Amy Irish Brown, Phil Schwallier, Carlos Garcia-Salazar

Grand Rapids area tree fruit summary – Amy Irish-Brown and Phil Schwallier
As far as degree days go, 2009 started out on a rollercoaster, going from normal to above normal totals, back to normal and then very much behind normal averages for the Grand Rapids area. Here toward the end of the growing season, we are about nine days behind normal averages for GDD Base 42 and over 16 days behind average for GDD Base 50.

Despite the ups and downs with degree days, the overall season has been very good for all tree fruits. Fruit set for all species has been excellent due to very favorable weather during bloom. It was rather cool during the window for chemical apple thinning, so quite a bit of hand thinning had to be done on many varieties.

Precipitation has been more than adequate for the 2009 season. Early spring rain events led to issues with diseases throughout the season. The summer months continued to bring more than average rainfall amounts with measurable rainfall recorded on 26 out of 62 days in July and August, which are normally the driest summer months. It dried out for September with no rain recorded this month until September 21. Temperatures have been very cool this summer with August 2009 being the coolest August every recorded in the general Grand Rapids area in over 100 years.

Apple harvest got a later than normal start and many growers are carefully monitoring maturity sampling to harvest this very large apple crop at optimal conditions for long-term storage. There is concern about having enough bins for the large crop. Labor availability has been more than adequate.

Pest summary
Early spring rain events led to some long and heavy apple scab infections. During primary scab there were 22 wetting events, nine of which were infections. Apple scab ascospore numbers were some of the highest ever caught in a primary scab season. While growers did all they could to try to stay covered with fungicides, heavy rains and long wetting periods early in the season led to loss of control of primary scab in many blocks. Growers have done a great job keeping scab off the fruit for the rest of the summer, but it has been costly to do so. For all tree fruits, fruit diseases have been a challenge due to the extra rain.

Fire blight was generally limited to those sites known as problems. The weather during bloom was not too favorable for blossom blight infections. The use of Apogee has helped reduce fire blight spread as well. After the many hail storms of 2008, Mother Nature decided to give us a break in 2009 – there were very few thunderstorms due to the cooler overall temperatures. On August 9, there was a straight-line wind event that moved across a stretch of the Ridge. Some trees were toppled or broken off at the graft union and apples hit the ground. The most severe damage happened to a small number of individual growers where whole blocks were taken out. There appears to be no further spread of fire blight due to this weather event.

In general, insects appeared to take a back seat to the diseases this year. Codling moth is still a major apple pest, but most growers found their trap numbers to be very low this year. Obliquebanded leafroller numbers were down as were Japanese beetles. For some blocks, European red mites were on the high side with quite a few summer miticides being needed to keep them in check. It’s a bit puzzling to see so many mites in a season that really hasn’t been favorable to them – mites usually are more of a problem in hot and dry summers. We’ve had a cool and wet summer. Mite predators have been difficult to find in most blocks with mite issues, which are most likely leading to high populations despite less than favorable weather for European red mite.