A couple of years ago I tried an interesting method that I read about in a gardening newspaper and it turned out to be very effective in combating the onion fly. It turns out that these pests can’t tolerate the smell of mowing grass, so this method is ideal for gardeners who stick to natural-type fertilizers.
I used this method and the onion fly pretty much disappeared on its own, with no chemical treatment required. The smell of cut grass lingers in the air for quite some time, between 5 and 7 days, after which it is advisable to renew it. In addition, a mowed grass bed helps retain moisture in the soil and prevents crusting after watering.
How do you know if an onion fly has laid eggs on an onion? Usually this can be seen with the naked eye. Feathers. The onions begin to turn yellow and gradually fade. A clear sign of the presence of an onion fly is a strong yellowing of the tips of the feathers, this can occur in as little as a few days. I also tried several commercial products and liked a product called Zemlin.
The pellets are simply spread evenly over the garden bed, or they can be dissolved in water and watered with onions. However, this should be done no later than 40 days before harvest. That year, when I used Zemlin to water the onion bed, there were no onion flies.
Another way to combat the pest is to water the onion bed with a soda solution. This treatment can replace tobacco, pepper and even the well-known saline solution. To water, dissolve 2 tablespoons of baking soda in 10 liters of water. Do not carry out more than two waterings per season.
