Onion mol (Acrolepia assectella Zell) is a small night moth, a pest of onions and garlic. Onion mol caterpillars eat the leaves in the form of longitudinal stripes. Let’s analyze how to find it on the shoots of garlic and how to deal with this pest.
Description onion mol
Body length 8 mm onion mol, wingspan 12-14 mm.
The front wings are brown with white transverse stripes and a large white spot at the rear edge of the wing. Hind wings grey, with long fringe. Eggs are yellowish, oval, with a length of 0.4 mm and width 0.2-0.3 mm. Caterpillar length 10-11 mm yellowish — green with brown warts. Pupa with a length of 7 mm dark brown is formed in the web cocoon.
Larvae of the onion mol damage the onion and garlic.
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Onion mol life cycle
Onion mol can hibernate and able adult and pupa in various sheltered places, such as buildings, fences and plant residues.
Adult onion mol becomes active and appears in the spring, when the temperature reaches 10°C or shortly thereafter.
The first flight
After wintering. Approximately will begin in the end of April-beginning of May and ends in mid-May.
After additional feeding and when night temperatures are above 10°C-12°C, females lays eggs on the underside of the leaf, on the neck of the bulb, the flower arrows of onions and garlic. Oviposition continues for 3-4 weeks. Females lay up to 100 eggs, one per plant.
After 5-7 days the eggs appear larvae — caterpillars. They penetrate the leaf tissues of garlic or onion. After a few days, the larvae start moving to the base of the plants, to the place where young leaves are formed. They eat the inner tissue in the form of longitudinal stripes, leaving intact the epidermis of the leaf, which can crack.
After 6-12 days, the active power, the caterpillars crawl to the leaves to form a cocoon on the damaged plants, the weeds or on the soil surface, and pupate there. Development of pupa lasts 9-12 days, depending on weather conditions.
Related to onion mol damage to plants, tend to increase the season progresses.
In cold rainy weather is delayed the development of the mol.
The second period of the summer
The first generation. May begin as early as mid-June to early July and continues until the middle-end of July.
The third period of the summer
The latest, second generation. Usually starts in late July and ends in mid-August.
Due to uneven development in the nature of the generation overlap each other and therefore simultaneously can meet the caterpillars, pupa and imago.
The impact of the mol on onion garlic
Caterpillar onion moth damages the vegetative and generative parts of garlic.
Damaged leaves and shoots wither, collapse and die. The larvae can penetrate the unopened inflorescence and destroy the buds.
Plant growth is delayed and yield reduced.
The leek mol is especially dangerous in weakened, stunted plants.
Onion mole control measures
- crop rotation with return of culture to its former place in 3-6 years
- destruction of plant residues
- deep autumn plowing after harvesting garlic
- placement of crops in areas with good ventilation
Usually onion mol does not fly further than 100-200 m from the wintering grounds. However, it is important to remember that the wind flow can lead to the spread of this pest over longer distances.
Damage to onion and garlic onion mol can be reduced by covering plants with light mesh materials. These shelters can be removed during the day, but for protection from onion mol, they must return before sundown.
The threshold of economic damage to onion mol damage more than 5% of plants with at least one caterpillar.
Insecticides for suppression of onion mol
In particular, for spraying you can use the following drugs:
- Karate Zeon, the production of Syngenta, Switzerland (50 g/l Lambda–cyhalothrin) treatment 0.2 l/ha 2 times in 10 days
- Fastak, produced by BASF, Germany (100 g/l alpha-cypermethrin) treatment of 0.1 — 0.15 l/ha 2 times in 10 days.
On the video the caterpillar of the mol on onion garlic
Posted by: Andrey Marchenko
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