differentiation and collection of material from the natural population were carried out using potato varieties with known R-genes in the genome. Isolation and introduction into the culture were carried out from leaves with the dampening chambers method, followed by cultivation on nutrient media. The pathogen was identified by microscopic analysis. Culture filtrates were obtained on the liquid nutritious medium, followed by liquid filtration and autoclaving. Phytotoxic activity was determined by the effect on the seedlings of the nightshade, grass, and pea families by the standard method. Molecular genetic analysis of the isolates was carried out by ISSR analysis; the primer, amplification mixture, and temperature profile of the reaction were selected according to the literature data; the calculation of genetic characteristics was carried out using POPGENE software packages.Results. Samples of seven Phytophthora infestans isolates were collected and introduced into culture. As a result of in vitro cultivation, morphological differences were revealed, expressed in the structure and color of the mycelium, the shape of the colonies, the nature of sporulation, the color of the reverse, and the medium under the colonies. The genetic differences of the natural phytophthora material introduced into the culture, collected from potato varieties with single resistance genes (R1, R3, R4), were revealed. Differences in the phytotoxic activity of the studied isolates' cultural filtrates were revealed. The isolated isolates demonstrate differentiation at the phenotypic, genetic and physiological levels, which allows us to speak about their belonging to races.

The 28-spotted potato ladybird beetle is an endemicspecies of the Russian Far East. Nowadays the potato ladybird beetle is widespread across Primorsky and Khabarovsky kray, south Sakhalin, Kunashir Island, and in China, Japan, and India. This paper presents historical data on the dispersal of the potato ladybird beetle in Russia. The first records of the pest presence in the coastal area of Primorsky kray were made in 1929. In the 1950s and 1960s, the pest was observed to inhabit not only the forest steppe zone and the districts adjacent to the taiga in Primorsky kray, but also Khabarovsky kray, Amur oblast and Jewish autonomous oblast. The process of dispersal of the potato ladybird beetle can be divided in several stages: the formation of a new breeding ground, an increase in the size of the pest population, the dispersal of the pest. The range expansion of the potato ladybird beetle can be linked to two facts. First, the land area under potato cultivation increased and neared the breeding grounds of the pest. Secondly, thedietary preference of the phytophagous insect shifted to the new fodder plant. In addition, the development of transportation routes played an important role in the dispersal of the pest. Therefore, anthropogenic factors significantly affected the distribution of the potato ladybird beetle. These factors in combination with a high ecological plasticity of the pest allowed the phytophagous insect to spread across the whole area under potato cultivation in the south of the Russian Far East.

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Background: Henosepilachna vigintioctomaculata is a polytrophic pest, causing the greatest damage to plants from the nightshade family. The study aimed to research the resistance of potato cultivars that are promising for breeding to damage by a potato ladybug in laboratory and field experiments. Methods: In laboratory experiments, the indicators of fertility, mortality and duration of development, morphological anomalies and the effect of potato varieties on the composition of Epilakhna’s hemolymph were studied. The sample consisted of 50 individuals with a slight predominance of females. The experiment used 13 varieties of potatoes. Result: A specific dependence of the frequency of phytophage anomalies on the variety was revealed. The influence of nutrition on survival and the timing of ontogenesis has been established. The results obtained indicate the high breeding value of the material when recommending it for cultivation in regions with a high number of pests, as well as when creating new varieties.