In article the description of damages of plants is given by a stem nematode. Methods of fight against this wrecker are specified.
Stem nematode or ditilenx (Ditylenchusdestruction) – a parasitic worm of a threadlike form, length no more 1mm. The nematode only in living, healthy tissues of a tuber breeds at temperature 10… 15oS for one and a half month, at 20. 25oS – in three weeks. To find it it is possible on border of the healthy and struck fabrics. If potatoes are struck with wet decay or fitoftorozy, the nematode there isn’t present.
Defeat by a stem nematode similar to dry decay. The tuber becomes dry, wrinkled, on its surface are formed brown with gray or metal shine of a spot and a crack. In some cases the peel lags behind tuber pulp, when pressing fails. For comparison: at a mushroom infection the peel is covered with small pillows dispute, emptiness are filled with a mycelium of white, yellow or pink color (fuzarioz) or is penetrated brown and rusty tyazhami which get in a tuber (fitoftoroz). The site damaged by a stem nematode is at a tuber surface, deep into doesn’t leave.
The main sources of infection – a seed material and the soil. During vegetation the nematode from tubers gets at first into sprouts, stalks, stolony, then again in tubers. However the nematode is capable to occupy young tubers directly from the soil. About 70 types of plants on which the stem potato nematode lives are revealed. This type of a nematode strikes also a tomato, an eggplant, pepper, haricot, onions and garlic, pumpkin, peas and oats. The wrecker remains on the vegetative remains of corn, a clover red, buckwheats, on root crops of a beet, carrots, rhizomes of a rhubarb and irises, bulbs of gladioluses and tulips, tubers of dahlias. Except these cultures the nettle, a plantain, a lupine, a dandelion are damaged also – in them adult individuals remain till the next season. If to feed the infected plants or crude potatoes an animal, the wrecker will get
with manure to the soil. Therefore compost and humus is more preferable some fresh manure. In certain cases the nematode is extended by Colorado beetles who eat since the beginning on infected, and then on healthy plants. To get to a nematode into tubers provolochnik help also.
If on a site it is a little parasites, external signs of defeat aren’t appreciable. Only in a peel of separate tubers it is possible to find small light brown spots with white, as a powder, contents.
At a bookmark on storage of struck for 15-30 % food or seed potatoes epifitotiya of development of a nematode can already be observed. In a storage time, and sometimes already and when harvesting, on tubers are formed pressed, lead-colored color of a spot which can merge. The surface of a tuber seems to the touch elastic, as a dry sponge. Then the thin skin fissures, shelled, defeat extends on all tuber, and on its longitudinal section the struck part lags behind the healthy. And as a result the tuber completely collapses.
The nematode well transfers a cold snap and low temperatures. During a drought it becomes covered by a thick cover and with ease transfers adverse external conditions. Therefore ditilenx everything is more strongly carried about the country, grasping regions with the most different weather conditions.
The actions limiting and preventing distribution of a nematode
Landing of potatoes is necessary for carrying out only a healthy material. In the spring tubers warm up previously at temperature 18oS in a sunny weather within 11 days, and tubers with dark stains vybrakovyvayut. On a former place potatoes return not earlier than in 4 years. If there is a suspicion that the site is infected with a nematode, it is necessary to exclude cultures struck by the wrecker from a crop rotation.
It is desirable to sow wheat, a rye or krestotsvetny cultures on a site. The weeds growing about potato fields are necessary for mowing or processing herbicides.
It is necessary to select rather steady grades of potatoes – the Spark, Speed, the Katyusha, the Northern rose, the Willow, the Orbit, Ulyanovsk. Early grades are surprised more strongly.
Increase stability to a nematode introduction of ammoniac saltpeter (60ú/sq.m), increase of doses of phosphorus (120ú/sq.m) and potassium (180ú/sq.m).
Dug-out potatoes dry and touch. The container and a cellar before a laying of a crop on storage surely are disinfected by 1-3 % ammonia solution, thus strictly observing rules and equipment of safe work with chemical preparations.
In a crop storage time at the increased temperature the nematode is capable to get over from the infected tubers on the healthy. At temperature 2oS this ability sharply decreases, therefore the optimum temperature of storage of potatoes makes: in October – 7oS, in November – 4oS, in December – 3oS, in January-February – 2oS, in March – 3oS, and in April not above 6oS.
(On magazine materials Priusadebnoye an economy).