NH Alert: Garlic Bloat Nematode

clip_image001.jpgThe following alert is from the New Hampshire Department of Agriculture — please be aware that the zip code for Exeter, Brentwood, and Kensington is one of the destinations of infested garlic shipments. Garlic bloat nematode has already been confirmed widespread in New York, and also confirmed in Pennsylvania, Ontario, Vermont and Massachusetts.


Garlic bloat nematode is a microscopic worm that can destroy a whole garlic crop. If you have this nematode, it can be spread on equipment or boots, and has over 100 host plants, including many weeds. If you have an infestation, you may be rotating many crops for 3 to 4 years, and there is the possibility of contaminating your neighbor’s crops or soils. If you’ve been growing your same garlic for many years and have not introduced any new stock, it is doubtful you have this pest. However, if you’ve purchased or brought in new planting material on a regular basis, there’s the possibility you have this pest. [Garlic Seed Foundation]


Alert: Garlic Bloat Nematode


In the fall of 2010, garlic bulbs potentially infested with the garlic bloat nematode, Ditylenchus dispsaci, were exported from Canada into New York as a food product. However, following arrival in New York, they were distributed as seed garlic. They were then shipped throughout the northeast for production purposes. In New Hampshire, it is known that this garlic was distributed to the following zip codes: 03221 [Bradford], 03303 [Concord, Boscawen, Penacook, Webster], 03833 [Exeter, Brentwood, Kensington], and 03070 [New Boston]. No further information regarding distributors, size of shipments, etc., has been provided at this time.


This nematode, which is also known as a bulb and stem nematode, causes bloated, twisted, swollen leaves, and distorted and cracked bulbs with dark rings. Infestation with this nematode can weaken plants, causing them to be susceptible to secondary infections. Presence of this pest can affect export of the infested crop. Besides being a concern in garlic, this nematode can also affect other Allium species, such as leeks, onions, and chives, as well as other crops and plants including nightshades. The nematode can overwinter in the soil, and can be moved throughout the field on farming equipment, shoes, etc.


Management recommendations include destruction of dry plant debris which can harbor the nematode, management of nightshade near crops, crop rotation away from Allium species on a four year cycle, use of chemical fumigants or bio-fumigant cover crops, and good sanitation practices. Links for information about this nematode can be found by visiting: http://www.nh.gov/agric/divisions/plant_industry/index.htm and selecting the garlic bloat nematode link. You can submit plant samples for nematode identification to the Michigan State University Diagnostics Center (http://www.pestid.msu.edu/). Their basic nematode analysis for out-of-state samples is $75 per sample. Please check their website for more information and specific instructions for shipping out-of-state samples to Michigan.


For more information:  www.nh.gov/agric/.


See also the NH Vegetable, Berry, & Tree Fruit Newsletter (April 2011) from the UNH Cooperative Extension: http://extension.unh.edu/Agric/Docs/April2011vegfruitnewsletter.pdf

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