Hello David,

Thank you for your question.

As you know, garlic is generally an insect deterrent.

However, there are a few insects (and several other diseases) that can affect garlic.

The top two ways to avoid/solve the issue of garlic maggots is to rotate crops and to make certain that there aren’t any eggs in the garlic that is being used to seed.

Rotating carrots and garlic could be very helpful.

Additionally, soils high in organic matter may encourage maggots.

As a reference, the link below that specifically mentions garlic maggots.

https://ohioline.osu.edu/factsheet/hyg-1627

Garlic maggots are considered relatively rare.

So, I’m also including this links as it discusses nematodes, mildews and additional types of rot – in case one of these may also be an issue.

http://plantclinic.cornell.edu/factsheets/garlicdiseases.pdf