Tomato blight in 2024 came much earlier than in previous years. Potato blight is also starting.

– The plague occurred much earlier this year in field crops than in previous years. Everything is accelerated this year. Such a year – informs Dr. Eng. Sylwia Stępniewska-Jarosz, head of the Plant Disease Clinic and Pathogen Bank at the Institute of Plant Protection – National Research Institute in response to questions from the business editorial office of tvn24.pl. Adding that this disease occurs every year.

– Currently, in this growing season, we know of reports of tomato blight due to P. infestans in the areas of Łowicz, Żyrardów and Lower Silesia – informs Agnieszka Włodarek from the phytopathology laboratory of the Plant Protection Department at the Institute of Horticulture – National Research Institute in Skierniewice, asked by the business editorial team of tvn24.pl. Adding that currently, potato blight on tomatoes has occurred on a small scale compared to previous years. However, as she reports, it rained a lot in the south and north of Poland, so stopping the blight may be a problem there.

It is one of the most dangerous pathogens of tomatoes grown in the field and under cover, causing significant losses or complete loss of crops.

Moreover, as reported by Agnieszka Włodarek, the first symptoms of potato blight were also detected in some regions of Poland.

– The cause of tomato blight is Phytophthora infestans belonging to the Chromista kingdom. It causes a disease called potato blight, which occurs not only on potatoes, but also on tomatoes and other nightshade plants, explains Sylwia Stępniewska-Jarosz. She adds that the most favorable conditions for the development of the disease are cold nights and warm days (temperature range from 10 to 29°C) and appropriate humidity.

As she explains, “for over 150 years, attempts have been made to combat P. infestans, but with little success”. – The course of the disease can be very rapid, especially in crops grown under cover, within a few days the tomatoes can completely wilt, and on the leaves white, delicate spore-forming structures of the pathogen can appear – explains Stępniewska-Jarosz. She adds that symptoms of the plague also appear on tomato fruit in the form of brown or grey-green, oily spots that undergo hard rot. Slightly protruding spots appear on tomatoes that are still green and then they are easy to observe.

In addition, as Sylwia Stępniewska-Jarosz explains, the pathogen is able to survive the winter in the form of hyphae on dead organic tissues left in the field and in the form of oospores. Therefore, it can be reborn the following year on new seedlings.

As Agnieszka Włodarek from the Institute of Horticulture – National Research Institute in Skierniewice adds, the speed of the disease spread and its intensity depend on the weather conditions.

– However, the spread of the plague can usually be prevented – explains Włodarek – The first symptoms of the disease or the moment of threat based on the analysis of weather conditions are the condition for starting protection against the cause of the disease – he adds. He informs that when the first symptoms appear, the plantation should be protected with approved fungicides.

In turn, Sylwia Stępniewska-Jarosz from the Institute of Plant Protection – National Research Institute advises how to protect yourself from tomato disease. Avoid planting plants too densely, planting tomatoes and potatoes next to each other, and also successively growing potatoes after tomatoes in the same place in the next growing season and vice versa. In addition, she adds, infected plants should be removed immediately.