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SCAFFOLDS Fruit Journal, Geneva, NY                  Volume 4
Update on Pest Management and Crop Development       August 7, 1995

COMING EVENTS

                                                     43F       50F
Current DD accumulations (Geneva 1/1-8/7):          2514      1818
                       (Highland 3/1-8/7):          2718      2123

Coming Events:                              Ranges:
Comstock mealybug 2nd gen crawlers emerging    2106-2768   1447-1924
STLM 3rd flight begins                         2215-2783   1567-1963
Peachtree borer flight subsides                2230-3255   1497-2309
Comstock mealybug 2nd gen crawlers peak        2350-2649   1642-1736
San Jose scale 2nd flight subsides             2494-3191   1662-2302
Oriental fruit moth 3rd flight peak            2549-3267   1845-2326
Redbanded leafroller 3rd flight begins         2603-3113   1739-2196
Obliquebanded leafroller 2nd flight peak       2634-3267   1789-2228
Apple maggot flight subsides                   2775-3174   1958-2169
Lesser peachtree borer flight subsides         2782-3328   1796-2359
Codling moth 2nd flight subsides               2782-3624   1796-2582
American plum borer 2nd flight subsides        3005-3587   2154-2497

TRAP CATCHES (Number/trap/day)
Geneva:   
                                  7/24   7/27   7/31    8/3    8/7
Redbanded Leafroller               0.2      0      0    0.3    0.4
Spotted Tentiform Leafminer        161     82     79     35     24
Oriental Fruit Moth (apple)        0.5    1.0    2.3    7.3    6.5
Lesser Appleworm                   0.7    0.3    0.9    0.3    0.8
Codling Moth                       7.7    6.2    5.4    7.5    7.5
San Jose Scale                     5.8   13.8    0.9    2.3    5.4
American Plum Borer (cherry)       3.1    1.5    3.5    1.7    3.1
Lesser Peachtree Borer (peach)     3.3    4.0    2.8    8.0    4.0
Lesser Peachtree Borer (cherry)    1.2    1.8    2.3    3.3    2.3
Peachtree Borer                    1.5    1.8    3.3    2.0    1.0
Obliquebanded Leafroller             0      0    0.1*   0.2      0
Apple Maggot                       1.4    1.8    1.1    0.1    0.6

Highland (Dick Straub, Peter Jentsch)
                                  7/10   7/17   7/24   7/31    8/7
Redbanded Leafroller               1.6    1.6    0.6      0      0
Spotted Tentiform Leafminer       24.9   35.9   20.8   20.3   42.8
Oriental Fruit Moth                1.4    0.9    1.1    1.7    1.6
Fruittree Leafroller                 0    0.1      0      0      0
Codling Moth                       0.4    0.6    1.1    1.1    0.6
Lesser Appleworm                     0      0    0.6    1.6    0.7
Sparganothis Fruitworm             1.1    0.6      0    0.3    0.2
Tufted Apple Budmoth               0.1    0.4      0      0    0.6
Variegated Leafroller                0    0.1    0.1      0    1.1
Obliquebanded Leafroller           0.9    0.1    0.2    0.3    0.1
Apple Maggot                         0      0    0.2*   0.1    0.3

                                                        * = 1st catch

PEST FOCUS
Geneva:  
   Obliquebanded Leafroller 2nd flight began 7/31
   White Apple Leafhopper 2nd brood nymphs observed 8/2
   Oriental Fruit Moth 3rd flight began 8/3
Highland: 
   Rose Leafhopper 3rd generation nymphs observed on apple
   Apple Maggot numbers high
   Obliquebanded Leafroller 2nd brood moths flying south of Highland
   Pear Psylla egg laying increasing on terminals.
     

HUDSON VALLEY LEAFROLLERS

By:(Harvey Reissig, Entomology, Geneva

RIVER RATS

Two species of leafrollers, Variegated Leafroller (Platynota flavedana) and Sparganothis Fruitworm (Sparganothis sulfureana), have occasionally damaged fruit in the Hudson Valley, and have apparently become serious problems in some orchards during the last several years because they have developed resistance to organophosphate insecticides. The variegated leafroller is found from Kingston (in Ulster County) south to the Rockland County line, in a narrow band bordered by the Hudson River on the east and the Marlboro mountain range on the west. The Sparganothis fruitworm is found predominantly in Columbia County on the east side of the Hudson River and north to Albany. It is also prevalent in western New York, but is currently not a pest in commercial apple orchards there.

Both species overwinter as third-instar larvae in the orchard ground cover and begin feeding in early spring on weeds and plants under trees. Larvae pupate in the ground cover, and adult moths emerge shortly after petal fall. Adults lay eggs on apple leaves during June; eggs hatch and larvae are found from late June to July. A second flight begins in late July. These larvae may feed on fruit in late summer until they reach the third instar, at which time they spin down into the ground cover to overwinter.

Larvae of the summer generation may use dead leaves to build a feeding shelter beneath the apple. Most of the larvae from the overwintering generation probably feed primarily on leaves in the late summer, but they may occasionally damage fruit. This late-season damage is less extensive than that from the summer generation of larvae but usually consists of tiny pinholes on the fruit surface.

Males of both species can be monitored in pheromone traps, but numbers caught in the traps cannot be related to potential fruit damage in the orchard. Because these species are a serious problem only in certain orchards, the most reliable way to determine if a specific block requires treatment would be to monitor larval populations during June and July. No formal techniques have been developed to sample these larvae. Likewise, no formal studies have been done to estimate an economic threshold level for initiating summer treatments. It would not usually be considered economically feasible to apply special treatments to control these leafrollers unless at least 35% fruit damage was anticipated. This threshold represents a larger value than the cost of the spray, but leafroller sprays can never completely eliminate damage. Special leafroller sprays may also harm mites and beneficials and could increase the cost of mite management.

Several parasites attack leafroller larvae, keeping them to relatively low levels in unsprayed orchards. Because these parasites are susceptible to insecticides, they are not effective in controlling leafrollers in sprayed commercial orchards. Leafrollers in the Hudson Valley are resistant to the commonly used organophosphate insecticides. Other chemicals available for use are the same as those commonly used to control OBLR (Lorsban, Lannate, B.t., Asana, Penncap-M). Larger larvae are more difficult to kill with these materials, so sprays should be targeted against small larvae whenever possible.

EUROPEAN CORN BORER

By:(Art Agnello, Entomology, Geneva

NOW and THEN

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 unpredicatable; incidence in an orchard one year has no correlation with its likelihood to occur the next season. The ECB occurs in N.Y. as a single-brood (univoltine "Z race") and a double-brood (bivoltine "E & Z race") strain. Moths of the bivoltine strain peak in mid-June and in mid-August; the univoltine moth flight peaks in mid-July. In many areas of the state, the two strains occur as mixed populations.

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, and Lorsban 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.

LAST MITE ROUNDUP?

By:(Art Agnello, Entomology, Geneva

THE END IS IN SIGHT

Without question, controlling European red mites has been a constant struggle all season, as populations have had the benefit of nearly ideal weather conditions through June and July. A good amount of bronzing damage has been done, and predator mites (who don't do as well as red mites in hot weather) have only recently begun showing up in countable numbers. The good news is that many of the worst infestations we were tracking seem to be on the decline, whether from diminished leaf quality or simply because the populations have blown their biological budget and it's time for them to slow down. However, there are some orchards where the numbers were not so bad earlier and populations could still increase to punishing levels before calling it quits, and these should be monitored sometime before the middle of the month to determine the need for a final miticide application. The recommended threshold at this time is and average of 7.5 motiles per (intermediate-age) leaf, and a presence/absence sampling chart can be found on p. 93 of the Tree-Fruit Recommendations, or in a Table on p. 84. We don't consider treatment for ERM to be necessary after August 15.


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

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