Upcoming Events | Trap Catches | Pest Focus | Insects | General Info

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Upcoming Events | Trap Catches | Pest Focus | Insects | General Info

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Upcoming Events | Trap Catches | Pest Focus | Insects | General Info

Highland: Obliquebanded Leafroller 1st catch today, 6/4.          

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Upcoming Events | Trap Catches | Pest Focus | Insects | General Info

Geneva Predictions:
Roundheaded Appletree Borer
RAB adult emergence begins: May 27; Peak emergence: June 7.
RAB egglaying begins: June 2. Peak egglaying period roughly: June 22 to July 8.

Codling Moth
Codling moth development as of June 4: 1st generation adult emergence at 54% and 1st generation egg hatch at 4%.
1st generation 3% CM egg hatch: June 3 (= target date for first spray where multiple sprays needed to control 1st generation CM).
1st generation 20% CM egg hatch: June 11 (= target date where one spray needed to control 1st generation codling moth).

Obliquebanded Leafroller
1st generation OBLR flight, first trap catch expected: June 8.
Where waiting to sample late instar OBLR larvae is not an option (= where OBLR is known to be a problem, and will be managed with insecticide against young larvae):
Early egg hatch and optimum date for initial application of B.t., Intrepid, SpinTor or other insecticide with comparable efficacy against OBLR (with follow-up applications as needed): June 24.

Oriental Fruit Moth
2nd generation flight begins around: June 28.

San Jose Scale
1st generation crawlers appear: June 16.

Spotted Tentiform Leafminer
2nd flight begins around: June 13.

Insect model degree day accumulations:

Oriental Fruit Moth (Apples - targeted spray application at 55-60% egg hatch, predicted at 350-375 DD base 45°F after biofix):

Codling Moth (targeted spray application at newly hatching larvae, predicted at 250-360 DD base 50°F after biofix):

Plum Curculio (spray coverage required until 308 DD base 50°F after biofix; i.e., McIntosh petal fall):

[NOTE: Consult our mini expert system for arthropod pest management, the
Apple Pest Degree Day Calculator:
http://www.nysaes.cornell.edu/ipm/specware/newa/appledd.php
Find accumulated degree days between dates with the
Degree Day Calculator:
http://www.nysaes.cornell.edu/ipm/specware/newa/

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   Potato leafhopper (PLH) does not overwinter in the northeast but instead migrates on thermals (warm air masses) from the south.  It is generally a more serious problem in the Hudson Valley than in western N.Y. or the Champlain Valley; however, weather fronts such as the recent remnants of tropical storm Barry provide ample opportunity for most of the region to share the wealth, so it doesn't hurt to tour observantly through a few orchards now.  Because PLH come in constantly during the season, there are no distinct broods or generations and the pest may be present continuously in orchards from June through harvest.

Potato leafhopper damage

   PLH feeds on tender young terminal leaves.  Initially, injured leaves turn yellow around the edges, then become chlorotic and deformed (cupping upward) and later turn brown or scorched. 

Damage is caused by a toxin injected by PLH while feeding.  PLH also occasionally causes symptoms similar to the effects of growth regulators, such as excessive branching preceding or beyond the point of extensive feeding.  PLH damage is often mistaken for injury caused by herbicides, nutrient deficiency, or over-fertilization.  PLH injury may not be serious on mature trees but can severely stunt the growth of young trees.

Potato leafhopper adult and nymph

   Nymphs and adults should be counted on 50–100 randomly selected terminal leaves in an orchard.  Older trees should be sampled approximately every three weeks during the summer.  Young trees should be sampled weekly through July.  PLH nymphs are often described as moving sideways like crabs, whereas WALH generally move forward and back.  No formal studies have been conducted in N.Y. to determine the economic injury level for PLH on apples, so we suggest a tentative threshold of an average of one PLH (nymph or adult) per leaf.  Little is known about the natural enemies of PLH, but it is assumed that they cannot effectively prevent damage by this pest in commercial New York orchards. 

   Damage by this migratory pest is usually worse when it shows up early.  PLH can cause significant damage to newly planted trees that are not yet established.  When PLH, white apple leafhopper (WALH), rose leafhopper (RLH) and aphids are present, control measures are often warranted. 

   Field trials were conducted during 2000 in the Hudson Valley to evaluate reduced rates of Provado against all three species of leafhoppers. Provado was applied in combinations at a full rate (2 oz/100 gal) and a quarter rate (0.5 oz/100 gal), at varying intervals (3rd–5th cover). Nymphs of PLH, WALH, and RLH were sampled and leaf damage by PLH was monitored.

Performance of Reduced Rates of Provado, HVL - 2000

   Because of Provado's translaminar activity, all rates and schedules produced excellent control of WALH/RLH nymphs (however, reduced rates will not control leafminer).  Against PLH nymphs, the number of applications was shown to be more important than rate; i.e., better protection of new foliage.  Considering the percentage of leaves with PLH damage, the number of applications again appeared to be more important than application rate.

   Although data on aphids were not taken, we know that Provado is an excellent aphicide, and the same principle would hold as for PLH — maintaining coverage of new growth is more important than rate.  Moreover, reduced rates are likely to increase the survival of cecidomyiid and syrphid predators that are common and effective biological control agents.

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Upcoming Events | Trap Catches | Pest Focus | Insects | General Info

    A workshop on "Introduction to Growing Tree Fruit" will be given by Cornell specialists Ian Merwin and Greg Peck, who will discuss topics ranging from site selection and planting, to fertilization and pest control, in an introduction to tree fruit cultivation.  The instruction will be geared towards serious home gardeners and people interested in starting a small scale commercial orchard. Emphasis will be on sustainable production practices.

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.

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
P.O. Box 462
Geneva, NY 14456-0462
Phone: 315-787-2341 FAX: 315-787-2326
E-mail: ama4@cornell.edu

Online at <http://www.nysaes.cornell.edu/ent/scaffolds/>