Weather report

During the past seven days, west central Michigan experienced a period of daily low temperatures with relative dry conditions. However, by the middle of the past week, the weather started changing with daily temperatures reaching the upper 80s with scattered rain showers and thunderstorms that left 0.5-1 inch precipitation. The average daily minimum temperature was 59 degree Fahrenheit and the daily maximum averaged 83 F.

Small fruit crop conditions

Strawberries are the main berry crop harvested at this time. Strawberries have been harvested in Allegan, Ottawa, Kent and Ionia counties for the last three weeks and will continue during this week with fruit of good quality. Dry weather conditions have favored the presence of buyers and also helped with fruit rots. In comparison with past years when rains created problems for growers during harvest, this strawberry season has had almost no problems.

Raspberries, on the other hand, are still in the green fruit stage in Ottawa, Kent and Ionia counties. However, if the weather remains with temperatures in the upper 80s or higher, the first berries from early season varieties will be ready for harvest next week.

Blueberries still are in the green fruit stage, but in some early varieties, fruits started entering the fruit coloring stage (change from green to pink and finally to blue). Other varieties like Weymouth are ready for hand-harvesting. In this variety, the first harvest will start this week at Allegan County. Fruit is abundant and of very good quality.

As blueberries enter the fruit coloring stage, growers should be ready to monitor for the two flies that cause the most damage to our blueberry crops: blueberry maggot and the spotted wing Drosophila (SWD).

For blueberry maggots, yellow sticky traps with attractant should already be in place. Growers should make sure traps are placed correctly on the bush. The correct way to install the trap is by placing it in a “V” shape with the sticky side facing the ground and the lure in the middle as shown in the picture. There should be at least one trap per 5 acres of blueberries, and keep them clean by removing dead insects from the sticky surface every time the trap is checked.

SWD continues arriving into blueberry fields. So far in central Michigan it has been found only in Allegan County. The past week we found two specimens, one in Glenn, Michigan, and another near Grand Junction, Michigan. There were differences between the morphology of those insects. The two previous specimens found in Allegan County were small, but the last findings included a specimen that resembles the summer population of SWD – a large and robust female. That could mean that the SWD summer population is already multiplying in Michigan’s wild hosts.

Growers should be alert to the arrival of SWD in their fields. SWD monitoring traps should already be in place, especially in fields with early season varieties where the fruit is already coloring. Use the recommended SWD traps for early detection. Michigan State University Extension recommends a trap with an attractant made of brewers yeast and sugar as the best early detection devise. However, the commercial lures available are also a good and cleaner alternative. See MSU Extension’s “Building a spotted wing Drosophila trap” fact sheet for more information.

Pre-Harvest Twilight Meetings, June 28 and 29

There will be two pre-harvest meetings offered by the MSU Extension small fruit team. The first meeting will be Tuesday, June 28, in Van Buren County and the second meeting will be Wednesday, June 29, in Ottawa County. The agenda for those meetings will be the same, but the Van Buren County meeting will include a field demonstration of herbicide treatments for weed control in blueberries.

For more information on these meetings, including an agenda and speakers, see “Blueberry pre-harvest meetings June 28-29, 2016.”

Good Agricultural Practices (GAP) Training

On June 17 and 18 we conducted the second GAP workshop for English- and Spanish-speaking growers. On the first day, we reviewed the GAP main topics related to blueberry production and the main changes resulting from the new Food Safety Modernization Act (FSMA). On the second day, we reviewed the Risk Assessment procedures and visited a farm to practice the risk assessment procedures.