West Central Michigan small fruit regional report – June 10, 2014

Maintaining a good nutritional program is essential for quick recuperation of severely winter-damaged blueberry fields. Careful management of your pest control program will be required to avoid overuse of insecticides.

The weather conditions in West Central Michigan are back to normal temperatures of late spring and early summer. Currently, the maximum daily temperatures have been in the upper 70s with an average maximum temperature of 78 degrees Fahrenheit and a minimum temperature averaging 54 F. The growing degree day (GDD) accumulation since March 1 in West Central Michigan is approximately 550 GDD base 50 F. In addition, no substantial precipitation has occurred during the past seven days, only scattered precipitations that accumulated less than 0.25 inches of rain. These conditions have allowed for a rapid development of both plant and insect phenology.

For strawberries, the weather favored the beginning of the harvest of day-neutral strawberries. Quality is good and the crop seems to be normal. So far, few problems are reported and basically the season has begun problem-free. Raspberries have also continued developing without any problems. Since we are entering the period when the first spotted wing Drosophila flies start emerging, we will initiate its monitoring this week in strawberries. In selected monitoring (SWD) sites, we will install monitoring traps baited with the new SWD lure that is commercially available for the first time. The use of this synthetic lure will prevent the use of the mix of baker’s yeast and sugar, which will allow a better management and identification of flies collected in the trap.

Regarding the phenology of blueberries, most varieties are already in the “green fruit” stage aided by the good weather from the past few days. Since no important rains have occurred in the area for more than 10 days, growers are supplementing their fields with irrigation. It is important that fields showing considerable winter damage maintain a regular nutritional program to alleviate the impact of the lack of foliage. Since a large portion of nutrients utilized by the plant during the early portion of the plants growth are those stored the previous year in canes and in the roots, in blueberry plants with extensive winter injury those nutrients will not be available. Therefore, we need to maintain a good nutritional program to prevent further delays in the recovering of the plant structure and productivity.

For pest management in blueberries, fruitworm control has continued in the entire area. We are already in the period of oviposition for both cherry fruitworms and cranberry fruitworms, although there has been a decrease on the adult emergence of both cherry fruitworm and cranberry fruitworm ovipositions of both insects should already be visible in the field. At this time, growers should be applying the second application against fruitworms. Confirm, Intrepid, Lannate and Asana, among others, could be some alternatives for fruitworm control. Since some of the insecticides we use for fruitworm control are the same as those used for SWD, Michigan State University Extension recommends saving the organophosphate insecticides for SWD management. This will prevent overuse of the same insecticides and will allow for a better rotation of products to prevent the development of resistance to our best products.

For the most updated insecticides and doses for fruitworm control, please consult the 2014 Michigan Fruit Management Guide (E-154). You may also contact Carlos Garcia at 616-260-0671 or garcias4@msu.edu.

Please keep in mind that some of the insecticides used against fruitworms are restricted products that cannot be used in areas inhabited by endangered species. So, read the label to make sure that you are in compliance with the recommended guidelines.

Upcoming meetings

We are planning our next twilight meetings. The first pre-harvest meeting will be on June 18 in Van Buren County, the site will be announced soon. The pre-harvest meeting in Ottawa County has been scheduled for July 2 at the Olive Town Hall in Holland, Michigan. All meetings are scheduled from 6-8 p.m. and are free of charge.

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