Southwest Michigan fruit regional report – September 18, 2012

Apple and grape harvests are moving swiftly as cool wet weather moves into the area. Here’s a recap of the strange 2012 season.


Last week was pleasant. High temperatures fell from the 80s to the upper 70s. Rain moved across the region late Thursday, September 13. Rainfall totals ranged from 1/10 to 4/10 of an inch. Much cooler weather is forecast for the next two weeks with highs in the 60s and low in the 40s and 50s. Autumn has arrived and hopefully fall lake effect rains will recharge our dry soils. Our growing degree day accumulations are over four weeks ahead of normal.

Southwest Michigan Growing Degree Day Totals  from January 1 through September 16


GDD 42

GDD 45

GDD 50





Trevor Nichols




GDD since 9/2/2012




2012 in review

2012 will not soon be forgotten, although most growers would probably like to put it out of memory. It started with a warmer than normal winter and two weeks of spring-like weather in mid-March. This jump started overwintering perennials into early growth. Fruit trees were blooming immediately after President’s Day (February 20). Cold weather returned on March 22. Southwest Michigan dodged freezes in late March, but damaging freezes in early April damaged many fruit crops. Freezes on April 12 and April 27 really decimated tree fruit crops.

April and May were relatively dry and warm and the first 90 degree day was May 20, a harbinger of things to come. Soils were becoming quite dry by the end of May. The last significant spring rain (1 to 2 inches) fell on June 1. Ninety degree high temperatures were common place by the end of June. July continued the hot, dry weather with highs in the 90s and even over 100. In total, there were 35 days with highs of 90 or higher and another four days over 100 in 2012. Most of this heat occurred in July and August.

The hot, dry conditions quickly depleted soil moisture reserves. Drought symptoms were widespread by late June. Drought stress was very noticeable in blueberries and young plantings of grapes and tree fruit. Rain fell across the region on August 19 and scattered precipitation after that date reduced the drought stress on fruit crops, but soil conditions remained generally dry for most of the 2012 growing season.

Because of the reduced crop, pests and diseases were not much of an issue and many growers reduced inputs such as fertilizers, sprays and mowing to a bare minimum. Several pests are worth mentioning. Birds were a big problem. The hot, dry conditions and lack of fruit made large flocks of fruit-eating birds a major problem for growers with fruit, especially blueberries and cherries.

In insects, the spotted winged Drosophila (SWD) increased dramatically. This pest has been found in many small fruit plantings and many growers were forced to abandon infested fruit in the field, with an early end to harvest. This pest appears to have established itself in southwest Michigan. Trap numbers will likely increase through the rest of the fall.

Small fruit

In general, small fruit suffered less from the impact of the rapid spring warm-up than tree fruits, although juice grapes were damaged pretty severely.

Strawberries generally escaped freeze injury because sprinkler irrigation systems are used to protect strawberry fields from spring freezes. Strawberry plantings without sprinklers for freeze protection suffered significant freeze injury. Strawberries in the high tunnels were in bloom on March 20 and in the field, flower trusses were emerging from the crowns by March 27.

Harvest began in late May, several weeks early for strawberries. Fruit size and quality were variable with growers complaining of small fruit. Drought and potato leafhopper affected the early growth of many fields after renovation. Tarnished plant bug, a perennial pest, seemed less severe this season than usual. In the high-tunnel day-neutral strawberry plantings at the Southwest Michigan Research and Extension Center (SWMREC), fruit and flower production fell off in the summer heat and then increased with cooler temperatures in September.

SWD became a problem in August and September. The SWMREC strawberries received few insecticide treatments for SWD, and about 50 percent of the fruit was infested by the fly. Recent insecticide applications to control this pest in the tunnels have noticeably dropped the losses to SWD. Powdery mildew was severe on several experimental crosses of strawberries in the tunnels, but the commercial varieties seemed not to be affected. An unusual disease occurred on strawberries in the high tunnels at SWMREC this season. Sooty mold developed from an infestation of whiteflies that presumably came in on strawberries plants produced in a greenhouse.

In brambles, summer raspberry canes suffered cold injury from earlier freezes and canes began collapsing during midsummer, shortening the harvest season considerably. A new pest we saw this year in blackberries was redberry mite. Redberry mite damage is characterized by uneven ripening of drupelets, with some remaining hard and red. Extensive periods of drought and heat this summer also caused sunscald on blackberries and raspberries.

Fall raspberry harvest is still underway. Spotted wing Drosophila (SWD) continues to be a major concern. In high tunnel raspberries, potato leafhopper, spider mites and SWD were the primary problems this year. Recent insecticide applications to manage SWD and stricter sanitation measures have cut back the level of infested fruit, but it is definitely a pest that requires vigilance to keep it in check. Growers with field plantings of raspberries and blackberries have also commented on the challenges of controlling SWD.

Blueberries were initially set up for a very heavy bloom, promising a heavy crop before the April freezes. Growers with overhead irrigation and wind machines were able to prevent damage in many areas, especially for the freezes in mid-April. The final freeze on April 27 also caused severe damage. Many growers reported that the leaves and fruit seemed small after bloom. There was also significant fruit drop after bloom, apparently of freeze-damaged fruit. Fruit set was light in many fields and very variable across the region with large differences in the same variety depending on the location.

Many sandy sites were very dry in late May. Drought stress was common in July in unirrigated fields. Growers with irrigation were hard pressed to provide enough water in the heat. Unirrigated fields had the berries shrivel before harvest. Rains in August revived many plants. There is a fair amount of new growth visible in many fields. Bud set for next year looks good in many plantings. Plants that suffered damage during this year’s drought will need increased pruning and in severe cases cutting down to the crown may be the best alternative. Spotted wing Drosophila became a major problem after the rains in mid-August and some growers were surprised and had to abandon their final pickings because of wormy fruit.

Grape growth began very early with the warm weather in March. Juice grapes had reached bud burst to second leaf by March 26, while most wine grape varieties were still at late swell. Temperatures into the 20s on April 7 caused significant damage to many juice grape vineyards and another severe freeze on April 12 caused additional widespread damage. Many vineyards lost most primary buds. Still, another freeze on April 28 took out more juice grape primaries that had escaped previous damage. Growth from secondary buds took several weeks to get large enough to be susceptible to freeze injury, so many of the shoots from secondary buds escaped the freezes in late April. Wine grapes generally suffered much less injury – losses were estimated at 10 to 50 percent.

Grape flea beetles were present over a sustained period of time due to the prolonged period of bud development, although damage was rarely severe enough to warrant treatment. Biofix for grape berry moth (50 percent bloom on wild grapes, Vitis riparia) in southern Berrien County was set on May 18, and northern Berrien County and Van Buren County on May 21. The previous year (2011), biofix for grape berry moth was May 30-31 in Berrien County and June 1-2 in Van Buren County. Despite the early biofix and the occurrence of four generations, damage due to grape berry both this year was light.

Incidence and severity of most diseases was also lighter than usual this season. A dry summer reduced disease pressure for most foliar diseases. Favorable conditions for downy mildew and powdery mildew didn’t occur until late in the season, past the time when they could cause much damage to fruit. Increasing rainfall as we reached veraison and cluster ripening has resulted in more bunch rots than we saw last year. Harvest of Niagara juice grapes (September 4) began 10 days earlier than last year (September 14), and harvest of Concords (September 14) began more than two weeks earlier than last year (October 1).

Tree fruit

The 2011-2012 winter was relatively mild and easy on overwintering trees and their fruit buds. High temperatures in the 80s for several days in the latter half of March pushed growth early so that normal freezing temperatures in April resulted in significant fruit bud death for most southwest fruit orchards.

Tree fruit crops ranged from zero to approximately 50 percent of full crops with an average of 10 to 15 percent of a full crop. It was the worst crop for all the tree fruit crops across the region in many decades. The best tree fruit crops were reported on sites with excellent air drainage in the Eau Claire/Sister Lakes region in southern Berrien County and on the north edge of Bainbridge on the hillside facing the city of Coloma.

Frost damage was common on remaining fruit. Cool and wet weather during April resulted in some Phytophthora root and crown rot problems on young stone fruit planted deeper than recommended on heavier ground. Hot and dry conditions during July and August put young fruit plantings on sandy sites under drought stress. Growers carried water to one- and two-year old trees. San Jose scale had a third generation flight under the hot 2012 season.

A total of two brown marmorated stink bugs were caught in the southwest region by mid-September this year, so we have had another year of respite. Japanese beetles and grasshoppers were voracious feeders in some sites. Burrows of 13-line ground squirrels were prevalent in some trickled sandy orchards, undermining some newly planted trees.

In peaches, crops were generally very poor. Fruit size tended to be smaller where there was a crop due to dry conditions. Hot conditions in mid-season caused more red coloration than usual in the flesh and some pointed apex shapes to some varieties. Flavor was generally very good with the warm, sunny weather and dry conditions. Rusty spot symptoms due to the apple powdery mildew pathogen were very common on fruit across a wide range of varieties due to favorable conditions for infection in between shuck split and pit hardening. X-disease symptoms were common in some orchards. Oriental fruit moth trap catches for the first generation were high, but the freezing temperatures in April apparently caused considerable mortality of the new larvae.

In sweet cherries, crops were generally non-existent and birds ate the few fruit that escaped the freezes. Due to the freezing temperatures during bloom, bacterial canker symptoms were prevalent on leaves, spurs and the occasional surviving fruit, with bacterial canker-prone varieties showing more symptoms. Spur decline and gumming and leaf spot due to bacterial canker was severe in some blocks.

In tart cherries, the crop was generally dismal and birds feeding on the fruit were a problem in the few blocks that had a commercial crop. Birds stripped the fruit from all cherry orchards in the southwest this year. Dry conditions in mid-summer slowed the onset of cherry leaf spot, but rains in August allowed the disease to cause defoliation by early September in unprotected orchards. Prices per pound were the highest in memory, but the volume was low.

In plums, crops were very poor, with early blooming pluots generally doing better than European or Japanese plums, but still poor.

Apple yields in the region were very poor, with Honeycrisp, Goldens and Red Delicious varieties generally doing the best. Harvest dates generally matched the predicted dates, which were two to three weeks ahead of normal. Record-high fruit prices were common due to widespread fruit shortages in Michigan and neighboring states. Poor fruit finish was generally the case due to frost damage in bloom, sunburn during the drought, lenticel disorders and some hail during the hot summer months.

Bitter rot, an uncommon fruit spot disease in the cooler Michigan climate, showed up in a few blocks. Blossom blight due to fire blight was rare this year, but some terminal blight was noted later due to overwintering cankers that were missed during early season pruning. Scab was only moderately severe. Powdery mildew was particularly significant on Jonathan and Gala due to the hot, dry daytimes but humid evenings in mid-summer. Necrotic leaf blotch on Golden Delicious and closely related varieties caused some mid- to late season defoliation after rains ending the drought.

Codling moth first generation flight was strong, but the second and third generation flights were weak, perhaps due to the very poor fruit crop. San Jose scale crawlers resulting from the third generation were expected to cause problems on fruit of late season varieties such as Braeburn, Fuji and Rome.

In pears, the crops were very poor. The Canadian variety Harrow Sweet was notable in that it was the only tree fruit variety of any type (apples, pears, peaches and plums) at SWMREC with a full crop. Frost-related russeting was common on all varieties. Pear psylla was a minor problem.

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