Neem oil can be used as a natural insecticide for controlling garden pests, including the garlic fly.

The garlic fly is a small fly that damages the leaves, stems, and bulbs of garlic plants, causing deformity and drying out of the plants.
Neem oil contains azadirachtin, a natural compound that disrupts the growth and development of insects, prevents their feeding, and inhibits their reproductive capabilities. This ingredient acts as a repellent to many pests and can be effective against the garlic fly.
Neem oil against the garlic fly works in several ways. Firstly, the oil acts as an insecticide, killing both larvae and adult flies. The oil also serves as an antifeedant, preventing adults from feeding and reproducing. Finally, neem oil has antimicrobial effects, preventing the development of harmful fungi that often lead to bulb rot in garlic. Overall, the use of neem oil can help reduce garlic fly populations and prevent infestations in garlic fields.
To use neem oil against the garlic fly, you need to dilute it in water according to the instructions on the product. Then, you can apply the mixture by spraying it on the plants, particularly on the leaves and stems, once a week. This should help prevent and reduce garlic fly attacks on your plants.