October 17, 2005

ENTOMOLOGY

Pesticide label changes.  On August 17, 2005, EPA announced the planned termination of labeled uses of azinphos-methyl (Guthion, Azinphos-methyl 50WS) on peaches, nectarines, caneberries (brambles) and cranberries.  The following timelines have been established:  1) January 31, 2006 - last day registrants can manufacture product labeled for use on above crops; 2) March 31, 2006 - last day registrants can distribute product labeled for use on above crops; and 3) September 30, 2006 - last day distributors/retailers can sell and growers can use product labeled on above crops.  In effect, EPA's action allows growers one more use season for azinphos-methyl products that are labeled on the above crops.  Use of azinphos-methyl products on apples, pears, cherries, and blueberries is not affected by this action.  More information on EPA's ruling can be found in the Federal Register (volume 70, number 158) at:  www.epa.gov/fedrgstr.

Labels for Imidan will begin appearing with a longer restricted-entry interval (REI) of 72 hrs. sometime in 2006.  This means that at some point (most likely mid season)  there will be an overlap of both 24 and 72 hr REI products in the marketplace.  Be sure to check the REI of the Imidan in your possession when scheduling orchard activities following spray application next season.

2005 pest summary.  Internal worms  (codling moth, oriental fruit moth) continue to be the most troublesome pest complex for WV growers in terms of fruit injury and loss.  Although both species are responsible, injury from codling moth has increased.  Most internal worm injury is occurring after mid-July.  Warm temperatures  this summer resulted in the completion of an entire third generation egg hatch of codling moth from mid-August through late September.  Pheromone trap counts of oriental fruit moth (4^th and 5^th flights) were especially high (over 100/week) in quite a few orchards during this same time period.  Every effort should be made to remove dropped apples in those blocks which experienced a high incidence of internal worm injury.  Also, bins used to harvest fruit in high injury blocks should not be stored near blocks without injury in order to prevent establishment of new infestations from overwintering larvae.

Rosy apple aphid was more problematic than last year, but not as abundant as in 2003.  More cases of poor performance of pyrethroids against this pest were observed, whereas neonicotinoids (Actara, Assail, Calypso, Provado) performed very well.  In general, incidence of spirea aphids, leafhoppers and leafminers was very low in most orchards.  In spite of hot temperatures during July and August, populations of European red mites requiring control were not as numerous as expected.  Japanese beetles were quite abundant over a prolonged period for the second year in a row.  Following two wet seasons, it is expected that the dry conditions this August and September will reduce populations next year.  Incidence of fruit injury from leafrollers (tufted apple bud moth, variegated leafroller, redbanded leafroller) was generally low throughout the area.  Pheromone trap counts of redbanded leafroller have been increasing and were significantly higher than tufted apple bud moth during August this year at the WVU-KTFREC.

PHEROMONE TRAP COUNTS
WEST VIRGINIA UNIVERSITY KTFREC

RBLR = Redbanded leafroller; STLM = Spotted tentiform leafminer; OFM = Oriental fruit moth; CM = Codling moth; TABM = Tufted apple bud moth; DWB = Dogwood borer; LPTB = Lesser peach tree borer; PTB = Peach tree borer; AM = Apple maggot.

PLANT PATHOLOGY

Peach leaf curl control that is virtually 100% effective can be achieved by a single fungicide application during the dormant season. A dilute application should be made under calm conditions anytime after most (no less than 90%) of the leaves have fallen and before hard freezing weather sets in. Thorough coverage of each bud is essential for controlling the leaf curl fungus. If leaf curl was severe in your peach or nectarine blocks this year, make fungicide applications this fall and next spring before bud swell. Treatments with copper compounds are recommended where bacterial spot has been a problem. In orchard blocks that have been intensively scouted and where the grower knows with certainty that the disease is entirely absent from the block for a period of two or more years, this spray can be omitted until the disease begins to recur.  See the 2005 Spray Bulletin for fungicides and rates of application.

Phytophthora root rot can be managed with mefanoxam (Ridomil Gold EC and Ridomil 5G) and will aid in the control of crown, collar, and other root rots caused by Phytophthora spp. on both bearing and non-bearing apple trees. Ridomil 5G can be used in nonbearing orchards only. Applications should be made on a preventative schedule before symptoms appear, especially in orchards where conditions are favorable for disease development. This would include any young blocks of trees on M.26 rootstock. Ridomil should not be expected to revitalize trees showing moderate to severe disease symptoms. Ridomil is not registered for use as a preplanting dip treatment. For best results, make one application at the time of planting or in the spring before growth starts. Make another application in the fall after harvest. Ridomil is highly specific and will not control other agents causing similar tree decline symptoms, including but not limited to other fungal root rots, graft union necrosis (tomato ringspot virus) and vole damage. 

Dipping the roots of nursery-grown trees into a solution of the fungicide Aliette prior to planting may reduce, but not eliminate, Phytophthora inoculum on infested rootstocks. To use, thoroughly mix Aliette at a rate of 3 lbs/100 gallons of water, in the desired volume of water and dip the entire root system for 30 to 60 minutes in the mixture prior to planting.

Apple scab urea application.  A 5% solution of urea (46-0-0) in water may be applied to apple trees as leaves begin to fall in the autumn (42 lb. urea in 100 gal. water, applied at 100 gallons/acre). This should be done as late as possible to prevent the urea from being translocated into the tree. However, it should be early enough to have most of the leaves still on the tree. Note that trees sprayed with urea may defoliate more quickly than unsprayed trees. Urea may also be sprayed on the leaves on the ground, after all the leaves have dropped. The ground spray can also be done in the spring.

READ THE LABEL CAREFULLY AND USE THE CHEMICALS IN ACCORDANCE WITH LABEL CAUTIONS, WARNING AND DIRECTIONS. REQUEST A MATERIAL SAFETY DATA SHEET (MSDS) FROM THE MANUFACTURER FOR EACH PRODUCT YOU USE.

The West Virginia University Cooperative Extension Service, U.S. Department of Agriculture, West Virginia County
Boards of Education and County Commissions Cooperating.  Equal Opportunity / Affirmative Action Institution