Changes in Orchard Chemicals for 2001

As has been the case in recent years, some new types of pesticides have been labeled for use in orchards for the 2001 growing season. Others are waiting in the wings and may yet receive federal registration before the 2001 growing season ends. Still others have undergone some label modifications. Here’s a brief summary of how things stand as of April 9, 2001. More information on the performance of some of these compounds is given in the 2001 March Message.

New Federally Registered Insecticides and Miticides

Avaunt (indoxacarb): 30% WG, 5-6 ozs./acre. Registered for control of tarnished plant bug, plum curculio, codling moth, oriental fruit moth, lesser appleworm, leafrollers, apple maggot, and leafhoppers. Maximum of 4 applications per year at no more than 24 ozs. total annual per acre. Make no more than 3 applications prior to hand thinning. No hand thinning after 4th application. For best results, apply in 50-150 gal. water per acre and never more than 200 gal. water per acre. Performs well against tarnished plant bug, plum curculio, some leafrollers, and leafhoppers. Performance against apple maggot has been variable. Avaunt represents a new class of compounds (oxadiazines) and is more toxic when ingested by insects than by contact alone. Toxic effects are not immediate but gradual, sometimes requiring 3 or more days. It is not systemic and does not protect new growth. Does not redistribute readily on foliar surfaces once sprayed. Residual activity last 7-14 days depending on conditions. Safe on most beneficials. Restricted entry interval is 12 hours. Preharvest interval is 28 days.

Distance (pyriproxyfen) 0.86 lbs/gal L, 6 to 8 fl. ozs./100 gals. for aphid suppression on non-bearing trees; 8 to 12 fl.ozs/100 gals. for San Jose scale and spotted tentiform leafminer on non-bearing trees. The active ingredient (same as Esteem) is an insect growth regulator, so it does not affect adult insects. Restricted entry interval 12 hours. Preharvest interval: non-bearing trees only.

Intrepid (methoxyfenozide): 80 WSP, 3-6 ozs./acre. Registered for control of codling moth, lesser appleworm, leafrollers, and leafminers. Effective also against oriental fruit moth. Maximum of 20 ozs. total material per acre per year. Performs best in conjunction with an adjuvant to maximize deposition, redistribution, and weatherability. Belongs to diacylhydrazine class of insecticides and has novel mode of action that mimics action of molting hormones of moth larvae. Must be ingested by larvae to be effective. Works best against internal feeders when application is just prior to egg hatch. To avoid resistance, do not use against more than 3 consecutive generations of a pest. Very safe on beneficials. Restricted entry interval is 4 hours. Preharvest interval is 14 days.

Valero (cinnamaldehyde) 30%L, 1-9 gals/acre. Registered for control of aphids and spider mites. Label recommends a phytotoxicity check before treating, to ensure that treatment is safe for your varieties. Experience with products that have this ingredient (but used in greenhouses) suggests that it loses effectiveness several weeks after being opened. Cinnamaldehyde is a component of cinnamon, the ground inner bark of certain tropical trees in laurel family. Spray water should have a pH of 3.5 to 7.5, or product degradation may result. Restricted entry interval is 4 hours. Preharvest interval is 0 days.

Label Change

Lorsban (chlorpyrifos). In the March Message for 2001, we provided information available to us as of early February on the status of Lorsban. Since then, that status has changed. There is now a new supplemental label that does allow application of Lorsban to apple tree trunks after bloom. This new label still does not allow application to apple foliage or fruit, even if you have leftover material. But Lorsban 50W and Lorsban 4E can be applied to the lower 4 feet of tree trunks for control of dogwood borers, American plum borers, apple bark borers, and roundheaded and flatheaded apple tree borers. No more than 2 applications per year are allowed and no application is allowed within 28 days of harvest. If available residue data to be submitted in 2002 demonstrate detection of chlorpyrifos at concentrations greater than 0.01 ppm (resulting from above-type application directed only at apple tree trunks), then the supplemental label may be revoked for 2002. This is good news for 2001, allowing growers to continue to use Lorsban in an effective way for controlling bark and tree borers on apple trees. The same permitted use also applies to peach and plum trees. Note: Lorsban can now be purchased, mixed and applied only by a licensed applicator.

A Daily Dose of SkyBit

Growers interested in ‘piggybacking’ with the SkyBit E-weather products we are currently receiving at the UMass Horticultural Research Center may do so by contacting SkyBit. The cost is $10 per month, and includes Hourly, Forecast & Summary, Apple Insect, Apple Disease, and Canopy (Frost) Forecast products delivered daily by e-mail. Caveats include the products can only be delivered by e-mail, and are site-specific only to the HRC. Of course you can also purchase the products based on your specific orchard location at greater cost, and this is recommended. Growers familiar with SkyBit have said the wind and spray forecasts are particularly useful.

Calibrate those Sprayers

Now is a good time to get your sprayer calibrated. Based on Tree Row Volume (TRV), air-blast sprayers should be calibrated to deliver Dilute Gallons Per Acre (GPA) that will ensure adequate coverage and proper pesticide dosage. Improper calibration can result in two things: failure in pest control (under-dosing), or over-dosing (too much pesticide, i.e. waste of money and potential label violation). Please take the time to calibrate your sprayer before the first spray, and check it periodically during the growing season. To help you calibrate, check out the ‘Block-Specific Sprayer Calibration Worksheet’ on the UMass Fruit Advisor. Using the worksheet, you can quickly calculate Dilute GPA on a block-by-block basis, and then use Dilute GPA to calculate desired sprayer output in Gallons Per Minute (GPM) based on tractor speed and individual block row spacing. For more information on getting your sprayer ready for the season, see the article
‘Preparing the Airblast Sprayer for Work’ in the March 26, 2001 issue of Scaffolds Fruit Journal.

Early Season Peach and Nectarine Disease “Gotcha’s”

Two important diseases of peaches and nectarines—peach leaf curl and bacterial spot—warrant control measures at this time. Peach leaf curl is easily controlled with a fungicide spray, (Ferbam, Ziram, Bravo) however, the spray must be applied before bud swell—remember, it can even be applied in the fall. Copper is also an effective spray for leaf curl, and is recommended for peach orchards planted to cultivars with bacterial spot susceptibility and where ‘bac spot’ was a problem last year. For more information on life histories and control of these diseases, see the March 26, 2001 issue of Scaffolds Fruit Journal.

Pruning Apples At Planting

Get those newly planted trees off to a good start—HEAD at planting! Following is a guideline for pruning newly planted apple trees as presented by Cornell’s Terence Robinson at the International Dwarf Fruit Tree Association’s Annual Conference last February. Please, do heed his advice upon planting:

• For large caliper highly feathered trees (8-10 feathers): Head the leader at 48” high.
• For whips, raise the heading height to 36” for non-tip bearing varieties and to 42”+ for tip bearing varieties.
• Feathers:
  • Remove all feathers below 24”.
  • Remove feathers that are larger than 2/3 diameter of leader. If there are less than 3 good feathers then remove them all with a bevel cut.
  • If 3 or more good feathers remain then head feathers that are longer than 12” back to 12”.
    

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