Scaffolds Fruit
Journal, Cornell University NYSAES

Insects | Chemical News | Credits


Volume 6, No. 13			  		June 16, 1997


COMING EVENTS

                                                     43F       50F
Current DD accumulations (Geneva 1/1-6/16):         818	      448
                       (Highland 1/1-6/16):        1063       597

Coming Events:                              Ranges:
American plum borer 1st flight peak              360-962   134-601
Codling moth 1st flight peak                    547-1362   307-824
Obliquebanded leafroller 1st catch              686-1104   392-681
Black cherry fruit fly 1st catch                 686-985   392-636
European red mite summer egg hatch               773-938   442-582

PEST FOCUS
   Geneva: 1st Pandemis Leafroller trap catch (this usually precedes 
           1st OBLR catch by up to 4 days.)
 Highland: 1st Rose Leafhopper adult observed on apple 6/11.
           Spotted Tentiform Leafminer tissue feeders observed.

TRAP CATCHES (Number/trap/day)
Geneva:   
                                   6/2    6/5    6/9   6/12   6/16
Redbanded Leafroller               2.3    0.7    0.8    0.3      0
Spotted Tentiform Leafminer        131    177     67     80      8
Lesser Appleworm                  13.7    1.8    0.6    0.3    1.4
Oriental Fruit Moth (apple)        0.5    3.3    0.5    1.3    1.0
Oriental Fruit Moth (peach)          0      0      0    0.2    0.1
San Jose Scale                       0      0    9.5    2.5    0.1
Codling Moth                       3.7    6.0    5.4    2.3    6.0
American Plum Borer                1.3    1.2    1.4    3.7    2.4
Lesser Peachtree Borer             1.3*   0.5    3.9    5.8    3.4
Peachtree Borer                      -      0    1.1*   6.7    2.0
Pandemis Leafroller                  -      -      0      0    0.8*
Obliquebanded Leafroller             -      -      0      0      0

Highland (Dick Straub, Peter Jentsch):
                                  5/19   5/27    6/2    6/9   6/16
Redbanded Leafroller               3.2    0.4    0.4    0.1      0
Spotted Tentiform Leafminer       28.6    3.5    5.6    0.1    7.4
Oriental Fruit Moth                4.2    0.4    1.1    1.2    1.4
Lesser Appleworm                   0.3*   1.1    1.3    1.6    1.3
Codling Moth                       0.3*   1.6    1.6    1.7    1.6
Fruittree Leafroller                 -      -      0      0      0
Tufted Apple Budmoth                 -      -      0    2.9*   2.0
Obliquebanded Leafroller             -      -      0    0.2*   1.8
Sparganothis Fruitworm               -      -      0    0.1*     0

                                                       * = 1st catch


Insects




THE USUAL SUSPECTS

by Art Agnello and Harvey Reissig
Entomology, Geneva

We can take a hint, and last week's balmy temperatures were the apparent go-ahead for the official start of summer insect mode. First of all, as of today, 6/16, a total of 345 DD have accumulated in the Hudson Valley since the "1st adult catch" codling moth biofix; in Geneva, the value is 256. The recommended spray window to control 1st generation codling moth is 250-360 DD, so 1st brood larvae are approaching the end of the susceptible treatment window in the Hudson Valley. For those growers with severe CM pressure in blocks where apple maggot sprays are not generally applied during the summer, we will maintain DD readings and once again begin posting them when the next control window approaches (1260 DD from the biofix date).

For plum curculio, the situation is much the same in advanced and inland sites. Recalling that curc movement into orchards for oviposition should be about over by 340 DD (base 50°F) after petal fall, the accumulated value (for McIntosh) in Geneva is at 203. For other sites: Highland, 455; Appleton and other late sites, 146; Williamson and other early sites, 247. We're past the endpoint in the Hudson Valley, so at least in western N.Y., it would be prudent to make sure your blocks are protected through next week, and then we'll be done with this character for the season.

Agri-Mek probably has little more than this week to go for consideration as a treatment option (mainly in western N.Y.), for either European red mites in apples or pear psylla in pears. With scant rainfall this spring, the foliage is coming to the end of its most absorptive phase, so an application of this material possibly could be made in selected blocks, depending on leaf condition. However, delaying past this week would be pushing your luck on the utility and economics of such a decision.


OBLIQUEBANDED LEAFROLLER

Moths have been flying in the Hudson Valley since last week, but their appearance in western N.Y. is somewhat overdue. Deb Breth reports the first OBLR moth catch in Knowlesville (below Rt. 104 between Albion and Medina) late today, 6/16. I would expect that many areas will begin to see initial catches starting this week. First hatch is generally assumed to occur about 360 DD (base 43°F) after flight starts, and for Highland our value stands at 189 as of today. We have just received official word that New York's Section 18 application for the use of Confirm has been approved and it should be available in plenty of time for use against summer brood larvae (see article at end for more information).

SPOTTED TENTIFORM LEAFMINER

As reflected in the pheromone trap counts, the 1st brood spotted tentiform leafminer flight is subsiding in Geneva this week, and the 2nd brood should be starting any day. The 2nd flight has just begun in Highland. By the second or third week of July, this flight should peak and eggs will have hatched, at which time we recommend sampling leaves for the young (sap-feeding) mines of the second generation, to determine the need for a spray.


Sap feeding mine caused by early spotted tentiform leafminer instars on leaf underside

Sampling should be conducted when the first of the mines reach the tissue-feeding stage. This is the time when most of the population is in the sap-feeding stage, and it usually occurs about 500-700 degree-days (base 43°F) after the start of the second moth flight. The larvae can be found easily, but at that stage they have not yet caused much damage to the leaf. You may wish to make a note of the 2nd flight's start date in your region, or use the Geneva date for accumulating degree-days in your locality if you don't happen to document this event in local traps.

EUROPEAN CORN BORER

Infestations of ECB in orchards are not very common, but when they do appear, as has been the case occasionally in N.Y., they can be quite serious. Considerable feeding damage will be noted in late June in terminals of newly planted apple and cherry trees, and early fruit feeding on apple is often evident by this time of the year. Infestations of this pest on apple are spotty and unpredictable; incidence in an orchard one year has no correlation with its likelihood to occur the next season. The ECB occurs as two separate strains in N.Y. The univoltine "Z" race (peak flight in mid-July), can be found almost continuously from Buffalo to Albany. The bivoltine "Z" race (peak flights in mid-June and mid-August) is present from Buffalo to about Rochester, and the bivoltine "E" race (also with peak flights in mid-June and mid-August) picks up from Rochester to Syracuse or thereabouts.

In the Hudson Valley, all 3 races are probably present. What this means to most apple growers is that most places have flights in the middle of June, July AND August. Susceptible orchards (young nonbearing, and others in proximity to sweet corn populations) must therefore be protected almost continuously during the summer, using something that's relatively long-lasting.

Damage to newly planted, non-bearing trees is caused by larval tunneling in the current season's growth. Browning of terminal leaves is a good indication of corn borer larval presence. The feeding will kill the terminal and disfigure the tree. Nonbearing, newly planted orchards normally do not receive the intensive cover spray program bearing orchards do; therefore, corn borer infestations can build up more easily in young orchards. Corn borer attack on young trees can occur from June through August. Damage to the fruit usually shows up in late summer, when the August flight of the bivoltine strain is active.

Bearing orchards are more likely to show some early corn borer damage on the fruit if growers relax their spray program in June or early July. However, most fruit feeding occurs between the last cover spray (mid-August) and harvest. Weedy sites provide plenty of alternative hosts for this insect, especially those containing broadleaf dock, ragweed, pigweed, smartweed, and barnyard grass. Penncap-M, Lannate, Lorsban and Asana can give very good control of ECB larvae, provided application is made before the caterpillars become concealed in the plant tissue. Potential problem plantings should be checked periodically in August for shoot infestations of this caterpillar, which is cream colored with a dark head.

SAN JOSE SCALE

If any of your apple blocks yielded fruit last fall with the characteristic red-purple spots indicative of SJS feeding, now is the time to place a few double-sided tape bands around the tree limbs and start checking them for crawler emergence.


Red and purple discolorations marking San Jose scale feeding sites on fruit

This normally coincides with a timing of about 310 DD (base 50°F) since the first adult appearance; in Geneva, this occurred on May 30, so our current tally is at 235. A spray of an effective material (such as Lorsban 50WP, Provado, Guthion, Imidan or Penncap-M) is recommended timed for the first and peak crawler activity, which are usually 7-10 days apart. We don't have data from the Hudson Valley, but figure at least one week earlier for sites in eastern N.Y. Keep in mind that these sprays may also help in the control of OBLR, apple maggot, and codling moth.

GREEN APHIDS

We have already begun to see some problem populations of green aphids in western N.Y. apple blocks, so it looks like this may be one of those years to keep a vigilant eye open. Although small numbers of these insects - primarily Apple Aphid, Aphis pomi, and Spirea Aphid, Aphis spiraecola - may be present on trees early in the season, populations generally start to increase in mid- to late June. Large numbers of both may build up on growing terminals on apple trees during summer. Both species are apparently common during the summer in N.Y. orchards, although no extensive surveys have been done to compare their relative abundance in different production areas throughout the season.

Nymphs and adults of both species suck sap from growing terminals and water sprouts. High populations cause leaves to curl and may stunt shoot growth on young trees. Aphids excrete large amounts of honeydew, which collects on fruit and foliage. Sooty mold fungi that develop on honeydew cause the fruit to turn black, reducing its quality. Aphids should be sampled several times throughout the season starting in mid-June. Inspect 10 rapidly growing terminals from each of 5 trees throughout the orchard. Record the percentage of infested terminals. No formal studies have been done to develop an economic threshold for aphids in N.Y. orchards; however, treatment is currently recommended if 30% of the terminals are infested with either species of aphid.


Aphidoletes aphidimyza, a cecidomyiid whose larvae prey on aphids


Syrphid (hover fly) maggot preying on an aphid

The larvae of syrphid and cecidomyiid flies prey on aphids throughout the growing season. These predators complete about three generations during the summer. Most insecticides are somewhat toxic to these two predators, and they usually cannot build up sufficient numbers to control aphids adequately in regularly sprayed orchards. Both aphids are resistant to most organophosphates, but materials in other chemical classes control these pests effectively. Examples include Provado, Thiodan, Lorsban, Cygon, Lannate and Vydate (given roughly in order of decreasing effectiveness and increasing detrimental effect on predator mites).


Chemical News

SECTION 18 "CONFIRMED"

On Friday, 6/13 (interestingly the same day as last year), the EPA approved New York's Section 18 application for the use of tebufenozide (Confirm) to control OBLR in apples. Rohm and Haas informs us that product should be moving to the distributors beginning tomorrow, 6/17, so that it should be in the hands of growers wishing to use it in good time for use against the summer generation. Following are the specific conditions and restrictions of this exemption:

A further note on use recommendations: The label recommends the first spray be applied at first egg hatch (360-400 DD, base 43°F after the first sustained moth catch). A few issues back, we advised a modification of this timing to basically a first-catch-and-spray recommendation. We felt that this would be a bit more conservative approach that might forestall some of the terminal feeding we saw last season. Rohm and Haas does not feel there is enough data to strongly support this use timing, but there will be further field trials this season to re-examine the efficacy of an earlier first spray. The label calls for a second application 10-14 days later, and a third after another 10-14 days in cases of high population pressure or sustained moth flight. Unlike last year, the use of Latron B-1956 is mandated only "if a spray adjuvant is required".


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
Department of Entomology, NYSAES
Geneva, NY 14456-0462
Phone: 315-787-2341
FAX:315-787-2326
E-mail: ama4@cornell.edu


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Photographs courtesy of New York State Integrated Pest Management Program