Blueberry Insect Scouting Report for April 15-21, 2012
Cool weather is slowing down insect development.
The MSU Blueberry Team has moved to a new format for information delivery in which timely articles and these scouting reports will be prepared for online delivery at the Michigan Blueberry Facts website, or www.blueberries.msu.edu, and MSU Extension News. If you want to get an email alert when new articles are posted, just go to the bottom of the Michigan Blueberry Facts website and sign up for the RSS feed. Or just check back regularly for new information, such as these scouting reports. Please let us know what you think of this new format.
In Van Buren County, Jersey in Paw Paw, Grand Junction, Gobles and Covert, Mich., are at trace bloom, Bluecrop and Rubel are approaching 50 percent bloom, and Elliot are at late pink bud.
In Ottawa County, Jersey are at late pink bud, Bluecrop, Rubel and Blueray are at trace to 25 percent bloom, and Elliot are at mid pink in West Olive, Mich.
Weekly insect pest report
Cherry fruitworm moths have been caught in traps at all the farms we visit in Van Buren and Ottawa counties, and we expect to see the flight of this pest continue, but with fewer captures because of cool weather forecast over the next week. In addition, with slow growing degree day (GDD) accumulation, we expect cherry fruitworm egglaying will be delayed until next week. Egglaying should begin approximately 100 GDD after cherry fruitworm moths are caught consistently, and we still have not reached that point. At all locations we are still catching a contaminant moth in cherry fruitworm traps. This moth is larger than a cherry fruitworm moth and has mottled dark patterns on the wings, while cherry fruitworms are dark with a series of thin shiny bands across the wings. See this previous article for pictures to help distinguish these two moths and for more information on fruitworms.
Growers and scouts should be checking cherry fruitworm traps now to ensure detection of the start of the flight for cherry fruitworm. Traps should be baited with a pheromone lure and hung in the top half of a bush on the perimeter of a field. Place traps in known "hot spots" where the pest has been seen in the past. These areas are generally adjacent to woodlots, so if you are not sure if you have cherry fruitworms, these are the best areas to begin trapping. Put traps in the upper part of the canopy on a sturdy branch.
Traps should be checked twice weekly until moths are caught consistently. This will not only identify fields with pressure from cherry fruitworms, but will also enable the identification of the start (biofix) of cherry fruitworm flight, when moths start to be trapped consistently. The first chance for egglaying by cherry fruitworms is predicted to be 100 GDD after biofix, so this timing can be used to protect fields that have had significant infestation from this pest previously and where fruit set has started at 100 GDD after biofix. A detailed article about fruitworm management has been posted at the MSU Extension News website.
At the farms we scouted, we did not see leafroller larvae or feeding damage, but growers and scouts should be on the lookout for these early season pests. To scout for leafrollers, examine five flower clusters and five leaf clusters on 10 bushes on the field border and five flower clusters and five leaf clusters on 10 bushes in the interior of the field. Look for leaf or flower clusters that have feeding holes or webbing in the cluster. These pests are generally not economically important in Michigan, but if 3 to 5 percent of buds have feeding damage, growers may want to consider a specific control targeting these insects. View more information and pictures of leafrollers from our scouting pages posted at blueberries.msu.edu. It has been our experience that sprays targeting cherry and cranberry fruitworms are also well-timed to effectively control other moth pests such as leafrollers, spanworms and tussock moths.
We are seeing the beginning of gall wasp emergence at infested sites in Ottawa County, but growers should not use bee toxic chemicals for gall wasp control at this time in fields where bees are foraging.
We do not yet expect to see cranberry fruitworm flight this week with the cool weather. Still, this would be a good time to hang monitoring traps for this pest if that hasn’t been done yet, to ensure a zero-catch before identifying the start of flight and the biofix.
MSU Extension to offer spotted wing Drosophila workshops this spring
MSU Extension will provide three, in-depth workshops on spotted wing Drosophila (SWD) biology and management this spring. The first of these is Tuesday, April 24, with two more opportunities to attend the training on May 15 and June 12. Spotted wing Drosophila is an invasive insect that was first detected in Michigan in late 2010 and in many other eastern U.S. states in 2011 and is now found in most major fruit producing regions of the country. Spotted wing Drosophila is a pest of berries and other soft fruits, and will require active management by growers to minimize its economic impact.
This workshop will include the latest research information as well as hands-on training in monitoring, identification and fruit sampling. It will be led by members of the MSU Department of Entomology who have been studying this insect since its arrival in Michigan. The workshop has been developed for fruit growers, scouts and crop consultants to help them integrate SWD management into their IPM programs.