West Central Michigan small fruit regional report – May 13, 2014
Disease management and the beginning of fruitworm control are the main priorities for blueberry growers and IPM practitioners. Consider registering for the third spotted wing Drosophila workshop.
After weeks of temperatures below the 50s, West Michigan is experiencing temperatures more typical of spring time. For the past seven days, the average daily minimum temperature has been around 48 degrees Fahrenheit, while the daily maximum has been on average 74 F. Growing degree days (GDD) accumulated since Jan. 1 in West Central Michigan are 387 base 42 F and 182 base 50 F.
As a direct result of this weather pattern, all small fruit crops are progressing rapidly. Currently, blueberries are showing the most rapid development. As of May 12, early blueberry varieties in most places were already in the 0.5-inch green stage and some fields in the early pink bud stage.
Although no mummy berry shoot strike infections have been reported, growers need to continue with their mummy berry and Phomopsis preventive treatments. Current conditions of humidity and temperature are conducive for disease outbreaks. For growers who have already completed their first treatments against mummy berry and Phomopsis canker and twig blight, Michigan State University Extension recommends rotating fungicides to prevent disease resistance. At this time, if you already used Indar for your first application, Quash, Orbit, Bravo and Pristine are good alternatives to prevent outbreaks of both mummy berry and Phomopsis. Just remember, Pristine needs to be applied alone. For more information on products and doses, please consult the 2014 Michigan Fruit Management Guide (E-154).
It is time to put in practice your integrated pest management (IPM) program for fruitworm control. Currently, pheromone traps for cherry fruitworms should already be out. According to our research, cherry fruitworm monitoring should be as follows:
- Cherry fruitworm pheromone‐baited traps need to be deployed at around 200 GDD base 50 F. GDD accumulation starts on March 1.
- Check pheromone‐baited traps every other day until the first moths are trapped. After sustained moth catch, monitor traps twice a week. In Michigan, cherry fruitworm moths emerge at 238 ± 30 GDD base 50 F.
Up until May 12, GDD accumulation since March 1 in West Central Michigan is around 180 GDD base 50 F. This puts the biofix date for cherry fruitworms approximately three to four days from May 12. The first insecticide application should be applied 80-100 GDD after the first moths are caught in the pheromone traps. For insecticide recommendations, please review the 2014 Michigan Fruit Management Guide (E-154).
The next spotted wing Drosophila (SWD) workshop has been set for May 20 at the MSU Trevor Nichols Research Center in Fennville, Michigan. The program will start at 9 a.m. and conclude at 1 p.m. Growers may register online.
These workshops have been focusing on how to conduct a successful SWD control program in 2014. One of the main goals of the program is to teach growers how to effectively use insecticides currently recommended for SWD control. If in 2013 your SWD control failed or you were not satisfied with the level of control, come learn how to take maximum advantage of the pesticides you are applying and the recommendations for SWD management.