Apple Pest Report July 2, 2003

Apple Pest Report: Wednesday, July 2 , 2003
Vol. 11 No. 9

INSECT and MITE PESTS

Plum Curculio
The Plum curculio control period ended in Corinna (the most northern and latest location I am tracking) on June 29. This means that renewed insecticide coverage is not needed for this pest assuming that previous coverage killed all plum curculio the immigrated into the orchard up to that date.

Surround does not kill plum curculio. For growers using Surround, there is still a week or more to go before a Surround program can safely be discontinued. Surround coverage should be maintained at the very least until July 8 in the Sanford area, and through July 12 in Corinna. Allowing Surround coverage to dissipate after these dates may allow some late damage, but plum curculio activity should be declining by then.

About 50-80% of fruit have been damaged by plum curculio so far in our unsprayed monitoring plots, and there is still more egglaying activity yet to occur where the weevils have not been killed.

European apple sawfly are winding up their annual devastation in unsprayed trees. I have seen few newly infested fruit over the past 7 days.

European red mites are actually hard to find this year. Normally by now second generation mites are easy to find and in some cases approaching threshold level. In Monmouth, third generation ERM should start hatching roughly around July 8 and begin producing fourth generation eggs around July16. The fourth generation is typically the most abundant generation. This is because starting with 5th generation, some of the eggs laid are overwintering eggs that do not hatch until next spring.

Codling moth

Codling moth stings and fruit entries at the calyx and stem ends started showing up about 7 days ago in unsprayed trees. As mentioned in the explanation of the new Orchard Radar model, codling moth is not normally a pest in blocks where conventional insecticide applications are made for plum curculio. But in no spray and organic blocks where there is ineffective control, codling moth damage regularly exceeds 30% of the crop. With proper timing, proper dosage, and excellent spray coverage, organic growers can control codling using Bt and/or Entrust.

Leafroller feeding damage is also appearing as shallow depressions often with fine powdery frass on apples, especially where two apples are pressed against each other.

Apple maggot flies will begin emerging soon in the Sanford area, and probably by July 9 in the Monmouth area. In coming weeks I will be reporting apple maggot trap captures from Highmoor Farm, but that is no replacement for having your own traps. Local AM populations can very greatly, and trap information can save you sprays, damage, or both.

You can purchase traps from Gempler's (800-383-8473,
http://www.gemplers.com/a/shop/catpest.asp
and Great Lakes IPM (517-268-5693,
http://www.greatlakesipm.com/

Mineral spirits are an effective solvent for cleaning traps from last year.

New Orchard Radar models

By 8pm tonight there will be three new tables for each Orchard Radar site to help with timing insecticide spray for codling moth control.

The new models track accumulated rain and number of days from the last spray date to estimate when residual coverage will begin losing ability to kill codling moth larvae before they penetrate apples.

Codling moth does not normally require specific attention in orchards where full block insecticide applications are made to prevent European apple sawfly and plum curculio damage. While those applications are not ideally timed for control of codling moth larvae, experience shows that their lethal effect on adult codling moth or their residual effect on larval hatch is enough to prevent noticeable codling damage.

However, alternative measures such as perimeter sprays or Surround applications used for plum curculio control may not provide adequate secondary control of codling moth. The purpose of the codling moth insecticidal control model is to indicate how insecticide application dates and expected residual efficacy depletion dates line up with codling moth egg hatch. This information is particularly important for organic growers who have only Surround, Bt and Entrust for codling moth control options. Using these materials efficiently and effectively requires knowing when to start applications and how long to continue coverage.

The Orchard Radar Codling moth model applies generally accepted "rules of thumb" for how long a given full-dose application will last before losing their effectiveness due to time, rainfall, ultraviolet light, tissue growth and other influences. Two sets of rules are used to estimate depletion of effective control from a full dose insecticide application.

The first set evolved over many years for Imidan and Guthion (azinphosmethyl). After discussion with manufacturer representatives for Avaunt and Assail, these rules also seem applicable for those products. Excellent coverage is essential for codling moth control. This may be even more important for Avaunt and possibly also Assail, because they are more "rainfast" and less affected by redistribution by subsequent rainfall than Imidan or Guthion.

      Residual protection from previous full-dose Imidan, Guthion (azinphosmethyl), Avaunt or Assail application is considered depleted when one of the following conditions is met:
    2 inches of cumulative rain within the first 10 days after application, or
    1.5 inches of cumulative rain from 10-14 days after application, or
    14 days.

        After checking with product labels, a second set of rules was adapted for Bt insecticides (e.g. Agree, Dipel, Javelin, MVP, Xentari) and Entrust. These materials provide shorter effective residual codling moth control, and they are considered depleted when one of the following conditions is met:
    1.5 inches of cumulative rain within the first 7 days after application, or
    1 inch of cumulative rain from 7 - 10 days after application, or
    10 days.

Scab, Fire blight, Flyspeck

No news is good news. In Sanford and Monmouth, nearly all of the season's scab infection potential has had time to appear as second generation lesions. In Morrill and Corinna, the last chunk will be developing over the next week or so. Most scouted orchards are clean. If your orchard is scab free at this point, pat yourself on the back because unsprayed trees show that scab did not take a vacation during the rainy spring. If you have more than 5 scab leaves per 100 shoots, refer to the suppression guidelines in the New England Apple Pest Management Guide and in the June 17 Apple Pest Report.

Scab fungicide coverage keeps what risk there is from first generation flyspeck under control. The risk from flyspeck increases with the production of second generation spores starting roughly around July 17 -21 in Sanford and Corrina respectively.

I am not aware of any fire blight outbreaks in Maine this year.

Summer Orchard Tour Ricker Hill Orchards is hosting this event on Wednesday July 23, 8:30 am to 3:30 pm, in conjunction with the Maine State Pomological Society and the University of Maine Cooperative Extension Directions: Coming south from the Maine Turnpike, take exit 12 (Auburn) and go 18 miles North on Rt. 4 into the town of Turner. There are signs on Rt. 4 to help direct you to the stand. At the intersection of Rt. 4 and Rt. 117, go south on 117. Continue on Rt. 117 for 1.5 miles. You will come to our fruit stand, on the right, above the cranberry bogs. Parking is at the farm stand. Map Agenda 8:30 to 9:00 Registration Coffee and donuts provided by Randy Drown, UAP 9:00 to 11:00 Orchard Tour We will be taking a bus to the Allen Farm to view 25,000 Gala and Honeycrisp trees planted between 1999 and 2002. Then on to Apple Ridge farms which has newer varieties planted from 1994 to 1996. Last, we will visit the home farm on Ricker Hill with one or our oldest orchards, organic blocks, highbush blueberries and great views of the western hills. 11:30 to 12:00 Integrated pest management update Glen Koehler, University of Maine			12:00 to 1:00 Lunch Burgers, hot dogs, french fries, chips, salad, apple cider and soda. Desserts from the bakery. $7 per person, children under 10, free. 1:00 to 1:30 Business meeting of the Maine State Pomological Society 1:30 to 2:00 Apple promotion options for Fall 2003. Jim Unker, Maine State Pomological Society market promotion coordinator. 2:00 to 2:30 George Greene, guest speaker George was with the Penn State Univ. Dept. of Horticulture for over 30 years. He was located at the Fruit Research and Extension Center in Biglerville for most of that time working on research and extension. His research program involved rootstocks, apple varieties, peach tree winter hardiness, apple nutrition, PGRs and postharvest studies. He retired in 2002 but continues some of his fruit endeavors. 2:30 to 3:00 Efficiency Maine Small Business Program Tim Clark will tell us about cash incentives for the installation of eligible energy efficient electrical products. Learn how your business can take advantage of this program. 3:00 to 3:30 Apple production and storage update Renae Moran, University of Maine

Sincerely,
Glen

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