February 4, 2008

SPRAY BULLETIN

The 2008 Virginia/West Virginia/Maryland Spray Bulletin For Commercial Tree Fruit Growers will be available by late February, however, the cost is yet to be determined. Contact the WVU-KTFREC at 304-876-6353, or at Libby.Nester@mail.wvu.edu after February 22 to determine availability and cost.

ENTOMOLOGY

Assail 30SG (acetamiprid) received EPA registration last fall for insect control on stone fruits. Application rates per acre are 2.5-5.3 oz for aphids and 5.3-8 oz for oriental fruit moth, plum curculio, catfacing insects (tarnished plant bug and stink bugs), cherry fruit fly, black cherry fruit fly, San Jose scale, and Japanese beetle. A minimum spray volume of 50 gallons per acre is required for ground application. Restrictions include a seasonal maximum of 4 applications and 32 oz per acre; PHI of 7 days; and REI of 12 hours. 

Avaunt 30WDG (indoxacarb) from Dupont was registered on 84 new crops last summer, including the stone fruit group. It is labeled for the control of plum curculio (5-6 oz per acre) and suppression of oriental fruit moth (6 oz per acre). Use is limited to a maximum of 3 applications prior to hand-thinning and 4 applications (24 oz per acre) per season. Recommended spray volume is 50-150 gal per acre, with dilute applications not to exceed 200 gal per acre. Avaunt has a PHI of 14 days and REI of 12 hours. 

Delegate 25WG (spinetoram) from Dow AgroSciences was registered by the EPA on September 28 for insect control on pome and stone fruits. Spinetoram is related to spinosad (SpinTor, Entrust) and derived from the fermentation, followed by the chemical modification, of a naturally occurring soil organism. This product effects the insect nervous system through both contact and ingestion, with excellent translaminar activity. Targeted pests in this area include internal worms (codling moth, oriental fruit moth), leafrollers, and leafminers on apple; pear psylla on pear; and oriental fruit moth, leafrollers, thrips, and cherry fruit fly on stone fruits. Delegate will only provide suppression of apple maggot and plum curculio. This product has demonstrated excellent control of internal worms and leafrollers in tests conducted on apple in the mid-Atlantic region. Application rate is 4.5-7 oz per acre, with a seasonal maximum of four applications and 28 oz per acre. To reduce the potential for resistance development, Delegate should not be applied to consecutive insect generations, but rotated with other chemistries for the management of internal worms and leafrollers. The product has a REI of 4 hours. The PHI is 14 days on peach and apricot; 7 days on apple, pear, cherry, plum, and prune; and 1 day on nectarine. 

PLANT PATHOLOGY

Peach leaf curl should be controlled in the spring with a fungicide application before the buds swell, unless you already made a leaf curl application in the fall. If leaf curl was severe in your peach and nectarine blocks in 2007, and you made your fall fungicide application to control the disease for 2008, a spring fungicide application may be needed to ensure complete disease control. In orchards where careful monitoring is practiced and where leaf curl has not been present for two or more years, this spray can be omitted until the disease begins to recur. For best control of peach leaf curl, make a dilute application of fungicide under calm conditions, making sure to cover each bud thoroughly. Using one of the fixed coppers for the leaf curl spray may help suppress bacterial spot in blocks where this disease is a problem. See the Spray Bulletin for fungicides and rates of application.

Apple scab urea application: A spray of 5% solution of urea (46-0-0) in water may be applied to apple leaves on the ground if this was not done in the autumn (42 lb. urea in 100 gal. water, applied at 100 gallons/acre). The nitrogen will hasten leaf litter decomposition and may result in reduced inoculum from the apple scab fungus. Moving leaves from under the trees to the row middles with a leaf blower and then shredding them with a flail mower is a good alternative to the urea spray for small acreages.