June 27, 2006
In this issue
Tree fruit news
§ Monitoring and management strategies for the apple maggot
§ Controlled Atmosphere Clinic set for July 21
Small fruit news
§ TNRC trapline data: Blueberry maggot
§ Mites in Michigan strawberry fields and their management
§ Monitoring and management strategies for the blueberry maggot
Other news
§ MSU expanding web resources for fruit production
§ Regional reports
§ Weather news
Note: We are reaching the point in the season when our publishing schedule switches from weekly to every-other-week. Our next issue will be published on July 11. – Joy N. Landis, editor.
Apple maggots overwinter as pupae and are developmentally
ready to emerge as adults in early summer (900 growing degree-days base 50). Adult
fly emergence is often delayed, however, if soils are dry. Peak emergence
generally occurs between 1400 and 1700 growing degree-days, but is highly dependent
on site-specific weather conditions. The precipitation patterns we have
experienced this June across most parts of the state will likely result in adult emergence
as soon as GDD requirements are met. Indeed, adult emergence
began last week in southern Michigan’s apple production regions.
Monitoring adult apple maggot flight is key to effective management of
this pest. Adult activity can be monitored using yellow sticky boards with
ammonium bait, or a red sphere trap covered with an adhesive and baited with
synthetic fruit volatile. The yellow trap is most useful during the
pre-oviposition period when newly emerged females are actively feeding. The red
sphere trap is effective throughout the season, because it mimics the ripening
fruit that flies are attracted to during egg-laying. Comparisons of the two
trap types in Michigan have revealed that the red sphere baited with fruit
volatiles is the better choice, consistently catching 3 to 4 times more flies. Traps
should be placed on the south-facing side of trees in perimeter rows because
most flies are expected to be immigrating from wild hosts outside the orchard. Optimally,
traps should be checked twice weekly starting just before 900 GDD base 50ºF
until the first fly is captured, then once a week thereafter to indicate the
end of the flight.
Identifying apple
maggot generally requires the use of a 10X hand lens. Adults are dark flies,
approximately 6 mm in length. The most characteristic feature of the fly is the
dark pattern on their wings (See accompanying photo and figure). These
wing-banding patterns are used to differentiate between fruit fly species.
Apple maggot has four distinct black bands toward the wing tips, as seen in
this illustration. Further identifying characteristics for the apple maggot
include a white spot on the back of the thorax, and white bands across the top
of the abdomen.
The greater the number of traps deployed per
block, the greater the confidence level in basing treatment decisions on fly
catch. Place at least two traps along borders that historically have been a
source of infestation. Proper trap maintenance is crucial to trap
effectiveness. Over time, the adhesive
can be fouled by leaves, twigs, other insects and debris. Remove debris and
insects each time traps are checked. The adhesive should then be evenly
redistributed. In determining control treatment
timing, on-farm fly catches should be used in conjunction with regional
trapping information. Basing treatment
decisions solely on regional information may lead to unnecessary insecticide
applications. If you employ a good trapping program, a control treatment for apple
maggot is not warranted until flies are captured on your farm. If flies are
trapped on-farm, and a regional trap catch was recorded prior to the on-farm fruit
fly capture, the treatment should be timed based on the earlier regional
capture. This conservative approach is the best way to ensure that the
control is applied prior to egg hatch. Chemical control of apple maggot is focused
almost entirely on the adult, with the goal of preventing egg-laying.
Upon emergence there is an 8 to 10 day period before female flies begin to lay eggs. During this time they are searching for nutritional sources needed to become sexually mature. After female flies complete this pre-oviposition period and have mated, they will seek out fruit for egg-laying. They lay eggs just under the skin of ripening fruit with a needlelike ovipositor, making visual detection of the puncture wound difficult to distinguish from lenticels on the apple surface. Fly larvae, called maggots, hatch from eggs within a week and begin to feed in the flesh of the fruit. Maggot infestations will sometimes cause fruit to abort, but often the fruit will hang till harvest. Mature maggots drop out of fruit and enter the ground, where they pupate, starting the next generation’s life cycle.
Control of the apple maggot has been traditionally achieved with organophosphate insecticides, like Guthion and Imidan, but some label or processor restrictions may limit their use near harvest. Carbamate and synthetic pyrethroid compounds like Lannate and Asana are also active on adult fruit flies, but are generally viewed to be moderately effective because they have a shorter residual. There are several new reduced risk and OP-replacement insecticide products that include apple maggot on their labels. The neonicotinoids Calypso, Clutch and Assail are labeled for apple maggot control. All three have performed well against apple maggot in small plot field-performance trials. Calypso and Assail have also performed well in on-farm trials conducted in Michigan over the past few years. The Spinosyn compounds SpinTor and Entrust are highly active on apple maggot when ingested, but have shown to be only fair control materials in field trials with high pest pressure.
GF120 NF Fruit Fly Bait (spinosad) is registered on pome fruits for control of apple maggot and is listed by the Organic Materials Review Institute (OMRI) for use in organic production. Because the primary route of entry is through ingestion, applying this product during the fruit fly pre-oviposition period is important for optimal performance. GF120 must be applied with specialized equipment, and is designed for low-volume application by air. Field efficacy data is encouraging, but we have limited experience with this novel tool to date.
The use of Surround WP for fruit fly control is based on creating a protective barrier between the plant and the pest that: 1) reduces host recognition of the pest, and 2) prevents adult oviposition (egg-laying). Because it is not toxic to adult flies like conventional contact poisons, complete coverage of the plant is critical. Multiple applications are typically needed to attain initial coverage; further sprays may be necessary to respond to wash-off from rain or excessive wind. Field trials indicate that when adequate coverage is maintained, excellent fruit protection can be achieved.
|
Compound Trade Name |
Chemical Class |
Life-stage Activity |
Optimal Spray Timing for apple
maggot |
Residual Activity |
** Mite Flaring Potential |
Effectiveness rating*** |
|
Guthion, Imidan, Malathion |
Organophosphate |
Adults |
7-10 days after the first fly is captured |
14+ days |
L - M |
E |
|
Lannate, Sevin |
Carbamate |
Adults |
7-10 days after the first fly is captured |
5-7 days |
M - H |
G |
|
Asana, Warrior, Danitol, Decis |
Pyrethroid |
Adults |
7-10 days after the first fly is captured |
7-10 days |
H |
F-G |
|
SpinTor, Entrust*, GF120 NF* |
Spinosyn |
Adults |
Immediately after the first fly has been captured |
7-10 days |
L |
F |
|
Assail, Calypso, Clutch |
Neonicotinoid |
Adults |
Immediately after the first fly has been captured |
10-14 days |
M |
E |
|
Surround WP* |
Particle Film Protectant |
Adults |
Multiple applications before fly emergence |
As long as thorough coverage of the tree canopy is maintained |
L |
E |
* OMRI approved for organic production.
** Pollinator/Parasitoid Toxicity rating; S – relatively safe, M – moderate toxicity, H – Highly Toxic.
*** Effectiveness rating of
insecticides (2006 Fruit Management Guide, MSUE bulletin E-154); E – excellent,
G – good, F – fair.
Mark your calendars for July 21, 2006 for the Controlled Atmosphere (CA) Clinic to be held at the Clarksville Horticulture Experimentation Station in Clarksville, Michigan. The CA Clinic targets information of interest to packinghouse and storage operators handling and storing fresh fruit. Attendees should expect to be brought up-to-date on the most recent scientific findings and related practical developments in the field of CA and refrigerated storage.
Topics and demonstrations to be covered by expert academic and industry speakers include:
§ Recommended storage regimens for Eastern apple varieties.
§ Storage potential for apple fruit gathered from the wilds of Kazakhstan, the origin of the domesticated apple.
§ Advantages in the use of plastic bins for bulk fruit storage and handling.
§ Thermofogging technology for application of DPA and fungicides.
§ Industry offerings for postharvest fungicides, cleaners and waxes.
§ Use of ‘Propods’ for administering 1-MCP to small quantities of apple fruit.
§ Recent progress in the non-destructive quality assessment program of the USDA at MSU: prototype evaluation.
§ Update on 1-MCP recommendations and use by AgroFresh.
§ Reducing refrigeration costs through computerization.
Drs. Jennifer DeEll and Dennis Murr will be the featured speakers for the clinic. Dr. DeEll is the fresh market quality program leader in the Crop Technology Branch of the Ontario Ministry of Agriculture, Food and Rural Affairs in Simcoe, Ontario. She works closely with storage operators there and has made significant contributions to resolving a number of practical problems they face. Her two presentations are entitled: 1) Ontario experiences with ‘Honeycrisp’ apples and, 2) Trials and tribulations of 1-MCP technology in Canada.
Dr. Dennis Murr is a postharvest physiologist from Guelph University. His research efforts are focused on retaining as mush as possible of the “at harvest” quality of apples following long-term storage. Dr. Murr will speak on Ethylene Biology 101: Manipulating ethylene by deception, conception, and perception.
Please join us for coffee and donuts at 8:30 AM. Presentations will take place from 9:00 AM to 4:30 PM.
If you are interested in attending this conference or if you have any questions please feel free to phone or email either:
Sandy Allen
Phone: 517.355.5191 x 1339
Email: allens@msu.edu
Randy Beaudry
Phone: 517. 353.5191 x1303
Email: beaudry@msu.edu
Or visit www.hrt.msu.edu/caclinic
Mites can be significant pests of strawberry, feeding on leaves and reducing the ability of plants to grow, ripen fruit and store energy for the following season. In most Michigan strawberry plantings, mites do not cause economic injury and their abundance is kept in check by predatory mites. However, pest mites can reach levels requiring the application of a miticide when these predators are not present, or conditions are appropriate for the rapid mite development. It is important for strawberry growers to know how to scout for pest and predator mites in their fields, so that damaging populations can be avoided or controlled. Two pest mite species infest strawberry in Michigan: twospotted spider mite and cyclamen mite.
Twospotted spider mites are the most common mite pest of strawberry and brambles in Michigan. This mite overwinters in and around fields on strawberry and on other broad-leaved plants. The mites start feeding and laying eggs in the spring when temperatures rise, and there are several generations each season. These mites can disperse by "ballooning" in the wind on small silken threads that they secrete while feeding.
The adults are about 1/60 inch in length and yellowish-white with two dark patches (See photo). Their eggs are about the same size and are shiny clear spheres, found on the undersides of leaves. They feed by rasping on the underside of strawberry leaves, and this causes strawberry leaves to turn yellow or brown on upper surfaces as feeding continues.
As strawberry rows become green and leaf tissues expand, weekly monitoring for pest and beneficial mites is the best way to ensure that pest mite populations don’t reach damaging levels. Mites grow more quickly during warm and dry weather conditions, but there have been years where abundance of these mites was high in Michigan strawberry fields even after cool conditions.
To monitor for twospotted spider mites in strawberry fields, examine 60 trifoliates per field, taken on a zig-zag pattern across the field, and count the number of leaves with mites. A hand lens is a helpful tool for this job. This sampling method saves you having to count the number of mites per leaf; just the presence or absence of mites is determined. If predators are not present, the threshold is 25 percent of leaves infested (15 of 60 leaves), but predatory mites can efficiently reduce pest mite growth at this density. Even one predatory mite per 10 twospotted spider mites is sufficient to control populations without the need for miticides. If predator mites are not detected at this level, a miticide should be applied to protect the plant with application targeting the underside of leaves.
The cyclamen mite is tiny and not visible to the naked eye, so a hand lens or microscope is required to see the mites (See photo). Mature mites of this species measure only about 0.001 inch long. They are pinkish-orange and shiny and the eggs are translucent. Adult females lay about 90 eggs, 80 percent of which develop into females. Cyclamen mites overwinter as adult females in the strawberry crown and can often be found in this part of the plant before they spread to new tissues. During summer, newly hatched mites develop into mature adults within 2 weeks and populations build rapidly soon after they begin to infest a field. At low population densities, cyclamen mites are usually found along the midvein of young unfolded leaves and under the calyx of newly emerged flower buds. At high population densities, these mites can be found anywhere on non-expanded tissue.
Because cyclamen mites require high temperature and humidity to thrive, they are most common in greenhouses and can be brought to a planting on new plants from greenhouses. Leaves heavily infested with cyclamen mites become severely stunted and crinkled, resulting in a compact leaf mass in the center of the plant. Feeding may also result in flower withering and poor fruit production. Identification of infested transplants before planting is the most effective way of preventing their establishment, and these plants should not be used.
There are no well-developed thresholds for cyclamen mite management in eastern North America, but the University of California recommends monitoring newly unfolding leaves and treating with an appropriate miticide if 1 cyclamen mite is found in 10 leaves. This low threshold is an indication of the potential for this insect to reproduce rapidly and to cause significant injury to plants. If cyclamen mites are found at levels above threshold early in the season, application of a miticide immediately before bloom and 10-14 days later is recommended. Some insecticides registered for control of tarnished plant bug and clipper are also active on cyclamen mites, so the spectrum of pest activity should be considered when selecting a miticide.
Predatory mites can be seen on the underside of leaves, where they actively search the leaf surface for pest mites to eat. In one study in southern Michigan, the predator Neoseiulus (=Amblyseius) fallacis was the only species of predator mite present. This mite with a big appetite is a light color and slightly smaller than twospotted spider mite adults (See photo). A hand lens is usually required to see them, and their population increase is typically delayed behind that of the pest mites that they feed on.
Preservation of these natural enemies is the best (and cheapest!) way to prevent mite problems, and so growers should consider using selective insecticides and miticides that do not kill the predators. For example, the commonly-used insecticide Sevin and many pyrethroids have been shown to reduce survival of predator mites. Use of selective products is becoming increasingly possible as more are developed and made available to strawberry growers.
There have been many new registrations of miticides for strawberries in recent years. These miticides vary in the life stage they target, speed and duration of activity, and their pre-harvest interval. The following table is designed to summarize several key variables that can help you determine which miticides registered for use in strawberry are optimal for your Integrated Pest Management program. Selecting a miticide with long residual activity and low toxicity to predators will help provide the best long-term effective control of mites, and there are now some options that can provide this long-term mite control. More information on mite control in strawberry is available in the 2006 edition of MSU’s Fruit Management Guide, publication MSUE-154. This is available online at: http://web1.msue.msu.edu/pestpubs/E154
|
Compound |
Life
stage target* |
Resid. Activity (weeks) |
PHI (days) |
Toxicity
to predators*** |
|
Savey, hexythiazox |
egg/larvae |
8-10 |
3 |
S |
|
Zeal, etoxazole |
egg/larvae |
6-8 |
1 |
S |
|
Acramite, bifenazate (pH 7) |
motiles |
6-8 |
1 |
S |
|
Agri-Mek, avermectin |
motiles |
6-8 |
3 |
S |
|
Kanemite, acequinocyl |
motiles |
6-8 |
1 |
S |
|
Thiodan, endosulfan |
motiles |
4-6 |
4 |
M |
|
Kelthane, dicofol |
motiles |
4-6 |
2 |
M |
|
Oberon, spiromesifen |
egg, motiles |
4-6 |
3 |
S |
|
Stylet oil** |
egg, motiles |
4-6 |
0 |
S |
|
Vendex, fenbutatin-oxide |
motiles |
4-6 |
1 |
S |
|
Danitol, fenpropathrin |
motiles |
2-4 |
2 |
T |
* Motile forms include mite larvae, nymph and adult stages.
** Organic formulation available.
*** S = safe, M = moderately toxic, T = toxic to mite predators.
The blueberry maggot goes through one generation per year, overwintering as a pupa below the soil surface. Most pupae emerge one year after going into the soil, although depending on climatic conditions, a small proportion will remain as pupae through another year or two before emerging. Adult emergence typically begins in mid to late June with adult flight continuing through August.
First adult emergence can be predicted by using a Growing Degree Day (GDD) model, because adult fly emergence should begin at 750 GDD base 50. Actual emergence can be delayed if the soils are dry, as pupae usually respond more readily to a moist environment. Thus, initial adult emergence often follows a rainfall event in late June and in July. After emergence, female flies require approximately 7-10 days to become sexually mature and mate, at which point they will begin laying eggs. Eggs are oviposited under the skin of ripening blueberries with a single egg deposited per fruit. Eggs hatch in about 5 days, at which point the maggot begins feeding, completing their development within a single berry. Upon maturity, the maggot drops to the ground, burrowing up to several inches into the soil before pupating. In Michigan’s climate, these pupae will not emerge until at least the following growing season.
Monitoring adult blueberry maggot flight is key to effective protection of blueberries from this pest. Initial adult emergence is best monitored using yellow sticky boards baited with ammonium acetate (or ammonium carbonate) as a food attractant, because newly emerged females are actively feeding during this pre-oviposition period. These traps should be placed on a stake or hung on an upper branch of a blueberry bush in a perimeter row (south facing side of bushes) with enough foliage cleared from around the trap so leaves don’t stick to it. Traps should be deployed before first anticipated flight (late June), since most flies are expected to be immigrating from wild or non-sprayed hosts outside the commercial planting. If a resident fly population is suspected from previous infestation, a trap placed inside the field is a good idea to detect internal infestations. Traps optimally should be checked twice weekly starting 750 GDD50 until the first fly is caught. After the pre-oviposition period is complete, female flies will begin actively searching for fruit to lay eggs in, and there is a trap available that mimics the visual stimulus of a fruit. A green sphere trap, baited with synthetic fruit volatile lure (mixed blend of butyl hexanoate plus other ingredients) can be used to monitor fly activity in fields. Again, these traps should be placed in perimeter rows of the field unless there is evidence of a resident population far in the interior.
Control of the blueberry maggot has been achieved for many years using broad spectrum insecticides. These kill the adult fly on contact and prevent the insect surviving to the point of being able to lay eggs into the fruit. Guthion is highly active against blueberry maggot, with long residual activity and has a 7 day pre-harvest interval. The organophosphates Malathion and Imidan are also active, with shorter pre-harvest intervals and potential for use closer to harvest. Carbamates such as Sevin and the pyrethroid Asana are also active on adult fruit flies.
There are several new insecticide products that include blueberry maggot on their labels. The neonicotinoid Provado is registered for use in blueberry against Japanese beetle and aphid control, and now also has a supplemental label (http://www.cdms.net/ldat/ld6AQ003.pdf) for control of blueberry maggot. Small plot trials of Provado have shown that it protects fruit from this pest, and in large-scale trials over the past three years in Michigan blueberry farms, we have found no blueberry maggot infestation in fields that were treated with Provado during July and early August. The spinosyn-containing compounds SpinTor (non-organic formulation) and Entrust (organic formulation) are highly active on blueberry maggot adults when ingested, but in field trials with high pest pressure and two week application intervals their performance has been rated as good (See accompanying table.). Performance would be expected to be higher in fields with lower pressure and with less time between applications.
GF120 NF Fruit Fly Bait (spinosad) is registered for control of the blueberry maggot and is listed by the Organic Materials Review Institute (OMRI) for use in organic production. Because the primary route of entry into the insect is through ingestion, applying this product during the fruit fly pre-oviposition period is important for optimal performance. GF120 must be applied with specialized equipment, and is designed for low-volume application by air. Field efficacy data is encouraging, but we have limited experience with this novel formulation in large-scale trials in Michigan.
The use of Surround WP for fruit fly control is based on creating a protective barrier between the plant and the pest that 1) reduces host recognition of the pest, and 2) prevents adult oviposition (i.e.; egg laying). Because it is not toxic to adult flies like conventional insecticides, complete coverage of the plant is critical. Multiple applications are typically needed to attain initial coverage; further sprays may be necessary to respond to wash-off from rain or excessive wind. Field trials indicate that when adequate coverage is maintained that excellent fruit protection can be achieved, although the white residue makes this not suitable for fruit destined for the fresh market.
|
Compound Trade Name |
Chemical Class |
Optimal Spray Timing for BBM |
Residual Activity |
Effectiveness rating** |
|
Guthion, Imidan |
Organophosphates |
Within 7 days of the first fly being captured |
14+ days |
E |
|
Malathion |
Organophosphates |
Within 7 days of the first fly being captured |
5-7 days |
G |
|
Lannate, Sevin |
Carbamates |
Within 7 days of the first fly being captured |
5-7 days |
G |
|
Asana |
Pyrethroid |
Within 7 days of the first fly being captured |
7-10 days |
G |
|
SpinTor, Entrust*, GF120 NF* |
Spinosyns |
Immediately after the first fly has been captured |
7-10 days |
F-G |
|
Provado |
Neonicotinoids |
7-10 days after the first fly is captured |
10-14 days |
E |
|
Surround WP* |
Particle Film Protectant |
Multiple applications before fly emergence |
As long as thorough coverage of the tree canopy is
maintained |
E |
* OMRI approved for organic production.
** Effectiveness rating of
insecticides (2006 Fruit Management Guide, MSUE bulletin E-154);
E – excellent, G – good, F – fair.
The crops are growing and so are the web resources we are offering at MSU for fruit production. Here are some sites to check if you haven’t visited our webs recently:
§ http://ipm.msu.edu/fruit.htm
IPM Resources page for fruit.
Includes direct links to seasonal IPM advice, the Enviro-weather web site, MSU
Diagnostic Services, the Soil/Plant nutrient lab, links for ordering pocket-sized
scouting guides and the apple scouting DVD.
§ http://www.fruitinfo.msu.edu
Fruit info search helps locate
bulletins and other resources for fruit growers and consultants.
§ http://ipm.msu.edu/fruit-cat.htm
Fruit CAT Alert home page. Search
previous 5 years of CAT Alerts using
a keyword search. Sign up to get an email announcement when new issues are
posted at the web site.
§ http://www.enviroweather.msu.edu
Enviro-weather was described in detail in our April 25 issue of
the Fruit CAT Alert newsletter. MSU
has plans to expand the pest models at this site and add additional weather
stations. Visit the home page, click on the station nearest you, select “fruit”
resources and bookmark the resulting page for future reference. The site offers
links to the IPM Resources web for your reference when making pest management
decisions.
§ Sites for growing specific fruit. For grapes, visit http://www.grapes.msu.edu/ and for blueberries, visit http://www.blueberries.msu.edu/ . The MSU Fruit Area of Expertise Team has additional resources for more crops from its home page at: http://web1.msue.msu.edu/fruit/
§ http://www.msue.msu.edu
MSU Extension’s portal with links to local county as well as statewide
resources
§ http://www.maes.msu.edu/
New web site of the Michigan Agricultural Experiment Station.
Temperatures last week were in the 70s and 80s with lows in
the 50s and 60s. Scattered rain fell Thursday (June 22) and Sunday with
rainfall totals less than a tenth of an inch. Top soils are very dry and
growers are irrigating. Soil temperatures are in the 70s. This week’s forecast
is for cooler weather with highs in the 70s and chance of thunderstorms. The GDD in the table are from the Enviroweather
site. We picked up 200 GDD42, and 170 GDD45 and 130 GDD50.
|
Southwest Michigan growing degree day totals |
Grapes, from April 1 |
|||
|
Location |
GDD 42 |
GDD 45 |
GDD 50 |
GDD 50 |
|
1512 |
1255 |
886 |
854 |
|
|
1605 |
1348 |
974 |
949 |
|
|
1398 |
1151 |
804 |
776 |
|
Leafhoppers are abundant. Japanese beetles are out, but not
in great numbers. Expect more beetles to emerge after a good rain. Picture wing
fruit flies such as cherry fruit fly, apple maggot and blueberry maggot will
also emerge now after 0.25 inches of rain. Redbanded and obliquebanded leafrollers
are out. Tarnished
plant bug activity is declining. Rose chafers are declining. Plum curculio activity is
light. You can use the Enviroweather
web site to monitor the GDD model for some pests if you know its emergence or
Biofix at your site.
Apricot fruit are coloring; harvest is about two weeks away.
Peach growers are still hand thinning. The second generation of Oriental fruit moth is emerging. Biofix in Southern Berrien County was about April 18 at 180 GDD45. Egg hatch of the second generation of OFM should begin this week about 11500 GDD past biofix. Thrips are showing up. The dry weather is helping this pest. Peach fruit show tarnished plant bug damage and rusty spot (powdery mildew). Bacterial spot is generally minor.
Sweet cherry
harvest is underway. Birds are a problem. Brown rot has been reported in fruit
clusters so fungicides to control brown rot should be applied. Cherry fruit fly traps
should be out, especially where sweet and tart cherry varieties are grown
together.
Tart cherry harvest should start this weekend. Growers need to protect against cherry leaf spot. Cherry fruit flies have not been caught.
The plum crop is variable. Shoot growth is stopping, so black knot is no longer a problem. White apple leafhoppers are causing stippling of the leaves.
Apple growers are hand thinning fruit. Some grower have applied ethrel to knock more fruit off. Oriental fruit moth trap catches are up, signaling the beginning of the second generation. Codling moths were still flying and egg hatch continues. We set biofix for codling moth on May 25 with 328 GDD at SWMREC. We expect egg hatch to continue for another 1000 GDD past biofix about 1325 GDD50. Obliquebanded leafroller egg hatch is beginning. OBLR biofix on Monday, June 12 at 1150 GDD42 and egg hatch should begin 400 to 450 GDD after biofix. European red mites and predator mites are being found. Five mites per leaf is the treatment threshold for European red mite from mid-June to mid-July. Apple maggot has been trapped in Southern Berrien County. Fungicides to reduce sooty blotch and flyspeck should be included in cover sprays. Leaf drop due to scab is common in unsprayed orchards. Growers need to maintain scab protection if they have leaf lesions in their orchards. Fire blight shoot strike symptoms are appearing. Shoot strike is when the bacteria are carried from infected shoots to healthy shoots by leafhoppers. The infection occurs on new shoots, but does not appear to be associated with any adjacent infections. Trauma blight could be a problem if we get severe weather in these orchards with oozing shoots. Applications of Apogee this late will not affect the susceptibility of young tissue to fire blight.
Pear fruits are sometimes attacked at the end of the first generation of codling moth.
Blueberry harvest has begun in early varieties. Anthracnose fruit rot is the main disease concern now. Alternaria fruit rot is more a disease of over ripe fruit. Cane collapse due to phomopsis is common. Powdery mildew is showing up. Cherry fruitworm and cranberry fruitworm are still being caught in pheromone traps: this means egg laying is continuing. Blueberry maggot flies are out and growers and scouts should have traps out. Growers should be scouting for Japanese beetle, leafrollers and tussock moth larvae. Blueberry tip borer damage can be found in new unsprayed plantings.
In grapes, primary and secondary fruit clusters are past bloom and into the small fruit stage. Grape berry moth larvae are feeding in the clusters. Post bloom sprays are due. Grape leafhoppers are becoming easy to find. Rose chafers are scarce. Phomopsis leaf lesions are common in most plantings.
Strawberry harvest is over on most farms. Sap beetles were common in many U-pick fields. Some growers have begun renovation. Potato leafhopper burn is common in many fields.
Raspberry harvest is about a week away. Growers should be scouting for Japanese beetles. Pre-harvest fungicide and insecticide sprays should go on soon.
Cranberry bloom continues.
There will be no Monday Fruit IPM update on July3. The next
and last Monday Fruit
Update meeting will be Monday, July
11, at the Fruit Acres Farm in
Berrien County, at 5:00 PM. Grape IPM meetings
will be held in Berrien and Van Buren Counties on Thursday, 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
Southwest Michigan Research & Extension Center from 2:00 to 4:00 PM. There will also be a twilight grape IPM
scouting meeting on July 20 at Bob Dongvillo's farm, south of Benton
Harbor.
Slow moving widely scattered thunder storms have moved across the region on several occasions over the last week. The strongest band of these thunder showers moved across Lenawee and MonroeCcounties, bringing between 2 and 4 inches of rain. A fair amount of hail was also reported with many of these events. Another band of thunderstorms moved through the Flint area on Monday night (June 26) bringing over 4 inches of rain to many areas. Growers not receiving these storms mostly received around 0.3” to 0.9” of rain. So in many of these areas that did not receive significant rainfalls, soils remain dry and irrigation systems continue to be used. Both tree and small fruits that have received significant rain have put on a fair amount of new growth with excellent fruit size for this time of year. It’s also a bit odd to see that we are now picking strawberries, sweet cherries, tart cherries and summer red raspberries at the same time at some farms.
|
Southeast Michigan growing degree day totals for March 1 - June 26 |
|||
|
Location |
GDD42 |
GDD45 |
GDD50 |
|
Flint |
1499 |
1261 |
897 |
|
Lapeer |
1575 |
1325 |
952 |
|
Petersburg |
1614 |
1358 |
991 |
|
Romeo |
1549 |
1303 |
954 |
Apples are sizing very well with most Red Delicious in the Flint area being around 1.5 inches to 1 5/8” in diameter. Many other varieties such as Empire, Honeycrisp, Romes, and Paulas are mostly at 1.75 inches. It appears as if we are at the end of June drop.
Insect activity in apples is picking up over last week. We’ve had strong flights of codling moth in many apple blocks, with some trap catches in conventional blocks at 80 to 90 moths per trap. Codling moth trap catch numbers in pheromone disruption blocks remain low. Oriental fruit moth trap catches are also on the rise again: this should be the start of the second generation flight. I’m also seeing a few riental fruit moth larvae in apple terminals. Obliquebanded leafroller trap catches are also on the rise and appear to have a good strong flight this year. Many farms report trap catches in the range of 20 to 30 per trap. Apple maggots were caught for the first time late last week by a fruit grower seeing it in a codling moth trap. While it is not uncommon to see apple maggot being caught in codling moth traps, it was a bit early for them. This tells me that we need to be on the lookout for apple maggot over the next week, especially after some of these rain events. Redbanded leafroller larvae are out in pretty good numbers at some farms. Green apple aphid populations continue to build, which has both negative and positive aspects. Woolly apple aphid populations also continue to build with some migration taking place from the terminal branches back toward pruning scars on the centered leader. Spotted tentiform leafminer mines have almost all been fed upon by predators. Potato leafhopper nymphs are common in many places and need an insecticide application to control them. Japanese beetles are starting to be seen on the edges of some apple blocks, as are eastern tent caterpillar. There are a number of farms that have reached threshold levels for European red mite populations. These numbers have been building slowly over the last several weeks. Twospotted spider mites continue to be seen in low numbers, as do apple rust mites. There are a good number of predators being found across the region this season.
For diseases in apples, cedar apple rust is starting to be seen in a few apple blocks, particularly on low vigor trees. I continue to see a fair amount of apple scab lesions, primarily on foliage, but also on fruit. Remember that we called an end to primary apple scab season just last week. Many growers are discouraged with their apple scab control program this year. However with the 10 day wetting period that we had starting on May 10, most of our fungicides were stretched to the maximum and in many cases growers could not get back into blocks quick enough to totally burn out that early season scab infections. Light amounts of new fire blight strikes continue to be seen in many apple blocks across the region. It does not appear to be a serious problem for the most part.
Pears continue to grow well with most being around 1 3/8 inch in diameter. Growers continue to remove interior suckers or water sprouts to help break the cycle of pear psylla.
Peaches continue to size quite nicely with most of them being 1.5 to 1 5/8 inches for Red Haven. Bacterial spot infected foliage continues to drop to the orchard floor. Most peach thinning is complete for the first time through. Many growers are reporting that they are going to need to go back to touch-up their thinning job, most likely starting next week. Rusty spot is a new disease to me, and was seen in three different peach blocks last week. The disease causes a spotting on the fruit with no symptoms on the foliage or twigs.
Sweet cherry harvest is now in full swing across the region with great pick-your-own demand. Sweet cherries are ripening very quickly. Most of the fruit that is now being harvested is 22 mm to 25 mm. However, many of the small fruit do not seem to be sizing very well, and have turned a bright to deep red, meaning that they will be ready for harvest fairly quickly. Bacterial spot infected foliage continues to be seen. One grower reported seeing brown rot in sweet cherries for the first time early this week; however it was on trees that were close to buildings which could not be covered with fungicide adequately. Cherry fruit flies continue to be caught in traps in many sweet cherry blocks. I also had first catch of black cherry fruit fly mid week last week.
Tart cherry harvest is now underway across the region with most fruit sizing quite nicely to 20 mm to 22 mm in size.
Plums continue to grow fairly well with most being around 23 mm to 25 mm in size. We had a fair amount of plum drop over the entire season this year.
Strawberry harvest continues across the region. Most growers are anticipating harvest through the end of this week and possibly through the weekend depending on heat and berry size. Berry size has now dropped off at many farms. If you are one of these farms that did not receive adequate rain events, I encourage you to continue to water both newly planted and bearing strawberry patches. Cultivation will also help to prevent weed growth as well as to help stimulate rooting of runners. A few growers continue to report seeing angular leaf spot symptoms; however they do not seem to be spreading within the patch this year as they have in the past. Strawberries are runnering quite well at this time.
Grower are starting harvest for the early summer red raspberries. I’ve also picked a few handfuls of black raspberries, and they will come into harvest in a more significant way in about a week. Fall red raspberries are now about 24 inches in height and I am starting to see some flower bud development on a small number of canes. I am just starting to see collapse of summer red and black raspberry canes, dying from the tip end. I believe this to be caused by delayed winter injury. Stay tuned for details.
Blueberries continue to size quite nicely with most being around 12 mm to 13 mm for mid season berries, with early varieties at 14 mm to 15 mm. Some are developing color quite nicely. I encourage blueberry growers to set blueberry maggot traps this week, as we are getting close to the time when they could be caught.
Grapes are pretty much at fruit set across the region with a fairly good crop of grapes appearing to be coming along at this time.
Concerning fire blight, there is still a concern for trauma blight in apples if we get hail or high winds with any of the rain called for over the next several days. Summer diseases such as sooty blotch and flyspeck have had enough hours that they will begin to be seen on fruit unless a control is applied. Regarding insects, a regional biofix for codling moth was set for May 10 and we’ve accumulated 650 GDD50 since then. This tells me we should be past peak egg hatch for first generation codling moth, but controls are still necessary for another week to 10 days for any remaining eggs that need to hatch. Trap numbers continue to drop off in most blocks indicating first generation flight is ending. Second generation flight is probably a week or two away yet.
I set a regional biofix for obliquebanded leafroller on June 12. We’ve accumulated 375 GDD42 since then. Early egg hatch occurs at 400 to 450 DD42 past the biofix, which will probably occur in another day or two. If you’ve had problems keeping OBLR in check in the last year or so, you should consider starting with early egg hatch to target new larvae and not wait until you can actually see them to spray. If you’ve controlled OBLR well, you can wait to spray when you see small larvae – that’s probably a week or 10 days away yet.
Many more newly laid European red mite eggs were found over the past week. Continue to monitor these populations closely. Rosy apple aphids can still be found, but there are many winged forms and they should be moving on to alternative hosts soon. Green apple aphids continue to build. Predators are more common in aphid colonies as well, but green apple aphids numbers are still building.
White apple leafhopper and potato leafhopper can be found now in all life forms. Potato leafhoppers have been causing significant damage in non-bearing trees.
Oriental fruit moth second generation flight should begin at anytime. Lures should be changed soon. Larvae from the first generation are still causing damage in peaches and controls need to be maintained.
This past week the temperatures were seasonable or slightly below. Several rain events starting with the rain on Wednesday, June 21, that deposited various amounts of rain. Yesterday afternoon (June 26), a thunderstorm bearing hail rolled through the area. It was moving north-northeast with the most severe outbreak over parts of Oceana and Mason Counties.
West Central
Michigan Growing Degree Day Totals Since March 1 to June 25
|
Location |
GDD42 |
GDD45 |
GDD50 |
|
Hart |
1296 |
1068 |
745 |
|
Ludington |
1245 |
1020 |
704 |
|
Manistee |
1322 |
1098 |
778 |
Apples are sizing well. Rain on Sunday was an infection event only in Manistee and Oceana Counties. The most recent wetting event that started yesterday afternoon has created conditions for an ongoing infection throughout the area. Scab lesions from previous infections are visible in some orchards. Blocks that are having a problem with scab lesions on the leaves need to be protected from the onset of the secondary scab. Fire blight strikes are not very common, but could be seen in blocks with a history of a problem. In blocks hit with yesterday’s hailstorm, a streptomycin application is advised to prevent trauma blight. Powdery mildew is becoming more evident. There is proliferation of new terminal growth that is particularly susceptible to pathogen invasion. Nectria reported last week is showing up in a few more blocks.
Since last week our codling moth counts have gone up from 1.4 to 2.1 moths per trap. As of Sunday, June 25, we have accumulated 467 GDD50 since biofix, which indicates that we are about half way through the egg hatch of first generation.
Obliquebanded leaf roller numbers have gone from 13 to 61 moths per trap. Regional biofix was set for June 17 at 1065GDD42. As of Monday, June 26, we accumulated 218 GDD42 since biofix. The timing of control applications will depend on the material. Generally, it will be between 350-450 GDD42 since the biofix. Check following site (Enviro-weather’s Ludington OBLR report) for more detailed information: http://enviroweather.msu.edu/run.asp?stn=ldt&mod=f_obl&yr=2006&mo1=4&da1=1&mo2=6&da2=26&ds=
Leafhoppers are present and in some blocks doing quite a bit of damage to the leaves. Aphids are heavy in many blocks throughout the area. European red mites are not a problem at this time.
Sweet cherries are coloring very nicely. There is a very nice crop on the trees. There
is a concern for fruit cracking with all this rain coming. There is some fruit
cracking in Regina, Cavaliers and Ulsters already. So far, we have received
more than 3.5 inches of rain in Ludington with the other areas not far behind.
Sweet cherry harvest is expected to start by the end of the week. Many growers
are putting on ethrel and getting ready for the full swing of harvest. With the
possibility of cracking, bird and hail damage, there is a need to step up brown
rot control. Tart cherries are getting more
color as well. Some blocks have a very nice crop. Overall, it appears that the
crop will fall short from last year. CIAB has posted on their web site, http://www.cherryboard.org/ crop estimate for 2006. For the west central
area, the USDA estimate is 45 million pounds, which would be the last
three-years’ average. Grower/processor guesstimate is slightly smaller, posting
43 million pounds. The National Agricultural Statistics Service estimates
Michigan’s total tart cherry production at 185 million pounds. Nationally, the crop
is expected to be between 246 (Guesstimate) and 256 (USDA estimate) million pounds.
Expected harvest date for west central Michigan is July 8-10.
Peaches are continuing to size well. Thinning is still going on. Overall, there is a good crop of peaches. Weather conditions are favoring disease development. Bacterial diseases have been common throughout the area. Powdery mildew is showing up more and more. Cherry leaf spot is becoming more evident throughout the area. Some blocks have lost a significant number of leaves that might jeopardize ripening and quality of the fruit. Cherry fruit fly has been reported in Oceana and Manistee Counties, but none in Mason County. Lesser peachtree borer and greater peachtree borer numbers have gone up since last week. Rose chafer is present, but not in high numbers. Japanese beetles are starting to show up. Green peach aphids are everywhere. There are high numbers of predators associated with aphid colonies.
GDD42 1381
GDD50 801
Temperatures were fairly normal this past week with highs in the '70's. Rainfall varied in the region, but amounts were generally low. Rainfall at the NWMHRS totaled 0.1 inches for the week, bringing the total precipitation for the month of June to 1.7 inches. Base 42 degree day accumulation is the same as this date in 2005.
Most apple orchards are looking pretty clean in terms of scab, despite regular rainfall this season. We have biofixed for obliquebanded leaf roller on Monday, June 19. Again this week, we caught an average of 27.5 moths per trap in cherry, while apple traps at the NWMHRS only caught an average of 1.5 moths per trap. Oriental fruit moth and codling moth trap counts are down. Red sticky spheres are in the orchard, but no apple maggot adults have been caught.
Cherry leaf spot symptoms can be found in most cherry orchards at this time, and powdery mildew is showing up on inner branches as well as some terminal branches. Brown rot is starting to show up in sweet blocks around the region. We are observing heavy leaf drop from cherry yellows virus this season. We have picked up a few new plum curculio stings in a minimally sprayed block. American plum borer and lesser peach tree borer counts are down at the NWMHRS, but we are still catching an average of 5 greater peach tree borer adults per trap. Using the new method of high trapping for cherry fruit fly, we picked up four traps completely covered in our "Entomology" (aka unsprayed) block. Harvest of early dark sweets for the local fresh market is getting underway in warmer areas of northwest Michigan.
Strawberry berry size has been below normal this year, and harvest is expected to wrap up with below average yields.
Grape bloom is finishing up for most cultivars; fruit set looks good at the NWMHRS. Powdery mildew continues to be very high in most sites. Potato leafhopper numbers are up significantly with many nymphs present now. Treatment has been needed in many vineyards. Rose chafer numbers have increased slightly in the last week, but this insect should be nearing the end of its activity soon. Grape growers should be on the lookout for Japanese beetle in their vineyards, especially in Leelanau County.
The upper air pattern Tuesday morning (June 27) across North America includes a ridge across western sections of the U.S., a trough over the Great Lakes region and another ridge just off the eastern shore in the western Atlantic. Nearly all of the current forecast guidance suggests that this general pattern will persist for the majority of the next two weeks. Near the surface, a persistent plume of semitropical-origin moisture streaming northward across the eastern U.S. has been in place since the weekend. These conditions have led to torrential rains and widespread flooding across portions of the Delmarva region. The state of Michigan is on the western edge of this plume and is expected to remain there for the next several days, setting the stage for an almost daily chance for showers and thunderstorms, especially over eastern sections of the state and during late afternoon and early evening hours when atmospheric instability tends to be greatest. Best chances for rainfall will be Tuesday with some storms possibly containing heavy rain and hail. Wednesday through Saturday, look for a continuing chance for scattered rainfall each day, with lesser amounts and only scattered areal coverage. Rainfall totals during the next five days are expected to reach the 0.25-0.50 inch range over most of the state, with some isolated 1.0-2.0" totals possible.
Temperatures through Sunday will remain close to the climatological normals with highs generally ranging from the upper 60's or low 70's far north to the low 80's south. Low temperatures will generally range from the mid or upper 50's north to the low 60's south.
Medium range forecast guidance basically suggests a continuation of the pattern described above. The NWS Climate Prediction Center 6-10 day outlook (covering July 2-6) calls for below normal temperatures statewide with precipitation totals ranging from near normal levels across eastern sections of the state to above normal levels across the west. During the 8-14 day period (covering July 4-10), the outlooks calls for mean temperatures to moderate to near normal levels, with precipitation forecast to fall back to below normal levels across Upper Michigan and to remain at near normal levels across the Lower Peninsula.