Table 1 lists suggested use rates and timing for different size trees. These rates are a guide for moderately vigorous trees and need to be adjusted up when used on highly vigorous trees. Table 2 lists factors to consider when selecting a rate to use. Apogee is compatible with all typical materials used during the time Apogee is applied except for calcium, boron and thinners. Don't mix Apogee with calcium and boron in the same tank. Table 3 lists suggested Apogee use on various varieties. Apogee will sometimes increase fruitset. More aggressive thinning is suggested when using Apogee. Apply thinners separately from Apogee. Separate thinner treatments by two to three days before or after an Apogee treatment.

Apogee must be mixed with AMS or a substitute in equal amounts and with a surfactant. Empire and Winesap fruit can be checked by Apogee.

Editor's note: This article was submitted by Gary Thornton and reprinted from Cornell University's Scaffolds Fruit Journal.

Over the past 30 years, the apple scab fungus has developed resistance to dodine (Syllit), the benzimidazoles (Benlate, Topsin M), and the SI fungicides (Nova, Rubigan, Procure). The first indications from orchard tests clearly indicate that the new strobilurin fungicides (Sovran and Flint) will not be exempt from resistance. This article outlines recommendations for minimizing further selection for resistance and suggests strategies for controlling scab in orchards where many of the fungicides mentioned above are no longer fully effective.

Apple scab has never developed resistance to any of the "contact" fungicides, a broad grouping that includes copper, the EBDC fungicides (mancozeb, Polyram), captan, the other carbamates (ferbam, thiram, ziram), or sulfur. The contact fungicides are multi-site inhibitors. That means that they disrupt several metabolic pathways in fungi, thereby making it difficult for the fungus to circumvent the action of the fungicide. Contact fungicides prevent spores from germinating on the surface of susceptible tissue, be it leaves or fruits. Once spores are allowed to germinate and to infect tissue beneath the surface, contact fungicides can no longer control the infections.

By comparison, dodine, the benzimidazoles, the SI's and the new strobilurins can stop the scab fungus after apple tissue has already been infected. Therefore, these fungicides are effective when applied on a post-infection schedule (in the absence of resistance, of course). These fungicides arrest fungal development by interfering with a single critical metabolic pathway in the fungus, but resistance develops when the target fungus develops mechanisms for bypassing the blocked pathway. The mechanisms used to bypass the fungicide activity are different for the different fungicide groups. Initially, the number of resistant strains will be very low and will not compromise good control of scab. Because they survive treatment, however, they will multiply more rapidly than sensitive strains and will increase in proportion over time. At some point, they will cause scab even though the fungicide has been applied at the same rates and timings that provided good control in previous years. The goals of anti-resistance measures are to slow the build-up of resistant strains and to control existing resistant strains by using other fungicides that are still effective.

For the SI fungicides, Wolfram Koeller and Wayne Wilcox have demonstrated methods for slowing the expansion of SI-resistant populations and for controlling resistant strains that escape. SI-resistant strains are not immune, and many of them can still be controlled by using a high rate of SI fungicides. However, the level of control will still be less than for the sensitive strains and a contact fungicide must therefore be included in tank mixes to control SI-resistant strains. This strategy has worked well for more than a decade in many orchards. We have tested orchards where SI+contact fungicide tank mixes have been used in a regular program for 12 years, and scab in several of these orchards remains fully SI-sensitive. However, we have also identified orchards in which scab is fully resistant to the SI's. In the latter group of orchards, the SI's were routinely used in post-infection applications and not always in mixtures with contact fungicides. The current situation in most New York orchards is somewhere in between these two extremes, with scab populations that are neither fully SI-sensitive nor fully SI-resistant.

The new group of strobilurin fungicides (Sovran, Flint) provides an alternative for reducing selection pressure for SI resistance. Of course, two questions are important: How fast will the strobilurins develop resistance by themselves, and do they control SI-resistant strains as effectively as SI-sensitive strains? Proactive research conducted in Wolfram Koeller's lab and in cooperation with Wayne Wilcox has shown that development of resistance to strobilurin fungicides is more complex than it has been with previous classes of fungicide chemistry. Following are their essential findings and predictions:

1. There is no doubt that scab will develop resistance to the strobilurin fungicides. Lab experiments, orchard trials, and experiences from Europe suggest that development of resistance will proceed in two phases. First, scab strains that are not entirely immune to the strobilurins will emerge. As with the SI's, these strains will still be controllable by using higher strobilurin rates. In the second phase of resistance development, strains that are totally immune to the strobilurins will slowly emerge. How long will the first phase last? The first phase lasted for five years in Europe, and it still persists in a large majority of European orchards. Preliminary laboratory tests suggest that dependence on post-infection applications (especially applications >48 hr post-infection) might speed the development of strains immune to strobilurins.

2. Do the strobilurins control SI-resistant strains as effectively as SI-sensitive strains? Not necessarily. Scab isolates that are resistant to SI fungicides are somewhat less sensitive to post-infection activity of strobilurin fungicides. Where minimum label rates of strobilurin fungicides were applied in fully SI-resistant orchards, SI-resistant strains were not controlled as well as the SI-sensitive strains. At maximum label rates, the strobilurins controlled both SI-resistant and SI-sensitive strains equally well. This means that using low rates of strobilurins at post-infection timings will maintain selection pressure for SI resistance and that post-infection sprays of strobilurins may not perform well in orchards with SI resistance.

3. The strobilurin fungicides remain fully effective against SI-resistant scab when the strobilurins are used as protectants. This means that the strobilurins are not cross-resistant to the SI's because only the post-infection activity of strobilurins is compromised when they are applied to SI-resistant populations of apple scab.

The discovery that there is some linkage between strobilurin activity and SI resistance impacts the usefulness of strobilurins as tools for managing SI resistance. To conserve their usefulness, strobilurins should be applied at rates in the upper half of the rate ranges indicated on the product labels whenever they are used in post-infection timings.

Increased emphasis on resistance management for apple scab is warranted because, in orchards where dodine, benzimidazoles, and SI's are no longer effective, the strobilurins represent the last currently known chemistry that can provide any post-infection control of scab. Strobilurin resistance that resulted in total loss of post-infection activity would leave some growers with nothing but contact fungicides to control scab. Contact fungicides used alone are very unforgiving precisely because they lack post-infection activity. Thus, growers have a great incentive for preserving strobilurins (and SI's where they are not already compromised). These chemistries represent the only remaining tools that have the post-infection activity necessary for emergencies and for suppressing "escapes" (i.e., those few infections that escape control by protectant fungicides or by strobilurins and SI's used in preventive programs).

Key strategies for avoiding problems with fungicide resistance include the following:

1. Emphasize preventive fungicide timing. Over the past decade, various "IPM strategies" have been developed to reduce fungicide use by omitting early sprays in low-inoculum orchards, by using a 4-spray SI program that often stretched the interval between pink and petal fall sprays, or by using electronic scab predictors to time post-infection SI sprays. In retrospect, we believe that these programs often contributed to rapid selection for SI resistance, especially when they were used in high-inoculum orchards. The party is over: We now need to revert to more conservative scab-management programs to preserve fungicide activity.

Spraying preventively means the first scab spray should be applied early enough to ensure that no infections become established on young foliage. Sprays should be applied ahead of predicted infection periods rather than regularly depending on post-infection activity of the fungicides. Spraying preventively utilizes the strength of the strobilurin fungicides as spore germination inhibitors and the strength of the contact fungicides in SI+contact tank mixes. It also ensures that pathogen populations will remain low and that resistant strains will be controlled rather than left to "run wild." When used in post-infection spray timing, however, contact fungicides in tank mixes will not reduce selection pressure for resistance, nor will they control resistant strains.

The most rigorous preventive timing would involve spraying on a regular five- to seven-day interval to ensure that new leaves are always protected ahead of any infections. In orchards with SI resistance, this level of preventive spraying may be needed unless growers believe that higher label rates of the strobilurin fungicides are more cost-effective than reducing the spray intervals. In orchards where the SI fungicides are still working, we believe that a ten-day spray interval is still OK when using strobilurin and SI+contact fungicides in rotations or alternations. However, remember that protection from these fungicides only lasts about six to seven days. (The last three to four days in a ten-day schedule are dependent on the post-infection activity of the strobilurin or SI.) Therefore, if scab is still active when switching from a ten-day program to a contact fungicide, the contact fungicide should be applied within six to seven days of the last strobilurin or SI+contact application.

2. Plan to use strobilurin or SI+contact fungicides beginning at tight cluster or pink. This is another aspect of preventive spraying that will help to ensure complete control of primary scab and mildew. Beginning mildew control at petal fall worked well in the early years of SI use, but it is no longer recommended.

3. When post-infection activity is needed, use higher rates. This is true for both strobilurin and SI fungicides. Using the low label rates on a post-infection basis is a recipe for disaster. ("High rates" mean at least the middle of the rate range given on the SI and strobilurin product labels.)

4. High rates of strobilurins may reduce selection for resistance more effectively than low strobilurin rates mixed with contact fungicides. Koeller points out that the high rates of strobilurins provide the best post-infection and protection activity. Low rates plus a contact fungicide may provide equal or better protectant activity, but the contact fungicide cannot compensate for the selection pressure exerted by the low rate of the strobilurin. However, Rosenberger suspects that a contact fungicide such as mancozeb or captan may redistribute to new foliage more effectively than strobilurin fungicides. If that suspicion is correct, then the redistribution of the contact fungicide applied as part of a tank mix would prevent infections on newly-emerged (and therefore unsprayed) foliage that would otherwise be controlled only via post-infection activity of the next SI or strobilurin spray. The jury is still out on whether growers should spend the extra dollars to buy a higher rate of a strobilurin used alone or whether they should buy a contact fungicide to use with the strobilurin.

5. Alternating strobilurin and SI+contact sprays is better than using blocks of two or three sprays before switching to the alternative chemistry. We are not certain why that is true, but we seem to get more effective disease control. More effective disease control means less selection pressure because there is less chance of generating secondary inoculum in trees.

In orchards where SI's are no longer effective, the key to effective scab control will be preventive timing, a tighter spray interval, and higher rates of strobilurin fungicides any time that post-infection activity is needed. Using a delayed-start program followed by low rates of strobilurins on a ten-day schedule will likely result in control failures where SI-resistant scab strains are present at high numbers. It will also speed the development of resistance to the strobilurins.

Resistance management strategies for apple powdery mildew are based on the same principles as those used for apple scab. The only problem with mildew is that none of the contact fungicides have mildew activity. Therefore, there is even more reason to start early and use higher rates of SI and strobilurin fungicides where mildew is a problem. "Starting early" with mildew means including a mildewcide beginning at about tight cluster and certainly no later than at pink.

For apple growers, managing resistance and selecting appropriate fungicides is difficult because there is no way to predict existing levels of resistance to the various fungicides within individual orchards. The proportion of fungicide-resistant scab strains varies from region to region and from orchard to orchard within regions. Even where resistant strains are present, the fungicides may still appear effective if the size of the resistant population is still low. Diagnosis of resistance problems is largely based on field experience. However, fungicide resistance can be implicated in control failures only in those cases where growers can verify that sprays were well timed, that spray coverage was excellent, and that appropriate rates of the fungicide were used.

Fungicide strategies for controlling apple scab and powdery mildew remain mostly unchanged from those recommended for the 2001 season and published in Scaffolds last year (see citations at the end of this article). This article provides a brief summary and update of the recommendations published last year. Key recommendations for early-season disease control on apples in 2002 include the following:

1. Start early! Plan to use contact fungicides (mancozeb, Polyram, captan) beginning at the green tip bud stage and again seven to ten days later. Appropriate spray intervals will vary depending on temperature (i.e., tree growth rate), rainfall, and predicted infection periods. Copper applied at green tip to suppress fire blight inoculum provides scab control equivalent to that of a mancozeb spray. None of the protectant fungicides (including copper) have postinfection activity. Therefore, scab infections that occur at green tip will not be controlled if the first spray is not applied until half-inch green.

Delaying the first spray beyond green tip is risky except when apple scab ascospore maturity is considerably delayed compared with "average" years or where orchards had virtually no scab the previous season. The latter can be determined only by carefully observing terminal leaves for scab symptoms during October. Growers should not assume that they have "clean" orchards just because they failed to notice scab from the tractor seat.

Sprays between green tip and tight cluster can prevent early scab infections that would otherwise generate secondary inoculum for infecting leaves and fruit between bloom and first cover. In most cases where significant fruit scab is present at harvest, the origins of the problem can be traced to poor scab control during the prebloom period.

Even the best fungicides will often fail when the following three conditions occur simultaneously:

• Trees are growing rapidly, thereby generating large quantities of susceptible tissue.
• Extended rains favor scab and interfere with spraying during the period between late bloom and second cover.
• Primary scab lesions are visible at petal fall, thereby providing huge quantities of inoculum.

The first condition occurs every year during the spring growth flush that begins near petal fall. The second condition is both unpredictable and uncontrollable. Therefore, the only foolproof way to avoid a scab disaster is to prevent condition number three. Careful prebloom scab control is the key to ensuring that no secondary inoculum is available during the interval between petal fall and second cover.

For powdery mildew, starting "early" means including a mildewcide in the spray program starting at the tight cluster bud stage, or at the very latest, by the pink bud stage. When the SI fungicides were first introduced, they sometimes provided adequate mildew control when applied only in the petal fall and first cover sprays. In most orchards, the SI fungicides are less effective against mildew now than they were 10 to 12 years ago, so mildew control must be initiated earlier before inoculum from primary mildew infections can spread to new foliage. Remember that powdery mildew can spread in the absence of rainfall or leaf wetting. Therefore, new foliage should be protected with fungicides even when no scab infection periods are predicted.
We can expect high levels of overwintering mildew in 2002 because the mild winter will have allowed most mildew-infected buds to survive. For 2002, delaying mildewcide applications until petal fall will be somewhat like closing the barn doors after the horses have run away.

2. Strobilurin or SI+contact fungicide sprays should be introduced at tight cluster or pink. Sovran and Flint are strobilurin fungicides; Nova, Rubigan, and Procure are SI fungicides. A strobilurin or SI fungicide should be used at tight cluster and/or pink to ensure adequate mildew control and to ensure complete control of apple scab during this critical period. The strobilurin and SI fungicides have postinfection and anti-sporulant capabilities that are lacking in contact fungicides. The time between tight cluster and petal fall usually encompasses the peak of scab ascospore discharge, the period of most rapid leaf expansion, and the period when any primary infections that became established shortly after bud-break will begin to produce conidia. Dollars paid out for fungicides between tight cluster and petal fall often pay dividends by reducing the need for fungicides to control secondary scab and mildew during summer.

Apple growers with low-inoculum orchards and good management skills may be able to save on fungicide costs by using only contact fungicides until petal fall. However, scab programs built exclusively on contact fungicides are likely to fail in orchards with high inoculum levels and in years when weather conditions favor severe scab and limit preventive spray timing. Furthermore, none of the contact fungicides control powdery mildew. If no mildewcide is applied before petal fall, mildew control may be compromised and selection pressure for fungicide resistance will be increased.

3. Consider an alternating program of strobilurin and SI+contact fungicide sprays. There is no single "correct" scheme for configuring strobilurin and SI+contact fungicide sprays during the period between tight cluster and second cover. However, an alternating program (e.g., stroby, then SI+contact, then stroby, then SI+contact) may be slightly more effective than blocking programs wherein two or three applications of one chemistry are followed by several sprays of the alternative chemistry. This is especially true where the strobilurins are applied alone and rust diseases are prevalent. As suggested last year, a "fill-in" spray of mancozeb or captan alone may be needed to bridge the period between strobilurin or SI+contact sprays applied at pink and petal fall.

4. Should the strobilurin fungicides be applied in combination with contact fungicides? No one has a definitive answer for this question. An obvious reason for using strobilurin+contact combinations is to gain better control of rust diseases than that provided by strobilurin fungicides used alone. If one assumes that contact fungicides will redistribute better than strobilurin fungicides, then tank mixes might perform better than a strobilurin fungicide applied alone in situations where spray coverage was incomplete or rapid terminal growth might leave new leaves unprotected. However, we currently have no data to prove that contact fungicides have better redistribution capabilities than strobilurin fungicides. Tank-mix combinations of strobilurin+contact fungicides have been proposed as a resistance management strategy for apple scab, but that assumption is now questionable based on recent work by Dr. Wolfram Koeller.

If growers opt to use strobilurin fungicides in combination with a contact fungicide, it is imperative that the rate of strobilurin in the mixture be maintained at the same level as for sprays where the strobilurin is applied alone. Tank-mix combinations involving a contact fungicide plus a full rate (minimum label rate) of a strobilurin fungicide can be expensive, but they may provide enough risk-reduction to warrant consideration during the critical period between pink and first cover.

5. Regardless of tree-row volume calculations, never apply Flint at less than 1 oz/A or Sovran at less than 2 oz/A. These minimum rates for small trees have been adjusted upward since last year due to changes on product labels and concerns about fungicide resistance. The only exception is that if trees are sprayed to drip with a hand-held wand, then rates of 0.67 oz of Flint/100 gallons or 1.33 oz of Sovran/100 gallons are sufficient. When directed sprays are applied with a hand wand, then the actual rate per acre might drop below the minimum rates recommended for airblast applications.

6. On mildew-sensitive cultivars, mildewcides will be needed until shoot growth slows or terminates. After four or five applications of strobilurin and SI fungicides, sulfur may useful for suppressing mildew infections during June and early July.

Focus on preventing early infections of scab and mildew. Over the past 20 years, many of us have proposed IPM strategies for controlling scab and mildew that involved omitting early fungicide applications or stretching spray intervals during bloom. Based upon what we are learning about fungicide resistance, many of those strategies now appear unwise and unsustainable. We are increasingly aware that fungicides with post-infection activity are valuable tools that will be quickly compromised if they are overused or misused.

In recent years, there has been a dramatic increase in the abundance of Asian ladybird beetle (Harmonia axyridis) in Michigan and other Great Lakes states. Although this predator is highly beneficial because it is a predator of aphids and leafhoppers, it has also become a nuisance for some producers of late-ripening small fruits, even forcing the premature closure of some U-pick fields during last fall.

Asian ladybird beetles have recently become active and are being found with regularity in homes and some fruit crops around the state. Last winter the beetles could be found congregating on the walls of homes, looking for a sheltered and warm place to overwinter. Once one beetle finds a way into the wall space, others will follow and spend the winter protected from the elements snuggled amongst the insulation.

When temperatures recently began to rise, the sun warmed the outside walls of homes enough to get the beetles active. Once awake, the beetles are faced with a choice of going out, or coming in. As those with this insect problem can attest, most choose to go inside where it is warmer and then congregate around windows.

The best way to get rid of these pests indoors is to use a vacuum with a hose attachment. Put an old nylon stocking over the end of the hose and start vacuuming. The nylon stocking allows you to easily remove and dispose of the beetles. Avoid crushing the beetles as this causes them to release a foul odor and also dispense insect "blood" from their legs, which has been shown to stain porous surfaces. They are definitely a nuisance, but it is not advisable to use insecticide in the home to get rid of these pests. An insecticide application could linger extending the time you, your family, and any pets are exposed, and these insects will soon be out of the house, or can be vacuumed.

At many winter extension meetings this year, one of the first questions was "What can we spray for Asian Ladybird beetles?" Before thinking of spraying a fruit crop, we will need to watch this season to see if they once again become a problem. Their classification as beneficial insects tells us a few things. First, you will probably not see a pesticide label in the near future that lists this insect. Second, populations of this insect grew primarily because conditions were favorable for its favorite foods, which are soft-bodied insects. If weather conditions are not favorable for these insects this year, you can expect to see a decrease in the number of Asian Ladybird beetles. Third, as populations of a species increase, the population per area increases as well. This makes it easier for disease, natural enemies, and any number of things that prey on the species to find them and do them harm.

The point to make here is that Mother Nature may well take care of this problem for us. However, we are going to be keeping our eye on this critter this year.

Quadris (azoxystrobin) has received a supplemental label for use on strawberries. This fungicide belongs to the strobilurin class and has the same active ingredient as Abound. The active ingredient, azoxystrobin, is a synthetic version of a fungitoxic compound first isolated from in a small forest mushroom. It is considered a reduced-risk fungicide, has activity against a wide range of fungi, and has surface-systemic properties.

The strawberry label lists anthracnose, powdery mildew, and Rhizoctonia root rot as target diseases. More field trials are needed to assess its efficacy against strawberry diseases in Michigan. Trials conducted in Michigan strawberries with a related compound (BAS 500 - a strobilurin also) have shown excellent control of foliar diseases and fruit rots.

Because of its favorable toxicological profile, Quadris may be applied the day of harvest. Quadris should be integrated in a disease management program that includes resistant varieties, removal of infested plant debris, and proper timing of irrigation. An application rate of 6.2-15.4 fl oz of product per acre is recommended on the label, but a more typical application rate would be 10 fl oz per acre. The label recommends that applications begin prior to disease development and continue on a 7 to 10 day schedule. However, to reduce the chances of resistance development, Quadris should not be applied more than three times per season, and no more than two times consecutively before alternating to a fungicide with a different mode of action. Applications can be made by ground, air, or chemigation. An adjuvant may be added at recommended rates.

For control of soilborne diseases, Quadris must be applied early in the growing season as in-furrow or banded applications directly over the row. For banded applications, use Quadris at a rate of 0.4-0.8 fl. oz. product per 1000 ft of row. Remember to read the label carefully before use.

Project GREEEN has again provided funding for a joint weather-monitoring grant between MSU and SimpleSoft, Inc. This year's grant will allow us to deliver real-time disease and insect prediction information to all interested fruit growers, consultants, chem reps and scouts in Michigan. The information will be based on the recently developed Michigan Agricultural Weather Network (MAWN). These are a series of electronic weather stations that are all connected via phone to MSU. This season's PestNet forecasts will include information from a total of 23 weather stations throughout the fruit belt of Michigan.

This network will provide growers with predictions based on real time information for wetting events for the following diseases: apple scab, cherry leaf spot and fireblight. It will also provide reports that will aid in the timing of sprays for codling moth and plum curculio control. The reports will be sent for every wetting event in your region, up to twice a day, depending on the length of the wetting event. Fax and e-mail reports will go out between 7:00-8:00 am and 6:30-7:30 pm when it rains. Disease prediction reports via the PestNet Code-A-Phone will only be updated at that time as well. Information can be received via three methods: email, fax and phone.

Fill out steps one and two and click on download. You may consider "unchecking" the boxes in step two that will prevent them from contacting you with new product information.

Reports will be sent via fax to those subscribing. The cost for the season is $25. Subscribe by contacting the NW Michigan Horticultural Research Station (231-946-1510). If you subscribed last year, you will be sent two free reports before payment will be required. Please let us know if you would like to subscribe again. Make checks payable to Michigan State University and mail them to: NWMHRS, 6686 S. Center Hwy., Traverse City, MI 49684.

This is available for free to anyone who has access to a touch-tone phone. The phone numbers for those wishing to access the PestNet are 947-3063 (Local) 1-877-763-3300 (Toll free, statewide).

You will also need to let us know the station(s) that you would like the reports from. The following are the stations available for 2002: Eastport, Yuba, Northport, East Leland, Northwest Mi. Hort. Res. Station (Traverse City), Benzonia, Old Mission, Elk Rapids, Kewadin, Manistee, Mason, Hart, Fremont, Sparta, Belding, Clarksville, West Olive, Fennville, Grand Junction, Bainbridge (Coloma), Southwest Mi. Res. & Ext. Center (Benton Harbor), East Lansing and Petersburg.

Tuesday will be warmer with wetter weather Wednesday and Thursday. Another frost is possible on Friday. Soil moisture conditions are good. Soil temperatures have fallen to 45° .

Growers should assess fruit damage from Tuesday's frost. Most stone fruit are at or near the bloom stage where freezing temperatures of 27° or 28° F will result in ten percent loss and 24° F in 90 percent loss. From the temperature range we expect to see 50 percent or more loss in most fruit plantings. With large fruited fruits (apples, peaches, plums and pears) this is not significant but small-fruited fruit such as cherries, blueberries and grapes where many small fruit are needed for good yields this frost is a disaster. Scouting for frost damage will also allow them to scout for bud damage from leafroller larvae. Many growers are reporting large numbers of Asian multicolored ladybeetles in their trees. These predators may be eating everything in sight. We are find little or no mite, aphid and pear psylla eggs in the orchards. Growers may not need to apply pink sprays in apples. Blooming stone fruit are at risk to brown rot blossom blight. Warm showers are forecast for Wednesday and Thursday, with highs in the 65° to 70° F range. These are ideal conditions for blossom blight caused by brown rot.

Apricots are in the shuck. Since most apricots are grown in high sites there should be only moderate damage from Tuesday's freeze. In general fruit set looks good.

In peaches, Tuesday's frost will significantly reduce the crop, but we should still have a good crop in most sites. No signs of peach leaf curl yet. There were adult Oriental fruit moth caught early last week, but cool weekend temperatures reduced the catch to zero. We believe that the cool weather this week will delay biofix until warm weather returns.

In cherries, crop losses due to freezing temperatures will be significant. Due to the small size of the fruit, the number of fruit needs to be large to have a full crop. Tart cherries are at white bud and scattered bloom has begun. Blossom blight is rare in tart cherries. As the leaves unfold they become susceptible to cherry leaf spot. Growers should be protecting against this disease as weather warmers. Sweet cherries are still in bloom. Sweets are probably the most susceptible stone fruit to brown rot blossom blight.

In plums, crop losses due to freezing temperatures will be significant, but we should still have a good crop. European plums are at full bloom. Japanese plums are past full bloom. Plum growers need to protect new shoot growth against black knot and open blossoms against blossom blight of brown rot.

In apples, we have probably lost the king bloom and some of the side bloom so we still have excellent crop potential but chemical thinning will be much harder. An apple scab infection occurred in some areas on April 12. The symptoms of this infection should be visible on about May 1. There was no scab infection from the April 21 rain. Scab spores are being caught after each rain. Scab spore release is about 25 percent complete. Most scab spores are released in the period from pink to petal fall. Growers need to maintain protection against scab. Powdery mildew will become a problem as bloom nears. Growers are planning their pink sprays to control leafroller larvae and rosy apple aphid. There is no insect activity to report cold weather has shut them down. Redbanded leafroller and Oriental fruit moth were flying last week. Scout your orchards for leafroller larvae and European red mite eggs. Look for tiny red eggs in the wrinkles and bud scales of fruit spurs and two to three year-old wood to determine if you need to apply early season controls.

Pears are likely little damaged by the frost. Pear psylla is the only pest out in pears.

Growers should assess fruit damage from Tuesday's frost. Small fruit were not as far along developmentally, but I expect to see 50 percent or more loss in most fruit plantings.

Blueberries are at early pink bud. Leaves are a half-inch long. It is likely that we have lost 10 to 50 percent of the crop. Mummyberry trumpets have been out for almost a week. Frost should kill the mushrooms out now, reducing the risk from the showers forecast for mid-week. Growers should scout for obliquebanded leafroller larvae feeding on flower buds and monitor for new mummyberry trumpets.

Concord grapes in Van Buren County are at bud burst. Freezing temperatures below 25° to 27° F will result in loss. It appears likely that depending on the site, we have lost 10 to 50 percent of the crop. Southwest Michigan Grape Growing Degree Days base 50 from April 1 to April 22 are 150. No damage from cutworm has been reported and we seem to have moved rapidly past the swollen bud stage where these pests cause serious damage. Cool, wet conditions should favor phomopsis. No black rot infection periods yet.

Summer-like weather over the last week with high temperatures climbing into the mid 80's to low 90's and lows in the 60's each morning have forced about two weeks worth of normal spring growth or development into five days. Our season is currently running a least a week to ten days ahead of normal. Soil moisture conditions are adequate to above normal. Soil temperatures have moved quickly in the last two weeks from the high 40's to as high as 77 and they have now dropped down back to the high 40's. These soil temperatures are taken under bare soil at the two-inch depth.

Cold temperatures on the morning of April 23 (this morning) have been recorded in the range of the mid 30's in the southern part of the district and around 30 in the Ann Arbor and Flint areas. Even though peaches and sweet cherries are in full bloom, it does not appear that we will have any damage from these cold temperatures. It will be toward the end of the week when we know more fully if we have experienced cold damage. Again peaches and sweet cherries are the two crops that I'm most concerned about.

A few growers had a short wetting period over the weekend. It depended on when rain showers moved over and whether or not the sun came out to dry things on Sunday morning. Planting of tree fruits and small fruits has begun at most farms. However, there is still a fair amount to be planted in East Michigan.

Pears are at tight cluster. Pear psylla eggs and adults have not been evident thus far this season. It is very unusual to find so few adult pear psylla flying this year. Again, this may the result of the Asian lady beetles feeding on them.

Peaches are in full bloom across the district. Peaches need to be covered for brown rot fairly quickly.

Sweet cherries are also at full bloom. Brown rot and cherry leaf spot control sprays need to be applied fairly quickly. No plum curculio has been observed in any stone fruit as of yet.

Tart cherries are mostly at early white bud.

Summer raspberries have about one inch of newly expanded growth and fall bearing raspberries are fully emerged from the soil with about one to two inches of growth. There appears to be little to no winter kill to cane tips this season.

Blueberries are mostly at swollen bud and appear to have a good crop this year. Traps need to be set for cranberry fruitworms fairly quickly.

The wild temperature fluctuations over the past two weeks have been interesting. Warmer than normal temperatures last week moved the Ridge area to degree day totals above the average. The cooler than average temperatures for this week and next will slow things down a bit. Overnight temperatures on Monday (4/22) morning were in the upper 20's to low 30's and on Tuesday morning (4/23) temperatures dropped even further into the mid- 20's. Tuesday morning temperatures will most likely damage some peach and sweet cherry blossoms that are exposed.

Sweet cherries are coming into bloom for many varieties.

Peaches are in full bloom.

Apple growers should contact their bee source as soon as possible - it looks like much of the southern lower peninsula will come into full bloom at around the same time and bees may be hard to come by.

What a difference in just a few days? The week started out with summer-like temperatures and ended with snow! Hopefully, the cloud cover will stay with us and moderate the temperatures so we are not left without a crop!

As of April 21.

Apricots are almost in full bloom. Temperature of 27° F would cause ten percent bud loss. It is important to mention that any prolonged period of cool temperatures that would interfere with bee activity will result in no apricot crop.

Pears are in tight to open cluster. No significant damage will occur unless temperatures go below 24° F.

Peaches are just beginning to bloom. Only in Michigan we can see the snow on the open peach blossoms! They should withstand temperatures of 25-26° F with only minor bud kill.

Plums are quite advanced in their development. Japanese plums are in full bloom. European plums are mostly in white bud to first bloom. Critical temperature for them at this stage is 27-26° F.

Sweet cherries are mostly in tight cluster, though there are some varieties (Ulster) that are in white bud. Critical temperature with a possibility for about ten percent bud kill is 28-29° F respectively.

Tart cherries are in tight cluster to open cluster depending on location. Critical temperatures for them are 26° to 28° F respectively.

Except for some psylla and green fruitworm activity before this cold front there is no much activity in the insect world. Oriental fruit moth traps are being set.

Concerning apple scab, warm rains and higher temperatures last week caused rapid vegetation development. The apple buds "moved" from silver tip to tight cluster in only 8 days. The rain we had Friday morning did produce spore discharge so we are officially in the primary scab infection period. Consequent rains are very likely to cause infections. From now on apples must be covered to prevent early infections.

Stone fruit is (apricot, peach, plum) or will be (sweet and tart cherries) at the stage very susceptible to brown rot infections. Coverage is necessary.

Growers are finishing up with pruning and brush removal. Tree planting is underway.

Following is the schedule for the In-Season Fruit Management Meetings for West Central Michigan:

Oceana County: May 6 and May 20 at the MSU-Extension Office starting at 7:00 PM.

Mason County: Every Tuesday starting May 7 at MSU-Extension Office in Scottville, starting at 7:00 PM. Last meeting is scheduled for June 18.

Manistee County: Every Wednesday starting May 1 at the MSU-Extension Office in Onekama, starting at 7:00 PM. Last meeting is scheduled for June 19.

Pesticide recertification applicator credits have been applied for these meetings.

Record high temperatures last week were followed by a return to winter temperatures. Sunday night (4/21), during the snow event, temperatures were in the 27° to 28° F range for several hours, with wind. On Monday afternoon, I was surprised at the extent of bud damage in tart cherries that resulted at the higher elevations at the NWMHRS. Buds in lower areas looked better. A more conventional inversion frost occurred Monday night/Tuesday morning, with warmer temperatures on the higher sites than the previous night, but colder in lower areas.

Last week a light infection period for apple scab was reported in some areas of NW Michigan. The temperatures were on the cool side, but significant spore release could have taken place based on the plant phenology at that time. Some growers ignored the infection period. Those who did should keep a close watch for lesions, and if they show up, modify their spray program.

Overwintering egg numbers of European red mites appear to be down all over the state. The few orchards checked here in NW Michigan have had low numbers.

Southwesterly flow aloft over the central and eastern U.S. led to abnormally warm weather during the past one to two weeks. Mean daily temperatures reached 90° F at some locations in the state for the first time this year (at least 35° F above climatological normal high temperatures for the season). New maximum temperature records for the date were set at many locations during April 16-18. Seasonal growing degree (GDD) accumulations, which had been near zero due to cooler than normal temperatures during much of March and early April, surged to above normal levels. The result was rapid early growth and development of most overwintering crops (see accompanying figure for GDD accumulations at Lansing). Base GDD accumulations for April 8-20 ranged from about 40 units in the far northern Upper Peninsula to more than 150 units in the southern Lower Peninsula. These totals are nearly double the normal accumulation for this time of year and seasonal totals last seasons.

The unusual warmth came to an abrupt end on April 20 with the passage of a cold front through the region and a return of northwesterly flow aloft, which continues to the present. The change in jet stream was accompanied by snowfall on April 21 and 22, and near-record minimum temperatures, which fell into the upper teens and 20's on the morning of April 23.

Looking ahead, the jet stream troughing feature currently in place across central North America is expected to persist for the remainder of the week. The result will be a continuation of cooler than normal temperatures statewide. Look for high temperatures only in the 50's to low 60's with low temperatures remaining in the 30's. Frost and freezing temperatures will be a continuing threat statewide, especially under clear, calm nighttime conditions.

Rainfall is likely with the passage of a weather system to our south on April 24, and again this Friday and Saturday. The latest NOAA 6-10 and 8-14 day outlooks covering April 28 -May 2 and April 30 - May 6 calls for near to below normal temperatures and above normal precipitation totals. Due to disparity between some of the computer guidance, forecaster confidence in this outlook is considered less than normal.