Mass rotting of stored potatoes is not expected in Ukraine this winter despite summer weather damage to individual tubers, according to Tetyana Oliinyk, a candidate of agricultural sciences and deputy director for scientific work at the Institute of Potato Farming of the National Academy of Agricultural Sciences.
Speaking to news outlet Glavcom, Oliinyk explained that while localized cracking and mechanical injuries could leave certain tubers vulnerable to disease and bacterial infection, Ukraine will avoid a repeat of last year's widespread storage losses.
Heat waves and dry weather across Ukraine suppressed classic late blight, known scientifically as phytophthora, which requires cool and humid conditions to spread rapidly. Although late blight appeared earlier in the season, drought conditions forced the fungal disease to recede.
In contrast, dry summer weather accelerated the spread of alternaria, also called dry spot disease. Agricultural inspectors and farmers also recorded occurrences of potato scab and fusarium wilt across individual growing plots.
Sudden weather shifts further complicated growing conditions. In regions where heavy downpours followed prolonged periods of intense heat, potato plants experienced secondary growth, causing tubers to crack and opening paths for bacterial infections.
Harvesting techniques and storage risks
To prevent losses during winter storage, Oliinyk recommended selecting smooth potatoes that show no signs of cracking or mechanical damage. She noted that overall rot risks will depend heavily on the harvesting techniques employed by growers.
Following the removal of potato haulm, farmers must wait at least 10 to 14 days before digging up tubers. This period allows the potato skin to fully form and toughen, protecting crops from mechanical trauma during extraction.
If extreme heat causes potato vines to burn out prematurely and harvesting begins too quickly, skin fails to develop properly. Mechanical injuries sustained during rapid digging subsequently cause potatoes to rot during winter storage.
Specialized agricultural enterprises generally follow strict cultivation and harvesting protocols, including chemical desiccation and mandatory waiting periods prior to digging. These professional measures are expected to significantly reduce crop losses during the winter months.
Impact on potato size and market prices
Weather challenges during the late summer months are also expected to influence crop yield composition and retail market prices in Ukraine.
Oliinyk previously stated that a severe moisture deficit throughout July and August could increase the proportion of small potatoes in this year's harvest. A shortage of large tubers, combined with the additional labor costs required for sorting, is likely to push consumer prices higher.
The Institute of Potato Farming, based near Kyiv, operates under the National Academy of Agricultural Sciences of Ukraine to conduct specialized research on potato breeding, seed production, and plant protection. Tuber diseases such as phytophthora, alternaria, and fusarium wilt represent persistent agricultural challenges in Eastern Europe, where fluctuating seasonal rainfall directly influences post-harvest storage stability.
