Northern Michigan FruitNet 2009
Weekly Update
NW Michigan Horticultural Research Station
| Nikki Rothwell District Horticulturist |
Erin Lizotte District Fruit IPM/IFP Agent |
Bill Klein Farm Mgr, NWMHRS |
| Duke Elsner Agricultural & Regional Viticulture Agent |
June 2, 2009
GROWING DEGREE DAY ACCUMULATIONS THROUHG JUNE 1st AT THE NWMHRS
Year |
2009 |
2008 |
2007 |
2006 |
2005 |
2004 |
19yr. Avg. |
GDD42 |
590 |
553 |
796 |
820 |
663 |
561 |
639.7 |
GDD50 |
270 | 257 | 428 | 436 | 318 | 252 | 322.3 |
Growth Stages at NWMHRS (6/1/09- 5:00 p.m.)
Apple: McIntosh – 8 mm fruit
Yellow Delicious – 8 mm fruit
Gala – 8 mm fruit
Red Delicious – 9 mm fruit
Pear: Bartlett: 9 mm fruit
Sweet Cherry: Hedelfingen: 12 mm fruit
Napoleon: 12 mm fruit
Gold: 12 mm fruit
Tart Cherry: 9 mm fruit
Balaton: 8 mm fruit
Apricot: 20 mm fruit
Plum: 7 mm fruit
Weather
Temperatures remain cool in the north, and the degree accumulations have slowed in the last week. We have accumulated 590GDD base 42, which is about 40 GDD behind this time last year. At base 50, we have accumulated 270 GDD, and our 19-year average is 322 GDD. We have received some rain in the past two weeks: 0.51” on May 16, 0.7” on May 27, and 0.63” on May 28. Overall, the rainfall totals for May were 2.16”, but the evaporation totals were 6.10”. We also kicked off June with another 0.3” of rain. We have had some overnight cold temperatures with lower areas reporting frost. Conditions have also been windy this spring.
Crop Report
Pears are starting to size – 9 mm-11 mm. Apples are in the 8-9 mm range, and growers are looking to start thinning and are hoping for warm temperatures. Apogee sprays have been going on last week and into this week; these applications are more wide spread than in years past. Tart cherries are in the 8-9 mm range while sweets are larger at 12 mm. Fruit set has been interesting in sweet cherry – growers are finding a lighter set than originally anticipated. Pollination may be the reason for this variability due to windy and cool conditions that limit pollinator activity. The tart crop appears to be plentiful at this time. Grapes are moving along with 4-8” shoot length. Strawberries are blooming, and growers frost protected over the weekend.
Pest Report
In apples, spotted tentiform leafminer numbers are down with catches averaging 8 adults per trap, compared with 50 per trap last week. Eastern tent caterpillar webbing is still visible throughout the region at higher levels than commonly seen. Caterpillars are moving out of nests and looking for places to pupate. We caught our first codling moth last week, but did not catch any this week, we have no reports of sustained catch in the region. Oriental fruit moth catch is averaging 3 moths per trap. High levels of European red mites eggs have resulted in pre-bloom miticide applications.
Between Tuesday May 26 and Friday May 29, the regional weather stations recorded a 68 hour wetting period that triggered a heavy primary scab infection despite the cool temperatures. The model estimates 90% ascospore maturity and 60% dispersal as of this morning. Based on forecast data, there is a possibility that primary scab could end on Tuesday June 9th with 100% ascospore discharge forecasted. With cool temperatures, the fire blight model accumulated EIP values of over 100 only once or twice during apple bloom with no significant accumulations predicted in the 7 day forecast.
In cherries, American plum borer numbers are down this week with an average of 6 moths per trap compared to 37 moths per trap last week. As fruit develops, growers are aware of potential damage from plum curculio despite the cool temperatures. Warm temperatures will likely result in a major oviposition period. One plum curculio sting was reported in tart cherry in Benzie County this week, and oviposition scars have been reported in sweet cherry blocks in Leelanau County. We have also been hearing reports of higher than normal levels of two-spotted spider mites before last week’s wetting event. Lastly, the wetting event that started last Tuesday resulted in a high infection potential for cherry leaf spot.
In grapes, we have caught our first lonely potato leafhopper on Old Mission. Last week, we also caught our first two grape berry moths in a Leelanau vineyard with a history of high pressure. For an updated version of the pest report during the week, call (231) 947-3063.
PRE-HARVEST INTERVAL (PHI) REMINDERS
N.L. Rothwell, District Horticulturist, MSU-E
All pesticide chemistries have pre-harvest intervals (PHI’s), which are the minimum number of days from the last pesticide application to harvest. This reminder is intended to give growers a heads’ up as we approach harvest for different crops. We will be running this reminder on a regular basis throughout the season to help growers accurately time different pesticides. However, growers should be sure to check the label before applying any pesticide.
EBDC’s: These fungicides have a long PHI for apples and pears (77days) and grapes (66 days).
Centaur: 60 day PHI for apples, pears, and peaches.
Nexter: This miticide is restricted to post-harvest use in cherries and apricots (300 day PHI), but in apples the PHI is 25 days. In pears, peaches, plums, and grapes, the PHI is only 7 days.
Platinum: This insecticide has a 50 day PHI in strawberries, so this product cannot be used at this time (1 June). It also has a 60 day PHI in grapes.
THINNING CAUTION
P. Schwallier and N. Rothwell, District Horticulturists, MSU-E
This year we have had heavy bloom in apple throughout the region. Most growers observed that when we have a heavy bloom, many blossoms fall off during and around petal fall. Often a ‘snowball’ bloom is weak due to the considerable amount of energy needed to produce the bloom. However, even if a lot of bloom falls off in the coming days, we often have enough blossoms left to set a full crop. In Phil’s experiences, snowball bloom is easy to thin, so growers should be cautious during the thinning window. Unfortunately, the weather forecast does not appear to be conducive for optimal thinning as the high temperature in the coming days are forecasted to be in the mid-60’s and the lows in the 40’s. Thinning may be challenging this season, but from what we hear from growers, thinning is always a challenge.
EUROPEAN BROWN ROT OBSERVED
Nikki Rothwell, District Horticulturist, MSU-E
The cool, wet weather and cherry bloom is the combination required for European brown rot (EBR) to infect tart cherries. Although this pathogen (Monilinia laxa) rarely infects Montmorency, it can be a problem in years under the right conditions. Based on our recent observations, the 2009 season appears to have provided all the right conditions for infection. Montmorency trees infected with the European brown rot fungus are visible throughout the northwest area. Some orchards appear to be more problematic than others, particularly low areas of the orchard or along hedgerows--locations that do not dry off quickly. On the other hand, most Balaton blocks have some level of EBR infection, which is to be expected as cultivars like Meteor, English Morello, and Balaton are highly susceptible to EBR.
To control this disease, two fungicide sprays should be applied; the first spray is at the popcorn stage, followed by a second spray seven days later. We have had reports of infection even following these recommendations. Therefore, if growers see the symptoms of EBR in the orchard, tree phenology will dictate the next steps: 1) if cherries are coming out of the shuck, nothing further can be done to prevent EBR infection, or 2) blossoms are still visible on the tree, another shot of Indar at 2oz is recommended.
APPLE SCAB FUNGICIDE SENSITIVITY SCREENING 2009
Erin Lizotte, District IFP/IPM Educator
The NWMHRS, in collaboration with the Michigan State University Tree Fruit Pathology lab, will be screening apple scab samples from northwest Michigan for sterol inhibitor and strobilurin sensitivity. We are looking to screen 30-50 sites and need to collect 50 leaves with active, brown scab lesions. If you have a site with active scab infections, we can collect the sample or you can bring the sample to the Research Station or the next IPM Update in your area. To collect a sample yourself, collect 50 leaves from as many trees as possible and store in a paper bag in the refrigerator until you can deliver them. Leaves may be stored together in one bag. A brief history of the use of sterol inhibitors and strobilurins for the orchard along with your contact information is greatly appreciated. For more information, please contact Erin Lizotte at (231) 946-1510.
RESISTANCE MANAGEMENT INSECTICIDE COMPATIBILITY CHART
David Mota-Sanchez and John Wise, MSU Department of Entomology
To use the Resistance Management Insecticide Compatibility chart, find the cell that intersects the row and column from two compounds of interest. The shaded code in the intersecting cell represents the compatibility of the two compounds for generational rotation.* The following codes are relevant for lepidopteran pests of fruit crops, including codling moth, Oriental fruit moth, and obliquebanded leafroller:
The black square represents insecticide chemistries with the same mode of action, thus should NOT be used in a preceding or subsequent pest generation.
The shaded square represents insecticide chemistries with known cross-resistance, thus should NOT be used in a preceding or subsequent pest generation.
The white square represents insecticide chemistries that are known to be good rotation partners for a preceding or subsequent pest generation.
* Recommendations are based on current published resistance studies from Michigan pest populations.
** Insecticides within a given chemical class have the same or similar mode-of-action (MOA).
Key to names of insecticide classes and associated MOA:
- OP - Organophosphates (Acetycholinesterace inhibitors)
- Carb - Carbamates (Acetycholinesterace inhibitors)
- Pyrethroids - (Sodium Channel Modulator)
- Neonic - Neonicotinoids (nicotinic acetylcholine receptor agonist/antagonist)
- Spinosyns - (nicotinic acetylcholine receptor agonist)
- MAC - Molt Accelerating Compounds (ecdysone agonist molting disruptors)
- CSI - Chitin Snthesis Inhibitors (benzoylurea and buprofezin)
- JH - Juvenile Hormone Mimic
- Av - Avermectins (chloride channel activators)
- Ox - Oxidiazines (sodium channel blockers)
- Vi - Granulosis virus (viral infection)
- Diamides - (rianodine receptor modulators)
- Pre-mix: products that are formulated with two or more active ingrediants of different MOA
-Voliam flexi contains the neonicotinoid thiamethoxam and diamide chlorantraniliprole
-Leverage contains the neonicotinoid imidacloprid and pyrethroid cyfluthrin
-Tourismo contains the CSI buprofezin and diamide flubendiamide
MITES ALREADY?
Nikki Rothwell, NWMHRS
John Wise, TNRC
Last season, we reported high levels of two-spotted spider mites (TSSM) and European red mites (ERM) in cherry and apple orchards around the state. Because of their late appearance, we predicted that these mites would not cause economic injury last season. However, our main concern was how those late-season mite populations would impact the 2009 production season.
ERM adults laid eggs on spur shoots and limb crotches last fall, and these eggs will serve as the starting point for this year’s spring mite population. Growers that did not apply a 2008 miticide in orchards with high ERM populations should have conducted apple pre-bloom monitoring for mites this season, and if ERM eggs numbers were high, a pre-bloom miticide application should have been made. If scouting reports indicate a high level of mite eggs and no miticides were applied earlier this spring, growers will likely battle ERM on apple fruitlets as nymphs can build to high numbers and feed extensively.
Late season populations of two-spotted spider mite (TSSM) provided a slightly different situation. In cherries, post-harvest management of TSSM is common, particularly with the old miticides and their limited PHI’s. Control of TSSM is important to maintaining healthy foliage into the fall, important for sustainable fruit production the following year. Overwintering adults and immatures move to rough areas of tree bark or in leaf litter on the ground in early to mid-September and once this overwintering migration begins, control actions are no longer warranted. Orchards with high TSSM populations in August should have been marked for scouting this May or June, which is much earlier than would be necessary under typical conditions. We have seen high populations of TSSM in both sweet and tart cherry this spring, and these orchards will likely require a pre-harvest miticide application. Most TSSM mites have been observed on cherry leaves on the inner canopy. As the tree grows and foliage expands, these mites will move out into the canopy. Growers should be sure to investigate many leaves on many trees as TSSM mite numbers look extremely high in spring when limited cherry foliage is present.
Additionally, we want to remind growers about rotating miticide compounds. Mites can develop resistance to commonly used miticides, so growers should choose their products based on rotation as well as price. Because of costs of miticides, the most economical option is appealing, but growers should keep in mind that overuse of a particular compound will likely lead to resistance issues. Also, miticide availability has been in question, so call in advance if applying a miticide in the coming weeks. We are fortunate to have a number of miticide products available for tree fruit, and a list is provided in Table 1 below.
We also recommend that scouts/growers document the levels of predacious mites in orchards this spring. If healthy populations of mite predators exist, they will continue to feed on ERM eggs and nymphs. To report on predacious mites, scouts/growers should collect a 100-leaf sample and count the numbers of each of the predator mite species. The three most important predaceous mites are Amblyseius fallacis (Phytoseiidae), Agistemus fleschneri (Stigmaeidae), and Zetzellia mali (Stigmaeidae) (see “A Pocket Guide for IPM Scouting in Michigan Apples” – E-2720 for pictures). Predaceous mites are smaller than adult ERM, but they can be seen with a hand lens and typically move very quickly across leaf surfaces.
Compound Trade Name*** |
Mode of Action |
Life-stage |
Mite Species Controlled** |
Residual Activity |
Savey, Onager, |
Mite growth inhibitors |
egg/larvae |
TSSM, ERM |
8-10 weeks |
Nexter, Portal |
Electron transport Inhibitors |
motiles* |
TSSM, ERM, PNM |
6-8 weeks |
Acramite |
unknown |
motiles* |
TSSM, ERM |
6-8 weeks |
Kanemite |
Electron transport Inhibitors (METI III) |
motiles* |
TSSM, ERM |
6-8 weeks |
Agri-mek |
Chloride channel activator |
motiles* |
TSSM, ERM |
8-12 weeks |
Envidor |
Lipid synthesis inhibitor |
eggs, motiles* |
TSSM, ERM, PNM |
8-10 weeks |
Vendex |
ATP synthesis inhibitor |
motiles* |
TSSM, ERM |
4-8 weeks |
* Motile forms include mite larvae, nymph and adult stages.
** TSSM - two spotted spider mite, ERM – European red mite, PNM – plum nursery mite.
*** Check the label to determine the specific fruit crops that each compound is labeled for use.
RUP PRODUCTS
Eric McCumber, MDA Pesticide Specialist
We’ve had a number of inquiries from different agencies regarding private certification recently. Most of the inquiries seem to be agriculturally related questions, but we also are receiving some non-agricultural certification questions. I’ll attempt to address some of those issues with this memorandum.
First, for clarification, we often hear people refer to their “license”, when what they’re really talking about is their certification credential. For this memorandum, please understand that when I refer to a license I am referring to the Pesticide Application Business License, which is required for anyone who holds themselves out as being in the business of applying pesticides (i.e., a for-hire applicator like Orkin or TruGreen or Hamilton Farm Bureau or a Wilbur-Ellis).
Secondly, again for clarification, the ONLY situation in which someone can “work under another person’s certification credential” is for a private agricultural situation. A person who is working for a firm that is required to be licensed MUST always have their own commercial certification or registration credential to apply any pesticide, even if it is general-use ready-to-use pesticide.
A person who is required to be a commercially certified or commercially registered applicator MUST have their own personal credential. Generally speaking, a person applying pesticides at work, such as a golf course or applying pesticides to a right-of-way area or applying weed-and-feed to a school’s athletic field would need to be a commercially certified or registered applicator. However, if the product is a general-use ready-to-use pesticide (i.e., used from its original container consistent with label directions) AND the applicator is not holding themselves out as being in the business of applying pesticides, then the applicator would generally NOT need to be certified or registered. An example would be a person who applies RTU Roundup to control weeds in a sidewalk area at a grocery store where they work. They would not need to be certified or registered. If more information is needed, contact Eric McCumber at the MDA office in Traverse City, 231-922-5210 or Rob Sirrine, Leelanau MSU-E office, 231-256-9888.
Insect and disease predictive information is available at:
http://www.enviroweather.msu.edu/home.asp
http://www.agweather.geo.msu.edu/agwx/forecasts/fcst.asp?fileid=fous46ktvc
http://www.cherries.msu.edu/
Fruit CAT Alert Reports
http://www.ipmnews.msu.edu/fruit/
This issue and past issues of the weekly FruitNet report are posted on our website at: http://www.maes.msu.edu/nwmihort/faxnet.htm
ACTUAL
AND PREDICTED DEGREE-DAY
ACCUMULATIONS
SINCE MARCH 1, 2009
Please send any comments or suggestions regarding this site
to:
Bill Klein, kleinw@msu.edu
Last Revised: 6-2-09
