Jun 18, 2019

Funds available to replant fields infested by blueberry stem gall wasp

Blueberry stem gall wasp has become a challenging insect pest for Michigan growers to control in a few susceptible cultivars, leading to significant plant and yield loss in some fields. To assist growers with transitioning fields out of these susceptible cultivars, effective June 14, 2019, the Michigan State Farm Service Agency committee has determined that the losses from this pest can be covered by their Tree Assistance Program, assuming all other programmatic requirements are met. This program will provide financial assistance for the expenses associated with removing and replacing blueberry bushes.

To qualify for the Tree Assistance Program, a blueberry stand must have sustained a mortality loss of more than 15% after adjustment for normal mortality. Under the Tree Assistance Program, if a tree, bush or vine is damaged to such an extent that it is no longer commercially viable, the tree, bush or vine may be considered dead in determining the 15% mortality loss threshold.

In our recent surveys of blueberry fields, we have found many cultivars of highbush blueberry that are resistant to gall wasp. This information has been determined from sampling over 100 fields in regions where this pest is prevalent. In contrast to the Jersey cultivar fields that had an average of about 100 galls per bush, Elliott, Rubel and Spartan cultivars had less than 0.1 galls per bush. In other fields we sampled, Bluecrop, Blueray, Draper, Nelson and Weymouth had zero galls even though they were near to infested fields.

Michigan blueberry growers interested in accessing the Tree Assistance Program funds should contact their local county Farm Service Agency office for more details and to discuss eligibility.

– Rufus Isaacs, Department of Entomology, Michigan State University Extension