After several weeks, the remainder of the garlic harvest was ready to be trimmed for storage. On closer inspection, we were disappointed to find some damage from garlic mites, also known as dry bulb mites, on individual cloves. This is a common problem, one we’d hoped was solved through the selection of clean, undamaged cloves last season, each painstakingly peeled before planting.
To be certain that mites were the issue and not something more devastating, we contacted Eric Sideman, who, as Organic Crop Specialist at MOFGA, provides their periodic Pest Report. After sending a couple of photographs of our garlic, Eric’s first take was that it could the beginning of penicillium. However, additional photos seemed to allay his concerns: “Bad mites would have taken many of the roots, but that does not seem the case. I bet you are ok.”
Garlic mites can also infect others in the allium family, including onions and leeks. The Oregon State University Extension Service recommends the following preventative measures to keep in mind:
• Avoid successive onion and garlic crops.
• Flood irrigation or heavy winter rain will reduce mite populations.
• Hot water treatment of bulbs prior to planting can reduce mite populations, but effective temperatures also reduce germination. Effective times and temperatures were 130°F fir 10–20 minutes, or 140°F for 10–15 minutes.
• Good control was reported with soaking affected cloves for 24 hours in 2% soap (not detergent) and 2% mineral oil.
• Light or moderate infestations are controlled with the normal drying process prior to storage.
The problem of garlic mites may have been there all along, something we just may have never noticed before. Once we spotted it, we wondered if it was something minor or more serious. We won’t really know the extent of the damage to our bulbs until the fall planting. In the meantime, we hope that the care we took in drying them will have resolved this year’s infestation.
– Eriophyid mites on stored garlic, Oregon State University Extension Service
– Onion and Garlic Bulb Mites, UC-IPM Online, UC Davis
– Bulb Mite Found in Garlic Fields, Weekly Crop Update, University of Delaware Cooperative Extension
– Another Garlic Pest – Bulb mites (Rhizoglyphus spp), MOFGA’s Pest Alert, October 23, 2012