Fruit Pest News

Volume 8, No. 2  March 20, 2007

A weekly, online newsletter whose goal is to provide all interested persons with timely information on diseases and insects of commercial fruit and vegetable crops 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. Apples: Copper Sprays

    3. Vegetable Pesticide Update

    4. Pheromone Trap Update

    5. Strawberries: Suggested Fungicide Spray Schedule

    6. Copper Special Review Verdict

1. Current Conditions

 Warm weather continues. Strawberry and peach bloom season looks good, with nothing even approaching a frost in the forecast. Apples are at green tip to tight cluster and progressing rapidly. Cedar-apple galls have produced the dry, brown tentacles that will become large, orange tentacles with the next rain. TIME FOR THE RUST SPRAY. Use a material with good apple scab activity while you're at it, such as Nova, Procure, or Indar.

The upcoming extended period of warm days and nights will build the fire blight bacterial population. The bacteria won't cause a problem until bloom, but if we don't get a cold snap to re-set the population before or during bloom, expect to buckle down on your fire blight sprays during bloom. Coppers would serve a useful role under these conditions, but see the next article for cautionary information, considering all the green tissue that is showing.

Plasticulture strawberries are in bloom. Don't forget the importance of the early bloom fungicide application for Botrytis fruit rot control (see article 5, below). By walking through the field now and freeing any shoots trapped under the plastic, you can reduce the chance of Botrytis crown rot. If Phytophthora crown rot was seen in your plants last fall, now would be a good time to apply Ridomil through the drip.

See last week's issue for information on obtaining this year's spray guides for all the fruit and vegetable crops. (SB)

2. Apples: Copper Sprays

Fixed coppers and Bordeaux mixture can be 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. Many apple trees in the state are already past this stage of growth.

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 (called epiphytic growth). Fixed coppers and Bordeaux mixture can be mixed with dormant oil if the job is concluded by 1/2-inch green tip. (SB)

3. Vegetable Pesticide Update

In the Insect Control section of the upcoming 2007 Commercial Vegetable Disease, Insect and Weed Control, PB 1282, Dimethoate 2.67 EC was removed throughout the publication. Disulfoton (Di-Syston) was removed for lima beans. For endosulfan throughout the publication, Thiodan was replaced with Thiodex and Phaser was removed. Azinphos-methyl (Guthion 50 WP) was removed throughout the publication.

There were many additions of insecticides and miticides. Buprofezin (Courier 40 SC) was added for whiteflies on snap bean, cantaloupe, and tomato. Bifenthrin (Capture 2E) and imidacloprid (Admire 2F, Admire Pro 4.6 F) were added for whiteflies on snap bean and lima bean. Spiromesifen (Oberon 2 SC) was added for whitefly and spider mites on cantaloupe, cucumber, pumpkin, squash, watermelon, eggplant, pepper, and tomato. Dinotefuran (Venom 20 SG) was replaced throughout the publication with Venom 70 SG. Venom 70 SG was added for aphids and whitefly to cucumber, cantaloupe, pumpkin, squash, and watermelon. Added acetamiprid (Assail 30 SG) for whitefly on eggplant, pepper and tomato.

Bifenazate (Acramite 50WS) was added for spider mites on eggplant, pepper, and tomato. Novaluron (Rimon 0.83 EC) was added for beet armyworm, cabbage looper and diamondback moth caterpillar for broccoli and cabbage.

In the Greenhouse Vegetable Insecticide section of PB1282, Thioden was changed to Thionex. The BT insecticide Ketch DF was replaced with Xentari, Dipel DF, and Crymax. Buprofezin (Talus 70 WSP) was added for whiteflies, mealybugs, and leafhoppers on tomatoes. Chlorfenapyr (Pylon 2 lb/gal L) was added for spider mite, broad mite, cyclamen mite, rust mite, and caterpillars on fruiting vegetables (do not use on tomato varieties with diameters of less than one inch when mature). Bifenazate (Floramite SC) was added for twospotted spider mite and other label listed mites on tomatoes (varieties greater than 1 inch in diameter when mature). (FH)

4. Pheromone Trap Update

Unknown tortricid moths have been caught in the codling moth trap and the Oriental fruit moth trap. These generally gray moths with some dark markings are larger than either the Oriental fruit moth or the codling moth. Take a close look at these moths under magnification and do not confuse these unknown tortricids with your target pest species. The redbanded leafroller moths are the first significant pest species that should be caught in your orchard. They are plentiful now and they will be laying eggs on the new foliage. (FH)

5. Suggested Strawberry Fungicide Spray Schedule

Below is a recommended spray schedule to follow for springtime disease control in strawberries. The exact design of a spray schedule can vary depending on disease control needs and products available. However, the principles illustrated below should serve as a good general guide for management of the two most common diseases, Botrytis and anthracnose.

(SB)

6. Copper Special Review Verdict

You may recall the special review of copper pesticides that took place last year. The verdict appears to be favorable, but you may see some label changes. EPA's Office of Pesticide Programs has determined that agricultural uses of copper-containing pesticide products are eligible for reregistration provided that data needs are addressed, certain risk mitigation measures are adopted, and labels are amended accordingly.  

Copper products are used in Tennessee for disease control in production of tomatoes, peppers, cucurbits, peaches, apples, and other crops and are valuable for organic gardening and farming operations. Coppers are also used in residential settings as a root killer in septic systems and for moss control. Copper products are used as a preservative on wood and other materials, and for control of algae and certain weeds in farm ponds. Concern over exposure of non-target organisms, especially certain aquatic species, to direct applications of copper and runoff from fields adjacent to bodies of water led to the review. The Agency has determined that there are no dietary, residential or occupational risks of concern resulting from exposure to copper products.

Based on information from the user community that indicated that most typical use rates are significantly lower than the labeled maximum use rates, the manufacturers have agreed to refine their pesticide labels by reducing application rates, defining application intervals, and determining seasonal maximum application rates.  (SB)

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@utk.edu

Both authors available at:

615-832-6802

fax 615-781-2568

Plant and Pest Diagnostic Center

5201 Marchant Drive

Nashville, TN 37211

Copyright 2006 The University of Tennessee. All rights reserved. This document may be reproduced and distributed for nonprofit educational purposes provided that credit is given to University of Tennessee Extension.

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