Late blight is recognized as the most harmful disease of potatoes in most countries of the world. The main danger of infection is the incredibly fast speed of its spread. From single infected plants within one week, the infection can spread to the entire planting area, which, in the absence of protective measures, will lead to the loss of a significant part of the crop. Timely monitoring and effective fungicidal programs for protecting potatoes will help to prevent the development of such a scenario.
According to the All-Russian Research Institute of Phytopathology, agrarians of all potato-growing regions of Russia have to fight against late blight (the causative agent is the oomycete Phytophthora infestans).
Well-developed plants are susceptible to the disease. The pathogen infects leaves, stems and tubers. So, brown growing spots appear on the leaves. On the underside of the leaf around the spot at the border of healthy and diseased tissue in conditions of high humidity, a white bloom appears, representing the sporulation of the oomycete. Spores are carried by rain and wind, and spread to healthy bushes and infect them. In dry weather, the affected tops turn brown and dry, in wet weather they turn black and rot.
On the stems and leaf stalks, the disease manifests itself in the form of dark brown spots. When the infection spreads strongly, the stems become brittle. Often, the primary foci of late blight consist precisely of plants with affected stems. On diseased tubers, slightly depressed, sharply outlined brown spots are formed, the flesh under which has a rusty-brown color. The causative agent of late blight overwinters in the form of mycelium in the affected tubers, as well as in the form of oospores in the soil and on plant debris.
“The primary source of infection can be both seed material and weeds (especially black nightshade),” says Anastasia Ukolova, crop manager at Adam Rus. - The infection can be spread by tomato seedlings, which are also affected by late blight. For this reason, you should not place these cultures next to each other. " “In addition, - the expert adds, - the vector of the disease can be plant debris not removed from the field or discarded tubers left after the bulkhead”. All these factors can aggravate the situation with the spread of infection through the air through oospores.
Errors in the fight against late blight
Despite the widespread popularity of the disease, not all potato growers can effectively fight it. Among the most common mistakes is the late (after the detection of signs of the disease) the start of spraying. Such treatment does not lead to the desired result, since most fungicides have a protective and prophylactic effect. These drugs can help in the early stages of the development of the disease, but are not suitable "to extinguish a fire when it has already flared up."
The second common mistake is to stop spraying early. An unjustified reduction in the number of treatments leads to a weakening of plant protection. The disease can manifest itself at the end of the growing season, which is especially dangerous if the tubers were planned to be stored.
The ill-conceived alternation of fungicides with similar or identical mechanisms of action also leads to big problems. “This is fraught with the formation of resistant forms of late blight,” warns Anastasia Ukolova. "In addition, the wrong sequence of fungicide application on potatoes is already a violation of environmental protection requirements, since exceeding the recommended amount of active ingredients can lead to their accumulation in soil, water and products."
Measures to reduce the damage from late blight to a minimum are well known to all agricultural producers: compliance with crop rotation, selection of disease-resistant varieties, the use of healthy seed and the timely use of effective plant protection products.
Among them is the new fungicide Banjo® Forte from ADAMA. It is a two-component drug based on dimethomorph and fluazinam. A combination of active ingredients, unique on the market, provides reliable protection of potatoes not only against late blight, but also against alternaria, white rot, and also protects onion crops from infection with peronospora.
“Banjo® Forte protects not only leaves and stems, but also tubers at the final stages of the growing season and in the pre-harvest period,” Anastasia Ukolova emphasizes. "This is especially important if the potatoes are to be stored in storage, because the danger of latent infections is the difficulty of detecting them at the stage of harvesting, and their latent presence leads to significant losses during storage."
An important advantage of Banjo® Forte is its effectiveness against all known races of late blight, which makes it an indispensable tool in antiresistant strategies to combat this harmful disease.
The preparative form of the fungicide - suspension concentrate - is easy to use. It does not cause blocking of the spray nozzles and ensures high-quality dissolution of the drug in water. In addition, the drug has a high rain resistance, which gives great flexibility in the timing of chemical treatments.
8 800 30 10 999