In this issue
Tree fruit news
Welcome to our 2006 publishing season
2006 fruit insecticide registration update
Plan ahead to manage pear psylla
Early-season copper application to reduce of fire blight inoculum
Section 18 crisis exemption granted for Mycoshield use
Small fruit news
Blueberries receive Section 18 for Indar and Topsin M for 2006 season
Berry varieties worthy of trial
Other news
2006 fruit IPM meetings in southwest Michigan
Grape IPM meetings in southwest Michigan
Regional reports
Weather news

If you have suggestions related to the print or on-line version of these newsletters, please feel free to contact us at (517) 353-4951 or catalert@msu.edu

Out next issue of the Fruit CAT Alert will be published April 11.— Joy Landis, editor and Rebecca Lamb, assistant editor.

This is a summary of insecticide/miticide label additions and corrections to the 2006 MSU Fruit Management Guide.  Agri-chemical labels and regulations change quickly so use this information within the context of each compound's actual label. To order a copy of the guide, call 517-353-6740.

Admire Pro (imidacloprid) is a new “thyxatropic gel” formulation of this soil-applied insecticide and is registered for use in blueberry, strawberry and cranberry for control of aphids, Japanese beetles and the white grub complex. It is also labeled in grapes for the control of leafhoppers, mealybug and phylloxera. Admire should be applied to moist soil and irrigated in with 0.5 to 1 inch of irrigation within 24 hours of treatment, or by chemigation to the root zone. Admire Pro contains 4.6 lbs of active ingredient per gallon of formulation product, and allows a maximum application of 14 oz per acre.

Baythroid XL (Cyfluthrin) is a new formulation pyrethroid insecticide registered for use on pome fruits, stone fruits and grapes for control of a broad spectrum of insect pests. This material is highly toxic to mite predators and should be used carefully to prevent mite population buildup. Baythroid XL follows the label rates of Baythroid 2E is restricted to two applications per year and a total of 2.8 oz per season.

Danitol 2.4EC (fenpropathrin) is a pyrethroid insecticide newly registered (Federal label, State label pending) for use on blueberries for control of 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 is expected to have a 3-day PHI and 24-hr REI for use in blueberries.

FujiMite 5EC (fenpyroximate) is an insecticide/miticide registered for use in apples, pears and grapes. FujiMite 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, two-spotted spider mites, pear rust mites, apple rust mites), but requires thorough coverage to ensure pests will contact the product. FujiMite 5EC has good in-season flexibility and is restricted to two applications per season and a total of 2 pints per acre per year .

Oberon 2SC (spiromesifen) is an insecticide/miticide labeled for use in strawberries for control of spider mites and white flies. Oberon is part of a new chemical class called tetronic acids and has a novel mode of action characterized as a lipid biosynthesis inhibitor (LBI) and is active by contact to all life stages. Oberon 2SC is restricted to three applications per season and 48 fl oz per acre per year.

Onager 1EC (hexythiazox) is a new formulation miticide (same active ingredient as Savey) for control of European red mites and two-spotted spider mites on stone fruits. It is an active mite ovicide and larvacide, providing 10+ weeks of control depending on mite pressure. Control is achieved when eggs/larvae come into direct contact with the spray or contact with treated plant surfaces. It can be used after bloom up to a 28-day PHI. It may be applied only once per year.

Proaxis 0.5CS (gamma cyhalothrin) is a microencapsulated synthetic pyrethroid insecticide that is labeled for use on pome and stone fruit crops. It is labeled for control of a broad spectrum of sucking and chewing pests, including leafrollers, leafhoppers, plum curculio, scarab beetles and internal feeders like codling moth and Oriental fruit worm. This material is also highly toxic to mite predators and should be used carefully to prevent mite population buildup. Proaxis is restricted to 1.6 pints per acre per season.

Venom 70SG (Dinotefuran) is a new neonicotinoid insecticide registered on grapes for the control of leafhoppers, grape berry moth, multi-colored Asian lady beetle and mealybug. Insecticide application rates in the 2006 Fruit Management Guide are for the Venom 20 SG formulation, which are different than the current 70 SG label. For foliar applications Venom 70SG should be applied at 1-3 oz/acre, whereas soil application rates are 5-6 oz/acre to control mealybug, leafhoppers and thrips. Soil applications should be applied to moist soil and irrigated in, or by chemigation to the root zone. Venom foliar applications allow up to 6 oz per acre per season with a 1-day PHI, and soil treatment is restricted to 1 application and a 28-day PHI.

Zeal 72WDG (etoxazole) is a growth regulator miticide newly labeled for use in grapes for control of mites. Zeal is primarily active against major tetranychidae mites (spider mites and red mites) in the egg and larval stages of growth, providing control ranging from eight weeks to full season depending on mite pressure, the extent of tree vegetative growth and predator mite populations. Zeal controls susceptible mites by inhibiting the molting process through disruption of the cell membrane. Since Zeal’s activity depends upon mite development, control may not be observable for several days. Etoxazole exhibits pronounced translaminar movement in plant leaves, enhancing activity when the pest is located on the undersides of leaves. Zeal is not known to have risk of cross-resistance with other currently registered miticides. Zeal is restricted to one application per acre per season.

Pear psylla management can be difficult, especially if you do not have a program outlined for the season. If control measures are not taken early in the spring, the summer may be spent trying to get a handle on this pest. A little planning can go a long way toward limiting your commitment of time and money over the course of the season. Knowing a little about pear psylla biology provides a foundation for sampling and timing of control measures.

Overwintering psylla adults become active early in the spring as temperatures rise above 45ºF. Adults can be monitored at this time by holding a cloth-covered catching frame under a limb and jarring the limb to knock adults onto the tray surface. After leaving their overwintering sites, females mate and lay eggs on pear trees. In the spring, eggs are most commonly found in creases in the bark, old leaf scars, at the bases of terminal buds or on newly emerging leaves and fruit spurs. To determine if eggs are being laid in your orchard at this time, simply pick fruit spurs as you wander through the orchard, and examine the woody portion and bud scales using a hand lens. Summer eggs are primarily laid along the midveins on the undersides of leaves. Eggs and young nymphs will primarily be found on new growth. Cutting down shoots and examining the young leaves near the shoot tips is a good sampling strategy for determining the densities of young nymphs and eggs in your orchard. Estimates of the total number of eggs laid per female range from 200 to 650. The eggs hatch in as few as 10 or as many as 30 days depending on the temperature. There are three generations of psylla in Michigan.

Types of injury
Psylla nymphs use their needlelike mouthparts to suck plant juices, discharging a waste product called honeydew. The primary injury is caused by black sooty mold growing in the honeydew deposits on the fruit, causing russeting. Other symptoms of psylla injury include sooty mold and tissue necrosis on the leaves. Affected trees may be stunted, lose leaves, set fewer fruit buds and produce undersized fruit which may drop off the tree before maturing. These symptoms are called “psylla shock” and are a result of a toxin in the insect’s saliva. Psylla may also spread disease while feeding. Fire blight and pear decline are thought to be spread in this manner. Prolonged exposure to psylla feeding can kill a tree. Asian pear varieties are less susceptible than European varieties to psylla injury. The variety “ Bartlett” is very susceptible, making it a good one to monitor for evidence of psylla problems.

Management
Insecticide resistance in psylla is widely found; therefore careful attention must be paid to the class of insecticides used for control. Psylla management begins with a late dormant or delayed dormant oil application. An adulticide is sometimes mixed with the oil. An early oil spray helps deter egg laying for several weeks. This helps to synchronize the age of the following generations and makes management during the rest of the season a little easier.

A pesticide application at white bud stage targets the early egg hatch period. Insecticides in the pyrethroid class can be used against the overwintering psylla but are not recommended for summer applications. The insect growth regulator pyriproxifen (Esteem) stops egg hatch and prevents nymphs from reaching the adult stage, making it an option while eggs and nymphs are present.

A variety of pesticides representing several chemical classes are available for in-season psylla control. Page 65 in the Fruit Management Guide (Extension publication E154) outlines many of the options available. A threshold of one psylla nymph per three leaves provides a guideline for deciding when a treatment is needed in the summer. Sprays should be applied in a minimum of 100 gallons per acre to ensure thorough coverage. It is also very important that the entire orchard is covered at once, rather than making alternate row middle applications.

Cultural practices can help lessen the incidence of psylla infestations in the summer. Pruning of water sprouts, reducing nitrogen over fertilization and avoiding of aggressive dormant season pruning can all help decrease terminal shoot growth and reduce feeding sites.

Pear psylla can prove to be a tough pest to beat, but with a well thought-out management program that includes attentiveness early in the season, pesticide rotation and monitoring, this insect can be kept below damaging levels.

The 2006 season is fast approaching, which means that the 2006 disease season is approaching as well. Warming temperatures (highs in the 60s to 70s), which will occur eventually, favor growth of bacterial pathogens. This is a critical timing period for an early copper application targeted towards reducing of inoculum of the fire blight pathogen, Erwinia amylovora.

Copper is an excellent bactericide for fire blight control. The only limitation is application timing as coppers applied after 1/4 to 1/2 inches green tip could result in phytotoxicity including fruit russeting. I think that an early season copper application is an important tool for fire blight inoculum management, particularly in orchards known to contain streptomycin-resistant fire blight bacteria.

The predominant location of overwintering bacterial inoculum for fire blight is in cankers. These cankers are initiated from shoot blight infections occurring in the previous season and represent internal populations of the pathogen. As temperatures warm up in a growing season, cankers begin to ooze bacteria that can then colonize blossoms.

Fire blight infections leading to blossom blight are initiated during bloom. Bacterial colonization and infection of open flowers lowers yield, and initiates internal, systemic infections of trees that can lead to rootstock blight and death of younger trees planted on susceptible rootstocks. The occurrence of shoot blight (wilting and dieback of actively growing shoots) is also typically higher in orchards where blossom infections have occurred.

The best method for lowering initial populations of plant pathogenic bacteria in orchards is to use an early application of copper to cover trees with a "blanket" of copper. Entire trees should be sprayed, not just alternate rows. High rates of copper can be used (~ 2.0 metallic copper per acre), with timings immediately prior to the trees breaking dormancy or up to about 1/2 inches green tip. Be sure that the correct rate of copper is used and that sprayers are properly calibrated. Any formulation of copper should be effective in disease control (copper sulfate, cupric hydroxide, copper oxychloride, etc.). The goal of this management practice is to have copper available to protect the plant tissue from bacterial colonization as the tissue develops, thus lowering initial inoculum levels.

The EPA granted a Section 18crisis exemption for the 2006 season on March 23 and effective on April 1. The exemption is for applications of Mycoshield for fire blight control in Michigan apple orchards with application initiated during bloom. The crisis exemption period ends June 30, 2006. 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 label for Mycoshield will be posted on the MSU Fruit AoE webpage at: http://web1.msue.msu.edu/fruit/MIfrt_s18.htm

Blueberries have received an emergency exemption (Section 18) for the use of Indar 75WSP (fenbuconazole) and Topsin M (thiophanate methyl) for disease control in blueberries in Michigan. The exemption for Indar is valid from March 16 to September 1, 2006 and Topsin M from April 1 to September 30, 2006. Growers have to be in possession of the Section 18 label at the time of application. Contact your Extension educator or commodity representative for a copy of the label. The labels will also be available under the pest management section of the blueberry website: www.blueberries.msu.edu.

Indar is mainly used for control of mummy berry disease, although it is also effective against Phomopsis twig blight and canker. The material is locally systemic and has limited curative activity, so it is best used on a preventative basis. The recommended application rate is 2 oz per acre using ground or aerial equipment. Sprays should begin at early green tip and subsequent applications made at 7 to 14 day intervals depending on disease pressure and growth rate of the foliage. Spraying within 24 hours after a frost event may improve disease control, since frost injury predisposes the young shoots to infection. While a maximum of five Indar applications per season is allowed, it is recommended to limit the number of applications to two to three per season and alternate and/or tank-mix Indar with fungicides in other chemical classes to lower the risk of fungicide resistance development. Indar has a 30-day pre-harvest interval.

Topsin M is a systemic fungicide. Target diseases are Phomopsis twig blight and canker, Fusicoccum canker, mummy berry, anthracnose fruit rot, and Botrytis blossom blight. The recommended application rate is 1 lb per acre, and a maximum of three sprays may be applied per season. No post-harvest applications are allowed. Use of this fungicide is most cost-effective in the period from pink bud through early fruit development, as most of the pathogens are active at that time. Topsin M should always be used in combination or rotation with non-benzimidazole fungicides, such as Ziram or Captan, to reduce the risk of fungicide resistance development. The pre-harvest interval for Topsin M is 7 days.

Newer berry varieties often require many years to fully test and recommend for commercial plantings. However, growers may want to purchase a few plants of promising new varieties to see if they fit on their farm. Here are a few types that are too new to recommend for large-scale planting, but have shown enough potential to plant on a trial basis.

Day-neutral strawberries are types that can initiate flowers and produce fruit from June to October. In Michigan, these varieties tend to produce a flush of fruit in June and September, but produce little in mid-summer because temperatures are too high. Tribute and Tristar are two older day-neutral varieties that have performed moderately. Two newer types worthy of trial are Seascape and Everest. Both produce larger berries than Tribute or Tristar, although the plants may be less hardy.

Fall-fruiting raspberries
The recommended fall-fruiting (primocane-fruiting) raspberries for Michigan are Heritage, Autumn Bliss and Autumn Britten. Caroline is a promising newer type to try on a trial basis. It begins fruiting between Heritage and Autumn Bliss and is very productive and somewhat tolerant of gray mold. Jaclyn is a very new variety that we have not tested in Michigan. It also is worth testing because it is very early fruiting.

Summer-fruiting raspberries
Recommended varieties for Michigan have been Boyne, Canby and Latham. Two very promising early fruiting types are Nova and Prelude. Both appear hardy even for colder locations in the Lower Peninsula. Prelude is very early and produces some fall berries in southern Michigan. Two new late season types that have promise are Encore and K81-6. Encore may suffer some winter injury in very cold locations.

The Monday Fruit IPM update meetings will be at Annette and Randy Bjorge’s Fruit Acres in Berrien County again this year. The meetings will begin on April 10 and run until July 10. There will be no Monday meetings on Memorial Day, May 29 and July 3. The meeting will run from 5:00 PM to 6:30 PM. Each meeting will be a review of the current fruit pest situation in Berrien County with displays of insects and fruit collected that day from area fruit plantings.

Al Gaus, Bill Shane and Mark Longstroth will share the results of their scouting and discuss current and upcoming pest events and emergences. (Each week will change with changing pest complex.) The meeting dates are April 10, 17, 24, May 1, 8, 15, 22, June 5, 12, 19, 26, and finally July 10. RUP credits have been applied for private pesticide applicators and commercial fruit (1C).

There will be a series of Grape IPM meetings in Van Buren and Berrien Counties again this year. The meetings will be on the following Thursdays: April 20, May 25 and July 13. 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 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.

The format for the meetings will be a review of insect and disease control in grapes specific to either early, mid or late season, focusing on the pests of each season during that meeting. The April 20 meeting will review prebloom insect and disease control. The May 25 meeting will discuss bloom sprays and the July 13 meeting will cover late season insects and diseases.

Al Gaus and Mark Longstroth of MSU Extension and Terry Holloway of National Grape who will share the results of their scouting will host the meetings. Drs. Rufus Isaacs and Annemiek Schilder will be the featured speakers and discuss current and upcoming pest control windows. RUP credits have been applied for private pesticide applicators and commercial fruit (1C).

Regional reports
1 -- Southwest
Mark Longstroth
Bill Shane
Al Gaus

Weather
The winter was relatively mild. Early December was cold and snowy, but January was mild. February and March have been seasonably cold. A cold snap occurred in mid-February. Temperatures were close to 60 on February 16 and near zero on February 18 and 19. This may have caused some damage to fruit buds and young plants, but generally conditions look good. There was little snow after New Years, but soils have adequate moisture at this time. Growing degree day accumulations are about average for this time of year. All the accumulation occurred from March 11-13, when highs were near 60 and lows about freezing. The GDD accumulations for all sites are similar. This week’s forecast is for warmer weather, which should move fruit buds along so that green tissue is showing by this time next week.

Apricot buds have burst and are at red tip. In some varieties only a few buds have swollen, many buds have not swelled indicating that the February cold snap did cause some damage.

Peach buds are swollen. Winter fruit bud loss has been reported in some varieties and on lower, colder sites. The time is quickly passing for peach leaf curl sprays.

Both sweet and tart cherries are at the swollen bud stage, in warmer sites a few buds are approaching green side.

In plums, Oriental plum buds have burst but European plum buds are just beginning to swell.

Apple buds are swelling. Early varieties such as Empire are at silver tip. We should be at green tip by next week and growers will need to worry about apple scab. Because of the mild winter, I expect scab spores in the leaf litter will be ready as soon as green tissue is available for infection. Growers should be ready to apply scab sprays.

Pear buds are just beginning to swell. Pear psylla adults are out.

Grapes are dormant.

Strawberries are beginning to put out new leaves. Growers are applying herbicides and putting down straw mulch.

Raspberries and cranberries are dormant.

The first Monday fruit update meeting will be Monday, April 10 at the Fruit Acres Farm in Berrien County.

2 -- Southeast
Bob Tritten

Weather
The winter of 2005-06 was mild. There was a bit of a close call for some of our more tender fruit crops, such as peaches, that occurred with a warm to cold temperature drop on March 13 (in the mid- to high 60s) to a low on March 14 of 29 degrees. At some weather stations there was a 37 degree drop in temperatures in a matter of 16 hours. In forcing twigs and cutting buds from many of our fruit crops, it appears however that we have not experienced any damage as a result of this event. We had a fair amount of snowfall and moisture to replenish soil moisture supplies.

March has remained cool, as a result bud growth and development has been kept to a minimum. Our season is ahead of last year. However, with warmer temperatures expected later this week, things could change dramatically. Growers have made great progress in pruning tree fruits and most are now looking toward the end of that operation.

Pear buds show little movement.

Peach buds are swelling. Now is the time to apply peach leaf curl sprays if controls were not applied late last fall. Pruning has not begun.

Cherry buds are slightly swollen.

Raspberries show little to no movement. Summer raspberry growers are beginning to work at removing fruited canes as well as doing some tipping. Fall raspberries were mowed at most farms several weeks ago.

Blueberry buds appear to be dormant with little movement at this time.

Grapes are dormant with no movement.

Weather news
Jeff Andresen

After several weeks of a predominantly northwesterly flow pattern over the Great Lakes region, the jet stream is expected to turn more zonal or west to east in orientation across North America during the next one to two weeks. This will bring a series of Pacific-origin air masses and weather systems through the Midwest and preventing cold Arctic-origin air from moving southward into the region.

In the short term, this change will lead to a milder, spring-like weather pattern across Michigan during the upcoming week and possibly longer. Mostly fair conditions are expected Wednesday and Thursday this week (March 29-30) with temperatures increasing to daytime highs from the 50s north to 60s south. Low temperatures will generally fall back to the 30s north to 40s south through Friday. An area of low pressure and accompanying cold front is forecast to move into Michigan by Friday, bringing the likelihood of showers and thunderstorms to most of the state. The rain (and possibly some snow in northern sections of the state) is expected to end by Saturday morning statewide. Some severe weather is possible across southern sections of the state Friday afternoon.

Fair and cooler weather is expected next weekend with high temperatures falling back to the 40s north to mid-50s south. More rain is possible again by early next week (most likely Monday) along with warmer temperatures.

Further ahead, medium-range forecast guidance suggests a continuation of the west to east, zonal jet stream pattern mentioned above along with the passage of a series of mild, Pacific-origin air masses.

The official NOAA 6-10 day and 8-14 day outlooks (covering April 2-6 and 4-10) both call for above normal temperatures across Michigan and much of the eastern United States. Precipitation is forecast to range from near normal levels in southern sections of the state to above normal levels elsewhere during the 6-10 day period. Near normal precipitation totals are forecast statewide during the 8-14 day time frame.

Latest NOAA CPC long lead outlooks for Michigan have shifted towards a wetter forecast during the next couple of months. The outlook calls for an increased likelihood of above normal precipitation during April across sections of the Northern Great Plains eastward to the western Upper Peninsula, and over nearly all of Michigan during the April-June period. Mean temperatures for both April and the 3-month April to June period call for the equal odds scenario of below-, near-, and above-normal values.