West central Michigan small fruit update – June 18, 2019

Adult cranberry fruitworm flight peaked last week in our region, and egglaying began around June 9. Insecticide sprays are necessary now to coincide with the egg hatching period.

Winter damage in Elliott blueberries
Winter damage in Elliott blueberries on June 17, 2019. Photo by Carlos Garcia-Salazar, MSU Extension.

Weather conditions in west central Michigan have remained unchanged. Below normal temperatures and above normal precipitation continue dominating the region. Daily minimum temperatures over the past seven days averaged 53 degrees Fahrenheit and the maximum averaged 72 F. Regarding precipitation, it varied from 0.2 to 1.3 inches of rain during the same period. The rain has been persistent but with little accumulation except for June 13 when we registered an accumulation of 0.4 to 1.0 inch of rain. The highest accumulation occurred around the West Olive – Fennville, Michigan, region.

Growing degree day (GDD) accumulations, on the other hand, have been also limited. Due to the prevailing weather conditions, there has been a daily GDD accumulation that varied from 11 to 13 GDD per day.

Because of these weather conditions, small fruit crop growth and development have been staggered. Except for strawberries that are in the second week of harvest, blueberries and summer raspberries are at least one week behind their normal developmental stage.

Raspberries are in the green fruit stage. So far, no problems have been observed or reported by growers, and the fruit load is excellent.

Blueberries are in the green fruit stage. However, due to the unusual low temperatures that prevailed for most of spring, some blueberry fields with the variety Elliott still had some flowers up until last week. Some blueberry fields around west central Michigan start showing some degrees of winter damage. However, this is a very common condition that occurs every year, especially in fields far from the lakeshores. Affected bushes may present shoots with plenty of fruit but no foliage, or with winter dieback (see picture). Those affected shoots need to be pruned. By the end of summer, they will be dead and fruit on them will not mature.

Regarding pest problems in blueberries, cherry fruitworm and cranberry fruitworm are out. After much delay, adult cranberry fruitworm flight peaked last week in west central Michigan, and egglaying began around June 9. Insecticide sprays are necessary at this time to coincide with the egg hatching period. Recommended insecticides for this application include Confirm, Intrepid, BT, Lannate, Asana LX, etc.—see the Michigan State University Extension bulletin E154, “2019 Fruit Management Guide,” for more insecticide options. If bees still are present, you may use Confirm or BT. If the bees have been already removed, you may use Lannate, Asana LX, Mustang Maxx, or other broad spectrum insecticides. However, due to current weather conditions, select an insecticide that remains on the fruit if rain occurs after the insecticide application. See “Rainfast characteristics of insecticides on fruit” by MSU’s John Wise for more information.

2019 managing spotted wing Drosophila in berries for Hispanic blueberry growers

If you had problems in the past controlling spotted wing Drosophila (SWD) and have early blueberry varieties, raspberry or strawberries, we recommend attending this SWD training offered on Wednesday, June 26, 2019, at the MSU Trevor Nichols Research Center in Fennville, Michigan, from 4-8 p.m.

This is the best opportunity to be updated and trained to deal with the early arrival of this pest. The workshop is based on using advanced integrated pest management (IPM) tools to manage SWD. These IPM tools translate directly to the bottom line, savings in pest control, fewer insecticide applications and minimum crops losses due to SWD.

There is not cost for attending this meeting. However, to ensure an accurate handouts count, please pre-register by calling Filiberto Villa at 269 830-2309. An online registration page will be provided soon—continue checking the MSU Extension Fruit & Nuts page for future information.

Those attending the training will receive two RUPs to renew their Pesticide Applicator Certification license.

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