What is a potato nematode?
The potato nematode is a quarantine pest that is a microscopic roundworm. It also infects tomatoes, physalis, eggplant and other plants of the nightshade family. The most common in Russia is the stem potato nematode (dielenhoz). The appearance of the potato nematode can be recognized in the early stages of the disease. At this time, brown spots of various sizes and shapes with a characteristic lead tint are translucent on the skin of the tuber.
The spots spread over the surface of the tuber, the peel lags behind and fails when pressed, cracks appear through which the rotten mass is visible. With a thin cut, small white spots of loose tissue with holes in the middle are visible. The affected tissue is usually near the surface to the vascular ring and does not extend into the pulp. But the tubers are completely destroyed due to secondary infection with dry or wet rot, depending on the humidity in the storage or basement.
The potato nematode persists in planting material and in the soil on plant residues. They are more harmful in years with high soil moisture.
Methods of dealing with potato nematode
To combat this disease, it is necessary in the fall after harvesting the potatoes to dry the tubers well under a canopy for 2-3 weeks (treatment period). Then carefully sort them, removing root crops with signs of infection. For winter storage, only healthy tubers are laid in the bins.
In the spring, before planting, it is necessary to germinate and warm up the planting material and do not use tubers with signs of disease for planting. Agrotechnical measures play an important role in the fight against potato nematodes – removal and burning of infected potato tops on the site, accurate cleaning of garden tools after completion of work.
With a strong contamination of the soil in the fall, nematodocidal preparations are introduced as a control measure for digging: thiazon 40% wettable powder 0.5 kg for every 10 square meters. m, thiourea 30-40 g/sq. m, nematofagin BL, etc.
In some cases, good results are obtained by sowing winter rye after harvesting potatoes, followed by plowing into the soil in spring before planting, as well as sowing white mustard with plowing in autumn before frosts. This method disinfects the soil well.
One of the radical measures to prevent the spread of pests is the cultivation of nematode-resistant varieties. Currently, there are more than 20 resistant varieties to this pathogen, including Crystal (Kaluga experimental station), Zavorovsky, Aspiya, Lukyanovsky, Zhukovsky early (VNIIKH), Pushkinets, Shumirsky 2, Rozhdestvensky, Prigozhiy 2, Belorussky 3, Naroch , Oleva, Nida, Sante, Cardinal, Anosta, Provita, Fresco (Netherlands).
In addition to cultivated plants, the causative agent of the stem nematode can infect weeds growing nearby – woodlice, bedstraw, field thistle, large plantain, chickweed, common dandelion, shepherd’s purse and others that must be removed from the site in a timely manner, since many of the weeds are perennial and ditelenhoz reservation.
Of course, one of the reasons for the accumulation of potato nematodes is the cultivation of potatoes year after year in the same area. Comprehensive methods to limit the spread of the potato stem nematode will help to significantly increase the yield of potatoes in your garden.