The sunflower stem weevil, Cylindrocopturus adspersus LeConte is a quarantine intra-stem pest of sunflower, distributed mainly in the United States, and discovered in the Kherson region of Ukraine in 2020. The objective of this study was to establish a possible distribution zone of this species in Ukraine based on the results of bioclimatic modeling. The model was built by using programs DIVA GIS version 7.5.0 and BIOCLIM, which search for areas that are suitable for a particular organism, through geographic information systems and by comparing the world climate with the climate of areas in which it has already been identified. Analysis of the model shows that in Ukraine the pest can acclimatize in the Kherson region only (zone with up to 2.5% probability). Geographically, the territory is limited to 46−47° of north latitude and to 33−34° of north longitude. It is located on the Black Sea Lowland and covers territory lying no higher than 50 meters above the Black Sea level, whose land- -surface temperature in July averages more than 28°С. The North Crimean Canal and Krasnoznaamyansky Canal pass through the territory, which is limited in the south by Sivash, Karkinitsky Bay and Dzharilgatsky Bay of the Black Sea, in the west − by the Dnipro Delta, and in the north − by Kakhovka Reservoir and Kakhovskiy canal. The analysis of values of climatic predictors for the territories which are suitable for acclimatization of a phytophage demonstrated its high ecological plasticity and potential ability to move not only on coastal territories, but also on territories with a continental climate.

Knowing the tritrophic interactions between plant-virus-insect is important in developing sustainable pest management practices. Myzus persicae is a well-known plant viral vector which can transmit over 40 plant viruses. We studied the impact of Cucumber mosaic virus (CMV) infection in Nicotiana tabacum on the colony development of M. persicae to understand how plant virus infection can affect vector growth and reproduction. Aphid growth, reproduction and fecundity were significantly affected by the virus infection. The mean relative growth rate of M. persicae on healthy plants was 0.29 mg–1 · mg–1 · day–1 and was significantly higher than that of CMV-infected plants (0.23 mg–1 · mg–1 · day–1). In contrast, the percentage of survival was significantly higher on CMV-infected plants. The estimated survival percentages of aphids at 20 days after introduction to CMV-infected and healthy plants were 55.8 and 25.8%, respectively. Therefore, the total population of aphids on CMVinfected plants was significantly higher on the 25th day after the introduction of aphids. The total population of aphids on the CMV-infected plants was 1,225 compared to that of healthy plants which was 713. Similarly, mean fecundity over a 30 day observation period was 61.25 and 35.65 for aphids grown on CMV-infected and healthy plants, respectively. Jasmonic acid (JA) upstream gene OPR3 and downstream gene COI1 was measured to quantify the changes in JA expression in the plants under the virus infection. Both genes tested were significantly downregulated in CMV-infected plants. From our results, it was evident that the JA related insect resistance was reduced in CMV-infected plants and hence aphid colony development was increased.