Buying Seed Garlic? Check for Eriophyid Mites.
That might not look like much - but you would be surprised what a colony of Eriophyid Mites can do to your garlic crop. The mites in this picture are commonly known as Wheat Curl Mites. This species of mite (Eriophyes tulipae) is primarily a pest of stored bulbs.
In heavy field infestations there may be foliar symptoms including streaking and curling, but more often the mites simply desiccate otherwise healthy bulbs and open the clove up to infestation by other facultative plant pathogens. Wheat Curl Mite is also known to vector some disease causing organisms.
This sample was picked up from a RI grower that recently bought this garlic for a fall planting. The grower noticed that some of the bulbs seemed dry and often had a ‘dead’ clove or two within the bulb. Upon pulling the bulb apart some of the cloves had discolored flesh likely the result of a secondary infection. Because the Wheat Curl Mite can only be seen under a high powered microscope growers should inspect their seed stocks closely and weed out unhealthy bulbs.
A detailed fact sheet on Wheat Curl Mite is available from the UC Davis IPM website.
Growers may want to try a hot water batch for garlic bulbs prior to planting. The University of Ontario recommends this process for heat-treating garlic bulbs:
•Select only healthy, disease-free bulbs for hot water treatment and planting. Unhealthy bulbs may not survive the hot water treatment, which could lead to poor germination and establishment.
•It is recommended to presoak the bulbs in 0.1% detergent and water solution for about 1 hour at room temperatures before dipping them into the hot water bath.
•Remove the bulbs from the detergent solution and submerge them immediately into the hot water bath maintained at 44°C for 1 hour ensuring that all bulbs are completely submerged.
•After one hour, remove the bulbs and submerge them in a cool water bath for another 15 minutes or until the bulbs have cooled down completely.
•Remove the bulbs and spread them on a clean surface to dry