Southeast Michigan fruit regional report – July 14, 2015

Summer red raspberry and blueberry harvest continues, cherry harvest is wrapping up and some apple blocks have high populations of obliquebanded leafrollers.

Weather

Rainfall totals for the last week are all over the board again for the region, ranging from a few tenths of an inch to some approaching 1.5 inches. Our soils mostly have plenty of soil moisture across the region, but there are a few isolated farms where soils remain dry. Farms in the southern tier of counties have seen flooding in the past week.

Our season is generally running a few days ahead of normal for growing degree day (GDD) totals for most of east Michigan. In terms of the beginning of harvest, fruit crops are about five days ahead of normal for most fruit farms.

East Michigan GDD totals for March 1 to July 13, 2015

Location

GDD 42

GDD 45

GDD 50

Commerce (Oakland)

1,807

1,528

1,108

Emmett (St Clair)

1,775

1,501

1,092

Flint (Genesee)

1,995

1,706

1,266

Lapeer (Lapeer)

1,849

1,575

1,158

Petersburg (Monroe)

1,964

1,675

1,237

Pigeon (Huron)

1,639

1,381

 979

Romeo (Macomb)

1,889

1,608

1,179

Tree fruits

Apples at most farms continue to size very well this season, most are 1.875 to 2.5 inches in diameter. Hand-thinning has wrapped up for most growers and continues for a few others. Terminal buds are just starting to be set on a few varieties, so it is about a week or so early to begin summer pruning. Leaf molding in Honeycrisp has been seen in the last few weeks.

I am continuing to find good numbers this week of very small larvae of mostly obliquebanded leafrollers and a few oriental fruit moths and codling moths feeding in the very small terminal leaves at just a few farms. It seems to be the case that growers either have a good number of these larvae or none at all. Growers need to do a good job of scouting for small larvae at this time.

The first trap catch of apple maggots on yellow sticky traps was July 3, and trap catch numbers have continued to build this week. There has not been any trap catch on red sticky traps. Apple maggots generally take about 10 days to begin to lay eggs in fruit after they emerge and have first trap catch on red ball traps. Codling moth trap catch is on the rise again; this is most likely the start of second generation adult flight, but I want to see another week of trap catch numbers to tell for sure. Oriental fruit moth adult trap catch has jumped up again this week. A few spotted tentiform leafminer second generation adults are flying. Japanese beetle adults continue to be seen and are starting to cluster together. A few potato leafhopper adults and nymphs, green apple aphids and rosy apple aphids continue to be seen, as are a few masses of woolly apple aphids.

European red mite adult and egg numbers are starting to build on leaves in a few apple blocks, mostly on the inside middles of larger trees. I saw a few eggs this week being laid in the calyx end of Red Delicious fruit. No brown marmorated stink bugs have been caught in traps this season, but I am hearing reports of homeowners finding them inside homes and outbuildings. I continue to find adults of other stink bug species. Good numbers of beneficial insects continue to actively feed in most apple blocks.

Widely scattered fire blight strikes continue to be seen, but should quickly slow down as growth slows for the season. Apple scab lesions continue to show up on leaves and fruit in some blocks. It’s not widespread, but Michigan State University Extension would like to remind growers to scout closely for scab lesions now that fungicide rates have been reduced by most growers. If there was some primary scab present, it begins to really show up once you switch to summer fungicide rates.

Summer disease control has started at most farms. Powdery mildew-infected twigs continue to be seen in a few apple blocks. The leaf stage of black rot, known as frogeye leaf spot, is being found in more apple blocks these past few weeks, even in young apple blocks.

Pears are mostly 1.5 to 1.75 inches in size. All stages of pear psylla continue to be seen.

Peaches are mostly 2.25 to 2.625 inches for growers with a crop this season; pit hardening has taken place. Hand-thinning has wrapped up. Green peach aphids continue to be found in a few blocks. Bacterial leaf spot-infected leaves and fruit continue to be seen in many peach blocks, especially in blocks with no crop this season where pest controls have been reduced.

Sweet cherry harvest continues, but will be wrapping up soon at most farms. Bird feeding and fruit cracking is a problem in most blocks. Spotted wing Drosophila (SWD) continue to be caught in traps in more and more sweet cherry blocks, but we are so close to the end of harvest that control measures are not needed. No cherry fruit flies have been caught in traps.

Tart cherry harvest continues at a few farms, but has wrapped up at most. Cherry leaf spot-infected leaves are yellowing at most farms, with a fair amount of leaf drop on trees that had a big crop. Cherry leaf spot should be controlled at this time and for the rest of the summer. SWD continues to be caught in traps in more tart cherry blocks, but we are so close to the end of harvest that control measures are not needed. No cherry fruit flies have been caught in traps.

In plums, we are seeing a fair amount of early color and dropping fruit in some Stanley and related varieties this past week. European plums are mostly 1 inch in diameter and Japanese plums are 1.25 to 1.5 inches in diameter. Japanese plums are starting to color. Some blocks have a lot of bacterial spot, mostly on leaves. Black knot continues to be seen on wild and unsprayed plum trees.

Small fruits

Grapes are almost at berry touch for Concord types and European varieties are approaching marble-sized fruit for the few varieties with a crop this season. Japanese beetle adults continue to be seen and are starting to cluster together. Downey mildew has been seen at a few more farms this week.

Strawberry renovation has begun at most farms where the soils have dried. Where soils are still wet from the heavy rains in June, growers are delaying renovation a few more days waiting for soils to dry.

Raspberry harvest of summer fruiting types continues, as does black raspberry harvest. Fall red raspberry canes continue to put on good new growth. Flower buds are starting to develop in fall raspberries. This season, I am finding numerous flower buds or “bud berries” forming at this time on the shorter lateral canes of fall raspberries. These early berries are not a part of the main crop. Spotted wing Drosophila adults were caught in traps in raspberries in the last few days, so growers are starting control programs. Japanese beetle adults continue to be seen and are starting to cluster together.

Blueberry harvest of early maturing varieties continues, with excellent berry size at most farms. I continue to be surprised at how quickly berries have ripened over the past few weeks. No blueberry maggots nor SWD have been caught in traps, but SWD have been caught in summer raspberries, sweet cherries and tart cherries, so growers are starting control programs. Japanese beetle adults continue to be seen and are starting to cluster together. Phomopsis canker and twig blight-infected canes are starting to wilt with leaves turning light brown.

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