Northwest Michigan fruit regional report – August 18, 2015
Peach harvest is beginning, berry crop harvest is underway and growers are protecting fruit from spotted wing Drosophila as populations continue to rise in the northwest.
The weekend weather across northwest Michigan was hot and muggy. Daytime temperatures approached 90 degrees Fahrenheit Friday, Saturday and Sunday, Aug. 14-16. Humidity levels were also high and continue to be as we move into the workweek. Predicted temperatures for the remainder of the week are in the 80s with the exception of Thursday, Aug. 20, which is only predicting a high of 67 F. The chance of rain for Tuesday and Wednesday, Aug. 18-19, are 91 percent and 100 percent respectively, and so far on Aug, 18, the Northwest Michigan Horticulture Research Center (NWMHRC) has yet to receive any measurable precipitation. Conditions are dry across the region and rain would be welcomed in all orchards in northwest Michigan.
The majority of tart cherry harvest is finished, although there may be a few growers to the far north that are winding up Balaton harvest. For the seventh week of tart cherry harvest, the Cherry Industry Administrative Board is reporting northwest Michigan to have harvested 86.7 million pounds; the 2015 estimate for the region was 83 million pounds. We are still unclear how many pounds of tart cherries we lost to the recent storms, but more than likely the total amount harvested would have been higher than the current harvested pounds.
Peach harvest is beginning in orchards that were not hurt by the harsh winter or the May 20 freeze event. Apples continue to size, and our apples at the NWMHRC that were hit by hail are beginning to drop from the trees.
It is not difficult to find spotted wing Drosophila (SWD) in cherries that have been unsprayed this season or fruit that remain on the trees after harvest. We have also received reports of SWD infesting caneberries in the northwest region, and many berry growers are concerned with SWD at this time. Michigan State University Extension would like to remind all berry growers, and in particular growers with U-pick operations, to check pre-harvest (PHI) intervals on insecticide labels when selecting materials for SWD control. Additionally, growers may want to do an occasional salt test to determine if their berries are indeed infested.
Some raspberry and blackberry growers are considering rotating a pyrethroid insecticide (Mustang Max, one-day PHI on caneberries) with a spinosyn insecticide (Delegate, one day PHI on caneberries) to keep fruit protected for as long as possible. Rotating insecticide classes will help reduce the possibility of SWD developing resistance to these materials. Furthermore, growers planning to use pyrethroids should monitor regularly for spider mites as pyrethroid insecticides can contribute to mite flaring. For additional information regarding SWD management in berry crops, please visit MSU‘s Spotted Wing Drosophila website.
Apple maggot activity is ongoing and although trap catches at the research station were high last week with 19 apple maggots total, numbers decreased to a total of two apple maggots on our traps. Apple maggot numbers in the region have on average also been low in the single digits, less than two per trap).
Codling moth activity at the station is holding steady with an average of four codling moths per trap last week and three codling moths per trap this week. We are continuing to catch a few obliquebanded leafrollers, but flight is winding down at this time.
No brown marmorated stink bugs (BMSB) have been found in the northwest region. However, apples at the station that were dinged up during the Aug. 2 storm have many dents that resemble feeding damage from sucking insects like BMSB. This damage is also difficult to distinguish from bitter pit on Honeycrisp apples; one indication of storm damage could be that fruit are exhibiting bitter pit-like symptoms on the west side of tree rows.