In this issue
Tree fruit news
§ Early summer scouting and management options for mites in apples
§
Sweet Cherry Variety Showcase July 12,
§ Cherry High Tunnel Field Day
Small fruit news
§ Post-emergent herbicides for blueberries
Other news
§ How effective is your irrigation system?- Field day on June 27
§ NW station IPM educator position interviews
§ Regional reports
§ Weather news
John Wise and David Epstein
Entomology
Mid-June is a good time of the season to be scouting for
European red mite and two-spotted spider mites in apple orchards. Initial
sprays (or other controls) for key early season pests, like codling moth, have
already occurred such that the impact of those actions on mite populations will
be readily evident. We recommend monitoring mites using a 100-leaf sample, 50
percent spur leaves and 50 percent shoot leaves, and counting the numbers of
each pest species along with key predator mite species. The three most important
predaceous mites are Amblyseius fallacis
(Phytoseiidae), Agistemus fleschneri (Stigmaeidae),
and Zetzellia
§ 2-3 mites per leaf from petal fall to mid-June
§ 5-7 mites per leaf from mid-June through July
§ 10-15 mites per leaf in August
The presence of predaceous mites (less than one per leaf) and heavy rainfall, which can remove mites from the canopy, may justify postponing a treatment. Continued weekly sampling with the above suggested 100-leaf sample, is the primary means to assure that mite pest populations remain in check, while potentially saving the application of an unnecessary spray.
Apollo, Savey and Agri-Mek all provide extended control of
European red mites, ranging from 10 weeks to full season depending on mite pressure,
tree vegetative growth and predator mite populations. Savey and Apollo work
primarily as ovicides, but are now labeled for in-season use with their
respective 28-day and 45-day pre-harvest intervals. Agri-Mek is most effective
when applied between petal fall and first cover (14 days past petal fall) with
the addition of one gallon of paraffinic spray oil per acre. Zeal and Envidor
are excellent mid-range residual materials
(8-12 weeks) that have flexibility for early or late season application. They
are relatively safe on predatory mites, but because of their unique
mode-of-action, they are somewhat slower acting than contact miticides.
Nexter, Portal, Kanemite and Acramite are good contact miticides, which when used in early summer can provide six to eight weeks of control, or later as a “clean up” application if early season products have lost control of mites. Vendex provides good control during warm weather. Vydate will kill some mites, but is very toxic to predators and causes fruit drop if used within 30 days after petal fall.
Photos are from A Pocket Guide for IPM Scouting in Michigan Apples. To order call 517-353-6740 or visit: http://www.ipm.msu.edu/ApplePocket.htm
Bill Shane
Southwest Extension Educator
International Plant Management, Inc., in cooperation with
MSU Cooperative Extension, is sponsoring a Sweet Cherry Variety Showcase on
Thursday, July 12, at 4:30 PM. The showcase will be held at the International
Plant Management sweet cherry test block at Fruit Acres Farms, owners Annette
and Randy Bjorge, in
The cherry test block has 85 plus sweet cherry varieties
including selections from New York State Agricultural Experiment Station in
On display will be cherry samples from research stations and
growers from
All growers, extension and university personnel and their employees are invited to attend. Refreshments will be provided. Fruit Acres Farms is located in Coloma, Michigan, one mile south of I-94 exit 39, on Friday Road. The test block is a quarter mile east of the corner of Friday and Carmody Roads. Registration is not required. For more information, call International Plant Management at 800-424-2765.
When and where: Tuesday,
June 26 at 2:30 PM at the
Station.
There will be a simple program in the orchard to talk about the tunnels – what
we've learned, what challenges remain, the Extenday, climatic comparisons in and
out, etc. We will meet rain or shine. This event is being orgranized by MSU
horticulturist Greg Lang.
Eric Hanson
Horticulture
Several post-emergent herbicides are labeled for use in
Aim, Gramoxone and Rely are burn-down materials. They kill treated plant parts, but do not move within the plant. As a result, perennial weeds are usually not killed because the chemical does not move to the roots. Rely may move slightly in plants, because it often provides a little better control of some herbaceous perennials, such as dandelion. Aim is relatively inexpensive, but does not control grasses. Rely is much more expensive, but controls broadleafs and grasses. All three herbicides kill green bark and leaves of blueberries, so take care to keep spray off blueberries.
Fusilade and Poast are selective grass killers; they have no effect on bloadleaf weeds or blueberries. Application time is critical for control. Grasses must be treated when they are 4-8 inches tall in the spring. If grass is taller, control is poor. These materials are often useful to control quackgrass or annual grasses in young plantings.
Roundup and Touchdown (glyphosate) are the most effective postemergent herbicides for blueberries, but also the most hazardous. These chemicals are absorbed by green tissues and move throughout the plant. Perennial weeds are killed because the chemical moves to below-ground plant parts. Translocation is a two-edged sword. Glyphosate applied to blueberry branches moves within the bush, and can kill large canes or whole bushes. The most effective time to treat perennial weeds is late in the summer because absorbed glyphosate tends to move down to the roots. This timing is also most hazardous for blueberries. Use extreme care to avoid contact with blueberry tissues.
Learn how to check your irrigation system with MSU Extension
educators. An irrigation system field day will be offered Wednesday, June 27.
This event will be held at three different locations and times for your convenience.
Bosch’s Countryview nursery at 10:00 AM,
Dr. Tom Fernandez, Department of Horticulture, will be demonstrating the techniques you can use to do your own system checks.
Please join us for interviews of candidates for the
Northwest Michigan Fruit IPM Extension Educator position, scheduled for Monday,
June 25, at the NW Horticultural Research Station,
Mark Longstroth
Bill Shane
Greg Vlaming
Last week’s weather was variable. Highs were in the 70s early, but Thursday was hot (90ºF) and very windy. A cold front moved through the region Friday, and the weekend was pleasant. There was no rain over most of the region last week. Crop growth continues at a fast pace. The forecast is for warmer weather with temperatures in the 80s. Soils are beginning to dry and growers should begin irrigation on sandy soils.
|
|
Grapes from April 1 |
|||
|
Location |
GDD 42 |
GDD 45 |
GDD 50 |
GDD 50 |
|
1316 |
1105 |
801 |
703 |
|
|
1391 |
1180 |
865 |
728 |
|
|
1167 |
982 |
692 |
612 |
|
There are still only modest numbers of rose chafers, but some growers report high numbers. Potato leafhoppers are easier to find. San Jose Scale crawlers should be out and growers can target sprays to reduce this pest. Aphid numbers are building.
Peach fruit are 1.5 inches in diameter. We are finding Oriental fruit moth larvae feeding in the shoot tips and fruit. The second generation of Oriental fruit moths should be emerging. Green peach aphids are causing leaf curling.
Tart cherries fruit are coloring and growers are applying ethephon. Maintain protection for cherry leaf spot.
Sweet cherries are coloring and harvest of early varieties has begun. We had significant losses due to wind last week. Birds are a significant problem. Put out cherry fruit fly traps.
Apple fruits are 1.25 to 1.5 inches in diameter, and the June drop is finished. Fire blight symptoms are becoming common and some of the symptoms are from shoot blight. Aphids and leafhoppers can spread the disease infected tissues to healthy shoots. Codling moth trap catches are down, but egg hatch is at its peak. We are catching obilquebanded leafrollers. We biofixed on May 28 (942 GDD42 at SWMREC). Treatment is timed for peak egg laying at 450 GDD post biofix or peak egg hatch, 600 GDD after biofix. This would be late this week to early next week. The second generation of Oriental fruit moths should be emerging soon and pheromones should be renewed in traps. European red mites number are building. Growers should treat young nonbearing trees to control potato leafhopper.
Pear fruit are 1.25 inches in diameter. Pear psylla are flying.
Blueberries have green fruit. Shoot growth has stopped, but many shoots have begun a new flush of growth. Fruitworms can be found feeding in the fruit. Growers should apply fungicides to reduce anthracnose fruit rot later. Blueberry maggot traps should be out.
In grapes, Concords are at berry shatter. Vinifera bloom is ending. The fruit set looks good. Treatments for grape berry moth should have been applied. Fungicides to control grape diseases are import in the post bloom period. Given the dry conditions forecast for this week, powdery mildew in the primary disease concern. Growers should watch the weather and apply control material in front of the next rain. We expect to see more rose chafers.
Strawberry harvest is well underway. Sap beetles are attacking ripe fruit. Black root rot has caused some fields to wilt. Growers should treat young plantings to control potato leafhopper.
Summer raspberry have green fruit. Leafrollers such as redbanded leafroller are curling up the leaves. Leaf feeding by raspberry fruitworm is tattering the leaves. Potato leafhopper can also be found. Japanese beetles usually emerge with the first ripe fruit.
Cranberries are blooming.
The next Monday Fruit Update
meeting will be Monday, June 18, 5:00PM, at the Fruit Acres Farm in
With seasonal temperatures over the last week, our season still is running ahead of normal in terms of degree days. We are around five to eight days ahead of normal at many reporting stations across the region. With the warm temperatures late last week, fruit growth continues at a rapid pace. In terms of phenology of our fruit crops, it depends on the crops in terms of where we are at. For example, strawberry harvest has begun a few days earlier than normal, and it appears right now that the beginning sweet cherry harvest will be much ahead of normal. It’s definitely a strange year.
|
|
|||
|
Location |
GDD42 |
GDD45 |
GDD50 |
|
Commerce ( |
1168 |
963 |
675 |
|
Emmett (St Clair) |
1108 |
913 |
642 |
|
|
1165 |
957 |
680 |
|
Lapeer (Lapeer) |
1152 |
953 |
677 |
|
|
1286 |
1074 |
775 |
|
Romeo ( |
1142 |
945 |
669 |
Apples in the
New pests to report this week include potato leafhopper nymphs, obliquebanded leafroller adults, rose chafers, powdery mildew and apple scab showing up in higher amounts. Potato leafhopper adults were seen for the first time in pretty good numbers last week, and this week I’m starting to see nymphs not only in apples, but also in peaches. Rose chafers are a new pest, report as of last week. They are being seen in light numbers. Obliquebanded leafroller adult flight is now under way; numbers are not very high at this time. Codling moth trap catches in mating disrupted blocks remain low, and in conventional blocks trap catch numbers are much higher. However, even in non-disrupted blocks, trap catch numbers are coming down. Oriental fruit moth trap catches are near zero as we are at the end of first generation flight. There is some shoot flagging of apples and also in peaches. Green apple aphids continue to be seen in light amounts, as do rosy apple aphids. Dogwood borer larvae continue to be seen feeding on burr knots. Oyster shell scale crawlers were active last week, and are now waxing over preparing for their long overwintering stage. San Jose scale females were seen late last week. More details on this pest as we move through the next several weeks.
Apple scab continues to show up in higher amounts on both fruit and foliage. We are still in primary apple scab season, as we have not had a rain event at either of our apple scab spore monitoring stations since last Tuesday, June 5. No new fireblight strikes were seen over the last week. I am continuing to see overwintering cankers become active and shoot death results. Powdery mildew is being seen on the leaves and the fruit, as well as on other tree fruits.
Pears continue to size quite nicely with most being around 1.25 inches in diameter. Pear psylla adults continue to fly, and egg laying continues.
Peaches have sized fairly well over the last week, with most now in the range of 1.5 inches in diameter. Oriental fruit moth larvae infected shoot strikes continue to be seen in peaches. Green peach aphids continue to cause some leaf curling at a few farms. Leaf drop from bacterial spot infected foliage is causing extensive leaf drop at some farms. Fruit thinning is about 50 percent complete at this time.
Sweet cherries
are continuing to size quite nicely, with most being 22 mm to 24 mm. They have
developed a great deal of color over the last week. Some of the very earliest
varieties of sweet cherries will begin harvest late this week or over the
weekend. I expect to see most of the earlier maturing varieties ready for
harvest next week. This will be a record early start for harvest in sweet
cherries in east
Tart cherries have not sized much in the last week, however many are turning straw color and there is even some red-colored fruit.
Strawberries are being harvested across the entire region. Many farms started picking early last week in the southern part of the state and then over the weekend in most of the rest of the region. Pickers have found good quantities and quality berries. I have been to a few farms where white grubs have been feeding on roots and causing plants collapse. Potato leafhopper populations have been high in a few new plantings. I am seeing more leaf spot diseases than normal.
Raspberries continue to have good fruit development. Summer red raspberries have large green fruit, with a bit of bloom remaining. I expect summer red raspberry harvest to begin in about three weeks. Fall red raspberries are now about 24 to 30 inches in length. Some of the small canes have a few early fruit on them. Potato leafhopper populations are high in a few fields of fall red raspberries.
Blueberries have small green fruit, mostly in the range of 11 to 14 mm in size. Some of the fruit is beginning to turn a light blue color. I’ve not seen any reports of cranberry fruitworm or cherry fruitworm in traps across the region over the last week.
Grapes are in full bloom for Concords, and it appears that we have a fairly good crop coming along this season. There has been extensive new growth this year in grapes.
Phil Schwallier
Amy Irish Brown
Carlos Garcia-Salazar
Apple fruits are
sizing well, and the crop is looking to be a better set than originally thought
in some blocks, and a bit lighter in others. The Red Delicious crop looks
excellent this year. Sweet cherries
are nearing harvest – probably about two weeks ahead of average this season.
The peach crop is average or
slightly below average in some blocks, depending on site and location. Strawberry harvest began late last week
in the
For apple scab, primary scab is done for the season. We most likely had our last apple scab infection on Saturday, June 2 and no additional ascospores have been caught since that wetting event. Growers and scouts should be watching carefully over the next week or two to make sure no primary scab lesions are present in your blocks.
We can expect fire blight symptoms from the hailstorms that moved through Saturday, June 2 to start to show up anytime this week probably by June 14 or 15 for sure if you have it. Any fire blight that may have infected from the high winds on June 7-8 probably won’t show up until early or mid next week. It usually takes about 10 to 14 days to begin to see strikes from trauma blight.
A regional biofix for Oriental fruit moth was set for
A regional biofix for codling moth was set for May 20. We have accumulated 345 DD50 since May 20 and 378 DD50 since May 15. Egg hatch should be well under way now, but not at a peak level yet. Peak egg hatch is predicted for the weekend or early next week at around 500 DD50 post biofix. Cover sprays for first generation codling moth will become very important over the next two to three weeks and should be of the most concern in blocks with very high numbers. The more you can do to control first generation, the easier it will be to deal with second generation.
European red mites have been more common this year than normal, and some petalfall miticide applications are starting to break in some blocks. The numbers of mites per leaf range from one to over 10, depending on the site. Five mites per leaf is the threshold for June. Predators are difficult to find in some European red mite populations, but they are starting to show up this week. I think the combination of high mite counts at petalfall, lack of rain events to naturally wash mites off and the unusual hot temperatures, has really pushed European red mite development over the last month in some blocks.
Green apple aphids are now present and starting to form colonies. Predators can be found more readily this week than last in aphid colonies.
Last week started with cooler temperatures that were only in the 60’s for highs with a few 30’s for the lows. On Thursday, June 7, a warm front from the south brought high temperature to the region as a prelude of the storm that came later on that night. Throughout the district, we had strong and sustained winds. The rain hit the northern part of the district first in the evening hours on Thursday, spilling over the entire district after midnight. Fortunately, the storm did not turn out the way it was predicted. Though we had very strong winds with gusts in access of 50 MPH, we did not get the predicted hailstorm. Though we had a few fallen trees and many broken limbs and branches, it was not as bad as it could have been. Precipitation was not as high as predicted either. We could have used more rain. Soils are getting dry due to winds and accelerated evapotranspiration.
Fruit is developing nicely for now, though that might be jeopardized if the soil moisture is not maintained at the higher than present level.
Apples are about an inch in diameter. Overall, thinning has been successful.
Pears are from 20-22 mm in diameter. It looks like it will be a full crop.
Tart cherries are starting to change color. There are more cherries on the trees than anybody expected after the frost events this spring.
Sweet cherries are getting some red color and may be ready for harvest a few days earlier.
Peaches are developing very rapidly and are approaching an inch in diameter (Red Haven).
Plums are from 18-20 mm in diameter. Looks like a full crop.
Our degree-day accumulation is running ahead of last year; 39 DD50 for the Manistee/Bear Lake area, 52 DD50 for Ludington and 91DD50 for the Hart area. Compared to the 30-year average, we are from four to five and nine days ahead of normal, respectively.
|
Location |
DD42 |
DD45 |
DD50 |
Rainfall last week |
Rainfall since 4/1 |
|
Hart |
1082 |
889 |
621 |
0.15 |
5.22 |
|
Ludington |
984 |
803 |
554 |
0.78 |
6.00 |
|
Manistee |
1053 |
869 |
607 |
0.32 |
5.08 |
This most recent rain resulted in a low scab infection event for Manistee/Bear Lake area, but none for Hart and Ludington. This rain event did produce spore release. I found one spore or 0.5 per rod. Scouts are reporting finding some scab lesions in a few blocks. Overall, it appears that the primary scab was controlled well in most blocks.
Following this storm, fireblight has been our main concern. With fireblight strikes/shoot blight as well as some blossom blight symptoms present in the blocks, and tree bashing by the high winds causing a lot of leaf and branch breakage, there is definitely potential for trauma blight. At the time, growers were advised to apply trauma blight treatment. Symptoms of this event could be expected in about a week or so.
Low cherry leaf spot infection period recorded for the entire district. There are a few reports about seeing lesions from the previous infections.
Powdery mildew is starting to appear in peaches (fruit) and cherries.
Bacterial canker on sweet cherries is widely spread through out the district. Well-defined symptoms are present on spurs and on the fruit.
Codling moth numbers have significantly dropped since last
week when we hit the peak of their flight. Greater peachtree borers have
started their flight. The numbers are still low. Lesser peachtree borer numbers
have just about doubled since last week. We are still catching red-banded
leafrollers, though the numbers are very low and only in the single digits.
Scouts are reporting finding spotty numbers of adult European red mites and
summer eggs. Rosy apple aphids and green peach aphids are gaining in their
numbers. Pear psylla is very active and numerous. First catch of obliquebanded
leafrollers was reported for
Scouts and consultants are finding evidence of Mullein bug
damage to the fruit. (view photo) Symptoms are pimple-like bumps on the fruit.
There is no particular preferred location on the fruit. It can appear near the
calyx end or on the side or towards the stem-end. The raised bump is
purple-brown in appearance. The bug itself is rather tiny, grayish-brown,
resembles tarnished plant bug. The nymphs initially feed on plant sap attained
from the leaf veins, but they also may pierce the young developing apple fruit
causing the pimple-like scars. The key is to control them around petal fall.
Later on in their life, nymphs become predaceous and start feeding on aphids
and European red mites.
Growing
degree day accumulations at NWMHRS
GDD42 1028
GDD50 584
Growth
Stages at NWMHRS (6/11/07—8:00am)
Apples have 20 mm fruit.
Pears:
Sweet cherries: Hedelfingen, Gold and Napoleon have 14 mm fruit.
Tart cherries: Montmorency and Balaton have 13-14 mm fruit.
Apricots have 33 mm fruit.
Plums have 19 mm fruit.
Grapes: Chardonnay have 25 inch shoots.
Degree day accumulation to date is very close to the
accumulation on this date last year. This is the fifth year since 1990 that has
exceeded 1000 GDD base 42 by this date. Most areas in northwest
Apples have generally sized beyond the ideal thinning window. Codling moth trap catches are way down this week. Obliquebanded leafroller larval populations have dropped to very low levels, while adult trap catches are up substantially. Rosy apple aphid) populations have increased in some area orchards; if rosy apple aphid populations warrant treatment consider selection of a material that is effective for both codling moth and rosy apple aphid. Potato leafhoppers are often present where no control has been applied. Rose chafers are now emerging and can become important in a few sites where populations are high.
In cherries, degree
days would indicate that fruit maturity at this point in the season is the same
as last year. However, keep in mind that orchards with heavy crops take longer
to mature the fruit than orchards with light crops. This delayed maturity is
most pronounced in tarts when the leaf to fruit ratio drops below two leaves
per fruit. Plum curculio egg laying continues where plum curculio are present.
The USDA cherry crop estimate will be announced on June 21 at 8:30 AM. The
USDA no longer conducts an objective yield survey for tarts. Instead, the
estimate is compiled based on a grower survey. Because of this change, the
estimate is no longer compiled by region within
In peaches, rose chafer has begun to emerge, so be sure to monitor peach orchards for this important pest.
In grapes, rapid shoot growth and leaf development has created dense canopies in many vineyards. Powdery mildew is the greatest disease concern as we continue to experience warm and dry weather. Potato leafhoppers are easy to find, with nymphs now present as well. The first rose chafers have arrived in vineyards. Growers should keep an eye out for populations of rose chafers on young vines where their numbers can be quite significant. See the Northwest Michigan Grape Scouting reports for more information at: http://grapes.msu.edu/current.htm
Jeff Andresen
Agricultural Meteorology
Geography
A strong upper air ridge and associated surface high
pressure across the central
Following the movement of the troughing feature through the region early next week, current medium range forecast guidance for the 6-10 day time frame covering June 17-21 suggests a mostly west to east zonal pattern across the United States, followed by the formation of troughing across the Midwest and Great Lakes during the 8-14 day period (June 19-25).
The official NOAA 6‑10
day outlook calls for temperatures to range from near normal in western and
central sections of the Upper Peninsula to above normal elsewhere, and for
precipitation to range from near normal in the Lower Peninsula to above normal
in