SCAFFOLDS Fruit Journal, Geneva, NY Volume 4 Update on Pest Management and Crop Development June 12, 1995
43F 50F
Current DD accumulations (Geneva 1/1-6/12): 911 578
(Highland 3/1-6/12): 1000 577
Coming Events: Ranges:
American plum borer 1st flight peak 535-962 273-601
Codling moth 1st flight peak 547-1326 307-824
Spotted tentiform leafminer 2nd flight begins 795-1379 449-880
Dogwood borer 1st catch 798-1182 456-718
Obliquebanded leafroller 1st flight peak 869-1482 506-964
San Jose scale 1st gen crawlers present 987-1247 569-784
TRAP CATCHES (Number/trap/day)
Geneva:
5/30 6/1 6/5 6/8 6/12
Redbanded Leafroller 0.2 1.0 0 0 -
Spotted Tentiform Leafminer 63 42 29 25 7.1
Oriental Fruit Moth (apple) 2.1 3.5 0.8 0.8 0.5
Lesser Appleworm 6.9 6.3 1.9 1.5 0.3
Codling Moth 1.9 21.8 5.9 11.8 6.5
San Jose Scale 0 3.5 2.3 0.2 0
American Plum Borer (cherry) 0.8 4.5 2.4 3.0 0.3
Lesser Peachtree Borer (peach) 1.1 2.5 2.9 4.3 6.0
Lesser Peachtree Borer (cherry) 0.6* 3.3 3.0 6.0 3.4
Peachtree Borer 0 1.3* 4.0 8.8 4.4
Obliquebanded Leafroller 0 0 0 0 0.1*
Highland (Dick Straub, Peter Jentsch)
5/15 5/22 5/29 6/5 6/12
Redbanded Leafroller 0.7 0.6 <0.1 0 0
Spotted Tentiform Leafminer 8.2 2.6 0.5 0.9 2.9
Oriental Fruit Moth 1.0 0 0.5 1.1 1.4
Fruittree Leafroller 0.2 0 0 0 0.3
Codling Moth <0.1* 1.9 4.6 4.9 3.5
Lesser Appleworm - 1.0* <0.1 0 0
Sparganothis Fruitworm - 0 0 0.1* 1.1
Tufted Apple Budmoth - <0.1* 1.1 1.4 1.0
Variegated Leafroller 0 0 0 0 0.5*
Obliquebanded Leafroller 0 0 0 0 0.8*
* = 1st catch
PEST FOCUS
Wayne Co.: European Red Mite summer eggs hatching
Geneva: Obliquebanded Leafroller 1st catch
Highland: Rose Leafhopper migration to apple complete, 6/9;
Obliquebanded Leafroller 1st catch, 6/12;
Spotted Tentiform Leafminer 2nd flight beginning;
Potato Leafhopper feeding damage observed on apple
This insect, a native of this continent and widely distributed, feeds on a large range of plants, particularly members of the rose family. Outbreaks of OBLR can cause severe damage to the fruit of apple, peach, pear, and blueberry, and last year it was even documented in loads of tart cherries going through the packinghouses in western N.Y. Depending on the locality, there can be 1-2 generations a year, but these are biologically ill-timed for convenient control measures in N.Y. orchards. Prebloom sprays at pink bud are not completely effective, because the insects are usually concealed in rolled leaf terminals or bud clusters, which makes adequate spray contact difficult. Also, not all of the population is fully active at this time, so any applications made then will simply not contact all the insects that will eventually emerge by bloom (and would need to be controlled at petal fall anyway.) During the next normal spray at petal fall, the larvae are extremely large and not susceptible to most commonly used organophosphate insecticides, and so must be treated with the "unconventional" OP, Lorsban, or else a B.t. product, a carbamate or synthetic pyrethroid. At the time of the next (1st summer generation) larval emergence in mid- to late June, growers were formerly in the habit of postponing a specific spray until the apple maggot treatments in July, but by this time the OBLR larvae are again quite large, and still not susceptible to OP's. The difficulty of obtaining thorough coverage through the canopy's thick foliage only adds to the problem; therefore, a preferred approach is to make applications somewhat earlier, timed with the occurrence of the smaller larvae. Finally, a second flight occurs in early August, and the 2nd summer generation larvae, which in former days were content to simply go into hibernation without feeding, now seem to be causing more trouble by feeding minimally on the fruit just before it's harvested (and put into CA).
The most serious injury caused by the overwintered generation is damage to the developing fruit before and shortly after petal fall. Many of these damaged fruits drop prematurely, but a small percentage do remain on the tree, developing deep corky scars and indentations at maturity. The two summer broods feed on the surface of developing fruit in July and August, causing injury that is virtually identical to that of several other leafroller species. Fruit damage caused by these broods is usually more serious than the feeding by larvae of the overwintered generation, because more of this later-injured fruit tends to remain on the tree until harvest. Also, biological studies have shown that populations of the summer generation of OBLR are generally higher in commercial orchards than are those of the overwintering larvae.
To control the summer larvae, most growers have traditionally applied a spray 10-12 days after the first adult catch in their area. This timing generally coincides with peak egg hatch, and does in fact kill some larvae, but usually a second spray is necessary 10-14 days later. Another approach is to time a single application in mid- to late July, after most lst-generation larvae have emerged, but before they begin to severely damage fruit, which occurs primarily during the fifth and sixth instars. This strategy used to give control as effective as the 2-spray option, especially if timed to reduce larval densities as much as possible -- at 600 degree-days (43 F base) after the catch of the first adult, which coincides with a cumulative egg hatch of approximately 40%. However, our OBLR populations are getting tougher to control this way, and this timing is probably better regarded as the preferred time for a first application, with a repeat spray (or 2) during the next 2-3 weeks.
Although no research has been done to determine optimum timing of sprays against second brood larvae, it is obvious that sprays applied in late July are not effective. We presume that sampling and spray measures, if necessary, would need to take place sometime around the third week in August. Currently, we are not recommending control of this second summer generation of OBLR for several reasons. Research trials have shown that 2nd brood damage is not a serious problem in orchards where the 1st summer brood was adequately controlled. Also, spraying in late August and early September can cause potential problems with harvest intervals and it is inconvenient for growers to apply sprays in late summer because they are preparing to harvest apples by then. Obviously, however, this situation can change, depending on the severity of the problems as this season wears on, so we may just have to see how everything looks in a couple of months.
As of today, it's still too early to predict when the best sampling and spraying period will be, other than to rely on historical records, which indicate sometime during the first week of July. At the designated time, use the OBLR sampling chart in the 1995 Recommends with a 3% infestation threshold for fresh fruit (pp. 85-86 or 89), or the 10% threshold for processing fruit (pp. 85-86 or 94). If a below-threshold decision is reached, wait for 100 additional degree-days (3-5 days) and repeat the sample. A second below-threshold result indicates a population low enough to ignore. As always, if spraying is necessary, good coverage is more than half the battle.
It is not too early to expect the first appearance of these adults (flies) in abandoned orchards by next week, particularly in Eastern N.Y. (western N.Y. should be a couple of weeks from now if all goes normally). Crop scouts and consultants have been using traps to monitor apple maggot (AM) populations for a long time. Some orchards have such high AM populations that monitoring for them is a waste of time (that is, sprays are needed on a calendar basis). But most commercial N.Y. orchards have moderate or erratic 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 20 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 an 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 this advance warning doesn't always have a chance to take place -- the catch of a single (sexually mature) fly then means that 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, which is often the case.
To regain this time advantage, researchers have developed newer traps that have the form of a "super apple" -- large, round, deep red, and sometimes even 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 was found that sphere-type traps baited with a lure that emits apple volatiles attract AM flies so efficiently, an insecticide cover spray is not required until a threshold of five 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 toward woods or abandoned apple trees). Then, periodically check the traps to get a total number of flies caught; divide this by 3, and spray when the result is 5 or more. 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 from 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 variety of traps and lures are currently available from commercial suppliers; among them: permanent sphere traps made of wood (from "Pest Management Supply") or stiff plastic (from "Great Lakes IPM" or "Pest Management Supply"), disposable sphere traps made of flexible plastic (from "Great Lakes IPM", "Olson" or "Pest Management Supply"),
and sphere-plus-panel traps (from "Ladd"). 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 field tests. Brush-on stickum is available to facilitate trap setup in the orchard. Apple volatile lures are available from Ladd Industries (septa) and Consep (membranes). Addresses of these suppliers follow:
Consep, Inc., 213 S.W. Columbia St., Bend, OR 97702-1013, 1-800-367-8727
Great Lakes IPM, 10220 Church Road NE, Vestaburg, MI 48891, 517-268-5693
Ladd Research Industries, Inc., P.O. Box 1005, Burlington, VT 05402, 802-658-4961
Olson Products, Inc., P.O. Box 1043, Medina, OH 44258, 216-723-3210
Pest Management Supply Co., 311 River Dr., Hadley, MA 01035, 1-800-272-7672
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.
Scaffolds is published weekly from March to September by Cornell University -- NYS Agricultural Experiment Station (Geneva), and Ithaca -- with the assistance of Cornell Cooperative Extension. New York field reports welcomed. Send submissions by 3 p.m. Monday to:
Scaffolds Fruit Journal
Editors: A. Agnello, D. Kain
Dept. of Entomology, NYSAES
Geneva, NY 14456-0462
Phone: 315-787-2341
FAX:315-787-2326
E-mail: art_agnello@cornell.edu