Устойчивость картофеля к фомозной гнили

The researches results for potato breeding material evaluation on resistance to to phomosis rot (Phoma exigua var. exigua) are presented during 2014-202. There are following results : 57.7% relative resistance to the disease, 38.1% are middle resistant, 4.2% the samples are susceptible to the disease among the received samples from Institute for potato study NAAS of Ukraine and Ukrainian Institute for Plant Variety Examination.

Limitation of the distribution of the latent form of potato phomosis with the use of biofungicides

Goal. To establish the spread of the latent form of the phomosis pathogen in the western region of the Forest-Steppe zone and to study the possibility of crop protection through the use of biofungicides. Methods. In the process of work used laboratory (cultivation of pathogens) and field (analysis, processing of tuber material). Results. The results of research conducted during 2019—2020 to detect latent infection of phomosis rot of potatoes in the western part of the forest-steppe zone of Ukraine (Zakarpattia, Chernivtsi, Ivano-Frankivsk regions) are presented. Within two years, the highest damage to tubers by latent phomosis infection was observed in varieties Yavir and Vodogray in the Ukrainian Carpathians (Ivano-Frankivsk region, Verkhovyna district, Bystrets village; Zakarpattia region, Mizhhirya district, Maidan village; Zakarpattia region, Rakhiv district, Yasinya village; Chernivtsi region, Vyzhnytskyi district, Berehomet village), which reached 25—33 and 21.0—23.0%, respectively. In the plain zone of Chernivtsi region (Hertsaiv district, Bukivka village; Novoselytsia district, UkrNDSKR IZR) a significantly lower percentage of tuber lesions with a latent form of the disease was observed. The minimum rates of tuber damage, both latent form of phomosis and with existing external signs, were observed in the variety Slovyanka and were in the plain zone 4.5—5.5% and 7.0—8.0 in the mountain. When treating tubers with biofungicides, the least pathogen tuber damage was observed in the variants using Trichodermin-Bio, PhytodoDoctor and Planriz, where the number of infected tubers was 10.0, 11.0 and 12.5%, respectively. In the control variant, the percentage of affected tubers with latent form of phomosis was 2.1—3.2 times higher than in the experimental ones. The effectiveness of biofungicides was greatest when using Trichodermin-Bio and PhytoDoctor and was 68.3 and 65.1%, respectively. Less effective drug against the latent form of phomosis, compared with other options was Hetomic, where its technical efficiency was 52.4%. Conclusions. The causative agent of phomotic rot of potatoes (Phoma exigua var. Exigua) in latent form is a widespread pathogen in the western part of the Forest-Steppe zone. To limit the spread of latent infection of phomos, biological drugs Hetomik (0.4 kg/ha) were used, Gaupbsin (5 l/t), Planriz (2 l/t), Trichodermin-Bio (2 l/t), PhytoDoctor (0.3 l/t), which helped to reduce the damage to the tubers by a latent form of the disease by 2.1—3.2 times compared to the control.

Use of cumin and lavender essential oils to control phoma exigua var. foveata on potato during storage

The antifungal activity of essential oils against Phoma exigua var foveata, was investigated by analyzing its inhibitory effect on the gangrene of potato tubers. The results showed that mycelium growth and spore germination of Phoma was suppressed by treatment with essential oils, and the inhibitory effect strongly correlated with the concentration of essential oils used in this study. The effectiveness of post-harvest treatment with essential oils was studied for induced resistance to Phoma rot in tubers of two potato varieties (Kolobok and Sante). The results showed the fungicidal effect of cumin and lavender essential oils against phomosis at concentrations of 0.1, 0.2, and 0.4, significant inhibition of mycelium growth (18.1-100%), and viability of conidia (12.8-100%) compared to the control. Moreover, both oils at a concentration of 0.4% caused 100% inhibition of mycelium growth and spore germination. Treatment with oils at a concentration of 0.01-0.04 l/t significantly reduced the degree of damage to tubers infected with phomosis. However, cumin essential oil at a concentration of 0.04 l/t had the greatest effect 97.1% compared to lavender oil 95.4%.

Methods of inoculation of potato tubers when assessing resistance to Phoma exigua

The results of studies on methods of inoculation of potato tubers when assessing resistance to Phoma exigua. For this is suitable both ways tuber infection, making inokulumu (agar blocks) in the hole and sinking bubbles in the suspension of mycelium fungus.