The greatest harm of garlic onion fly deals in may. The struggle is consist in preventive treatment and disposal of infected plants.
Onion fly — description
Onion fly (Delia antiqua Meigen, synonym Hylemyia antiqua).
Its damage different types of onions and garlic. It is light gray in color, 6-7 mm in length and resembles a normal fly.
The male has at the abdomen a pronounced longitudinal dark stripe which is absent in females.
Eggs oblong, 1.2 mm, white. The larva is whitish with a length of up to 10 mm. The pupa is in a fake cocoon (puparia), yellowish-brown, 4-7 mm long.
When an onion fly strikes the garlic
Flies will fly in early May when the sum of effective temperatures 103…141°C (the sum of average daily temperatures above 5°C), which coincides with the flowering of lilacs, cherries, dandelion. Plant garlic during this period can have 2-4 leaves.
Flies of the ongoing 30 to 40 days. They feed on the nectar of flowers and 5-10 days after emergence of females lay eggs in rows or piles of 5-20 pieces. Close to plants in cracks in the soil, on soil, on leaves, in leaf axils and between the dry scales of the bulb.
After 4-6 days at a temperature of 18-21°C and relative humidity of 65-75% of larvae emerge from the eggs. The larva immediately penetrates the fabric in juicy garlic often using the base of a leaf, sometimes through bottom.
The larva develops in the plant for 2-3 weeks and then moves into the soil to pupate.
Flies of the second generation fly in July. The first generation larva causes damage in June and the second in late July.
Emergence of flies is a critical factor. If you miss it and be late with processing of plants for a few days when the pest has time to lay eggs or worse – when the larvae are already in the garlic, the struggle against the onion fly is very problematic.
Pupae winter in the soil at a depth of 10-20 cm.
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Symptoms of defeat onion fly
The patient plants the leaves wither, become yellow-gray in color and then dry up.
How to deal with onion fly in garlic
In the fall, before planting garlic, to carry out a deep plowing. This contributes to the death of the pupae of the onion fly.
In the spring, systematic inspection of crops and removal of plants with symptoms of lesions. Cleaning is carried out with an interval of 5-7 days.
Non-chemical measures to control the onion fly
In the period of oviposition the onion fly (this is the period from mid-April to mid-May depending on the region and the weather) you can use substances that repel them. The soil along the rows dusted with tobacco dust or a mixture of it with lime (1 : 1), (1-2 kg per 10 m2). To this mixture, you can add bitter ground pepper (0.5 teaspoon).
Processing is carried out every 7-8 days against the first generation and one against the second.
During the summer flies crops can be treated with infusions of pine extract (200 g/10 l of water) or tobacco (400 g /10 l of water). The substrate is rinsed with hot water infused for two days and filtered. Before processing add liquid soap (50 g/10 l of extract) as an adhesive.
If the larvae of onion flies hatched, the plants can be watered with salt solution (200 g/10 l of water) or ammonia solution (3 tablespoons per 10 liters of water), avoiding contact of the solution on the leaves.
Insecticides for suppression of onion fly
In particular, for spraying you can use the following drugs:
- Anzio, the production of Syngenta, Switzerland, (141 g/l Thiamethoxam 106 g/l Lambda–cyhalothrin), pocessing of 0.18 l/ha 2 times in 14 days
- Karate Zeon, the production of Syngenta, Switzerland (50 g/l Lambda–cyhalothrin) treatment 0.2 l/ha 2 times in 10 days
- Ratibor, LLC “Presence technology”, Ukraine (Imidacloprid 200 g/l) 0,20 — 0,25 l/ha, treatment 1
Economic threshold the onion fly (number of individuals per unit of account) when economically feasible the use of chemicals:
- during the summer flies 5-8 flies per 10 sweeps of the butterfly net
- during the laying of eggs – 3 eggs per plant with colonization of 10% of the plants.
Posted by: Andrey Marchenko
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