Commercial Wine Grape Production On-Farm Meeting

For those tree fruit growers that might be interested in growing wine grapes (there might just be a market out there!), the UMass Extension Agroecology Program and DeCran Ag. Supplies are sponsoring an on-farm educational program on commercial wine grape production on August 15 at Sakonnet Vineyards (http://www.sakonnetwine.com) in Little Compton, Rhode Island. Cornell, Connecticut, and Rhode Island Extension are also cooperating in the meeting, which will feature: a tour of the vineyard and winery; a review of pest management and spray schedules for grape production; demonstrations of grape spray and irrigation equipment; and a mating disruption technique for grape berry moth. Pesticide applicator recertification credit is being offered by Rhode Island and is reciprocal for applicators from New York and New England. The meeting will run from 2 to 5 P.M. and is free of charge, however, pre-registration is suggested by calling 413-545-4347. (Light refreshments will be served.) For more information call Sonia Schloemann (413-545-4347) or Parker Mauck (DeCran Ag. Supplies, 800-882-3779).

ReTain Application Timing at Hand

A reminder that ReTain must be applied four weeks before anticipated harvest for maximum effectiveness. The timing for McIntosh and Gala is during the upcoming week to ten days (app. August 9 to 19). Later applications may not be as effective at minimizing pre-harvest drop and improving fruit firmness and size. Here is Duane Greene's 'Harvest the Potential' report for August 8:

"During the past week there was abundant moisture, but the cloudy conditions that prevailed during this time may have influenced fruit growth. Fruit size in monitored blocks of McIntosh, Delicious, and Gala was 2.59 in, 2.28 in, and 2.43 in. Fruit growth increase for the week in these three varieties was 3 to 5% which is below the 7% we would expect under normal conditions. From all indications it appears that fruit maturity is close to historical norms. We believe that ReTain should be applied to McIntosh and Gala in the next 10 days. If rain follows within 8 hours of ReTain application drop control and fruit effects may be diminished. The time period when you can apply ReTain is broad enough so that you can select a favorable day to apply ReTain to get good spray coverage while avoiding rain. Gala is very sensitive to ReTain. If full rates are used, ripening can be delayed by as much as 3 to 4 weeks. Unless a very long delay in ripening is desired, we recommend use of only a half rate of ReTain (25 gai/acre) on Gala."

 

Scaffolds 'Tidbits'

Here are a few timely excerpts from the August 7 NYSAES-Geneva/Cornell Cooperative Extension 'Scaffolds' Fruit Journal. 'Scaffolds' is available via e-mail (ama4@nysaes.cornell.edu) or on the web (http://www.nysaes.cornell.edu/ent/scaffolds/).

• European Corn Borer - To repeat some words from an earlier issue, corn borer attack on young trees can occur from June through August. Damage to the fruit usually shows up in late summer, when the August flight of the bivoltine strain is active. Bearing orchards are more likely to show some early corn borer damage on the fruit if growers relax their spray program in June or early July. However, most fruit feeding occurs between the last cover spray (mid-August) and harvest. Weedy sites provide plenty of alternative hosts for this insect, especially those containing broadleaf dock, ragweed, pigweed, smartweed, and barnyard grass. Lannate and Lorsban can give very good control of ECB larvae, provided application is made before the caterpillars become concealed in the plant tissue. Potential problem plantings should be checked periodically in August for shoot infestations of this caterpillar, which is cream colored with a dark head.
• Peachtree Borers - Eggs of both species are still able to hatch and get into your stone fruit trees, and this week is timely for any orchard on a seasonal control program of trunk sprays: cherries - Asana, Lorsban, Ambush, or Pounce; peaches - add Thiodan to the above list (do not spray fruit).

New Zealand Tour

Dr. Peter Hirst, a son of a New Zealand fruit grower and now the extension fruit specialist in Indiana will be leading a tour to New Zealand from Feb. 19 to March 4, 2001. Cost of the tour is $3000. More information regarding the tour can be obtained by calling Peter Hirst at 765-494-1323 or by E- mailing him at hirst@hort.purdue.edu.

Sticky Situations

Thus far, the seasonās apple maggot fly population hasnāt developed into much of a commercial threat. Only a few sampled orchards appear to be building substantial captures on odor-baited perimeter spheres, and even fewer blocks have seen increases in unbaited monitoring sphere captures in the past week. However, even with the generally light AMF pressure, there are a few orchard situations that may yet lead to a threat of AMF invasion and subsequent damage.

First, blocks of formerly harvested trees can pose pest management challenges, often acting as a reservoir for a wide host of insect and disease pests. Perhaps the greatest threat of major AMF infestation this season lies in orchard plots that are adjacent to (within ¹ mile or so) substantial blocks of apple trees that were abandoned in the past couple of years. Proximity to large, unmanaged blocks that bore fruit last season certainly increases the risk of AMF problems; this risk extends to within-orchard AMF emergence in blocks that were not harvested or removed last season following hail damage or other management concerns.

We also do not consider that the risk period for more traditional AMF invasion (from scattered wild hosts) has passed entirely. It is likely that the greatest threat will occur in blocks of highly attractive mid- to late-ripening cultivars such as Gala, Delicious, and Fuji÷these cultivars appear to draw in greater numbers of AMF, particularly as the fruit begin to color and ripen.

All told, with this seasonās light AMF pressure and spotty risk, we encourage growers to continue monitoring buildup of AMF in commercial orchards and treat in accordance with trap-capture thresholds. While most growers will be able to extend the interval between applications or reduce chemical rates in response to the light AMF pressure, regular monitoring of traps can also offer early warning of developing AMF problems, particularly in blocks of attractive varieties, areas that neighbor newly abandoned trees, or plots that face the risk of within-orchard AMF emergence.

Signing Off

On the entomology front, this is the last pest management report for the season÷barring any traumatic six (or more) legged events. In closing this seasonās arthropod management updates, it seems that only a few summer pests have put together much of a threat, while most annual pests have been all but absent. Likely owing in large part to the weather, populations of both European red mites and two-spotted spider mites have had a very poor year. We know of only a few sites that face recent buildup of ERM that may necessitate spot-treatment; most growers should enjoy a relatively mite-free harvest. Leafminers, on the other hand, appear to be generating quite a third-generation threat in many commercial orchards. While few orchards saw a need to treat against first-generation mines, the current (second) generation has picked up momentum that will likely translate into an ugly third-generation LM density. However, treatment of the pending third-generation mines is not particularly effective; studies in New York suggest that there is little advantage to be gained by treating the third generation, as the majority of damage appears to be caused by the feeding of second-generation larvae. This seasonās LM development is highly reminiscent of the 1998 season, and will likely lead to widespread treatments of the first-generation mines of 2001.

Healthy Fruit is written by Dan Cooley, Ron Prokopy, Jon Clements, Starker Wright, Arthur Tuttle, Wes Autio, Bill Coli, and Duane Greene except where other contributors are noted. Publication is funded in part by the UMass Extension Agroecology Program, grower subscriptions, and the University of Massachusetts IPM Program. A text version can be e-mailed to you if you contact Doreen York. Please cite this source if reprinting information.

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