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| Fruit Crop Advisory Team Alert newsletter | ||||
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| Vol. 22, No. 2, April 10, 2007 |
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In this issue |
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| Spring sends a warm, cold, windy mix Michigan and much of the country has been hit with warm and cold weather patterns that are keeping fruit growers guessing about the 2007 crop. On this morning’s Fruit CAT Alert team conference call, it was noted that it is too soon to accurately identify the extent of the damage from the recent frost and winds. Our next issue will be published April 24 and it will include advice based on what can be determined during the next few days. In the meantime, you may want to refer to the table developed by Mark Longstroth that is included in this issue: Critical spring temperatures for tree fruit and small fruit bud stages. – Joy Landis, editor. |
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Spring freezes and fruit bud damage |
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| One of the files there is a one-page table (Critical spring temperatures for tree fruit and small fruit bud stages) where I have collected published critical temperatures from other extension bulletins so that they are on a single sheet. Many of these numbers come from Washington State University bulletins. MSU’s Greg Lang has a webpage with this information also and by clicking on the Bud Stage Development for each fruit you can see a picture of the original WSU Bulletin photos of bud development: http://www.hrt.msu.edu/faculty/Langg/Fruit_Bud_Hardiness.html The original Washington State Bulletins can be found at: http://treefruit.yakima.wsu.edu/weatherbuds/weatherinfomain-3.htm These critical bud stage tables are for temperatures of relatively short duration no three days of snow, wind as cold artic air moves through the region. The freeze Michigan and the entire Eastern United States suffered was a classic advective freeze where cold air moves into a region. When you have a lot of cold air moving, everything quickly becomes the same temperature as the air and the cold can penetrate deeply into the tissues. I had hoped for conditions similar to the cold snow storm we had in 2005 when temperatures remained near freezing not to have temps in lower 20's for 6, 8 and 12 hours on successive days. It seems that the conditions were more similar to the wind freeze that affected Northwest Michigan’s cherry crop in 2002. Then cold winds killed swollen cherry buds at temperatures that were above the temperatures in the tables we use to estimate damage from recorded lows. There are other variables that can cause differences between the observed effect of cold and the predicted critical temperatures. MSU’s Stan Howell has done work showing that wet buds are killed at warmer temperatures than the predicted temperatures in the WSU bulletins determined in a freezer. The bottom line is that the published values in the table are for specific conditions and if the conditions are very different, the tables can be wrong. As I walked orchards and vineyards, I saw plenty of damage to exposed leaves that were brown, black or dark green and watersoaked and were obviously damaged from the prolonged cold. Many times when I cut open these obviously damaged buds, the flowers inside looked fine and I wonder how that could be since the one next to it was dead. Warmer temperatures will make it easier to determine damage as this tissue dries out when we get above freezing for a couple of days this week. |
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| Bacterial canker and cold spring temperatures Nikki Rothwell, NWMHRS George Sundin, Plant Pathology Bacterial canker is caused by the bacteria Pseudomonas syringae, and this pathogen can infect sweet and tart cherry and plums throughout Michigan. This disease is most problematic in sweet cherries, and epidemics often occur in conjunction with cold, frost-prone weather in the spring. Freezing temperatures can also dispose cherry tissues to bacterial canker infection, especially if the freeze event is followed by wet weather. Therefore, growers should be particularly diligent about early bacterial canker control in the coming weeks after these cold spring temperatures. Early copper sprays are the most common methods of control for bacterial canker on cherry. However, sweet cherry tissues are extremely sensitive to copper, and the sprays must be adequately timed to reduce P. syringae inoculum without causing phytotoxicity. If the trees are still in the dormant stage, two copper applications can be applied at one to two week intervals at a rate of 1.2-2lbs of metallic copper with either one pint of spray oil per 100 gallons of water or 6-9 lbs of hydrated lime per acre. Copper products sprayed during the dormant stage should have good retention properties to enhance disease control as longer residuals for copper should translate into an extended period of bacterial disease suppression after the spray is applied (Rosenberger, 2007). If the trees have broken dormancy and are in the pre-bloom stage (bud swell, side green or green tip), copper rates should be reduced to 25 to 35% of the dormant rate. Up to two copper applications with a one week interval should be used at this time. No copper applications should be made once any white can be observed on the tree. In tart cherries, copper compounds can be used at the 1.2-2lb actual copper rate at bud burst with weekly repeated applications until late May. Some of these later sprays may result in some leaf yellowing, bronzing, and potentially defoliation. Adding hydrating lime at 6-9 lbs/acre will reduce the phytotoxic effects of copper, but we do not recommend applying copper at temperatures above 75 degrees (F). Literature cited: Rosenberger, D. 2007. Early season copper sprays. Scaffolds Fruit Journal. April 9. 16:4. |
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| Section 18 Specific Exemption granted for Agry-Gent use for fire blight George W. Sundin, Bill Shane, Mark Longstroth, Amy Irish-Brown, Phil Schwallier EPA has granted a Section 18 Specific Exemption for the use of Agry-Gent 10-W (gentamicin) for the control of the blossom blight phase of fire blight. This use is for orchards where streptomycin-resistant fire blight bacteria are present. The Section 18 is only applicable to Berrien, Van Buren, Kent, and Ottawa counties where the streptomycin resistance problem is the worst. Agry-Gent 10-W should only be applied when the fire blight state experts or disease forecasting model determine that the weather conditions favor disease epidemics. Thus, the use of this material is limited to epidemic conditions; if these conditions are not present this year, other fire blight control materials such as Mycoshield should be used. Authorization for use will come from Michigan State University fruit horticultural educators and tree fruit disease specialists via web, radio, recorded message, telephone, email and handout. Code-a-phone messages (see numbers below) are the preferred method to get information on use authorizations. Code-a-phone numbers are as follows: Berrien and Van Buren counties (269-657-6380 or 269-944-1477 x805); Kent and Ottawa counties (616-451-8065). Authorizations will be specific to the county affected. Agry-Gent 10-W (gentamicin), from Gowan, is an alternative antibiotic for fire blight management. Agry-Gent 10-W will work equally on streptomycin-resistant and streptomycin-sensitive strains. The label rate is 3.5 lbs./acre. A maximum of two applications of Agry-Gent 10-W will be allowable during the bloom period in 2007 (check code-a-phone updates for use authorization). Agry-Gent must not be used as the first spray of the season – a first spray of registered antibiotics (Mycoshield and/or streptomycin) must be applied. Also, do not make consecutive sprays of Agry-Gent. This material may be sensitive to pH and thus the pH of the spray solution should be buffered to 6.0 to 6.5. In addition, do not use Agry-Gent 10-W with other spray materials with clay-based carriers such as Captan as the clay can bind up the gentamicin rendering it less effective. Any unused, unopened containers of product must be returned to dealers for reimbursement. The Specific Exemption period ends May 31, 2007. When it becomes available, the Section 18 Specific Exemption label for Agry-Gent 10-W will be posted on the MSU Fruit Area of Expertise team web site at http://web1.msue.msu.edu/fruit/MIfrt_s18.htm |
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| Section 18 Specific Exemption granted for Mycoshield use George W. Sundin, Bill Shane, Mark Longstroth, Amy Irish-Brown, Phil Schwallier EPA has granted a Section 18 Specific Exemption for the 2007 season effective on April 1, 2007. The Exemption is for applications of Mycoshield for fire blight control in Michigan apple orchards with application initiated during bloom. The Specific Exemption period ends June 30, 2007. Mycoshield (oxytetracycline), from Nufarm, is an alternative antibiotic for fire blight management. Mycoshield will work equally on streptomycin-resistant and streptomycin-sensitive strains; however, the overall level of control is not as effective as with streptomycin in orchards without streptomycin resistance problems. A maximum of five applications of Mycoshield can be made at a recommended rate of 1.0 to 1.5 lbs./acre. Only one post-bloom application can be made. Mycoshield should be used as a protectant in advance of fire blight conducive weather conditions. When it becomes available, the Section 18 Specific Exemption label for Mycoshield will be posted on the MSU Fruit Area of Expertise team web site at http://web1.msue.msu.edu/fruit/MIfrt_s18.htm |
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2007 Fruit insecticide registration update
Note about new labeled insecticide descriptions (below): MSU Fruit Management Guide product numbers are in parenthesis (). Battalion (70) (Deltamethrin) is a pyrethroid insecticide registered for use on apples and pears for control of a broad spectrum of insects including codling moth, leafrollers, plant bugs, plum curculio, leafhoppers, and San Jose scale crawlers. This material is highly toxic to mite predators and should be used carefully to prevent mite population buildup. Battalion 0.2 EC is restricted to 26.9 fl oz per acre per season. Brigade (20) (bifenthrin) is a pyrethroid registered for use on grapes, pears and caneberries for the control of many insect and mite pests, including leafrollers, grape berry moth, plant bugs, leafhoppers, crown borers, Japanese beetles and spider mites. This product has a short period of activity after application and is disruptive to natural enemies. Centaur (84) (buprofezin) is an Insect Growth Regulator (IGR) insecticide that is active on insect nymph stages by inhibiting chitin biosynthesis, and also suppresses egg laying of adults, and reduces viability of eggs. Centaur is labeled for use on apples, pears and peaches for the control of scale insects, leafhoppers and psylla. It is also known to be of general low toxicity to biological control agents of fruit systems. Centaur 70 WSB is restricted to one application per acre per year. Danitol (44) (fenpropathrin) is a pyrethroid insecticide newly registered for use on blueberries for control of a fruitworms, leafrollers, blueberry maggots and Japanese beetles. This material is also highly toxic to mite predators and should be used carefully to prevent mite population buildup. Danitol 2.4EC has a 3 day PHI and 24 hour REI for use in blueberries, and can be applied by air. Mustang Max (zeta-cypermethrin) is a pyrethroid expected to be registered (Federal and State labels pending) for use on pome and stone fruits, and grapes for the control of many insect and mite pests, including cutworms, plant bugs, leafhoppers, leafrollers, grape berry moths, beetles and spider mites. This product has a short period of activity after application and is disruptive to natural enemies. Portal (78) (fenpyroximate) is an insecticide/miticide registered for use in apples and pears. Portal works as a contact miticide/insecticide that provides good knockdown and residual control of mites, leafhoppers and psylla and should be applied when pest populations are beginning to build and before they reach economic thresholds. It is effective on a broad spectrum of mite pests (European red mites, twospotted spider mites, pear rust mites, apple rust mites) but requires thorough coverage to ensure pests will contact the product. Portal 5EC has good in-season flexibility and is restricted to two applications per season and a total of 2 pints per acre per year. Guthion (8) (azinphos-methyl) is no longer labeled for use on peaches, nectarines, plums, caneberries, grapes and cranberries. Guthion is still registered for use in apples, pears, cherries, and blueberries with some use restrictions. For 2007, the maximum yearly amount of Guthion 50 WP will be 8 lbs on apples, 6 lbs on pears, 3 lbs on blueberries, and 3 lbs on cherries. The Pre-Harvest Interval (PHI) for apple and pear use is 14 days with a 21-day PHI if the last application is greater than 2 lbs of Guthion 50 WP per acre. Additionally, growers must observe a 60 foot buffer from permanent bodies of water and occupied dwellings (which do not include farm buildings and barns). Pick-Your-Own growers must observe over 30 day pre-harvest intervals, with the PHIs increasing with the rate of product applied. Check the label for details for your crops. |
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| Meeting explains EQIP for blueberry farms
The MSU Trevor Nichols Research Complex along with the USDA Natural Resource Conservation Program will be hosting an “Environmental Quality Incentives Program (EQIP) For Blueberry Farms” this Thursday, April 12 from 1 PM to 5 PM. Participants will gain an understanding of what a conservation plan is and how it is tailored to their unique farm. This plan, when applied will provide resource protection to the environment and be the guiding document to the development of a contract with the USDA for reimbursement of conservation practices applied. The TNRC is located at 6237 124th Ave. in Fennville, MI. – John Wise. |
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| Blueberry IPM scout training program a success Carlos Garcia-Salazar West Central Michigan One of the main obstacles to maintaining a healthy blueberry industry is education of growers and farm workers on the use of new pest control tools and techniques to comply with the Food Quality Protection Act (FQPA) of 1996 which greatly reduced or restricted the use of organophosphate (OP) and carbamate insecticides in blueberries. Alternative reduced-risk insecticides are pest-selective knowledge-base tools that require intensive site-specific scouting to be effective. However, there is a chronic need in the Michigan’s blueberry industry for qualified IPM scouts that could speed up the transition to reduced-risk IPM programs. Thus, in order to comply with the FQPA limited-resources, small and part-time blueberry growers need to learn to scout their own fields. Another alternative is training a new generation of IPM scouts. In Michigan, the blueberry industry possesses a large workforce made up Hispanics and other underserved, disadvantaged growers and part-time farmers that are a potential source of IPM scouts. With this in mind, we developed a Blueberry IPM Scout training program with a bilingual technical curriculum alongside a “Cap Stone” social framework program. This program was intended to set the stage for the successful transition of the blueberry industry to environmentally friendly production practices, provide farm workers with job opportunities and awareness of pesticide health hazards for themselves and their families. As of December 2006, people trained under this educational initiative include 15 African American, 27 Hispanic and 74 Caucasian blueberry growers and farm workers. The after-training evaluation of the first two groups of trainees (2003-04) showed we enhanced the trainee’s pest management skills. Growers reported average savings in pest control ranging from $50 to $60 per acre. In addition 30 growers and farm workers obtained their Pesticide Applicator certification license through our training program. We also enhanced risk management skills that resulted in better yields and fruit quality. Growers reported average yield increases of 8 percent (max=15%, min=5%), and 73 to 77 percent of those growers reported high fruit quality. Our training improved profitability for both growers and farm workers. Trainees reported an average income increase ranging from 8 to 14 percent after applying what they learned in our training program. One of the major goals of Ottawa County established during the 2006 issue identifications process was to ensure Ottawa County maintains and enhances its diverse economy by increasing awareness and providing opportunities for small business agriculture and citizens to create new products and/or reach new markets. Our Blueberry IPM Scout training program provides the risk management skills needed for Michigan’s blueberry industry to meet those demands.Agriculture today needs a trained workforce to be profitable. Our training as shown by the long-term evaluation resulted in increases profitability for blueberry growers and farm workers. The success of the Blueberry IPM Scout Training is the result of the Small Fruit Team efforts and those that have collaborated in this Educational initiative. Special thanks to our team; Drs. John Wise, Rufus Isaacs, Eric Hanson, Annemiek Schilder, Anamaria Gómez-Rodas and Carlos García-Salazar, Mark Longstroth and Craig Anderson from Michigan Farm Bureau. |
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| 1 – Southwest Mark Longstroth Bill Shane Greg Vlaming Weather Temperatures in the end of March were seasonal. The beginning of April was warm with record high temperatures on Tuesday, April 4, but frigid weather arrived on Wednesday with snow and highs near freezing for the next four days. Lows near 20 occurred on Friday and Saturday mornings. Low temperatures were a few degrees higher close to Lake Michigan and the extreme cold did not last as long. Plant development was rapid at the end of March and many fruit crops were damaged by the freeze. We are only a few GDDs behind 2000 and 1996, other early warm years. The current forecast for the week is for temperatures near freezing with rain or snow likely and cloudy conditions. Most of the snow has melted and water is standing in poorly drained sites. We did have a radiation freeze Tuesday morning with lows in the low 20s.
Tree fruit Little insect active was noticed due to the freezing cold temperatures. Exposed green leaf tissues appear brown, black or watersoaked are obviously damaged from the freeze. Because of the long duration of the cold temperatures we are not sure if there will be affects due to damage to the shoots and leaves. Warmer temperatures will make it easier to determine the extent of the injury. This frost was very variable and we will be looking at damage and determining the extent of damage for several more days. Many exposed sites show more damage than is typical. Apricots were blooming and suffered severe damage from the freeze. Peaches were showing first pink and bloom had begun in Berrien County. Open flowers were killed by the freeze but closed flowers are still viable. A good crop of peaches is still possible in Berrien County, but further away from the lake, all the peach flowers were killed. Tart cherries are at green tip to bud burst. Growers report heavy losses in Allegan and Van Buren counties. The tart cherry crop looks better in Berrien County. It appears that the crop has been reduced by 60 to 75%. Sweet cherries were at tight or open cluster. Orchards located near Lake Michigan suffered little damage. Flower buds in orchards away from Lake Michigan were killed. In plums, European plums at tight cluster suffered no damage close to the Lake and light damage away from the Lake. Oriental plum flowers were opening and damage seems to be more variety specific with severe damage in some varieties, while growers report they still have crop in other varieties. Apples are at half inch green to tight cluster. Damage was widespread and again was due to the stage of development and distance from the Lake. Early developing varieties were severely affected in Van Buren County with less injury reported in Berrien and Allegan counties. Later developing varieties suffered much less damage. According to the Enviroweather disease forecasts, light scab infections occurred at a few sites on April 4. Growers need to be ready for apple scab. Pears buds are tight cluster and damage does not seem severe. Pear psylla adults were out before the freeze. Small fruit Blueberry fruit buds are swollen and are starting to burst in early varieties. Blueberries generally suffered little damage from the freeze. Early developing and blooming varieties showed browning of the buds. The ovules were generally viable, but the damaged corolla will not open, so these flowers will not set fruit. Older dead flowers were noted in several varieties from winter injury, but these losses were generally light. Green leaf tissue did show browning and damaged tissues are more susceptible to mummyberry. Mummyberry treatments after a hard freeze are effective at reducing mummyberry. Grapes: Concord buds are at early swell and vinifera grapes at scale crack. Losses to the freeze were wide spread. Growers report from 60 to 30 percent loss of the primaries. The losses are very variable due to site exposure, bud development and distance from the lake. Grapes were bleeding from fresh pruning cuts indicating that the sap was up and the buds were active. It will be easier to determine the potential crop after warm weather returns and bud swell of the live buds (both secondary and primaries) can be seen. Strawberries are putting out new leaves and the trusses are visible in the crown of the plant. Covered strawberries were not severely damaged by the freeze. Raspberries are quarter inch green. We have not yet assessed damage in brambles, but we expect that the growing points were damaged and the plants will be set back, but we should see good regrowth. Cranberries are dormant. Miscellaneous Growers are pruning and clearing brush. The next Monday Fruit Update meeting will be, Monday, April 16, at the Fruit Acres Farm in Berrien County. The first Grape IPM meetings in Van Buren and Berrien Counties will be on Thursday April 17. The morning meeting will be from 10:00 AM to noon at the Cronenwett Farm Shop at 70123 28th Street east of Lawton. The afternoon meeting will be at 2:00 PM in the Berrien County MSU Extension Office at the Southwest Michigan Research & Extension Center. These meeting are co-sponsored by National Grape Cooperative and MSU Extension and are open to all grape growers. There are pesticide applicator recertification (RUP) credits available for both the Monday Fruit Updates and the Grape IPM meetings. |
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| 2 – Southeast Bob Tritten Weather We certainly have been on a rollercoaster ride in terms of our weather over the last two weeks. The big story is the freeze event that started in the early morning hours of Wednesday, April 4 when we had temperatures in the lower 60’s. From there temperatures started to drop and remained cold through yesterday morning, April 9. I have not seen this kind of spring cold snap in my almost 30 years of experience working with the fruit industry in eastern Michigan. Many older fruit growers relate this cold weather to a similar event that occurred in the spring of 1945. At this time, our season is running about a week a head of “normal” in terms of both growing degree days and growth stages. I spent most of the day yesterday evaluating bud damage from these freeze events, and will report in more detail my findings further in this report. To summarize my findings as of yesterday afternoon, while it is very apparent that we have had damage to several of our tree fruit crops; it is still a bit early to tell for certain. We need a few days in the 50’s for the extent of the injury to flower buds to become more apparent. So, while the evaluation I did yesterday was premature, at least it gives some insight into the extent of the injury. This recent cold snap was different from earlier cold events in four distinct ways: 1) The length of the time that our temperatures were below freezing was extreme, in several cases up to 118 hours of temperatures below freezing and 51 hours (not continuous) with temperatures below 24 degrees. 2) The severity of the low temperatures was also abnormal, with our coldest temperature recorded at 16.5 degrees, with most weather stations reporting in the high teens early one morning. 3) The low temperatures were sustained for a number of hours at a time; in one case, up to nine hours of cold temperatures below 20 degrees. This is a bit unusual in that typically we would see one or two hours of extreme cold. 4) The high winds at the start of the freeze event not only drove the internal heat out of the bud more quickly, but also caused a great deal of desecration of the leaf and flower tissue. In brief, here is my current assessment of freeze damage. Remember that this is a preliminary evaluation, and one which will change as we move through the week. Apples that were mostly at early green tip saw 30 to 40 percent bud loss. Later developing varieties were damaged, but to a much lesser extent. A good description of apple buds is that they look “tired.” There is some “water soaked” tissue on these later varieties that I am concerned about in that it may not develop properly. Pears seem to be fine at this time. Peaches already had some extensive winter injury at many farms, however there is some additional damage. Sweet cherries received extensive injury at most farms, with 70 to 85 percent bud kill. Tart cherry damage is more difficult to assess, but greater than 50 percent injury at this time. Plums were at green tip and surprisingly show little to no injury. Strawberries that were still dormant and covered with straw appear not to be damaged; however there is a likelihood of crown injury in most strawberry plantings. Raspberries were at green tip, and most of these buds were frozen off. There may be some cambium injury that will develop later in the season. Blueberry buds appear to be fine at this time, with little to no injury. Grapes were dormant; however there was some sap movement that may cause some delayed injury.
Tree fruit Apples have moved very little in the last week with most at quarter-inch green to half-inch green in the southern parts of the region on a few varieties. There is green tissue showing on almost all varieties in areas to the north. Some growers have put on there first apple scab sprays, but it truly depends on the weather conditions at each farm and current growth stage. With anticipated rain events later this week and weekend, I anticipate that our first scab sprays will be going on late this week or over the weekend. I am continuing to catch low levels of apple scab spores with each rain event, however with the snow conditions it has been very difficult to “read” the spore rods with all of the other miscellaneous material found on them. Pears are at early green tip at most farms across the region. Pear psylla adults were flying prior to the cold events of late last week and over the weekend, but I’ve seen none since then. Peaches are mostly at late bud swell to early pink on a few of the early flowering varieties. I continue to see a fair amount of winter injury to peach flower buds. This seems to vary a great deal from variety to variety. I would not encourage growers to start pruning peaches at this time. I would advise growers to wait for peaches to grow a bit more to determine there viability for the season. Sweet and tart cherries are at early side green for many varieties. Plums are at early green tip for most varieties at this time. Small fruit Strawberry growth is now underway at farms in the south where berries were uncovered. Strawberry farms in the Flint area and farms to the north have generally not uncovered their berries as of yet. Growth has begun underneath the straw mulch. At this time I would encourage growers to wait to remove the straw mulch until the current cold snap is over. I was reminded by an astute grower of the possible long term effects of the kind of winter injury that we saw last week and weekend. The temperatures that we experienced can damage crowns, and therefore can impact the vigor of the planting. While strawberries may grow and yield a fairly normal crop this year, with the crown damage they can quickly collapse at a later date due to the onset of black root rot disease. So keep a close eye on strawberries. As I mentioned in the last report, strawberries looked weak already this spring and I was encouraging additional applications of fertilizer. I am more convinced than ever that this will be helpful to strawberry growers to maintain productive patches. Raspberries are mostly at green tip for summer varieties. Fall red raspberries are still dormant with no growth emerging from the soil as of yet. Blueberries are at bud swell with just a slightest bit of green starting to show in some of the early flowering types. Grapes are still dormant at this time, with pruning continuing. |
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| 3 -- Grand Rapids Area Tree fruit growth stages Earliest to mid-season apple varieties started to show the first signs of green as of March 26 at the Clarksville station – this was about 11 or 12 days ahead of the past three years. Then the cold weather moved in. Not all tree fruit buds were showing green, but nearly all of the early varieties of apples, mostly on highly dwarfing rootstocks and younger trees, had some green showing before the cold. At this time, freeze damage to apples doesn’t appear to be extensive, but we’ll know more once it warms up again. Sweet cherry buds were swelling and have some green showing as well. At this time, damage from the cold is unknown until things warm up again. Growers are wrapping up winter pruning of apples and removing brush from blocks. Ground applied fertilizer applications should be starting soon, but some may want to wait until crop load is known before making applications. Tree planting should start soon. Tree fruit Apple scab spore rods are in place and running. We’ve had three rain events since green tip and only the last one was a light infection period for scab, just before the cold weather moved in. If you are planning on using dormant oil sprays for overwintering mite eggs, aphid eggs and scales, please be careful because of all the cold weather we’ve had which will make tissue much more sensitive to oil and could cause more phytotoxicity than you expect.. Remember to watch the weather forecast closely for possibilities of freezing temperatures within 3 days after oil sprays to avoid tissue injury, but also, don’t apply oil if there were freezing temperatures in the three days before your application either. Announcements The Ridge area Code-A-Phone is operational. The number is 616-451-8065. The Annual Spring Spray Meeting and IPM Update is scheduled for Thursday, April 19. We will meet at Kent-Ottawa Storage on Kenowa Ave, between 10 Mile Road or Wilson and Harding in Kent County. We will begin the meeting at 4:00 PM and hope to end by 6:00 PM. |
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4 -- West Central Last month’s warm temperatures triggered vegetation movement. Buds are still where they were just before the cold snap. All apple varieties are starting to show some green. Pears are in swollen bud. Peaches are in calyx green to calyx red. Plums are showing side green. Tart cherries are in green tip. Sweet cherries are showing side green. Ever since last Wednesday (April 4) after a prolonged period of temperatures in 50’s and even a couple of days in 70’s, the whole area has been under the influence of a very cold front that brought snow showers and low minimum temperatures. Particularly troublesome are these low temperatures that stayed with us for a very long period of time. High winds may have contributed to the damage by steering up the air, mixing it and conveying the cold air to the higher elevations causing additional types of freeze to more common radiation freeze. The lowest average minimum temperatures were from 18.6 to 20.40F in Manistee/Bear lake area (April 8) and around 21 to 220F in Hart and Ludington area (April 5-6). Given the stage of bud development, bud damage is imminent though it is still early to give reliably accurate assessment. Low areas are going to have much more significant damage. West Central Michigan growing degree day totals since March 1 As of Sunday, April 9.
Diseases Apple scab. Rain event on April 3-4 did not produce any spore release. We have designated March 29 as the green tip event for running our disease predictive models. Bacterial canker. This prolonged cold with daily frost occurrence will favor bacterial canker development. There are two related bacteria that are causing canker development: Pseudomonas syringae pv. syringae van Halland Pseudomonas syringae pv. morsprunorum (Wormald) Young at al. This opportunistic disease of a cool season will multiply, reaching its peak at just about bud break. Bacteria find safe-haven in the buds near the cankers or near the affected spurs as well as in the vascular tissue. It will invade the trees through the wounds resulted from frost or pruning. It may be found on sweet cherries, sour cherries, peaches and plums. Early copper sprays will kill off some of the bacteria found on the surface diminishing inoculum pressure and contributing to the better disease control. For detailed information regarding weather conditions, growing degree-day accumulations and weather forecast as well as various models to be used as tools in disease and insect management, you can visit the Enviro-weather web site: www.enviroweather.msu.edu and choose the closest station to your farm. Click here for the Hart station’s fruit resources and change the MAWN station name in the drop down box for other locations. |
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5 -- Northwest
Growth Stages at NWMHRS (April 10 - 8:00 AM) The weather so far in 2007 is as crazy as ever. We collected degree days pretty quickly at the end of March and into April, but around April 5, we were revisited by winter. Temperatures on April 4 and 5 were chilly, but the winds made those temperatures seem downright freezing! Wind speeds on those dates were up around 15 to 20mph with gusts even higher. Sunday night, April 8, we had very cold temperatures around the region. The most notable lows were 7.8 degrees (F) in East Leland and 3.8 degrees (F) in Elk Rapids. As of today, April 10, we have accumulated 110GDD base 42 (32GDD base 50), where we were only at 69 GDD base 42 (19GDD base 50) at this same time last year. The forecast is predicting 30-40’s (F) during the day with 20’s at night for the remainder of the week. Tree fruit The thing on most growers’ minds is the state of the crop after these strong winds last week followed by the low temperatures of Sunday night. In the past, we thought most of our cold injury was a result of inversion freezes—cold air settling into the lower areas of the landscape or even the lower portion of the tree causing primary bud kill. However, 2002 showed us that our temperatures do not need to fall to single digits to have severe damage; we had temperatures fall to 26-27 degrees (F), which under calm conditions would not have resulted in bud damage. However, when these types of temperatures coalesced with strong winds, this weather combination resulted in greater than 95 percent crop loss. In the case of 2007, we seem to have had cold temperatures (mid-20’s) with very strong winds AND calm extremely cold temperatures. Based on this weather one-two punch, many growers are wondering where we stand. We have conducted some bud damage assessments in Leelanau County, and we can only surmise at the damage we have so far. At this point, our estimates represent only a very small glimpse into what we might expect for the 2007 crop. They are from limited sites/areas and from a limited section of each orchard. These cuttings were also collected early on Monday morning, and the full impact of the low Sunday temperatures may not be reflected in these numbers. We will not know the full effects of these spring weather events for a few weeks. Overall, we have observed some damage in both tart and sweet cherries, and far less in apples. Small fruit For grapes, it is too early to tell the extent of cold injury from the recent bout of cold weather. In a sample of over 600 buds taken at the NWMHRS on April 9, Vinifera cultivars averaged about 10 percent injury to primary buds; nearly all of this bud morality looked to have occurred well before the April freeze. Bud mortality was worse on small or poorly-colored canes, as would be expected even if such critical temperatures had not occurred. |
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| Weather news: Winter blues Jeff Andresen Agricultural Meteorology Geography Winter returned to the Great Lakes region in full force on the April 4, ending almost two weeks of abnormally mild weather across the state. An intense area of low pressure moved through the state bringing a variety of weather conditions ranging from thunderstorms in southern sections to heavy snow in the north. Cold, Canadian-origin air moved in behind the storm, bringing an unusual late season lake effect snowfall event to all areas of the state. Snowfall totals by Sunday, April 8 exceeded 50 inches in some areas of the Upper Peninsula. Sub-freezing temperatures occurred in all areas of the state from April 4 through April 8, with low temperatures falling into the teens and 20's in most fruit-producing areas. The total amount of crop damage related to the freezing temperatures is still not completely clear, but is known to be extensive in some areas. Looking ahead, a gradual moderating trend is expected, but mean temperatures will likely remain below normal levels. An area of low pressure will move just south of the state on Wednesday, bringing more snow to northern sections of the state and a mix of rain and snow in the far south. Several inches of wet, heavy accumulation will be possible in central and northern sections of the Lower Peninsula by early Thursday. Mostly dry weather is expected statewide Friday, followed by another area of low pressure and more precipitation statewide by Saturday. With daytime temperatures slowly recovering back to the 40's to low 50's and low temperatures into the upper 20's and 30's by Friday, the majority of any precipitation this weekend should fall in the form of rain. In the medium range time frame, forecast guidance suggests the continuation of an active storm track across the Great Lakes region. The official NOAA 6-10 day and 8-14 day outlooks (covering the 15th-19th and the 17th-23rd of April, respectively) both call for temperatures to remain at below normal levels state- and region- wide. Normal to above normal precipitation totals are expected statewide during both periods. |
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