Tobacco dust is popular among gardeners, and therefore it is commercially available and there is no need to grind tobacco into dust, as many people think. To use tobacco dust to protect against onion flies, you can simply sprinkle it on the soil surface of the area where the onion grows, spending about a tablespoon of oil per tablespoon, without dust, dust. If the pest has already appeared, that is, the fly has begun, then tobacco dust can be mixed with ordinary river sand or, more effectively, with naphthalene in equal proportions (this is more effective because naphthalene smells strong, driving the fly away).
Onion fly is said to be harmless if the soil of the garden is generously pollinated with a mixture of wood ash and ground hot pepper or a mixture of ground hot pepper and tobacco dust (a tablespoon of this mixture per square meter of soil).
Infected areas where the onion flies and may have already laid eggs or were infected last season can be sprayed with tobacco infusion. To do this, you need to dissolve 250 g of tobacco in a bucket of water, let it brew for a couple of days, strain, refill with a spray bottle and you can process the plants, spending about a liter of solution per square meter.
Ammonia against onion flies
If the onion fly flies actively and there is a high probability that larvae are about to appear, then ammonia can be used to combat them at the earliest stages, when they are especially sensitive. To do this, you need to dissolve three tablespoons of ammonia in a bucket of water and in the afternoon, closer to the evening, conduct treatment of onion plants with this composition.
Treatments with ammonia onion plants can be carried out two or three times per season, given the rapid development and fecundity of onion flies. The multiplicity of treatments is usually once every 30 days.
Wood ash is not only a pretty good source of potassium (up to five percent in it) but also a protection against onion flies. Wood ash is now sold in garden shops and flower shops, but you can get it yourself, it’s not at all difficult. To obtain wood ash, you need to collect dry branches, logs, bark and other parts of the wood and burn them to ash.
To protect against onion flies, the soil can be completely covered with wood ash, a layer of a couple of millimeters, or wood ash dissolved in water can be treated. To do this, approximately 500 g of wood ash should be diluted in a bucket of water, let it brew for a day in a warm room, strain, season with a spray bottle and you can process onion plants, trying to completely process both the leaves and the soil around. Consumption rate: liter and a half on a square meter of a bed.
Salt solution for the fight against onion flies
This method is considered effective, but it is quite harmful to the soil because the use of salt can lead to salinization of the soil. It is advisable to treat onion flies with salt-based formulations no more than once per season, and only if crop rotation is taken into account, that is, if onions are planted on the same site every four years.
Usually, treatment with saline onions is carried out two weeks after emergence. To do this, 200 grams of salt are bred in a bucket of water (no more!) And the soil is treated with a solution, being careful not to get on the onion leaves. It is advisable to carry out such treatments in the evening, and early in the morning, it is good to moisten the area with soft water.