Vol. 19, No. 3, June 8, 2004

In this Issue
Tree fruit news
2004 Trevor Nichols Research Complex Trapline Data - Cranberry fruitworm
Trauma blight
Summer leafroller management
Recognizing thrip damage on young nectarines
Mullein bug
Small fruit news
Monitoring for blueberry maggot flies
New strawberry herbicides
Other news
Notice to agricultural water users: New state law for agricultural water use reporting
Regional reports
Weather news

Trauma blight

George Sundin, Plant Pathology
Mark Longstroth, MSU Extension

Trauma blight infection represents yet another way that the fire blight pathogen Erwinia amylovora infects apple and pear trees. Trauma blight infections occur at sites of leaf or bark injuries resulting from hail damage or injury from severe windstorms. Trauma blight can also be associated with injuries caused by late frosts. Trauma blight infection looks similar to shoot blight, however, shoot blight infection is assumed to originate at the shoot tip while trauma blight infection can be initiated anywhere along the shoot.

Two major factors contribute to trauma blight, injury from a severe environmental event and the level of fire blight inoculum in an orchard. Inoculum level is critical because weather events that injure trees also typically move the fire blight bacteria around in orchards. The bacteria present in the orchard can rapidly colonize the wounds. This speeds up infection because the bacteria have easy access to internal tissues. Remember that trauma blight infections can also occur on varieties such as Red Delicious because this pattern of wound colonization and infection appears to breach the natural resistance of these varieties.

The importance of inoculum level cannot be understated. Orchards without a previous history of fire blight, where cankers have been effectively pruned out during the winter, and where blossom blight has been controlled, have the least risk. Trauma blight may occur at relatively low levels in such blocks. However, orchards with active cankers or blocks already showing symptoms of blossom or shoot blight are under severe risk if trauma events occur.

Check your orchards as soon as possible after hailstorms or severe winds. The presence of hail damage, tattered leaves or other signs of wind damage indicates that tree injury has occurred. If the severity of damage is high, apply streptomycin within 24 hours in an attempt to reduce the level of infection. Streptomycin does have some eradicant activity, however, streptomycin cannot eliminate internal infections, once they have been initiated.

Summer leafroller management

Larry Gut, John Wise, and David Epstein, MSU Entomology

Leafroller activity can be predicted using degree day models, although the information is not as reliable as that provided by the codling moth model. Using a base of 42 degrees F, growing degree days (GDD) for obliquebanded leafroller (OBLR) first adult emergence are approximately 900, 1150 to 1200 for peak adult activity and 1250 to 1350 for first egg hatch. First sustained moth capture in pheromone traps is used as a biofix, thus if moth flight peaks between 250 and 300 GDD after initial biofix, the heaviest egg hatch should be about 400 GDD later. If the overwintering generation was effectively controlled earlier in the spring, then scouting orchards for obliquebanded leafroller larvae in actively growing terminals is the best way to judge whether infestations will require further control. This investment of time could result in saving several sprays.

Optimal timing for summer sprays varies according to the product of choice. For conventional insecticides, like organophosphates and carbamates, the first sprays should be targeted between 400 and 450 GDD to control hatching larvae before they can damage fruit. If Bt products are used the latter timing (450 GDD) may be the better choice because they have a short residual, which must be present to the larvae at the time and location they are actively feeding. If the first application is applied too early, it may take four or more sprays to keep the foliage treated throughout the long period of larval activity. Spintor has a similarly short residual (seven to ten days), but provides some contact efficacy, which will help kill larvae as they move to the actively growing terminals. In contrast, if Intrepid is used early it should be targeted to cover obliquebanded leafroller egg masses, around 350 GDD post-biofix, so that larvae will consume the chemical immediately upon emergence. Intrepid can also be used later to protect fruit against damage from older larval instars. Though usually targeted for the overwintering generation of obliquebanded leafroller, the insect growth regulator Esteem applied at obliquebanded leafroller egg laying timing will also provide some control.

It should also be noted that use of Spintor for the summer generation of obliquebanded leafroller will provide some control of codling moth, Oriental fruit moth, and spotted tentiform leafminer. Intrepid applied at the earlier summer obliquebanded leafroller timing will also provide some added control for codling moth and tufted apple budmoth. Esteem will provide excellent control of San Jose scale crawlers and some added control of codling moth. Bt's can also be expected to control other leafrollers when applied for summer generation of obliquebanded leafroller. Neonicotinoid insecticides are not effective controls for leafroller larvae.

Obliquebanded leafroller

Recognizing thrip damage on young nectarines

Bill Shane
District Fruit Agent

During the hot summers of 1998, 1999, and 2000, many peach growers became painfully aware of western flower thrip damage to peaches shortly before harvest. The tiny, 1 to 2 mm long, narrow, light-colored insects (Photo 1) caused considerable silvering/defuzzing of peaches that was quite noticeable on highly red-colored varieties. Adults have narrow fringed wings, and fly about the fruit when disturbed. Nymphs do not fly but crawl rapidly over the fruit surface.

We wish to alert growers that another symptom may be seen on nectarines at this time of year that is due to feeding damage during the petal fall to early shuck split stage. As the picture shows, thrip populations can cause a crescent scar-like symptom of various shapes. This symptom will enlarge with fruit growth and will be a problem when marketing the crop. Based on observations at SWMREC, damage by the insects can occur quickly while the fruit are still in the shuck although not be apparent until several weeks later. Although too late for this year, control strategies to manage this early season damage will have to start at petal fall using one of the labeled materials such as Spintor, Surround, Carzol, or one of the pyrethrum insecticides. Carzol is not labeled after petal fall on peaches and Lannate, although labeled on peaches, does not have a nectarine label. Western flower thrip overwinter as adults in weeds. In spring, the adults fly to flowering plants and eventually onto developing fruit. Several generations are produced per year. Cultural controls to remove flowering broadleaf weeds before fruit are present will help to eliminate sites where the population can grow.

Mullein bug

Amy Irish-Brown
MSU Extension Fruit & Vegetable ICM Agent

There have been reports around the state of unusual damage to small apple fruits - small, upraised bumps on the fruit surface that looks a little like scab, but not quite. This is most likely damage from the mullein bug or Campylomma verbasci. This insect is commonly an important predator of European red mite and green apple aphids throughout the summer months, but can occasionally feed directly on small fruit in early to mid-June. Fruit often receive multiple stings and the large majority of these abort just prior to or during June drop and some of the affected fruits will drop off. Affected fruit that remain on the tree develop small corky warts or bumps surrounded by conical depressions. As the fruit sizes through the summer, distortion of the fruit often occurs. The mullein bug typically attacks only certain cultivars with Red Delicious being the most commonly affected. Other varieties it favors are Northern Spy, Empire and Spartan, Cortland, Gala, Jonagold, and Golden Delicious. It sometimes attacks pears or grapes and, of course, the mullein plant.

The mullein bug belongs to the Miridae family and has piercing-sucking mouthparts to extract plant sap or pierce prey. The nymphs are tiny, oval-shaped and translucent-green in color. They look somewhat like an aphid, but have distinctive pink or reddish eyes. Nymphs and adults are fast moving, especially when disturbed. There are 2 to 3 generations per year.

Some interesting facts from the Ontario Ministry of Ag website cited below state that "nymphs will initially feed on plant sap attained from leaf veins, but will also sting developing fruitlets. Several weeks after petal fall the nymphs become predaceous and begin feeding on small prey such as European red mite and aphids. Nymphs with red bellies are an indication that they have been feeding on mites. Nymphs progress through five instars before becoming adults."

Once you see the damage, it's too late to target controls in apple. Blocks with damage this season should be scouted closely for mullein bug during bloom next year.

For more detailed information and pictures of mullein bug, visit this Ontario Ministry of Ag website: http://www.gov.on.ca/OMAFRA/english/crops/facts/mullein.htm

Monitoring for blueberry maggot flies

Rufus Isaacs and John Wise
Entomology

The blueberry maggot fly is a primary pest of blueberry because its maggots develop inside the fruit, and there is zero tolerance for infestation. With the high soil moisture this spring and warm weather expected over the next few weeks, emergence of blueberry maggot flies is expected to start in the next two to three weeks. To ensure that the first flies are detected, blueberry growers should deploy monitoring traps before the middle of June to ensure detection of the start of this pest's emergence.

Yellow Pherocon AM sticky boards are recommended for monitoring flies early in their activity season. These traps should be hung in a V shape in the top of the blueberry bush, with the yellow side facing downwards. Twist ties can be used to hold the trap in this position, and leaves should be cleared from the area near the trap to prevent contamination and to allow flies easy access to the trap. Monitoring traps should be checked at least once per week. Any blueberry maggot fly caught on the trap should be counted, recorded and removed. These flies have an inverted W pattern on their wing, and this should be identified before counting so only the pest insects are being counted.

For maximum effectiveness, Pherocon AM yellow boards must be recoated or replaced after three weeks of exposure. To increase fly attraction to traps, they should be baited with ammonium acetate or ammonium carbonate baits. The traps can be purchased with bait mixed into the sticky coating, or the regular yellow traps can have "superchargers" added to them (small yellow plastic containers) that release the odors to attract flies. A supercharger should be hung with each trap and should be replaced or refilled periodically to maintain their activity, according to the manufacturers' recommendations.

For effective monitoring in commercial highbush blueberry operations, a minimum of two Pherocon AM boards are needed for every five acres. One trap should be placed in the field adjacent to wild host plants, and the other trap should be placed in the center of the five-acre block. This will allow detection of fly populations that move into the field versus those resident in the field.

If flies are trapped immediately after they emerge from the soil, there is a 7 to 10-day period before egglaying begins. Because of this, if flies are trapped the first insecticide treatments should be timed for within a week after the first fly captures. This maximizes the impact of the treatment against egglaying flies to prevent fruit infestation.

Sticky green spheres may also be used for monitoring blueberry maggot fly. However, these traps are more effective later in the season when the majority of the flies have attained sexual maturity. Sticky spheres should be placed within the bush approximately six inches from the top of the bush and baited.

New strawberry herbicides

Eric Hanson
Horticulture

Several changes occurred in strawberry herbicide choices. First, a Section 18 label was granted last year for Spartan 4F (sulfentrazone), and again this year. Spartan is a preemergent material from FMC that kills weeds by blocking chlorophyll formation. The label is expected to again include application during the postharvest renovation time (June 25 to July 25) and during dormancy (October 15 to December 15).

Use rates are 4 to 8 oz per acre, and a maximum of 12 fl oz per season. Spartan can burn leaves and damage strawberries if applied when emerged growth is present. This is why use is restricted to times when strawberries are not actively growing. Do not apply to sand soils that contain less than one percent organic matter. Potential for crop injury may increase if soil pH is 7.0 or above.

Experience with Spartan in Michigan is somewhat limited. However observations indicate Spartan may be safer on strawberries than Sinbar, and can provide control or suppression of several difficult strawberry weeds, including common groundsel (Senecio vulgaris), field pansy (Viola arvensis), mayweed or dog fennel (Anthemis cotula) pineapple-weed or chamomile (Matricaria matricarioides), several pigweeds (Amarathis sp.), white campion (Silene alba), and yellow woodsorrel (Oxalis stricta). Yellow nutsedge (Cyperus esculentus) may also be controlled.

The 24(c) label for Stinger (clopyralid) continues. Stinger is a selective postemergent herbicide that has some soil activity. Many weeds in the legume and composit families, including clover, vetch, thistle, dandelion, groundsel, and pineapple-weed are controlled. Other susceptible weeds include curly dock, nightshade, common and giant ragweed, and red sorrel. Because Stinger controls a specific spectrum of weeds, it will be useful only were those weeds are present. Consider spot-treating problem areas in fields.

Stinger can be applied in the spring at least 30 days before harvest in established fields, or late summer at renovation time after harvest. Rates are 1/3 to 2/3 pint per acre. Do not apply more than two times per year or exceed 2/3 pint per season. Stinger can cause minor cupping or twisting of leaves, and may cause fruit to ripen over a shortened period of time.

Amine 4 is a new 2,4-D amine product labeled for strawberries. I believe the older product Formula 40 is no longer marketed. Use Amine 4 at renovation if broadleaf weeds are a problem. Be sure not to apply any product containing ester formulations of 2,4-D. Esters can kill strawberries and are not labeled for use.

Since Spartan and Stinger are relatively new to Michigan strawberries, we need to know more about their strengths and limitations. If you used these materials last year, please share your observations with me (517.355-5161 ext 386, hansone@msu.edu) so other growers can benefit from your knowledge. As with any new herbicide, it is important to learn how strawberries and weeds respond on each farm. Plan on working with these newer products this year.

Notice to agricultural water users: New state law for agricultural water use reporting

As part of an effort to protect Michigan's water resources against diversions to other regions of the country and to improve our stewardship of this precious resource, the Michigan Legislature recently amended the Natural Resources and Environmental Protection Act, (Public Act 451 of 1994). The passage of P.A.148 of 2003, which became Part 327 of Act 451, specifies that agricultural water users that have the capacity to withdraw surface or groundwater that exceeds 100,000 gallons per day (70 gallons per minute) are now required to register and report annually actual water withdrawals or face penalties of $1,000 for each violation.

Agricultural producers with a combined capacity that exceeds 100,000 gallons per day from all sources (excluding residential use) under common ownership or farm as defined under the Michigan Right To Farm Act, can choose from one of the following two reporting options.

1. Register with the Michigan Department of Agriculture (MDA) at no cost and submit an annual water withdrawal reporting form, called an "Agricultural Water Conservation Plan." The MDA will combine your reported information with other reporting farms in your township and submit the totals to the Michigan Department of Environmental Quality (MDEQ), or

2. Register with the MDEQ and submit annually a water use reporting form and pay a $100.00 filing fee each year. This information will be recorded for your individual farm instead of being aggregated into a township total.

A registration form is available to determine if you are required to report and if so, whether you are going to report to the Michigan Department of Agriculture (MDA) or the Michigan Department of Environmental Quality (MDEQ). Please complete this form and send by U.S. mail to the address on the form no later than October 1, 2004 to be included on the mailing list for the final reporting forms. This registration form is available at MSUE, MDA or MFB offices, or on the web at: http://www.michigan.gov/documents/2004_Agricultural_Water_Conservation_Plan_86969_7.pdf

To help understand the reporting process, samples of both the MDA and MDEQ annual water use reporting forms may be downloaded and printed from the following web sites. These are NOT to be returned at this time. Actual reporting forms will be mailed to in December 2004 at the address you record on the Registration Form. In the meantime, producers are urged to keep records of their water withdrawals throughout 2004, which will be the first reporting year.

Information from this program will provide valuable information for protecting Michigan's economy and the environment of the Great Lakes. If you have any questions regarding the enclosed please feel free to contact Robert Pigg at the MDA (517-373-6893) or Ron Van Til at the DEQ (517-241-1414). This information package can also be found at www.mighigan.gov/mdamichiganwateruse or www.michigan.gov/deqmichiganwateruse.

Regional reports

1 - Southwest

Mark Longstroth
Bill Shane
Al Gaus

Weather
Last week was pleasant with highs in the 70s lows in the mid 50s. There was little rain with rainfall totals of one to two tenths of an inch. Soils temperatures are near 70. This week's weather forecast is very warm weather with highs generally around 80 and lows near 60.

Tree fruit
There was much more insect activity due to the warm weather. Rose chafers are out. Plum curculio egg laying resumed. Plum curculio enjoys warm, humid weather. Potato leafhopper symptoms are easy to find and young fruit plantings may need protection. Peach tree borer and lesser peach tree borer numbers are down. American plum borers are also out. Trap catches for most pests are up due to the warm weather.

Peach growers are thinning fruit. Bacterial spot symptoms are showing up on leaves. Flagging of peach shoot tips attacked by Oriental fruit moth larvae can be found in peaches. Oriental fruit moth biofix was April 29 at 300 GDD45. We are now at 875 GDD, 575 GDD45 since Biofix and past peak activity for the first generation. Second generation Oriental fruit moth should begin to emerge at 950 GDD45. We are accumulating 25 to 30 GDDs per day and should start to see Oriental fruit moth flying again in a week or less. Trap catches in some areas have already started to rise, and whether this is the beginning of the warm weather or warm weather is hard to tell. Plum curculio and tarnished plant bug damage can be found on peach fruit. Mowing of cover crops and adjacent hay fields can move tarnished plant bug into fruit trees where they will feed on the fruit. We are now catching both peach tree borers.

Sweet cherry fruit are straw colored and some verities are beginning to color. Birds are eating early coloring fruit. There was a substantial drop in some varieties. Growers need to protect against brown rot, cherry leaf spot, and plum curculio.

Tart cherry fruit are pale, and straw-colored fruit are common. Growers need to protect against cherry leaf spot and plum curculio.

Plums growers should be applying plum curculio sprays. Fresh plum curculio damage was found on plum fruit on Monday (June 7). We are now catching both peach tree borers and growers may want to apply trunk sprays. White apple and potato leafhopper have been reported in the region and growers should protect young trees.

Apple scab lesions are common in unsprayed orchard and infected leaves are beginning to fall. Some of the fallen leaves show Necrotic leaf blotch symptoms. This disorder often appears when cool, wet weather is followed by hot, dry heat. Flyspeck and sooty blotch should not be a problem until later in the season. We usually start treatment for these diseases after we had accumulated 20 to 250 hours of leaf wetness after the end of scab season. Fire blight symptoms are not as common as we had feared. They were easier to find during the week, but the cool weather has delayed symptoms. All the blossom infections should be visible and shoot blight symptoms are also showing up. By the end of this week, we should see trauma blight symptoms from May 26 about June 6 and we will be able to tell how severe a fireblight season we will have this year. In young orchards, prune out strikes as soon as they are seen. Be sure to cut a foot or more below all visible symptoms. See the articles in the last two Fruit CAT Alerts, May 18 and May 25, 2004.

We biofixed codling moth on May 7 at 235 GDD50, our current total is 610 GDD, 375 GDD after biofix. This week we should be picking up about 20 to 25 GDD per day. We are on the downhill side of the first generation's flight but egg hatch this week should be strong. Most growers are applying their second spray for codling moth control. There are leafroller larvae feeding on the shoot tips. We are catching obliquebanded leafroller. Biofix for Southern Berrien County was may 27 for areas further north biofix was probably about May 31 or June 1 when temperatures were warm. See the article on summer apple pests in the May 25, 2004 Fruit CAT Alert. Neonicotinoids have not been thoroughly tested against obliquebanded leafroller so growers will not want to depend on them for control. European red mite and aphid numbers are building. White apple leafhoppers are out and potato leafhopper damage has been found. Growers should protect young trees.

Pear growers should protect against pear psylla if they have any.

Small fruit
In blueberries cranberry fruitworm and cherry fruitworm egg hatch has begun. Growers should apply insecticides to protect the fruit. We are catching obliquebanded leafroller. Growers are applying fungicide sprays to protect the fruit from anthracnose. Cane collapse due to phomopsis is showing up. Poor growth has been reported in many older fields. It seems this is due to the lingering effects of last year's winter injury.

Bloom has begun in grapes. Concord was in full bloom over the weekend. Accurate yield estimates can be made in several weeks after fruit shatter and the final number of fruit is set. Broken shoots and tattered leaves from high winds and hail are easy to find. Rose chafers are out. Grape berry moth egg laying usually begins at about bloom and rose chafer emerges to feed on the bloom. Little grape berry moth larvae feeding have been observed yet.

Strawberries harvest has begun in full swing. Earliglo is finished growers are picking Honeyoye, Jewel, and Allstar off matted row plantings. Fruit size and quality are excellent.

Raspberries and blackberries have small green fruit and there is still some bloom.

Cranberries are beginning to bloom.

Miscellaneous
The next Monday Spray Meetings will be on June 14 at Fruit Acres Farms in Berrien County. There is no meeting on Memorial Day. Check the Fruit Code-A-Phones in Van Buren (269) 657-6380 and Berrien (269) 944-4126 ext. 1 for more information

2 - Southeast

Bob Tritten

Weather
With warm temperatures over Southeast Michigan the last few days, the growth rate of all of our fruit crops has moved along very quickly. Much of the region was dry over the last week. However, there were a few unlucky farms that had another 0.5 to 0.75 inches of rain in slow moving showers last Wednesday (June 2). Our season is still running about 7 to 8 days ahead of normal. Most growers have experienced a certain amount of hail across the region. Many diseases are starting to show up now in tree fruits and small fruits.

Tree fruit
Apples are sizing extremely well with Red Delicious being 1 inch in the Flint area. Apples in the southern part of the region are now nearing 1.25 inches in diameter. Growers are assessing the affect of their thinning applications this season. Most fruit growers appear to have an excellent crop of apples coming along this year. The one exception is Red Delicious, which are on the light side at many farms this season. There are however some farms in the Washtenaw/Lenawee county area that have a light crop of apples and peaches due to frost and freeze injury.

Again this week there are just a few new pest problems to report. Potato leafhopper is one insect that I'm continuing to see high numbers of at many orchards. Some leaf curling is now being seen. Keep an eye out for potato leafhopper as we move through the next couple of weeks to assess whether or not control measures need to be applied. White apple leafhopper numbers are starting to build a bit, but not a serious problem at this time. Obliquebanded leafroller trap catches are starting to rise. Several of the aphids are now starting to show in higher numbers, these include green apple aphid and rosy apple aphid. Numbers for all of these are relatively low at this point in time however. Codling moth trap catches remain low across the region. Most growers applied a spray early to mid last week for biofixed codling moth controls. We are now awaiting the start of flight of the second generation. Oriental fruit moth trap catches remain low. I am continuing to see some injury on terminals of apples as well as peaches. I expect to see trap catches begin to rise next week. Tarnished plant bug continues to be seen in apples, however the numbers are fairly low. I have had one report of mullein bug or Campylomma bug feeding injury in apples. This is a rare pest in this region. Mullein bugs are a beneficial insect later in the season. Plum curculio and apple curculio adults are still being found in trees, but no new stings are being seen. Dogwood borer adults are now flying and are being caught in traps. European red mite numbers are generally declining across the region. This is mostly due to the effects of miticides, which were applied to hot spots at several orchards as well as the effect of washing of foliage, and lastly the buildup of predators. I am finding many predators on apples and other tree fruits. Ladybird beetles and lacewing adults and eggs are present in good numbers at many farms. Minute pirate bugs are also common across the region.

Apple scab lesions continue to show up at many fruit farms across the region. These lesions are mostly showing up in the top centers of trees. Over the last week I also began to see a few lesions show up on fruit. The first fireblight strikes were reported late last week in the southern part of the region. Currently there are a limited number of strikes. However with hot weather over the last two days, I would expect to see more show up in the mid to northern part of the southeast region. There have also been some tree deaths as a result of fireblight cankers from last season. Powdery mildew continues to be seen at many farms across the region, with some curling of foliage and some folded terminal leaves. Nectria twig blight infected twigs are showing up on Rome's in a few blocks in Monroe County.

Pears are sizing quite nicely with most being around 1 inch. We have a fair amount of fruit drop this year in pears resulting in a below normal pear crop at most farms. Pear scab is beginning to show up on leaves and fruit. Pear psylla adults were seen at many farms where insecticide applications have not been made. No fireblight strikes have been seen in pears.

Peaches are also sizing very nicely with most being around 1.25 inches in diameter. Green peach aphid is starting to be seen. Peach leaf curl is showing up at several farms across the region. It seems as if it's been a bad year for peach leaf curl. No new terminal flagging from Oriental fruit moth has been seen. Tarnished plant bugs have been seen in fairly low numbers. Twospotted spider mite has been seen feeding at a few peach orchards, however their numbers are fairly low. I would encourage some good scouting to occur on peaches. I'm beginning to see some green peach aphids as well. Peach thinning continues at most farms across the region.

Sweet cherries have not sized much over the last week, and apparently this is fairly normal. Bacterial canker infected fruit and leaves are commonly being seen across the region. There has been a fair amount of fruit drop over the last two weeks. Some cherry spot symptoms are also being seen.

Tart cherries are mostly at 12-14 mm in size. Bacterial canker infected fruit is now starting to be seen on tarts as well.

Small fruit
Strawberry harvest is underway at many farms in the mid to southern part of the region, and other farms in the Flint and Romeo areas will begin harvest in a day or so. Fruit has colored very quickly over the last week. While I am seeing a few tarnished plant bug and twospotted spider mites in strawberries, I don't think it will be a serious problem this year. I am seeing very high numbers of potato leafhoppers over the last week in strawberries. This pest bears watching. I'm also beginning to see gray mold symptoms show up on a few fruit in the southern part of the region. Leaf spot symptoms are also starting to be seen particularly where fungicide was not quite adequate to cover foliage during the May rains. It appears that we have a good crop of strawberries coming along.

Fall red raspberries are now about 16-18 inches in length. Leafroller damage is very common across the region. Raspberry cane borer is showing up now at several farms checked late last week and Monday.

Summer red raspberries have small fruit on them. We are pretty much through bloom at this time. The leafroller damage mentioned earlier in fall red raspberries continues to be seen on summer raspberries as well. I am starting to see some cane collapse from what I believe may be Phytophthora root rot in wet or waterlogged soil conditions. Stay tuned over the next few weeks for more details.

Blueberries continue to size fruit very well this year. It appears that we have an excellent crop this year. We are pretty well through blossom at this time. We have many fruits on blueberries in the 10-12 mm size. No new pest problems to report on blueberries. I expect to see Phomopsis twig blight infected canes to start showing up soon.

Grapes are nearing bloom at farms that did not have spring frost/freeze damage. Grape berry moths are now present at several farms. Grape flea beetle damage is being seen at several small vineyards.

3 - Grand Rapids Area

Phil Schwallier
Amy Irish Brown
Carlos Garcia-Salazar

Degree days and precipitation are accumulated beginning January 1. Degree day totals continue to run about four days ahead of the 30-year averages.

Tree fruit
Blocks that are known hot spots for blight are showing signs of blossom blight and shoot blight - there are oozing cankers out there as well. Almost all the blossom blight that could be showing up should be by now - the infections are still not as widespread as I thought they would be with the conditions we had during bloom. In blocks with only a few shoots, you can cut out the strikes at least a foot below the symptoms - be sure to disinfect pruners between cuts. In blocks with too many shoots to cut out, it's best to just let it run its course. If you're seeing symptoms now, you should be concerned about any windy weather or hail we get in the next several weeks that will cause a trauma blight situation and could really spread the bacteria around.

Primary scab is over for the season, but you still need to scout for lesions very closely in the next few days to be sure you're not seeing any lesions from the heavy infections in mid-May that could lead to problems with secondary scab as you reduce fungicide rates for the summer. It appears that apple scab was controlled very well in many orchards this year.

Concerning codling moth, we're 302 GDD50 past my regional biofix of May 11. We should be at or very near peak egg hatch, so cover sprays will be very important over the next week and a half. In blocks that have started using mating disruption for codling moth just this season, trap numbers are still quite high and cover sprays still need to be maintained. Remember, it can take one or two seasons of mating disruption before the population is reduced enough to stretch out or even eliminate routine cover sprays.

Obliquebanded leafroller started flying last week - I'm setting a regional biofix for June 4. Our target for early timed sprays at early egg hatch is for 400 to 450 GDD42 after the biofix - this probably about 12 to 14 days away from now is we accumulate normal daily GDD of about 25 base 42 each day.

We are seeing isolated damage to small apples from Campylomma or mullein bug.

If you have Internet access, you can find weekly pest reports on the following web page - web1.msue.msu.edu/clarksville. Click on the fruits link on the right-hand column and look for the documents that begin with 2004 in their title.

Small fruit
Blueberries in West Central Michigan are in green fruit stage. The variety Bluecrop is in late green while the verity Jersey is in the early green fruit stage. Weather conditions in the region have improved allowing growers to conducted most pest control activities delayed by the rain. Most growers have completed the first application against fruitworms and the required fungicide applications. Applications of fertilizer for blueberries have continued but in some cases growers are applying a lower dose of fertilizer than the recommended for this crop. This situation occurs more frequently among small blueberry growers with no access to technical assistance from MBG or private consultants. Fields under these conditions are showing poor new growth and plants with small leaves or few of them. Another important observation is the effect of winter and drought damage that occurred a year ago. In some fields affected by those conditions we are seeing plants that resemble symptoms of severe nutritional deficiencies, shoots with few leaves and with sparse fruit clusters with small fruits or no fruit at all (Photo 1). Most of the affected fields have been observed in Allegan and Van Buren and the most affected variety is Jersey, but the symptoms can be observed also in Bluecrop plants adjacent to Jersey fields.

The low temperatures that prevailed during the past week also delayed the emergence of insects, especially the cranberry fruitworm. Although the cranberry fruitworm started emerging in mid-May around Grand Junction, in Allegan and Ottawa counties it started until the end of May. We observed the first peak of emergence in those counties during the past week when we captured up to 35 moths per trap during a four-day trapping period. Also, oviposition has increased from 1 or 2 eggs in 50 fruit cluster to 4 and 7 eggs. That corresponds to an approximately 2 percent fruit infestation.

Regarding the cherry fruitworm, adult captures have declined to only one to two moths per trap during a four-day sampling period. Cherry fruitworm oviposition as decreased as well, 1 to 2 eggs per 50 fruit clusters. However, during the past week egg hatching as started in blueberry fields located in Allegan Co. Fruit damage in unsprayed blueberry fields amounted 2.4 percent, but in commercial fields, fruit damage was less than 1 percent.

4 - West Central

Mira Danilovich

Weather
Except for the minor shower in Mason County, last week was dry and warm. Temperatures were generally in high 60's and low to mid 70's for the highs and 40's and 50's for the lows. The puddles in the orchards are finally starting to dry out. This change in the environmental conditions has had a positive impact on the overall fruit development. There has been a tremendous growth development in the foliage as well as in the young developing fruit. It is easier to judge the crop load and make predictions. It appears that the cherry crop looks better now than a week ago but still well below normal.

GDD totals since March 1 as of Sunday, June 6

Tree fruit
Pears have set very heavy crop. Thinners have been applied with not so great results. There are still too many clusters with more than three fruit in a cluster. The fruit diameter is mostly between 14 and 16 mm. Apples are spotty - very thick and very thin in parts within the same blocks. Thinning applications started last week with the onset of warmer temperatures. Fruit size for most of the varieties is still within the optimum thinning window. It is expected they will be out of it by the end of the week. It takes about ten days following thinning application to see some conclusive results. Scouts reported seeing some sporadic scab lesions through out the area. Not as heavy as one could have expected given the weather conditions during the primary. Generally cooler weather that followed fireblight infections and trauma blight event of last month prevented a full-blown epidemic. There are reports of very few lesions so far. These warmer temperatures will facilitate disease development. By the end of the week, especially after the forecasted rains on Wednesday and Thursday (June 9-10), we should be able to see more of them as well as some bacterial ooze.

European red mites adults and summer eggs are being found scattered throughout the area. Potato leafhoppers, oblique and redbanded leafroller larvae are present in about the same numbers as last week. Codling moth flight is still strong, though the trap catch numbers have drooped since the last report. Our biofix for Oceana and Mason Counties was on May 18 at 267 and 232 GDD50, and for Manistee/Bear lake area on May 19, at 227 GDD50. Total GDD accumulation since the biofix is 174 for Hart, 143 for Ludington and 149 for Manistee/Bear Lake. Given the forecasted temperatures, it is likely that we will be accumulating 15-20 GDD50 daily. Depending on a choice of application material, treatments for first generation control should be scheduled for the end of this week or early next week. For this time frame, following the suggested timings for some of the newer chemistries for codling moth control, we are still having an option of using Assail, Calypso, Organophosphates, and Pyrithroids.

Tart cherries, plums, and peaches are developing very rapidly. Tart cherries are 13 mm in diameter, sweet cherries are at 14-16 mm, Stanley plums are at 14-15 mm, and peaches are 15-18 mm. Scouts reported finding cherry leaf spot lesions from previous infections. They are quite heavy and widespread in southern parts of the district. Now that the temperatures are in 70's and 80's, the lesions are becoming even more visible and the leaves are starting to yellow and drop. There is not much to be done about those leaves, but there is a need to protect still developing leaves from further infections, particularly now that there is an abundance of inoculum in the orchards. There are quite a few bacterial spot lesions across the stone fruit species. Brown rot needs to be addressed as well, particularly in sweet cherries where there is a very heavy fruit set and the fruit is just roped. With the color change, this issue will become even more pressing. American plum borer trap catches have been stable, same as last week. Plum curculio numbers have gone up. There are a few fresh egg-laying scars on the fruit. Lesser peachtree borer trap catch numbers have gone up significantly since the first catch on May 30. We started catching Oriental fruit moths again this past week. Trap catch numbers have gone from 0 to 3. Overall, insects have been more active this past week.

5 - Northwest

Jim Nugent
Jim Bardenhagen
Duke Elsner

GDD accumulations at the NWMHRS
GDD42       674

GDD50             321

Weather
Temperatures this week have warmed significantly after the long period of cool weather.

Tree fruit
The sweet cherry crop is better than the last couple of years in Northwest Michigan. Golds are generally not set as well as most other varieties, possibly the result of later bloom timing. Two weeks of cool, wet conditions were favorable for the development of the bacterial canker pathogen. Symptoms are quite common on fruit and leaves. Cherry leafspot symptoms are also present in some blocks. Finally, some warm evening temperatures are resulting in plum curculio egg laying activity.

In tart cherries, the cold, cloudy weather during the pollination and fruit set time have hurt the crop. Warm weather this week will help develop the fruit to the point where a more accurate assessment can be made, particularly in the later areas of the region. Cherry leafspot symptoms are appearing now from recent severe infection periods. So far this has been a very challenging year to control it. Plum curculio is beginning egg laying. Green fruitworm populations generally appear to be fairly low. Obliquebanded leaf roller is more