Information on the main wreckers of onions plants is provided in a note: morphological and biological features of development. Measures of fight against them are given.
UDC 632
Onions fly – the wrecker widespread in all zones of cultivation of onions. The doll winters in the earth on depth of 10-20 cm, years of flies of the first generation begins at the beginning of May, 30-40 days proceed. They postpone eggs (till 5-12 piece) under earth lumps, near onions shoots.
Larvae get into an underground part of a bulb through a collum or a neck and eat away all its middle. At the damaged plant leaves at first fade, then turn yellow and dry up, the onions rot, become mouldering, watery with an unpleasant smell. In onions, onions-batun and a leek of a larva develop only in a bulb, in other its types they can leave the struck plants, creeping on others.
After the completion of a food of a larva leave onions and zaglublyayutsya to the soil where pupate. At the end of June – the beginning of July flies of the second generation take off. More all the onions fly strikes sweet grades of this culture.
Onions skrytokhobotnik – larvae are in the middle of an onions feather. Skrytokhobotnik – a bug in length of 2,5-3 mm, black, covered with white cheshuyka. A larva yellowish, legless with the brown head, length to 6,5 mm. Bugs under the vegetative remains, in forest belts, gardens, parks winter. In the spring at t9-120C occupy early crops of onions. Females postpone eggs on inside of a leaf, larvae eat a leaf parenchyma, vygryzy courses. On outer side of a leaf there are whitish, oblong courses, leaves, beginning from above, turn yellow and dry up.
The root onions tick – harms to onions, leek, batunu, to garlic, a lily, a hyacinth, a tulip, a gladiolus. Body of an adult tick light yellow, oval, length of 1 mm. Eggs white, oval, larvae with three, and an imago with four pairs of legs. Lives in open soil, hothouses, storages. Into a bulb gets through a collum, settling between cheshuyka. Therefore bulbs rot. Intensively breeds at t 130S and humidity of air of 70 %.
Onions moth – dolls or butterflies winter on the earth under the vegetative remains. At the end of April – the beginning of May butterflies take off, postpone eggs on the bottom party of a leaf, a neck, flower shooters. Caterpillars get into the middle of leaves, arrows, their development proceeds 12-16 days. Okuklivaniye occurs in a fodder plant. In 10-15 days butterflies of the second generation take off.
Fight measures: observance of crop rotations; early terms of crops, landing; onions warming up before a bookmark on storage at t 35-370C within 5-7 days; onions-seyanki peresypaniye chalk (2 kg/c of onions) – from an onions tick; cleaning of sites of the vegetative remains; deep zyablevy plowing; loosening of row-spacings in landings of long-term onions; periodic survey of crops; in a laying of eggs an onions fly – processing by a tobacco dust of 1-2 kg/10 of sq.m with addition of bitter ground pepper 0,5 teaspoons. Processings to carry out in 7-8 days, two against the first generation, one – against the second.
(On magazine materials Quarantine i a zakhist roslin).