In this issue
Tree fruit news
§ Predicted peak 2008 apple harvest dates
Small fruit news
§ Blueberry gall midge injury more common this year
§ Managing mid-late season grape berry moth
§ What to do when you start seeing disease in the vineyard
§ Grape IPM workshop July 24 in Scottdale, Berrien County
§ NW Wine Grape IPM “First Friday” meeting and Harvest BBQ on August 1
Other news
§ TNRC Field Day
§ SWRMREC High Tunnel Day
§ Agricultural field sanitation requirements in Michigan
§ Regional reports
§ Weather news
Next issue August 5
Phillip
Schwallier, District Horticulture Educator and Station Coordinator
Amy Irish-Brown, District ICM Educator
Apple maturity for 2008 is expected to be close to the long term normal date and seven to 10 days behind last year. Bloom dates were behind last year for the most part, and temperatures during and after bloom were cold. This results in a prediction of delayed maturity. However, actual harvest dates for this year may differ from predicted dates for four reasons. First, the spring multiple freezes killed or damaged bloom on older wood including the king flowers. With bloom on older wood being reduced, many of the fruits on the trees are borne on one-year-old wood, which tends to bloom up to a week later. Second, where cropload is light, the fruit will mature a few days earlier than our predictions. Heavy cropload trees will mature a week after our predictions. This year there is quite a variation in croploads, but most trees are light. Third, there was considerable variation in bloom dates from block to block and orchard to orchard. Some blocks bloomed three to five days after a neighboring block. There was also bloom variation up and down hills. Fourth, temperatures during bloom were quite cold causing an extended bloom, which contributes to a less accurate prediction.
This year’s weather gives us predicted harvest dates (Table 1) as much as four days ahead to five days later than the long term normal, depending on the variety and location. These predicted harvest dates are for the center or peak harvest of these varieties for CA storage. This year, the state will harvest apples roughly five to 17 days behind last year (Table 2) predictions.
Hot temperatures during July and August will hasten the maturity of some varieties. ‘Gala’ is notorious for ripening early when late summer temperatures are above normal. Other varieties are less prone to hot temperatures advancing fall maturity. Still other varieties ripen when cold temperatures occur at near harvest time.
The normal harvest dates for other varieties are listed in
Table 3 for the
Table 1. 2008 Predicted peak harvest dates
|
Full bloom date |
Predicted harvest date |
||||||
|
Station |
McIntosh |
Jons |
Reds |
McIntosh |
Jons |
Reds |
Observer |
|
SWMREC |
5-6 |
5-7 |
5-7 |
9-13 |
9-22 |
9-28 |
Shane |
|
|
5-7 |
5-8 |
5-8 |
9-12 |
9-25 |
10-1 |
Tritten |
|
|
5-8 |
5-9 |
5-9 |
9-12 |
9-23 |
9-29 |
Tritten |
|
Peach Ridge |
5-9 |
5-11 |
5-11 |
9-14 |
9-27 |
10-3 |
Schwallier |
|
Ludington |
5-15 |
5-17 |
5-17 |
9-19 |
10-3 |
10-9 |
Danilovich |
|
NWMHRS |
5-21 |
5-22 |
5-22 |
9-21 |
10-13 |
10-19 |
Rothwell |
|
Days relative to normal * |
Days relative to last year* |
|||||
|
Station |
McIntosh |
Jons |
Reds |
McIntosh |
Jons |
Reds |
|
SWMREC |
-3 |
-1 |
+0 |
+17 |
+7 |
+7 |
|
|
-4 |
-4 |
+1 |
+11 |
+10 |
+9 |
|
|
-2 |
2 |
+3 |
+9 |
+11 |
+10 |
|
Peach Ridge |
0 |
-1 |
+1 |
+13 |
+8 |
+7 |
|
Ludington |
+3 |
0 |
+5 |
+5 |
+10 |
+12 |
|
NWMHRS |
+1 |
-3 |
+4 |
+12 |
+5 |
+5 |
* - = days before, + = days later
|
Variety |
Normal date |
2008 predicted date |
|
Paulared |
8-24 |
8-24 |
|
Gingergold |
8-26 |
8-26 |
|
Gala |
9-10 |
9-11 |
|
McIntosh |
9-15 |
9-14 |
|
Honeycrisp |
9-18 |
9-18 |
|
Empire |
9-22 |
9-21 |
|
Jonathan |
9-28 |
9-27 |
|
Jonagold |
9-28 |
9-27 |
|
Golden Delicious |
10-2 |
9-30 |
|
Red Delicious |
10-5 |
10-3 |
|
Idared |
10-10 |
10-9 |
|
|
10-15 |
10-14 |
|
|
10-25 |
10-25 |
|
Braeburn |
10-25 |
10-25 |
|
Goldrush |
11-1 |
10-30 |
Rufus Isaacs
Entomology
The blueberry gall midge, Dasineura oxycoccana (Johnson) (Diptera: Cecidomyiidae), is a pest
of blueberries across the
Adult flies of the blueberry gall midge overwinter in the
soil and emerge in spring to mate and lay eggs. They are fragile and
approximately two to three millimeters long. Mature larvae are about one millimeters
long and 0.3 millimeters wide, legless, and yellow to red in color. The biology
of the blueberry midge is poorly known in
Information for this article was gathered from observations
in
Rufus Isaacs, Keith Mason, and Steve Van Timmeren
Entomology
We are conducting regular scouting of vineyards in southwest
Maintaining control of grape berry moth requires a combination of good timing, high insecticide activity, and excellent cluster coverage. This update will cover each of these issues.
The three main times for grape berry moth controlling insecticides are 10 days post bloom, just before berry touch and just before veraison (in juice grapes). These are the general timings of egglaying by the first, second and third generations of this pest. Using crop growth stages provides some adjustment for variation between the seasons, but we are also working to develop and validate a degree day model to refine these timings and ensure optimal timings for control sprays.
The best way to time sprays for this pest in your vineyard is the use of monitoring traps and weekly scouting of vineyards so that you know when moths and larvae are most active. Scouting can be focused on vineyard hot spots to save time, but it is useful to spread scouting across your farm to know where grape berry moth activity is highest. Most growers know hotspots on their farm, but monitoring can tell you when the pest is active in different blocks. Such information can ensure that pesticides are used efficiently, allowing you to focus your time, fuel, and spray material costs where they are most needed.
The summer generations of grape berry moths are difficult to time sprays for because there is often no distinct increase in moths in traps and the generations will overlap. From our detailed sampling for eggs in borders of high risk vineyards for grape berry moth, we see some egglaying during early to mid-July (the current egglaying observed during scouting) and a period of more intense egglaying that starts before veraison in August and continues through until harvest. This late-season generation can lead to infestation of clusters that are harvested and can expose clusters to fruit rots, making it important to reduce injury from this generation.
When selecting an insecticide, there are many options for berry moth control. Some of these are selective for this pest, while others will also provide control of leafhoppers, Japanese beetle and other insects that can occur at the same time. For details of registered pesticide options, consult MSU Extension publication E-154.
The selective insecticide Intrepid has shown good effectiveness against berry moth in small plot and vineyard-scale trials, and we have tested it in the mid-season timings in July and August at the 12 oz rate and at eight oz/acre. Although this is more expensive than many standard insecticides, the product lasts a long time (two to three weeks depending on the rate) and is resistant to wash-off. This helps make it an effective tool to use against the high pressure of egglaying seen late in the season, when maintaining control would otherwise require multiple sprays. This works on the molting system of the larvae, disrupting normal development and because it is selective, Intrepid will not control leafhoppers or beetles. It also has a 30 day PHI. During our 2007 trials, the eight oz rate of Intrepid applied at the start of the second and third generations was just as effective as sprays at the 12 oz rate, suggesting that eight ounces is sufficient to provide control of grape berry moth. Use of this insecticide has also reduced the number of infested berries and the number of diseased berries in samples taken at harvest. Another selective insecticide to consider is B.t. (Dipel, Javelin, Deliver etc.), which only targets the larvae of berry moth. Both of these selective insecticides need to be eaten to be effective, so their activity is greatest when temperatures are above 70°F. Intrepid is quite stable and resistant to wash-off once sprayed providing good residual control, whereas B.t. formulations degrade under ultraviolet light, providing three to five days of activity
Most pyrethroids are inexpensive insecticides with broad insect activity that can provide effective control of moths, eggs, and larvae of grape berry moth. They have relatively short residual control in the hotter summer weather when growers might be spraying for the second or third generation of grape berry moth. In our 2006 trials with Danitol, Baythroid, and Capture, the lower rates of these products declined in activity against grape berry moth after nine days. If using a pyrethroid to control grape berry moth along with Japanese beetle in the hot sunny conditions of July or August, using the full rate will provide the best residual control. Despite the temptation to look only at the price per acre when making decisions, be sure to rotate this class with other chemical classes to avoid resistance developing. This means that growers should rotate out of this group of insecticides (Baythroid, Danitol, Capture, Brigade, Mustang Max, or any generic pyrethroids) and use an alternative chemical class the next time an insecticide is used. Sevin or Imidan (buffered to pH 6) are both in different chemical classes and there are also many effective reduced-risk insecticide options. These include Intrepid that was mentioned earlier, and also Venom, Assail, and Avaunt. These last three can provide control of lower populations of grape berry moth while also reducing populations of leafhoppers and Japanese beetle. We have also had our first experience with the newly-registered insecticide Delegate WG this season, and in our trials at a five oz/acre rate it performed very well for control of first generation grape berry moth.
Getting cluster coverage with your spray material is essential for berry moth control. This is important for getting full activity from broad-spectrum insecticides and even more important if applying any of the newer chemistries that must be eaten to be effective. As the canopy becomes more dense after bloom, increase the water volume and slow down to ensure the pesticide has a chance to contact the pest. Juice grape canopies have many layers of leaves during the late summer, making it hard to penetrate to the clusters, but this is essential if the insecticide is to work against grape berry moth. If the spray doesn’t hit the cluster, a significant investment of time and money is being wasted.
To illustrate this, our research in a mature
One way to test your coverage is to spray water or Surround WP kaolin clay through the sprayer in a test run. Immediately after spraying (with water) or after the spray has dried (for the kaolin), lift the canopy of the sprayed and adjacent rows to see where the material hits the cluster. If there are untreated berries, these are sites where a berry moth larva could avoid the treatment and survive. These results emphasize the need to calibrate your sprayer and adjust through the season to ensure it is getting good cluster coverage, because it can make a big difference for control.
Annemiek Schilder, Plant Pathology
Note: Modified from an
article by Alice Wise and Wayne Wilcox,
We’ve had quite a variable season so far with rain and sun, humid and dry days after a particularly cool spring. Unusually rainy weather has provided plenty of opportunity for disease to become a problem in vineyards. Black rot, Phomopsis and downy mildew, have already been sighted this year. Our general approach to disease management is to apply preventative fungicide sprays and careful and timely canopy and fruit zone management. But sometimes a situation can get out of control even in the best vineyards, particularly if rain and wind have prevented application of fungicides at critical times. In that case, prepare to treat post-infection if necessary. Several fungicides provide good “post-infection” activity (e.g., the sterol inhibitors such as Elite and Nova). This means that they’ll stop disease development if applied after an infection period has occurred but before disease symptoms appear. However, very few fungicides have the ability to “burn out” (eradicate) active infections once symptoms have become apparent. At most you can expect to knock them back a little bit and suppress sporulation while you keep infections from spreading to healthy clusters and leaves. A few other points: Intervene as soon as possible and make sure coverage is good. If dealing with cluster infections, remove infected clusters (if possible) prior to spraying and leaf pull if time allows. It is unrealistic to expect any material to clean up a raging infection or to adequately penetrate a dense cluster zone. In addition to a post-infection material, remember that continued forward protection is also critical to protect clean fruit.
Not much is known about post-infection activity of fungicides against Phomopsis, as we have not had systemic fungicides that work against this disease until recently and have relied on mancozeb, captan, and ziram to do the job. While Phomopsis, cane and leaf spot are generally not harmful to the vine, fruit infections are and can lead to fruit rot and premature fruit drop as the fruit ripens. If cane and leaf spot infections are noted, it is recommended to protect the fruit and other healthy tissues from infections during rains at least up to bunch closure. With the phosphorous acids (e.g., ProPhyt and Phostrol), we believe we have potential post-infection fungicide options but research needs to be done to show much post-infection activity they actually provide. The strobilurins Abound and Pristine are excellent protectants and may have very limited post-infection activity (approximately 24 hours at most). Because they are systemic and redistribute to some extent in plant tissues, they provide good protection of clusters and leaves.
Both Nova and Elite have excellent post-infection activity and some forward action. The backward control is typically spoken of as extending to about 72 hours, that is, you’ll get control if they’re applied within 72 hours after the start of the infection period (rain). However, in two different field trials (and additional greenhouse experiments), Wilcox obtained good control when these materials were applied even five to eight days after the start of an infection period if excellent spray coverage was provided. This doesn’t mean you should relax after a “black rot rain” if the fruit were unprotected when it started - the sooner you can spray afterwards, the better. However, you’re better off waiting for good spray conditions (within reason) than you are spraying in the wind or rain just to meet an arbitrary 72-hr deadline. Both Nova and Elite have some forward activity, although it’s limited (less than a week); tank-mixing mancozeb or ziram with a post-infection spray of one of these materials will improve the forward activity significantly.
Phosphorous acid products such as Phostrol and ProPhyt provide post-infection control of downy mildew. Good coverage is critical. A dense cluster zone or where foliage is crunched up under bird netting (this is where we’ve had trouble in the research vineyard) can be difficult. Experience with these materials dictates that they are best used early in the infection cycle. Application on an abundance of healthy, sporulating lesions is not the best strategy. Also, phosphorous acid products are prone to resistance development. If downy mildew pressure continues at this high level, alternate phosphorous acids with a product of a different chemistry. Primary options would be Ridomil, copper, mancozeb, captan. Ridomil also provides excellent post-infection activity as well as good forward activity. But using it to try to “burn out” a bad case of active downy mildew is a recipe for resistance development.
There are several options to clean up powdery mildew
infections including JMS Stylet Oil; Nutrol (monopotassium phosphate);
potassium bicarbonate products like Kaligreen and Armicarb 100; and Oxidate
(hydrogen peroxide). Sulfur has good activity against very young infections,
but is not great once it’s easy to see that you have a problem to deal with. In
Of the products listed, only JMS Stylet Oil has provided the best eradication of active infections and is the only material that provides any forward protection. In addition to its post-infection and eradicative activities, the best information available indicates that Stylet Oil provides at least three days, sometimes more, of forward protection under dry weather conditions. However, the oil residue apparently washes off in as little as 1/3 inch of rain, after which most of the protective activity is gone. Thorough coverage is absolutely essential for this or any of the other post-infection post-infection materials to work. Direct spray at the fruit zone with lots of water. Experience dictates that Stylet Oil works if it makes contact with the infected berries. If the clusters are packed in, if leaf pulling hasn’t been done, spray coverage will be compromised and powdery mildew will persist. In the case of JMS Stylet Oil, read the label thoroughly as it is incompatible with a number of key materials including sulfur. Note that JMS Stylet Oil has both a standard and an organic formulation. They differ in the inert ingredients. Also be aware of warnings about application in hot weather (phytotoxicity risk). A study found that Stylet Oil may reduce brix accumulation in fruit when applied multiple times late in the season, so alternating with different fungicides is recommended.
These are alternatives to when the use of sulfur precludes the use of oil. According to Wilcox, Nutrol, Kaligreen and Armicarb function in the same topical, eradicative, “salt on a slug” mode. Again, these do not provide forward protection and they work best when powdery mildew infection is in the very early stages.
Oxidate in Michigan trials has shown fair to moderate activity against existing powdery mildew infections, but not sufficient to warrant recommendation. The Oxidate label calls for consecutive sprays at 128 fl. oz per 100 gallons and recommends consecutive sprays. Time may be a factor - getting the leaf pulling done and getting consecutive cluster sprays on is time prohibitive for some growers. There have been several questions on tank mixing Oxidate. BioSafe Systems feels that tank mixing Oxidate with either DF or a liquid sulfur should be no problem. To be sure, you might do a jar test first as per the Oxidate label.
1) Apply treatments as soon as possible after symptoms are seen. (Regular and careful scouting is a prerequisite.)
2)
If disease symptoms are showing up on leaves and
shoots, you can assume that there is plenty of disease pressure to infect the
fruit as well.
3)
Spraying fungicides on raging infections is less
effective and can encourage fungicide resistance development in the pathogen.
4)
Waiting a little longer to ensure good spray
conditions is a better option than spraying immediately under poor spray
conditions.
5)
Remove infected clusters (if possible) and leaf
pull to ensure good spray coverage of fruit zone and reduce humidity around
clusters
6)
Apply fungicides at the highest labeled rate to
ensure good post-infection activity.
7)
Ensure thorough coverage of leaves and bunches,
particularly for contact fungicides.
8)
Ensure forward protection of healthy plant parts
by tank-mixing or applying materials that have good protective activity.
9)
Always read the label for the pre-harvest
interval, incompatibility with other products, and other restrictions..
10) Scout
again to see if your treatment was effective, keeping in mind that some
developing infections may continue to manifest themselves over a couple of days
after the spray.
Rufus Isaacs, Steve Van Timmeren and Mark Longstroth
MSU Entomology and
The meeting will start with a barbeque at the barn at 6:00 PM and updates on insect and disease management trials underway at the Dongvillo farm. We will continue in the vineyard with MSU Extension educators and specialists presenting hands-on training related to scouting for insects and diseases, pest management, and crop estimation and adjustment. Presenters will include members of MSU’s Grape Team: Mark Longstroth, Steve Van Timmeren, Rufus Isaacs, Paolo Sabbatini, and Annemiek Schilder.
The meeting will be held at the Dongvillo Farm, in Scottdale
in
This meeting is open to anyone with an interest in growing grapes, and it is free. Restricted Use Pesticide applicator credits will be available. This meeting is made possible by MSU Extension, National Grape Cooperative, the Michigan Grape and Wine Industry Council, and MSU’s Project GREEEN.
Mark your calendars! A follow-up IPM workshop will be held
before grape harvest on August 28 at Lemon Creek Winery on
Paul Jenkins
MSU Small Fruit Education Coordinator
When: Friday, August 1, 3:00 PM - 5:00 PM
Where:
Paul Jenkins will lead a discussion on sustainable grape
production, including a new workbook for
For more information, contact Paul Jenkins at: jenki132@msu.edu or 517-432-7751.
We will be having a research field day at the Trevor Nichols Research Complex on Wednesday, September 24 from 1:00 PM to 4:00 PM. The field day will focus on insect and disease research and efficacy trials that were carried out this season by Larry Gut, Rufus Isaacs, Annemiek Schilder, George Sundin, Mark Whalon and John Wise.
The TNRC is located at
See our web page for directions: http://www.maes.msu.edu/tnrc/
The MSU/SWMREC High Tunnel Information Program will be held at the SWMREC Tunnels, beginning at 7:00 PM on Thursday, July 31 for growers interested in High Tunnel Production of small fruits, tree fruits, vegetables and cut flowers.
The MSU research plot host faculty are Dr. Eric Hanson, Dr. Ron Goldy, and Dr. Greg Lang, and there will be a representative from Haygrove Tunnels participating as well.
Vera Bitsch
Agricultural, Food, and Resource Economics,
The Michigan Occupational Safety and Health Administration (MIOSHA) has updated enforcement procedures for field sanitation standards in 2008. Inspections may be based on complaints or referrals, as well as, programmed inspections, which are conducted by MIOSHA personnel as time permits where they see hand-labor operations in the field.
Clean and safe potable water must be readily accessible to all employees. Heat-related illness can be reduced or prevented by drinking enough water and taking other precautions, including suitable clothing. Farm workers experience the highest risk of heat-related illness of all occupations.
Where 11 or more employees have worked on any day during the last 12 months, the water must also be suitably cool for the temperature conditions and dispensed by single-use cups or by fountains.
Toilet and hand washing facilities must be provided whenever work time plus transportation time to and from the field exceeds three hours. One toilet and hand washing facility shall be provided for each 20 employees or fraction thereof. The facilities shall be located together and as close as practical to the work location.
For small operations, where the 11 or more employees rule does not apply, the facilities must be either provided as above or available to employees by using employer furnished transportation.
Employees must be given reasonable opportunity to use these facilities. Toilets shall be ventilated and screened, have self-closing doors lockable from the inside, and constructed to ensure privacy. Toilets shall be operational and include an adequate supply of toilet paper. Hand washing facilities must have an adequate supply of potable water, soap, and single-use towels.
All facilities must be maintained in clean and sanitary conditions and waste shall be disposed in a sanitary manner. Where the 11 or more employees rule does apply, employers must inform all employees about the importance of good hygiene practices to minimize adverse health effects.
More information is available at www.michigan.gov/miosha,
and by calling the MIOSHA General Industry Safety and Health Division at
517-322-1831 or the district supervisor at 616-447-2650. Free consultation and
compliance assistance is available through the MIOSHA Consultation Education
and Training Division (CET) by calling the
To read Dr. Bitsch’s complete newsletter go to her website
at http://www.msu.edu/user/bitsch.
Under “News” click on “Agricultural Field Sanitation” or click on “Agricultural
Labor Issues in
Weather over the last two weeks has been seasonal with highs
in the 80s and lows in the 60s. Several storms have left significant rainfall. Precipitation
totals for the last few weeks are 1.5 to 3.0 inches. Soils are moist. Rainfall
total for the Fennville
station since January 1 is 24 inches compared to 16 inches for the southwest station
in the
|
Grapes, from April 1 |
|||
|
Location |
GDD 42 |
GDD 45 |
GDD 50 |
GDD 50 |
|
2104 |
1784 |
1343 |
1337 |
|
|
2173 |
1869 |
1406 |
1401 |
|
|
1940 |
1651 |
1217 |
1213 |
|
Leaf sampling for nutrient analysis in tree fruit is generally done from the end of July to early August. San Jose scale crawler damage to fruit has been showing up more frequently in recent days. Mite numbers are increasing, but not a problem in most sites. Japanese beetles are still active and will be around for another three to four weeks. Immature stinkbugs are becoming easier to find. Pheromone dispensers in insect traps need to be changed for many of the common types used.
In apricots, the harvest of midseason varieties such as ‘Hargrand’ and ‘Harlayne’ is underway. Quality is generally good with little brown rot problems.
Peaches are about
2 to 2.5 inches in diameter. Some young peach plantings have red hued leaves of
nitrogen deficiency brought on by excess rain. Harvest of PF-1 and ‘Queencrest’
began approximately July 9; PF5B started July 15 followed by ‘Harrow Diamond’
and ‘Early Star.’ Harvest of ‘Bright Star’ begins later this week. The
estimated start of significant commercial ‘Red Haven’ peach harvest for
Sweet cherry harvest is finished. Quality and prices were generally good with only moderate cracking. Alternaria fruit rot was only a minor problem. Post-harvest pruning can be done now. General recommendations (see Fruit CAT Alert for July 26, 2005) are to: prune no later than early September; avoid exceptionally heavy pruning; do not prune trees that have not filled their space. For triangular shaped trees, the height of the bearing area of the tree should be no more than three times the clear alleyway width. For rectangular shaped trees, the height of the bearing surface should be twice the drive alleyway distance.
Tart cherry harvesting has ended for ‘Montmorency.’ ‘Balaton’ harvest continues. Fruit quality was generally very good with only minor problems with deep sutures and wind-induced bruising. ‘Balaton’ fruit quality has been good, with a wide range of fruit sizes. Growers have been applying post harvest fungicide sprays to control cherry leaf spot. Yellow leaves are common, but most of these are due to bacteria canker leaf infections. Cherry leaf spot infections are becoming easier to see but this disease is relatively light in most orchards.
Apples are two to
2.8 inches in diameter. Fire
blight infections are still moving down infected branches, but generally no
new infections are showing up. Sooty blotch and flyspeck are a concern although
symptoms are scarce; fungicides for this should be included in cover sprays. Trap
catch for codling moth
continue to be low for most orchards. Codling moth larvae can be found in the
fruit. Apple maggots
have been caught for several weeks in
Pears are about two inches in diameter. Pear psylla numbers are generally low. Sooty blotch and flyspeck are a concern; fungicides should be included in cover sprays. Both codling moth and oriental fruit moth can damage pear fruit at this time.
Blueberry harvest of ‘Bluecrop’ began last week marking the beginning of the main season varieties and heavy harvest volumes. Japanese beetles and blueberry maggot flies are out. Preharvest sprays primarily target the diseases alternaria and anthracnose, as well as Japanese beetle and blueberry maggot. Leaf sampling for nutrient analysis in blueberries is generally done from the end of July to early August.
Grapes are at
cluster tightening. Crop potentials vary greatly from vineyard to vineyard,
depending on frost damage received. Due to light crops last year, crop load
potential was high coming into 2008. Vineyards with heavy crops may have
difficulty in ripening the crop this year if the heat unit accumulation is not
high in the next two months. Growers are applying their second postbloom spray.
Grape berry moth
trap catches are up, indicating the start of the second generation. Larval
stings and split berries are easy to find in vineyards with light crop and
minimum sprays. Grape
leafhoppers are scarce. Wine grapes need to be protected from potato leafhoppers. Japanese
beetles are easy to find. Fungicides at this time should target all four major
fruit diseases; powdery mildew,
downy mildew, black rot and phomopsis. Black rot berry
symptoms have been found in unsprayed vineyards as well as downy mildew.
Strawberry regrowth is underway from renovation. Growers should protect against potato leafhoppers to prevent hopper burn and stunting of new growth.
Raspberry and blackberry harvest is continues. Growers should be prepared to protect against Japanese beetles.
Cranberries are at pinhead and small green fruit.
There is a Grape IPM meeting this Thursday, July 24 in
The next Monday Fruit Update
meeting will be on Monday August 4 at the Fruit Acres Farm in
The annual Viticulture Day at the Southwest Michigan
Research and
Summer-like weather has persisted over the last two weeks
with a good amount of heating and precipitation. Most of east
|
Location |
GDD42 |
GDD45 |
GDD50 |
|
Commerce ( |
2063 |
1767 |
1319 |
|
Emmett (St Clair) |
2023 |
1740 |
1300 |
|
|
2061 |
1772 |
1326 |
|
Lapeer (Lapeer) |
2044 |
1755 |
1319 |
|
|
2158 |
1854 |
1399 |
|
Romeo ( |
2104 |
1806 |
1353 |
Apples continue to size very nicely with most being in the range of two to 2.50 inches. A slight amount of apple drop continues to be seen in many blocks. Growers are wrapping up hand thinning of apples. Deer browsing damage is more prevalent this season than the last five years or so.
Apple maggot emergence occurred almost three weeks ago, but the numbers caught on yellow sticky board traps has not been as great as it was two weeks ago. I have had only one report of apple maggot being caught on red ball traps, and that was in the last few days. Remember that apple maggot will spend a little over a week feeding in trees before beginning egg laying.
Codling moth trap catches have dropped back to very low levels over the last two weeks. We are between the first and second generations at this time. I have seen a few larvae in fruit. Oriental fruit moth trap catch is on the raise, as we begin the second generation adult fight. Most trap counts are in the 10 to 20 moths per trap range. I have seen a few small obliquebanded leafroller larvae, and trap catch remains low. I am continuing to catch obliquebanded leafrollers in codling moth traps.
Japanese beetles have been seen in many more apple blocks than a few weeks ago, they are mostly feeding in ‘Honeycrisp’ where fruit is clustered or on weak or stressed trees. Rose chaffers were also reported at a few farms. Green apple aphids are still a problem in many apple blocks, mostly feeding on leaves, however there are a few exceptions where they have been found on fruit. It is unusual to see this many aphids feeding so late in the summer. Spotted tentiform leafminer adult trap catch numbers has risen for the second generation flight, and now their numbers are starting to decrease as adult flight is ending. Dogwood borer adults continue to be seen, however there numbers are generally low.
Potato leafhopper has been doing some leaf curling and yellowing of apple foliage in a few blocks, they need to be watched closely. White apple leafhoppers numbers remain low across the region. European red mites are above threshold in many apple blocks over the last two weeks, especially in ‘Red Delicious.’ Two spotted spider mite adults and eggs are more numerous than two weeks ago, with most blocks being below threshold. Apple rust mites continue to be seen, however the numbers are generally low. I am seeing a good number of predators over the last two weeks. Most notably are high populations of lacewings and mullen bugs.
More growers are reporting new strikes of fireblight,
particularly in the
Pears are currently at 1.50 to 1.75 inches in diameter. Generally, at this time of year pears don’t size very rapidly. Fireblight has also been seen in pears over the last two weeks with some blocks being hit heavily. Fabraea leaf spot continues to be seen in a few blocks of pears. Some pear blocks hit with freezing temperatures this spring are seeing fruit finish problems.
Peaches are mostly in the range of 1.75 to 2.25 inches in diameter. Harvest has begun on ‘Harrow Diamond’ and other early varieties. Red haven are about two and a half weeks away from the beginning of harvest. Two-spotted spider mites are above threshold in a few blocks. These populations need to be watched closely in the next few weeks. Rose chafer adults continue to be seen on peach foliage, however they are not feeding on fruit. Oriental fruit moth trap catches are generally up in peaches across the region. X-disease is being seen commonly in many peach blocks across the region. Bacterial spot of foliage and fruit continues to be seen in a few blocks.
Sweet cherry harvest is wrapping up across the region. Fruit quality was excellent this year. Cherry fruit fly trap catch has been very heavy in many blocks of sweet cherries over the last two weeks. Japanese beetles are heavy in many sweet cherry blocks. Cherry leaf spot symptoms are starting to be seen. A post harvest application of both an insecticide and fungicide will need to be made to control all three of these pests.
Tart cherry harvest is winding down across the region. Brown rot has been reported in a few blocks of tart cherries.
Plums continue to size slowly with most being about one and an eighth in diameter. I have seen a few plum curculio larvae in plums over the last three weeks. Black knot is also starting to be seen in some of the more susceptible plum varieties.
Strawberry renovation is wrapping up across the region. Most strawberry growers report having an excellent crop this year, with a long season and good berry size even late in the season. There was excellent demand for pick your own strawberries this year. Newly planted strawberries are continuing to runner well, some have filled the row. Potato leafhopper feeding is common in many newly planted strawberry fields. I have seen a few strawberry blocks where two-spotted spider mites were a bit of a concern, however with the renovation process that should break their life cycle fairly effectively for the rest of the season.
Raspberry harvest of summer red and black varieties continues. I am continuing to see some fruit sunburn in some plantings. Fall red raspberries are about 24 to 30 inches in length, and appear to be growing quite well. A few folks have reported starting to harvest some of the shorter canes of fall raspberries in the last week. Raspberry cane borer is being seen in a few blocks of fall red raspberries. Japanese beetles are feeding heavily in foliage of raspberries, and potato leafhopper populations are high in many fall raspberry plantings. There is some anthracnose in raspberries this season.
Blueberry harvest is underway across the region. Berries have been slow to ripen at many farms, with excellent pick your own and ready pick demand. I have had several reports of blueberry maggot trap catch on yellow sticky board traps in the last two weeks.
Phil Schwallier
Amy Irish Brown
Carlos Garcia-Salazar
Degree day totals continue to run right about at normal
average accumulations for this time of the year. We are currently about a half
a day behind normal averages for base 42 and a day behind average for base 50.
Tree growth seems to be slowing down in some bocks with terminal bud set being
seen in several blocks. Tree fruits appear to be sizing well, but there a lot
of banged up looking apples out there from hail.
We should be out of the window for any more severe trauma blight situations as terminal buds are setting in many apples. If you have blocks with active fire blight in them, you should consider preventative sprays if we get more storms with high winds or hail, but for clean blocks, those cover sprays are most likely not needed any more this season.
A regional biofix for codling moth was set on May 24. Our degree day accumulations since then are right around 950 for most stations, which puts us at the very end of egg hatch and the end of first generation activity. Some trap numbers have been a bit higher over the last week, but not significant for most blocks. It could be the start of the second generation, but is most likely just a blip in the population as the first generation comes to an end. Regardless, if your trap numbers are over threshold, you need to keep cover sprays maintained.
We’ve accumulated about 914 DD base 42 since the regional biofix on June 14 for obliquebanded leafrollers – this indicates that egg hatch is nearly over for the summer generation of obliquebanded leafrollers. Close scouting is encouraged to make sure you don’t have a population of leafrollers that could lead to high numbers at harvest with the next generation of larvae.
Japanese beetles continue to move into tree fruit orchards, and growers are trying to keep their numbers down. Be sure to watch pre-harvest intervals and re-entry days for the spray materials you are using for Japanese beetles and all other pests.
There are still populations of green apple aphids and leafhoppers (both white apple leafhopper nymphs and potato leafhoppers) present in some blocks, but numbers seem to be overall down and controls worked well. Be sure to keep an eye on newly planted trees as aphids and leafhoppers can significantly reduce tree growth left unchecked.
All stages of red mites continue to be found, but just when you think the numbers will move to a threshold, the heavy rains move through to reduce the numbers, especially of adults. Predators can be found in many blocks feeding on red mites, so be sure to scout closely to determine if controls are necessary. Very few summer miticides have gone on in this area as of yet this year, therefore continue to monitor mites closely.
The second generation of Oriental fruitmoth larvae started
hatching about 10 days ago. As of July 21, there have been 1353 degree days
base 45 accumulated since the May 8 regional biofix. It’s expected that we are
very near the peak egg hatch timing for Oriental fruitmoth in the general
Apple maggot started to be reported on yellow sticky boards about two weeks ago, but have not been significantly caught on red sticky balls yet. The heavy rains from two weeks ago probably started driving them out of their overwintering sites in the soil. With all the rains this year, growers are encouraged to have red sticky ball traps in all their blocks so they can monitor apple maggot most effectively.
Symptoms of summer diseases can be seen in unsprayed trees.
A second application of summer disease fungicides will probably be needed in
the
Blueberry harvest in
There are some issues related to blueberry plant health resulting from the intensive rains that we had in the past. Fields that were flooded for several days are showing plants with die-back and intensive defoliation. Leaves on affected bushes showing brown spots that later on become necrotic (Photo 1). Damaged plants are located in sandy soils and the symptoms follow a pattern along the rows. New growth in affected plants shows deformed leaves and sparse foliage. The most damaged bushes are completely defoliated (Photo 2). So far, tissue samples have been sent to MSU Diagnostic Services for identification, but some preliminary reports indicated that no plant pathogen is associated with these symptoms. Therefore, we are learning to believe that the damage could be herbicide related. Because of the intensive rains and flooding, it is possible that pre-emergent herbicides applied early in the season could have been translocated to the root zone and absorbed by the plant. However, we are waiting for the grower’s herbicide application records in order to make better determination.
Regarding insect pests, the blueberry maggot is out as well as the Japanese beetle. Growers are spraying against those insects. At this time, many growers are selecting Imidan as the favorite tool to control both insect pests, especially those using aerial applications.
During the past two-week period temperatures were
seasonable, with milder temperatures in the first week and several degrees
higher during the second week. Generally, high temperatures were in the 70s and
80s with one day on July 16 reaching near 90°F. The overnight lows were in the
high 50s and a wide range of 60s. High humidity was more of a problem than high
temperatures. During this same period the region received quite a bit of rain.
Two week totals are 0.9-inch for
|
Location |
DD42 |
DD45 |
DD50 |
Rainfall July 15-20 |
Rainfall since April 1 |
|
Hart |
1804 |
1526 |
1108 |
0.20 |
15.66 |
|
Ludington |
1709 |
1526 |
1026 |
0.69 |
16.41 |
|
Manistee |
1768 |
1494 |
1086 |
0.49 |
15.46 |
Frequent rains are favoring vegetative growth and development. For the most part, trees are looking nice with a full head of leaves and not much fruit. Fruit, where there is some, is sizing well. Sweet cherry harvest is underway though quite a few growers had to abandon the fruit due to excessive splitting. Tart cherry harvest is starting slowly. In the first week of harvest, which ended July 12, the West Central area delivered only half a million pounds. The pace has picked up in the second week. Things are not very bright when people are finishing harvesting in the third week of harvest. Unfortunately, there are people that will have a very short harvest.
Rain and high humidity have induced brown rot and alternaria development in cherries. Quite a few blocks had to be abandoned. Cherry leaf spot is starting to show a bit more prominently. Fireblight symptoms are present in more blocks than we are accustomed to seeing in this area. As previously reported, this condition developed in response to many storms that violated the area earlier in June. Scouts are reporting seeing secondary scab lesions on the leaves and on the fruit. Powdery mildew in apples, cherries and peaches is present in quite a few blocks. Sooty blotch and flyspeck symptoms should be appearing at this time.
Insects are still quite active. Codling moth numbers have gone up significantly since last week. This might be the tail-end of the first generation, and the beginning of the second generation. American plum borer trap catches have doubled since last week. Greater peach tree borer numbers have gone up slightly. Lesser peach tree borer numbers have dropped to about half where they were just a week ago. Obliquebanded leafroller trap catches have increased significantly since last week; the numbers have almost doubled. Scouts are reporting finding small larvae throughout the area. Oriental fruit moth numbers have doubled since last week. Cherry fruit fly numbers have gone up. There was one report about apple maggot being seen on the leaves in the apple orchard 10 days ago, but there has been no confirmation with trap catches. I would expect to see them any day now. There are increased numbers of aphids, Japanese beetles, leafhoppers and tarnished plant bugs throughout the area.
Nikki Rothwell
Duke Elsner, Erin
Lizotte, Rob Sirrine
GDD42 1810
GDD50 1114
Apples are at 41 - 47 mm.
Sweet cherries: ‘Hedelfingen’, ‘Napoleon’, and ‘Gold’ are all being harvested.
Tart cherries: ‘Montmorency’ is at early harvest and Balaton have 23 mm fruit.
Apricots are being harvested.
Plums have 27 mm fruit.
Grapes are at berry touch.
We have had very interesting weather here in the northwest. The
rainfall has been extremely variable where one weather station reports nothing while
another less than 20 miles away reports over an inch of rainfall. This spotty
precipitation has been difficult to predict fungicide applications this season.
Hail was also reported in the southern portions of
Sweet cherry harvest is in full swing in the region. The quality of sweet cherries has been a challenge with frost scars, cracking from all the varied rainfall. The American brown rot and alternaria pressure is extremely high with the elevated humidity. Tart cherry harvest has also begun this week. Growers may be hard pressed to get off a moderate to high crop load in sweet cherries while the low yielding tarts are already ripening. Sweet cherry size is smaller than anticipated with the adequate rainfall this spring. Tart cherry size is good due to the lower crop load in most blocks. Balaton yields are particularly low in many orchards. Red raspberry harvest has begun in the region.
Obliquebanded leafroller populations are high at the Northwest Station with over 50 in one trap this week. Cherry fruit fly numbers are also quite high, with 68 being trapped in one managed station block. Lesser and greater peach tree borers, as well as American plum borers, are still emerging at relatively high numbers with up to 20 per trap at the station. We continue to see symptoms of cherry leaf spot intensifying, and the warm, wet weather is favorable for further spread of the fungi. American brown rot pressure is high, particularly in dark sweet cherry blocks. Powdery mildew has also been observed throughout the region with fruit infections occurring in one block of tart cherries at the station. Alternaria fruit rot seems to be more problematic this year. Alternaria is usually considered a minor problem on sweet and tart cherries. Lesions are circular, sunken and green-black in color. The disease is most severe on overripe fruit or where rain induced cracking exposes flesh to infection.
The station traps are catching an average of 20 codling moths per trap. Spotted tentiform leafminer numbers are up with almost 300 caught in one station trap. We are continuing to see the aftermath of early fire blight infections in susceptible apple varieties around the region. European red and two-spotted spider mites are reaching threshold levels in some area orchards. Green apple aphids have also been reported by area scouts.
Jeff Andresen
Agricultural Meteorology
Geography
A nearly stationary frontal boundary running through the
An area of high pressure currently over western Ontario will
move southward into the region by late Wednesday and lead to fair and dry
weather Thursday and most of Friday. The next chance for significant rainfall
will be late Friday or early Saturday as an area of low pressure approaches
In the medium range period, forecast guidance suggests upper
air troughs across northwestern and northeastern sections of the