In this issue
Tree fruit news
§ What to do if you have Ethrel damage?
§ Pre-harvest Oriental fruit moth management in peach
§ TNRC trapline data: Oriental fruit moth
§ ReTain use on apples in stress years
§
Small fruit news
§ Blueberry tip borer
§ Organic blueberry discussion meeting
§ Options for late-season disease control in grape vineyards
§ Grape IPM meeting for growers at Lemon Creek Winery
§ Fire blight on raspberries and blackberries
Other news
§ Development of drought conditions in Michigan
§ High Tunnel Meeting August 15th in southwest Michigan
§ New scouting resources for orchards on IPM web site
§ Regional reports
§ Weather news
Next issue August 21
Nikki Rothwell
District Horticulture, MSUE
A lot of Ethrel
damage has been showing up in the past few weeks in the northwest. This injury
has come as a result of highly stressed trees, most from drought stress. However,
we have seen San Jose scale on some sweet cherries in certain areas, and these
insects have put more stress on trees. This stress is then compounded when we
apply Ethrel, especially under hot temperatures. Injured trees have lots of
leaf yellowing and leaf drop, and there is excess gummosis in affected trees. The
gummosis is often clear, and it can be anywhere on the tree –
branches, trunks and branch angles.
Since the damage has
already happened, we need to have a plan on how to keep these trees as healthy
as possible. First, growers should avoid pruning until dormancy. We need to
make sure these trees have all possible resources heading into winter, and
pruning off any branches and leaves at this time will reduce the trees’ ability
to make these resources. Therefore, growers should save pruning efforts until
trees are in dormancy. When growers do prune in dormancy, they should be sure
to give the trees an extra hard pruning. This method will remove some of next
year’s fruiting area, and it will place the resources into fewer fruiting
points and keep the majority of resources in the tree rather than fruit.
We also want to make
sure to reduce any potential stress on the trees. We want to maintain good weed
control, and we need to have good cherry leaf spot control as we do not want
any premature leaf drop this season. Even though we have had little rain and
very low disease pressure, a post-harvest Bravo application is warranted if
trees are showing Ethrel damage. Another reason a disease spray should be used
is due to a long post-harvest period, as harvest ended so early this year. Also,
mite thresholds have dropped in situations where trees are showing Ethrel
damage and drought related symptoms. Trees that have been damaged by Ethrel
cannot tolerate high mite populations. The threshold for mites on sweet cherries
is usually around 30 mites per leaf in normal years, but sweet cherries suffering
from Ethrel damage have had their thresholds decrease to five to seven mites
per leaf. If this threshold is reached, a miticide is needed.
Lastly, a fertilizer
application may be warranted in orchards where nutrients are needed. Growers
should not apply any extra nitrogen this fall, except where it is needed. The
rates suggested at this time are 100-120 lbs. actual nitrogen in spring or a
split application in spring and fall of 50-60 lbs. We also need a good dose of
potash this fall if potassium levels are low.
John Wise, Trevor Nichols Research Complex
Dave Epstein, Entomology/IPM
Oriental fruit moth adult flight patterns over the last two
weeks (based on the TNRC trapline in
|
Compound trade name |
Relative activity |
Life-stage activity |
Total allowable product/acre/yr* |
Pre-harvest interval* |
Re-entry interval* |
|
Sevin XLR |
F |
Adult, Larvae |
14 qts |
3 day |
12 hr |
|
Lannate 90SP |
F |
Eggs, Larvae, Adults |
6 lbs |
4 day |
4 day |
|
Intrepid 2F |
G |
Eggs, Larvae |
64 oz |
7 day |
4 hr |
|
Baythroid XL |
G |
Eggs, Larvae, Adults |
2.8 oz |
7 day |
12 hr |
|
Imidan 70WP |
E |
Eggs, Larvae, Adults |
17 lbs |
14 day |
3 day** |
|
Asana XL |
G |
Eggs, Larvae, Adults |
72.5 oz |
14 day |
12 hr |
|
Mustang Max |
G |
Eggs, Larvae, Adults |
24 oz |
14 day |
12 hr |
|
Warrior 1CS |
G |
Eggs, Larvae, Adults |
1.6 pt |
14 day |
24 hr |
|
SpinTor 2SC*** |
G |
Eggs, Larvae |
29 oz |
14 day |
4 hr |
|
Entrust 80WP |
G |
Eggs, Larvae |
9 oz |
14 day |
4 hr |
|
Avaunt 30WG |
G |
Eggs, Larvae |
24 oz |
14 day |
12 hr |
* For peaches only.
** 14 day phi for general public in U-pick operations.
*** SpinTor not labeled for OFM control.
Activity Rating (from most to least effective based on MSU trials): Excellent (E), Good (G), Fair (F).
Philip Schwallier
Clarksville Horticultural Research Station Coordinator
ReTain is a very useful growth regulator on apples that has the following benefits. It will:
1) Delay fruit maturity of any variety.
2) Decrease fruit drop.
3) Improve the condition of treated fruit in storage.
4) Improve fruit quality and size.
ReTain needs to be applied 30 days before anticipated harvest to achieve the best results and highest effectiveness of the material. Full rate ReTain will delay maturity of most varieties seven to ten days and some very sensitive varieties up to 21 days. Gala and Jonagold are very sensitive to ReTain. Honeycrisp appears to be moderately sensitive and other varieties are less sensitive, but still respond to the ReTain treatment. Some growers will use half rate on Gala, Jonagold and Honeycrisp because of the sensitivity, but realize that this also will reduce the response.
ReTain will delay harvest, reduce fruit drop, improve storage condition life, reduce shoulder cracking in some years and sometimes increase fruit size if the fruit hang long enough. The delayed maturity is very useful to pick-your-own operations. The delayed maturity extends when varieties are available for U-pick customers to pick in excellent condition.
Growers with large acreage can use ReTain to help program harvest. For example, if a grower has large acreages of one variety like Red Delicious, then a portion of the Reds can be treated with full rate Retain to reduce drop and delay maturity. Another portion of the Reds could be treated with half rate to only slightly delay maturity. This will allow the picking to be more orderly, less drop and all the Reds will be picked in excellent condition.
ReTain is a helpful growth regulator with benefits to small and large growers. Time the applications 30 days ahead of anticipated normal harvest and then plan on picking treated fruit later than normal.
Stressful years
Apple trees under stress do not respond well to ReTain treatments. Hot, dry years seem to reduce the ReTain response. In those situations where trees’ stress is a factor, consider not applying ReTain or use the higher rate. One third and half rate will not provide good results on stressed trees. ReTain is also more effective closer to the 28 days before harvest timing rather that the 30 to 35 days before anticipated harvest.
Mike Hansen
Plum pox sampling in southwest
Samples are collected and processed at the MDA and MSU
laboratories in
As has been the case for many years,
Rufus Isaacs
Entomology
New shoots with leaves that turn brown from the tip end have been increasingly evident in the past few weeks. This may be evidence of blueberry tip borer (Hendecaneura shawiana), a sporadic insect pest whose damage symptoms become increasingly evident in late July. This insect is a species of tortricid moth, and fruitworm management programs after bloom usually keep this pest in check. Seeing the stems with brown leaves (Figure A) is an indication that this pest was not controlled and should be watched in fields where the symptoms are showing up. Although no estimates of economic impact have been made for blueberry tip borer, infested shoots will have reduced fruiting potential in the following year.
The damage can be seen during regular weekly scouting of fields, with infested shoots having leaves with brown tips (Figure A). These drying leaves are typically above where a larva is feeding inside the stem, and the larva’s point of entry is usually visible as a small (1 mm diameter) pinhole on the side of the stem with some brown tissue around this area (Figure B). This is the hole that a tiny young larva chewed earlier in the season when entering the stem. Larvae enter soon after hatching from an individual clear egg laid on the young stem by the female moth.
As the larva feeds and grows inside the stem, it tunnels through the tissues (Figure C), and can be seen with a hand lens if an infested stem is broken open (Figure D). A mature larva will bore 8-10 inches inside a stem before it pupates in the stem to emerge next year. There is only one generation per year.
Moth flight probably occurs during mid-late June around the time of fruitworm activity. However, because the pheromone of this pest has not been identified, monitoring traps cannot be used. The only alternative is to closely monitor for the presence of early larval tunneling into the stems, which causes the discoloration shown in Figure B.
Fields with high levels of infestation should be monitored for the distribution of tip borer infestation this year, so that appropriate adjustments can be made next year. If the damage is along the border of the field, or if it is only in the bottom half of the bush, an adjustment of the spray program in 2008 may be needed to get improved coverage. Pruning out infested shoots at this time of the year may also help suppress the infestation next year, but make sure to get the larva as it can be boring well below the symptoms. Larvae inside pruned shoots will dry out and die as the shoots desiccate.
Annemiek Schilder
Plant Pathology
The MSU blueberry team has received funding from Project GREEEN and the North Central SARE (Sustainable Agriculture Research and Education) Program to develop an organic blueberry research project. Before we establish the research planting at the MSU Horticulture Farm and get too far into the project, we would like to have a meeting to gather input from blueberry growers (organic growers and those interested in transitioning to organic production) and others with experience in this industry. We will present the project outline and objectives and will then start a discussion of possible treatments to evaluate and approaches to management of organic blueberry plantings. We would also like to invite growers, who are growing blueberries organically or are transitioning to organic production, to participate in the project.
The meeting will take place on Thursday, August 16 from 11:00 am to 1:00 PM (lunch will be provided) in the seminar room at the Trevor Nichols Research Complex on 6237 124th Avenue in Fennville, MI 49408 (Phone: 269.561.5040), Michigan. For more information, please contact Annemiek Schilder at 517-355-0483 or via email at schilder@msu.edu. Please spread the word to all those who may be interested.
Annemiek Schilder
Plant Pathology
A number of diseases have started showing up in
At this point, we are beyond the critical period for black rot control in juice grapes; this period runs from bloom to about five to six weeks after bloom, at which time the berries become naturally resistant to infection, and sprays are no longer needed. We have to keep in mind, however, that due to the spring frost, there may be clusters present in various stages of development. This means that we have to protect the clusters until the last ones have reached the point of becoming naturally resistant. Also, in some wine and table grape varieties, the berries do not become fully resistant to black rot infection until eight weeks after bloom. As they develop, grape berries also become naturally resistant to powdery mildew and downy mildew infection also (within three to four weeks after bloom); however, the berry and cluster stems remain susceptible a bit longer. By now we don’t expect any new Phomopsis infections, however, the symptoms that are already present on the clusters will increase in severity as we get closer to harvest. Lesions on the rachis will then rapidly expand and also infect berries and berry stems, resulting in fruit rot and premature fruit drop.
Botrytis bunch rot symptoms are promoted by late-season rains, particularly in tight-clustered varieties. A rapidly spreading brown rot and gray mold often becomes apparent on the clusters after veraison. It can easily be confused with sour bunch rot, however, the latter smells of vinegar, which is a product of Acetobacter bacteria. Yeast and other undesirable fungi are often also involved in sour rot development. Any injury to the berries, whether by insect feeding, hail, fruit cracking, or powdery mildew infection can increase the likelihood of sour Botrytis and sour bunch rot. Fruit flies also seem to play a role in spreading sour bunch rot. Bunch rot severity can be reduced by improving air flow through leaf and shoot removal in the fruit zone. Be careful that you do not remove too many leaves, as the berries may get sunburned if fully exposed to the sun.
There are still many late-season fungicide options for grapes; for descriptions, efficacy ratings, and pre-harvest intervals, see the Fruit Management Guide (http://web1.msue.msu.edu/pestpubs/E154/) to choose the most appropriate fungicide for your conditions. The chemical classes are provided so that growers can decide what fungicide rotations to use. During rainy periods it is better to use systemic products because they are more rainfast than products that are strictly protectants. Also, due to their penetration of plant tissues, they may be able to stop incipient infections that may have started during recent rain or dew events.
Ridomil Gold Cu (Phenylamides and inorganics; systemic + protectant; 42-day PHI), and Ridomil Gold MZ (Phenylamides and EBDCs; systemic + protectant; 66-day PHI). These fungicides have excellent preventive and curative activity, and are considered the “big guns” when you want to “smoke out” downy mildew. Under light disease pressure, it may be better to use other products though. In addition, the pre-harvest interval may preclude their use at this time of the season, especially for juice grapes, which will start to be harvested in less than a month.
ProPhyt, Phostrol, Agri-Fos, Aliette (Phosphonates; highly systemic; 0-day PHI), good preventive and curative activity. Use a higher rate if applying after infection period. Possible phytotoxicity when tank-mixed with sulfur, surfactants, foliar fertilizers, some pesticides and when applied during high temperatures.
Abound, Pristine, Sovran (Strobilurins; systemic/locally
systemic; 14-day PHI). Excellent preventive activity (less than 14 days), limited
post-infection activity. Abound is phytotoxic to apples, Pristine is phytotoxic
to ‘
Ziram (Dithiocarbamates; protectant; 21-day PHI): good preventive activity. Can be tank-mixed at a lower rate with phosphorous acids.
Dithane, Penncozeb (EBDC’s; protectant; 66-day PHI): good preventive activity; however, the long PHI precludes their use at this point in the season. Also, EBDCs are not allowed on juice grapes after bloom by some processors.
Captan (Phthalimides; protectant; 0-day PHI): good preventive activity; not allowed on juice grapes by some processors.
Copper (Inorganics; protectant; 0-day PHI): good preventive activity, some grape varieties are sensitive to copper, especially under cool, slow-drying conditions. Specific formulations can be used in organic vineyards.
Serenade (Biological control agent; protectant; 0-day PHI): moderate preventive activity. Organic formulation can be used in organic vineyards.
Nova, Elite, Rubigan, Bayleton, Procure (Sterol inhibitors, systemic;14-day PHI, except for Procure, which has a 7-day PHI; and Rubigan, which has a 30-day PHI). Excellent preventive activity and good post-infection activity.
Abound, Sovran,
Endura (Carboxamides; systemic; 14-day PHI): good preventive some post-infection activity.
Quintec (Quinolines; locally systemic; 14-day PHI): good preventive activity, little to no curative activity.
Topsin M (Benzimidazoles; systemic; 14-day PHI): good preventive and post-infection activity.
Sulfur (Inorganics; protectant; 0-day PHI): very good preventive and eradicant activity. Some grape varieties are sensitive to sulfur, especially under hot conditions. May be used in organic vineyards.
JMS Stylet oil (Oils; protectant; 0-day PHI): good preventive and eradicant activity, needs thorough coverage. Organic formulation may be used in organic vineyards. Be careful when applying Stylet oil, as more than a couple of applications may reduce brix accumulation. Also, do not tank-mix with copper or apply with or after a Captan spray; do not apply within 14 days after a sulfur application or apply sulfur within 10 days of an oil application. Thorough coverage is important for control.
Copper (Inorganics; protectant; 0-day PHI): moderate preventive activity. Some grape varieties are sensitive to copper, especially under cool, slow-drying conditions. Specific formulations can be used in organic vineyards.
Armicarb/Kaligreen/MilStop (Inorganics (salts); protectant; 0-day PHI). Moderate preventive and eradicant activity, needs thorough coverage. May be used in organic vineyards.
Serenade (Biological control agent; protectant; 0-day PHI). Moderate preventive activity. Organic formulation may be used in organic vineyards. Thorough coverage is important for control.
Elevate (Hydroxyanilides; locally systemic; 0-day PHI): good to excellent preventive and limited post-infection activity.
Vangard (Anilinopyrimidines; systemic, 7-day PHI): good to excellent preventive and post-infection activity.
Scala (Analinopyrimidines; systemic; 7-day PHI): good to excellent preventive and post-infection activity.
Endura (Carboxamides; systemic; 14-day PHI): good to excellent preventive and post-infection activity. Use at 8-oz rate for Botrytis control.
Rovral (Dicarboximides; locally systemic; 7-day PHI): moderate to good preventive activity; activity is improved by addition of spray adjuvant. Some vineyards may have resistant strains if Rovral was used a lot in the past.
Topsin M (Benzimidazoles; systemic; 14-day PHI): moderate preventive and post-infection activity.
Serenade (Biological control agent; protectant; 0-day PHI): fair to moderate preventive activity. Organic formulation can be used in organic vineyards.
Rufus Isaacs
Entomology
Join MSU’s Grape Extension Team for this month’s Grape IPM
meeting in southwest
Lemon Creek Winery (www.lemoncreekwinery.com) is on
Annemiek Schilder
Plant Pathology
While fire blight is most common in pears and apples, it
also affects raspberries and blackberries (Rubus
spp.). Summer red raspberries cultivars K81-6 and
The most obvious and striking symptom are blackened cane tips, which bend over and die, resulting in a “shepherd’s crook” appearance. Infections may proceed down the cane for up to 8.0 inches and may produce cream-colored bacterial ooze under high moisture conditions. As the disease progresses down the cane, the veins of leaf veins and portions of the leaf surrounding the midvein turn black. Entire leaves may wither and die. Typically, discoloration and dieback is limited to succulent young growth. In addition, the disease can affect fruit clusters. Infected peduncles (the stalks of fruit clusters) turn black and the young developing berries become brown, dry and very hard. Entire fruit clusters may be infected, but generally a few berries in each cluster remain healthy.
Fire blight is caused by the bacterium Erwinia amylovora. Although this is the same organism that causes
fire blight on pear and apple, it is a different strain. Thus the strain that
attacks raspberries and blackberries will not infect apple or pear and vice
versa. However, it has been found that ‘
Fire blight affects both red and black raspberries and
blackberries. The susceptibility of purple raspberries is unknown. While there
has been no thorough study of resistance to fire blight among commercially
available cultivars, Latham,
No specific control measures have been developed because of the sporadic nature of the disease. However, the following practices will limit establishment and spread of the disease:
1) Purchase and plant only certified, disease-free plants from reliable nurseries.
2) Remove and destroy diseased canes from the planting as soon as you see them. Pruning is best done during dry weather to avoid spread of the disease. Disinfest pruning shears in a 10 percent household bleach solution (containing one part bleach and nine parts water) between each cut to avoid transmitting bacteria to healthy canes. Isopropyl alcohol (70 percent) or quaternary ammonia may also be used, but the bleach solution is more effective.
3) Manage insect pests to avoid a possible means of moving the bacteria from plant to plant.
4) Avoid over-fertilization. Vigorous, succulent growth is most susceptible to the disease.
5) Orient rows, prune and thin plants to maximize air circulation. This will help lower the relative humidity within the plant canopy.
6) Destroy wild or abandoned brambles growing nearby. These plants may serve as inoculum sources for fire blight and other pathogens, particularly viruses.
7) Apply copper as a preventative material, starting before or as soon as the first symptoms appear.
Jeff Andresen
Agricultural Meteorology
Geography
Scattered showers and thunderstorms brought some much needed
rainfall to a few locations across
High tunnels are low-cost greenhouses that are gaining
popularity for production of a large range of crops worldwide. A twilight
meeting and research plot tour is scheduled for 6:00 PM on Wednesday, August
15, at the Southwest Michigan
Research and Extension Center in
Anyone interested in how high tunnels can be used to increase produce quality or yields, reduce chemical pesticide inputs, or modify harvest seasons for berries, sweet cherries, vegetables and even cut flowers are welcome. MSU researchers and extension educators will be on hand to discuss the Project GREEEN-funded research trials on production systems for various high value crops under Haygrove high tunnels.
To reach the Center, take exit 30 off I-94 (
The MSU IPM Program has developed two web resources featuring photos and descriptions from the popular pocket-sized scouting guides for apples and stone fruit. The information was developed by Dave Epstein, Larry Gut, George Sundin, Alan Jones and KimberlyMaxson-Stein.
Scouting for pests in apples: http://ipm.msu.edu/apples.htm
Scouting for pests in stone fruit: http://ipm.msu.edu/stonefruit.htm
Call the MSU Extension Bulletin office
(517-353-6740) or your local Extension office to order copies. These
pocket-sized guides have color photos, pest ID and damage descriptions and are
made of water resistant paper:
§
A Pocket Guide for IPM Scouting in
§ A Pocket Guide for IPM Scouting in Stone Fruits. Price $12. Bulletin E-2840 (Spanish E-2840SP).
A Practical Guide to Scouting Apple Orchards is a DVD that compliments the scouting guide. It is designed to give apple growers and consultants easy access to information that helps de-mystify the pest management decision-making process. The 90-minute DVD contains 21 modules covering topics from choosing a weather monitoring system to discussions on degree-day models and monitoring primary disease and insect pests. The DVD is designed for those who want to learn about specific topics at any point during the growing season by simply choosing the desired tracks from the DVD menu. Call the MSU Extension Bulletin office (517-353-6740) and request DVD273 (price $29.95).
Mark Longstroth
Bill Shane
Greg Vlaming
The last two weeks have been hot and dry. Highs have been in
the 80s with lows in the 60s. Rain fell across the region Sunday, August 5. Rainfall
totals were higher in the southern tier of counties and closer to the
|
|
Grapes from April 1 |
|||
|
Location |
GDD 42 |
GDD 45 |
GDD 50 |
GDD 50 |
|
2965 |
2587 |
2002 |
1904 |
|
|
3039 |
2627 |
2039 |
1962 |
|
|
2739 |
2370 |
1802 |
1722 |
|
Japanese beetle adults are still actively feeding, and we expect more following this rain.
Fruit crops continue to show signs of drought stress, such as sunscald of the fruit and leaf drop. The dry conditions this season have resulted in very little disease pressure in most fruits.
Peach growers are harvesting Coralstar and PF17 peaches. Color has been good. Because of high demand, peaches are being harvested with few pickings (two to three picks instead of a more typical three to four picks). There is thrip damage to the fruit in some orchards. The third generation of oriental fruit moth should emerge at about 2400 GDD base 45.
Cherry trees are dropping leaves due to drought stress. Only a little cherry leaf spot has occurred so far, but this rain should result in an increase in disease symptoms. Because there have been so few infection periods, it will take a long time for disease pressure to build and cherry trees should enter the winter in good shape.
In apples, codling moth trap
catches of the second generation have been heavy. Biofix for high-pressure
sites was July 14 (about 1275 GDD) and a lower pressure site biofix was
approximately July 21 (1674GDD). Areas that have had earlier flights and biofixes
for second generation codling moth may see a partial third generation in late
August. With wide spread rain, I expect apple maggot to emerge around the edges
of fields, so border sprays will be useful in some areas. We are finding
feeding damage of second-generation oriental fruit moth
in apple fruit. Scouts are reporting leaf drop due to the second generation
spotted tentiform leafminer. Dock sawfly larvae are feeding on broadleaf weeds
in some orchards. This pest is often confused with codling moth in apples later
in the season as it looks for an overwintering site and attacks the fruit. With
this rain, fungicides should be included in cover sprays to control sooty
blotch and fly speck.
Pear fruit needs to be protected from the second generation of codling moth. European red mites do not bronze the leaves of pears, but turn them black.
Blueberry harvest continues. Currently,
we are finishing Bluecrop, second or third picking of
Grape veraison has begun in early ripening varieties such as Foch, Reliance, and Himrod. Grape berry moth trap catch numbers are up. The second generation flight is underway and egg-laying is underway. Japanese beetle and grape leafhopper numbers are building. Backyard growers are reporting heavy losses to black rot. By now, the berries on most varieties are resistant to grape diseases. Phomopsis berry rot and drop has begun on early ripening varieties. A botrytis bunch rot spray is timed for veraison in wine and table varieties. The final grape IPM scouting meeting will be Thursday, August 9, at Lemon Creek Vineyards, west of Berrien Springs at 6:00 PM. Check the MSU grape website for scouting updates.
Strawberry growth is good where irrigation has been used and potato leafhopper controlled, Otherwise strawberries have suffered from the drought.
Raspberry cane borers are attacking primocane shoot tips. Remove the girdled section at the base of the wilted shoot tip and destroy. This girdled section contains the raspberry cane borer egg.
The continued drought remains the weather story for the region for the last two and a half months. Our soils remain very dry and signs of drought stress on fruit trees are more evident as each day passes. Newly planted tree fruits and small fruits are under the most stress, however many mature fruit trees are showing signs of smaller than normal fruit development and early leaf drop. It appears that the southern part of the region had a nice rain event on Sunday, August 5, with nearly 0.75 inches of rainfall being reported. The further north you go, more widespread drought conditions persist. Many growers have reported irrigation ponds that are very low or empty and recharging very slowly.
In my years as a district horticulture educator, the drought
of 2007 compares remarkably to what we had in 1988. In reviewing the Fruit CAT Alert and weather records from
1988, the spring was much dryer and the drought ended in mid-July. This year’s
drought seems to be more severe in many areas of east
Our season is still running about 10 days ahead of normal in terms of the beginning of harvest for our fruit crops. We are over a week ahead of normal in terms of degree day totals and are even ahead of last year’s late growing season.
|
Location |
GDD42 |
GDD45 |
GDD50 |
|
Commerce ( |
2753 |
2380 |
1814 |
|
Emmett (St Clair) |
2667 |
2304 |
1757 |
|
|
2741 |
2356 |
1796 |
|
Lapeer (Lapeer) |
2686 |
2320 |
1772 |
|
|
2865 |
2485 |
1911 |
|
Romeo ( |
2716 |
2341 |
1781 |
Apples have
continued to size in irrigated blocks, however, in unirrigated blocks, apple
size has stood still over the last two weeks. In irrigated blocks, fruit in the
Codling moth emergence has been heavy over the last week, with trap catches on the rise from the second generation adult flight. Most growers biofixed for the second generation trap catch early last week. Control measures are being taken mid- to late this week at most farms. Apple maggots have been slow to emerge this year, mainly due to the affect of the drought. I expect to see widespread apple maggot emergence with rainfall that the region is currently receiving. So, the cover sprays for codling moth will also catch apple maggot at this time. Oriental fruit moth trap catches are generally low; however I have seen a few blocks that have had pretty good flight. European red mites are pretty well under control at most farms with a few hot spots remaining. Where growers did not apply a miticide, mite predators have come on very strong. Over the last two weeks, twospotted spider mites continue to be seen in low numbers in apples, however, are heavier in other crops.
Some light amounts of sooty blotch and flyspeck are beginning to show up. Powdery mildew continues to be seen. I am seeing a fair number of apples that have developed sunscald over the last two weeks.
Pears have taken on a swell over the last week with most being in the range of 2.5 inches.
Peach harvest continues for Red Haven across the region. In irrigated blocks, Red Haven size is excellent this year and fruit is very flavorful. In unirrigated blocks, fruit size is suffering, however, flavor remains excellent. Twospotted spider mites have been a problem in some blocks of peaches. Leaf drop continues in many blocks, most likely due to a combination of drought, earlier season infections of bacterial spot and twospotted spider mites.
Strawberries continue to rebound from the renovation process, however continued drought has resulted in many fields not looking normal for early August. When we do get significant moisture supplies, I think this will turn around fairly quickly. I would recommend an additional application of nitrogen at that time to give plants a bit of a kick start. Newly planted strawberries that have been irrigated continue to runner well, however, most poorly irrigated new strawberry fields are looking very bad at this time. The combination of drought stress and potato leafhopper burn has caused stunted plants that have not runnered well, and the runners that are present have not flourished. Once we have adequate moisture supplies, I think that newly planted fields will look better.
Raspberry harvest is underway for most fall bearing raspberry varieties. Berries are now maturing from not only the lower shorter canes, but are also beginning to mature on the longer canes. Japanese beetles continue to be a problem in several fields. I’ve also seen light amounts of twospotted spider mites at a few farms.
Blueberry harvest is continuing across the region, and most farms are now well beyond their peak of production. In unirrigated blueberry fields, berry size is now small and harvest will be wrapping up here fairly quickly. Even in irrigated plantings of blueberries, I think that we will be at the end of production prior to Labor Day. There continues to be a general lack of catch for blueberry maggots across the region at many farms this year. Today’s rain will cause a flush of blueberry maggots to emerge. However, they should not be a major problem this late in the season. Japanese beetle populations have peaked in most blueberry plantings, but they bear watching toward the end of harvest. Birds continue to be a problem in most blueberry fields.
Phil Schwallier
Amy Irish Brown
Carlos Garcia-Salazar
Peach harvest continues, but is moving quickly with the lighter crop loads. Peach fruit size has been average. Apple harvest will probably begin for the earliest varieties, Gingergolds and Paula Reds, over the coming weekend and into next week. Some rain has moved through the area over the last 10 days, but totals continue to be variable across the region and, in general, not enough to make up for deficits. Non-irrigated, newly planted fruit trees continue to look quite stressed. Some established trees are showing signs of stress as well on lighter soils. Sunscald is becoming easier to find in apple as well.
ReTain applications
should be timed for 30 days before anticipated harvest. Looking at predicted
harvest dates, ReTain should be applied to Empires in the
Obliquebanded leafroller adult numbers in traps increased slightly about 10 days ago and have continued to be trapped over the past week, but numbers are low. Newly hatched obliquebanded leafroller larvae could be seen at any time.
Second generation Oriental fruit moth should be winding up for this area. Trap numbers have decreased quite a bit from last week – we’re probably trailing off for activity of second generation. There have been some reports of Oriental fruit moth damage in peaches.
A regional biofix for codling moth was set for second generation on July 10. As of the end of Monday, August 6, we have accumulated 514 DD50 past that second biofix, indicating that we are probably at peak egg hatch right now for this generation and cover sprays are once again, very important to maintain.
A few apple maggot initial
trap catches in the
European red mites continue to be a problem in some blocks, and bronzing is pretty easy to see in blocks with no controls.
Japanese beetle numbers have been down over the last few weeks. We did see an increase in activity a few days after the last rain event, 10 days ago. Growers should expect more beetles to be found after this current rain event. I don’t think their activity is over yet for 2007. Leaf feeding is prevalent, but fruit-feeding damage is being found more often this year as well, perhaps due to the dry conditions. The beetles are searching for the nearest water source, which might be the apple fruits.
Hot, humid and no rain has been the characteristic of the last two-week period. A little rain early this morning is hardly worth mentioning – we had only 0.02 inch for the Hart and Ludington area and 0.07 inch for Manistee/Bear Lake. Trees are showing signs of distress. There is some leaf drop even some fruit drop and, for the most part, sizing is compromised. Peaches seem to be most affected. Wherever there is an irrigation system, it has been used. Mineral deficiencies are accentuated by drought conditions throughout the area. We are seeing boron, iron, zinc, manganese and magnesium deficiencies.
Our season is still about 10-14 days ahead of normal. Peaches are being harvested. Early apple varieties are starting to appear on the farm market stands in the area. Plums, mostly Japanese varieties at the moment, are being harvested. Some of the early European plum varieties will be ready for harvest by the end of the week or early next week. Cherry harvest is done and it came under the estimate. The last CIAB report shows West Central with 52.4 million pounds or 7.6 million pounds under the estimate.
|
Location |
DD42 |
DD45 |
DD50 |
Rainfall last week |
Rainfall since 4/1 |
|
Hart |
2554 |
2198 |
1656 |
0.0 |
7.92 |
|
Ludington |
2332 |
1988 |
1474 |
0.17 |
11.54 |
|
Manistee |
2519 |
2165 |
1635 |
0.22 |
7.75 |
High humidity has been favorable for brown rot development on peaches and plums. Symptoms of bacterial leaf spot and powdery mildew/rust spot are present in peaches. Apple scab lesions are present in a few blocks throughout the area. Cherry leaf spot is basically not an issue this year. Some light symptoms are starting to appear in a few blocks at the tree tops.
Codling moth second-generation emergence has reached its peak. The second generation egg hatch is at the mid-point in the Hart/Shelby area and not quite there yet in the northern parts of the district. Blocks that do not have a mating disruption system in place need to be on a 10-14 day spray interval in order to maintain good control. Oriental fruit moth numbers have gone down since last report however, the symptoms of second-generation larval feeding are beginning to show up on peaches and apples. Obliquebanded leafroller numbers are down this week. Apple maggot numbers have doubled since last week, though the numbers are still low. We need rain to flush them out. Tight coverage is needed to keep them out of the fruit. It appears that we have experienced quite a few mite outbreaks during this hot weather. Many blocks are above the threshold of 7.5 mites per leaf requiring treatments. American plum borers were at the second flight peak at the week of July 28 showing some drop in their numbers this past week.
GDD42 2626
GDD50 1734
Apples have 61 mm fruit.
Pears:
Plums have 33 mm fruit.
Grapes: Chardonnay have green fruit.
We have had no rain in the past week, and the forecast does not look promising for any significant rainfall.
The last of the Balatons are coming off at the beginning of this week. Both sweet and Montmorency tarts are also finished. Ethrel damage is evident everywhere in the northwest. Growers are harvesting peaches. Sizing apples and irrigation systems have been major concerns in the past week. Growers are irrigating apples if they have a system, and some are considering putting a system in yet this season.
No apple diseases to report at this time. We have just been too dry to be fighting off fungal pathogens! In the insect world, spotted tentiform leafminers are down, but all other insects are on the rise. We caught an average of 24 codling moths per trap, which is up from over 14 last week. Obliquebanded leafrollers are also increasing with over 10 per trap this week, where we caught none last week. We also caught more Oriental fruit moths this week than last, and we caught a total of seven apple maggots on two red sticky spheres.
A little cherry leaf spot is showing up in the tops of tart cherry trees, but the overall amount of disease pressure is low. Obliquebanded leafroller numbers are also up in cherry with almost 30 moths per trap. All borer counts are down from last week, and we are still catching lots of cherry fruit fly in the entomology block. We caught one more cherry fruit fly in our managed block than last week – from two to three.
In grapes, vineyards are now showing some powdery mildew and downy mildew on more susceptible cultivars. Powdery mildew is still relatively light, probably due to few wetting periods during early shoot growth. Sun scald on berries is very common in the area, as are “pygmy” berries in clusters. It is not clear if these will fall out of the cluster as fruit development continues. Japanese beetles are being found on foliage in areas where this pest is now found. Many people have found stink bug eggs and nymphs, but it is not known if these are predatory or plant feeding species. Grape berry moth larvae have been found in clusters at a few sites, so be sure to start checking for this pest.
Jeff Andresen
Agricultural Meteorology
Geography
Showers and thunderstorms brought some much needed rainfall
to a few locations across Michigan late last week (mainly extreme southern
sections of Lower Michigan), but the rainfall was localized and drought
conditions persist in many areas of the state. In contrast to the persistent
ridging pattern over western and central sections of the
Another wave of low pressure (similar to the Tuesday=s system) is forecast to move across
the
In the medium range time frame, both 6-10 day and 8-14 day
outlooks, covering August 12-16 and August 14-20, call for a continuation
of above normal temperatures state- and region-wide. Precipitation totals
during the 6-10 day time frame are forecast to range from near normal levels in
Lower Michigan to above normal over the