Fruit Pest News

Volume 5, No. 2   March 23, 2004

An online newsletter whose goal is to update Extension agents and growers of commercial tree fruit and small fruit crops

on diseases and insects in Tennessee.

Text appearing in blue or red can be clicked to link to other web sites. Be aware that much of the linked information is produced in other states and may not be applicable to Tennessee.

In This Issue:

    1. Current Conditions

    2. Fruit Spray Guides: Where to Find

    3. MaryBlight Program for Fire Blight Management: Plans for the Year and What to Do Now

    4. Apples: Time for Copper Sprays

    5. Tree Fruit: Pheromone Trap Catches, Biofixes, and Identifying Codling Moths 

1. Current Conditions

Spring is taking its time this year. Saturday's very warm weather was interrupted by a two-day cold snap. Temperatures in the mid-20's on the nights of March 21 and 22 were problematic for plasticulture strawberries and a few blueberry cultivars. The Plateau may have even seen low-20's. However, most fruit crops are not yet in bloom. Here at Nashville, Golden Delicious apples are at 1/2-inch green tip, about the biofix stage for MaryBlight (see below). Red Delicious are at silver tip and Redhaven peaches are at pink tip. A few blueberry cultivars are in bloom and blackberry buds are about 1 inch long. All in all, a later than normal spring. That is going to change fast, however, because warm weather is predicted for the next week. (SB)

2. Fruit Spray Guides: Where to Find

All of the commercial fruit and vegetable spray guides that we commonly use in Tennessee have been revised and are now available.

• 2004 Commercial Vegetable Disease, Insect and Weed Control (University of Tennessee PB 1282). Printed, bound copies are available at county Extension offices. It is also available for downloading from our web site at http://www.utextension.utk.edu/publications/pbfiles/PB1282.pdf

• 2004 Commercial Small Fruit Spray Schedules (University of Tennessee PB1197). Printed, bound copies are available at county Extension offices. It is also available for downloading from our web site at http://www.utextension.utk.edu/publications/pbfiles/PB1197.pdf

• 2004 Integrated Orchard Management Guide for Commercial Apples in the Southeast (regional publication). Printed, bound copies are available at county Extension offices.

• 2004 Southeastern Peach, Nectarine and Plum Pest Management and Culture Guide (regional publication). Printed, bound copies are available at county Extension offices. It is also available for downloading from http://entomology.ent.uga.edu/peach/peach_guide/title.htm (SB)

3. MaryBlyt Program for Fire Blight Management: Plans for the Year and What to Do Now

One of the priorities for this newsletter is to provide training and updates for the MaryBlyt program. Fire blight will require increasing attention as time goes by, with the changes that are taking place in apple production.

I have a limited number of MaryBlyt programs (software and manual) available for free. Please let me know if you would like one. I only ask that the cooperator use it diligently and report to me when the program indicates that an infection period has occurred and when you see your first fire blight symptoms. The program is not difficult to operate, and can help tremendously in managing fire blight.

What it does: The program use temperature and rainfall amounts to tell you when you need to spray with streptomycin and to tell you when to expect fire blight symptoms to appear. The program will improve control efficiency, resulting in better control with fewer sprays than would be obtained by spraying on a fixed schedule. Fewer sprays mean less chance of resistance to streptomycin developing.

For those of you who have begun to use MaryBlyt, here are some points to keep in mind:

• Begin monitoring temperature and rainfall when 50% of the buds show green tissue. This is the "biofix," when the program begins calculating pathogen and plant development. In judging when to begin measurements, consider only blossom buds (those at terminals and spurs). Don't consider the leaf buds (those at the nodes).

• You don't need to enter the data into the computer until the blooms begin to open, but you do need to record the measurements every day, and reset the max-min thermometer and empty the rain gauge after the reading. When the first blossom bud opens, the data must be entered into the computer each day.

• The thermometer should be located in the shade, away from the ground. The rain gauge should be located in the open.

• Time of day to take measurements: Can be taken any time, but you should choose a time and be consistent with it each day. I think the most desirable time is late afternoon, because it would allow all of the measurements for that day to be kept together . . . and a spray decision based on that day's data to be made that night (streptomycin applications work well under the slow drying conditions of night). Remember to take note of whether a dew occurred in the morning, since dewfalls are also recorded. (SB)

4. Apples: Time for Copper Sprays

Fixed coppers and Bordeaux mixture are applied at this time of year to reduce fire blight bacterial populations on the surface of apple and pear trees. By doing so, there will be fewer bacteria to be carried to the blooms on the feet of insects or by splashing rain. This job should not be delayed, because application after the 1/2-inch green tip stage can cause fruit russeting in years when there is not enough rain to remove the copper residues before bloom. Don't restrict the copper application to fire blight-susceptible blocks. The fire blight bacteria can be found on the surface of resistant varieties, too. The bacteria don't require a susceptible host to multiply on the surfaces. Fixed coppers and Bordeaux mixture can be mixed with dormant oil if the job is concluded by 1/2-inch green tip. (SB)

5. Pheromone Trap Catches, Biofixes, and Identifying Codling Moths

A total of 12 unidentified tortricid moths (family of moths of codling moths, Oriental fruit moths, redbanded leafroller, obliquebanded leafroller etc.) were found in the codling moth (CM) trap at Nashville on March 15, 17, 19 and 22. These mottled olive green and gray moths are about the same size as CM (9 mm long). When viewed under magnification, four tufts along the wing margin down the back can be seen.

An actual codling moth, in contrast, is gray-brown, crisscrossed with fine alternating white and gray bands. The distal third of the front wings (furthest from head end) has prominent bronzed areas. The beauty of using pheromone traps is that at best they are only attractive to the target pest and at the worse only a few other closely related insects. It still bothers me when I have to view these under a dissecting microscope to see if they are codling moth or not. If you are having problems identifying moths in your traps check the digital images at a Michigan State University Extension online site at http://www.msue.msu.edu/vanburen/generali.htm (FH)


Nashville (Davidson County) Pheromone Trap Catches for 2004

* The three RBLR caught in trap left over from last year. New RBLR trap put out 3-4-04. Biofix for RBLR in Davidson County estimated as occurring on February 29.

Bradley County Pheromone Trap Catches

*Biofix for redbanded leafroller in Bradley County estimated as occurring on February 29.


Putnam County Pheromone Trap Catches

*Biofix for Putnam County estimated as occurring on February 29.

The Fruit Pest News URL is: http://web.utk.edu/~extepp/fpn/fpn.htm

Contacts:

Steve Bost, Professor and Extension Plant Pathologist

scbost@utk.edu

Frank Hale, Professor and Extension Entomologist

fahale@ext1.ag.utk.edu

Both authors available at:

615-832-6802

fax 615-781-2568

Plant and Pest Diagnostic Center

5201 Marchant Drive

Nashville, TN 37211

 Pesticides recommended in this publication were registered for the prescribed uses when printed.  Pesticides registrations are continuously reviewed.  Should registration of a recommended pesticide be canceled, it would no longer  be recommended by the University of Tennessee.  Use of trade or brand names in this publication is for clarity and information; it does not imply approval of the product to the exclusion of others which may be of similar, suitable composition, nor does it guarantee or warrant the standard of the product.

The Agricultural Extension Service offers its programs to all eligible persons regardless of race, color, age, national origin, sex, disability,

religion or veteran status and is an Equal Opportunity Employer.

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COOPERATIVE EXTENSION WORK IN AGRICULTURE AND HOME ECONOMICS

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Acts of May 8 and June 30, 1914. Agricultural Extension Service  Charles L Norman, Dean