June 17, 2002 Volume 11 No.14 Update on Pest Management and Crop Development
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TRAP CATCHES (Number/trap/day)
Geneva: 1st San Jose Scale adults caught in traps.
Highland: 2nd flight of Spotted Tentiform Leafminer at peak.
Roundheaded Appletree Borer
San Jose Scale
Roundheaded Appletree Borer
San Jose Scale
Plum Curculio. The spray cutoff for this pest is 340 DD (base 50°F) past petal fall. Numbers as of today, June 17, follow:
Oriental Fruit Moth. In Niagara Co., using May 6 as the biofix for first flight, the 341 DD (base 45°F) accumulation puts us at approximately 98% first brood larval hatch. Growers should have applied their second application of a pyrethroid for this insect (plus curc).
Codling Moth. With 250 DD (base 50°F) as a first spray date, we currently have:
Once again, it is nearly time to expect the first appearance of apple maggot (AM) flies in volunteer apple stands and abandoned orchards, particularly in eastern N.Y.; western N.Y. could be about a week later if this were a normal season, and the less said about that the better. Crop scouts and consultants have been using traps to monitor AM populations for a long time, but this tactic, useful as it is, nevertheless is not recommended in all cases. Some orchards have such high or such low AM populations that monitoring for them is a waste of time; that is, sprays are needed predictably every season in some blocks, and on a calendar basis; conversely, they are rarely needed at all in other blocks. However, most commercial N.Y. orchards have moderate or variable pressure from this pest, and monitoring to determine when damaging numbers of them are present can reduce the number of sprays used in the summer with no decrease in fruit quality.
Sticky yellow panels have been in use for over 30 years, and can be very helpful in determining when AM flies are present. These insects emerge from their hibernation sites in the soil from mid-June to early July in New York, and spend the first 7-10 days of their adult life feeding on substances such as aphid honeydew until they are sexually mature. Because honeydew is most likely to be found on foliage, and because the flies see the yellow panel as a "super leaf", they are naturally attracted to it during this early adult stage. A few of these panels hung in an orchard can serve as an early warning device for growers if there is a likely AM emergence site nearby.
Many flies pass this period outside of the orchard, however, and then begin searching for fruit only when they are ready to mate and lay eggs. That means that this advance warning doesn't always have a chance to take place -- the catch of a single (sexually mature) fly then indicates a spray is necessary immediately to adequately protect the fruit. This can translate into an undesirable risk if the traps are not being checked daily, something that is not always possible during a busy summer.
To regain this time advantage, researchers developed newer traps that have the form of a "super apple" -- large, round, deep red, and sometimes with the smell of a ripe apple -- in an attempt to catch that first AM fly in the orchard. Because this kind of trap is so much more efficient at detecting AM flies when they are still at relatively low levels in the orchard, the traps can usually be checked twice a week to allow a one- or two-day response period (before spraying) after a catch is recorded, without incurring any risk to the fruit. In fact, research done in Geneva over a number of years indicates that some of these traps work so well, it is possible to use a higher threshold than the old "one fly and spray" guidelines recommended for the panel traps. Specifically, it has been found that sphere-type traps baited with a lure that emits apple volatiles attract AM flies so efficiently that an insecticide cover spray is not required until a threshold of 5 flies per trap is reached.
The recommended practice is to hang three volatile-baited sphere traps in a 10- to 15-acre orchard, on the outside row facing the most probable direction of AM migration (south, or else towards woods or abandoned apple trees). Then, periodically check the traps to get a total number of flies caught; divide this by 3 to get the average catch per trap, and spray when the result is 5 or more. Be sure you know how to distinguish AM flies from others that will be collected by the inviting-looking sphere. There are good photos for identifying the adults on the Apple Maggot IPM Fact Sheet (No. 8). In home apple plantings, these traps can be used to "trap out" local populations of AM flies by attracting any adult female in the tree's vicinity to the sticky surface of the red sphere before it can lay eggs in the fruit. Research done in Massachusetts suggests that this strategy will protect the fruit if one trap is used for every 100-150 apples normally produced by the tree (i.e., a maximum of three to four traps per tree in most cases), a density that makes this strategy fairly impractical on the commercial level.
A variety of traps and lures are currently available from commercial suppliers; among them: permanent sphere traps made of wood or stiff plastic, disposable sphere traps made of flexible plastic, and sphere-plus-panel ("Ladd") traps. The disposable traps are cheaper than the others, of course, but only last one season. Ladd traps are very effective at catching flies, but are harder to keep clean, and performed no better than any other sphere trap in our field tests. Brush-on stickum is available to facilitate trap setup in the orchard. Apple volatile lures are available for use in combination with any of these traps. These tools are available from a number of orchard pest monitoring suppliers, among them:
Gempler's Inc., 100 Countryside Dr., PO Box 328, Belleville, WI 53508; 608-424-1544, Fax, 608-424-1555
Great Lakes IPM, 10220 Church Rd. NE, Vestaburg, MI 48891; 800-235-0285, Fax 989-268-5311
Harmony Farm Supply, 3244 Gravenstein Hwy, No. B, Sebastopol, CA 95472; 707-823-9125, Fax 707-823-1734
Ladd Research Industries Inc., 83 Holly Court, Williston, VT 05495; 800-451-3406, Fax 802-660-8859
Olson Products Inc., PO Box 1043, Medina, OH 44258; 330-723-3210, Fax 330-723-9977
Scenturion Inc., P.O. Box 585, Clinton, WA 98236; 360-341-3989, Fax 360-341-3242
By preparing now for the apple maggot season, you can simplify the decisions required to get your apples through the summer in good shape for harvest.
A number of new materials were evaluated during the 2001 season for the control of severe apple maggot populations. A western NY apple orchard that has been in organic production for several years was selected for use in this trial because high levels of apple maggot and internal Lepidoptera damage were observed in fruit harvested during the previous season. Sprays were applied dilute to runoff with a hand gun sprayer (450 psi) on either a weekly or bi-weekly basis depending on the material used; the exception was a Spintor-volatile bait mixture that was applied with a MeterJet spray gun connected to a CO2 backpack sprayer at 40 psi. All applications were started several days after the first flies were captured on monitoring traps in the orchard on 6 Jul and continued on 12 Jul, 19 Jul, 26 Jul, 1 Aug, 9 Aug. 18 Aug and 21 Aug. Treatments were replicated four times and included an untreated check on single 'Cortland' trees and were arranged in a RCB design. Treatments were separated by unsprayed buffer trees within each row. Red volatile-baited sphere traps were hung in each of the check treatments, as well as in one tree, two rows to the west of the test rows. Traps were checked on a weekly basis and cumulative counts were recorded throughout the season. Fruit was harvested on 29 Aug. Damage from AM as well as internal Lepidoptera was taken upon fruit inspection.
Guthion 50WP (1.5 lb. form/A), Actara 25WP (1.4 oz form/A), Calypso 4F (3.0 oz form/A) and Avaunt 30WG (5.8 oz form/A) were applied on a bi-weekly schedule. Surround WP (50 lbs. form/A), Aza-Direct EC (32.0 oz form/A), Spintor 2SC (7.5 oz form/A) and Spinosad Volatile Bait (32 ml form/tree) were applied each week throughout the season. The Spinosad Volatile Bait was applied with the metered sprayer in 8.0 ml aliquots. One aliquot was applied to each of the 4 directional quadrants of the outside of the tree canopy.
AM and internal Lepidoptera pressure in the test orchard was extremely high as indicated by the damage levels found in the untreated check plots (35.1 and 20.1%, respectively) and by high trap catches of flies throughout the season. The grower standard of Guthion gave excellent control of both pests with 0.4% AM and internal Lepidoptera damage. The weekly application of Surround also provided excellent control of AM damage (0.0%). The exact mode of action of this material against AM is not known. However, the coverage of kaolin reduces visual stimuli, and may affect the ability of the flies to recognize and orient to apples. Also, the buildup of clay on the apple may act as a deterrent to females attempting to oviposit. Surround was also quite effective in controlling damage from internal Lepidoptera (3.5%). The other organically approved material in this test, Aza-Direct, was not effective in reducing AM damage (42.0%), but did significantly reduce damage from internal Lepidoptera (6.9%). Avaunt, Actara, Spintor, and the Spintor bait all were relatively ineffective in preventing apple maggot damage (18-40%). However, Avaunt and Spintor were quite effective against internal Lepidoptera (2.9 and 1.1%, respectively). Actara also significantly reduced damage from internal Lepidoptera (6.9%), although it was not as effective as Avaunt and Spintor. Calypso was the only non-OP material that controlled both AM (2.5%) and internal Lepidoptera (2.0%), although it was not as effective against leps as the Guthion standard.
After a significant amount of back-and-forth negotiations between the NYS DEC and Syngenta, Actara 25WDG has finally been granted a FIFRA Section 24(c) Special Local Need label for use on pome fruit (apples and pears) in NY. Actara has shown efficacy and is labeled for the control of plum curculio, rosy apple and green aphids, tarnished plant bug, European apple sawfly, Comstock mealybug, and mullein plant bug. Although this has been a much-anticipated registration by the fruit industry in this state, the delay in this decision has effectively carried us past the recommended use timing of pink to petal fall, and the NY label carries the further restriction of one application per season, which serves to render the product's efficacy to essentially half of its optimum potential. Efforts are under way to address this label inadequacy, although no remedy should be expected this season. Actara has a 12-hr REI and a 35-day PHI.
This material is based upon work supported by Smith Lever funds from the Cooperative State Research, Education, and Extension Service, U.S. Department of Agriculture. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture.
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