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Insects | Credits

Volume 7, No. 20                                                 August 3, 1998


                                                     43°F      50°F
Current DD accumulations (Geneva 1/1-8/3):          2518      1705
                    (Geneva 1997 1/1-8/3):          2099      1394
                (Geneva "Normal" 1/1-8/3):          2228      1605
                       (Highland 1/1-8/3):          2835      1947

Coming Events:                              Ranges:
Apple maggot flight peak                        2033-2688  1387-1804
Obliquebanded leafroller 2nd flight peaks       2634-3267  1789-2231
Oriental fruit moth 3rd flight begins           2172-2956  1448-2013
Peachtree borer flight subsides                 2230-3255  1497-2309
Redbanded leafroller 3rd flight begins          2389-3113  1722-2209
San Jose scale 2nd flight subsides              2494-3257  1662-2302
Spotted tentiform leafminer 3rd flight begins   2215-2783  1537-2123

TRAP CATCHES (Number/trap/day)
                                  7/17   7/20   7/27   7/30    8/3
Spotted Tentiform Leafminer         51     13    9.7    807   12.1
Redbanded Leafroller               1.3    0.5    1.0    1.2    0.1
Oriental Fruit Moth (apple)        0.6    1.0    0.6    2.7    1.3
Lesser Appleworm                   0.5    0.3    0.9    1.5    1.1
Codling Moth                       2.6    5.0    2.9    2.8    0.3
San Jose Scale                     2.0    4.8    9.0   37.3    1.6
American Plum Borer                1.4    1.7    2.5    2.5    0.9
Lesser Peachtree Borer             0.5    0.8    0.2    0.7    0.3
Peachtree Borer                    0.9    1.0    0.2      0    0.3
Obliquebanded Leafroller             0      0    0.1*     0      0
Apple Maggot                       0.1      0      0    0.3      0

Highland (Dick Straub, Peter Jentsch):
                                   7/7   7/13   7/20   7/27    8/3
Spotted Tentiform Leafminer       43.0   13.6   26.9   45.1   25.9
Redbanded Leafroller               2.4    1.0    1.7    0.4      0
Oriental Fruit Moth                  0    0.2    0.1    0.6    0.4
Lesser Appleworm                   0.3    0.1    0.4    0.6    0.4
Codling Moth                       0.4    0.5    2.3    3.4    8.3
Obliquebanded Leafroller           0.1    0.1      0    0.1    0.1
Variegated Leafroller              0.6    0.1      0    0.6    0.7
Tufted apple budmoth               3.6    1.9    0.3      0    0.1
Fruittree Leafroller                 0      0      0      0      0
Sparganothis Fruitworm             0.8      0      0    0.1    0.4
Apple Maggot                       0.1   0.14    0.2      0   0.09

                                                      * = 1st catch



by Art Agnello
Entomology, Geneva

Before the crush of harvest activities closes in on us, now is a good time to take an almost-last look at the insect and mite situation in your orchards, to help ensure that the summer doesn't end with an unexpected sting when you thought everything was in good shape. Various weather irregularities always stir up potential trouble-makers, so you might make an informal accounting of what's going on with some of the following players:

Apple Maggot
We had been under the impression that catches were as light around the region as they seem to be in Geneva, but several fieldmen have reported very healthy catches in some localized spots, and the first half of August is historically the time of peak flight. Moreover, a few sudden showers can come through to soften the soil and allow more of the population to emerge. Be diligent in checking any traps you have out, and get sprays on susceptible varieties if you're catching sufficient numbers of flies throughout this month.

Apple maggot adult

Spotted Tentiform Leafminer
We're past the prime control window for the 2nd flight, but trees with more than 2 tissue-feeding mines per leaf might have plenty of time and good weather to be susceptible to a 3rd brood attack. Make a note of which blocks fall into this category now, and we'll be advising when the 3rd flight of this moth starts up. This usually takes place about August 8 or so, and although we've been ahead of schedule all season, there's apparently been some cooling off during the past weeks, and we may be approaching a more normal timing for some of these events. This could be a year when certain orchards will benefit from an assessment and treatment against the season's last population of this pest.

Spotted tentiform leafminer larva, "tissue feeding" (later instar) stage

European Red Mite
This has been a strange year for mites. The early summer heat generated healthy ERM outbreaks in blocks that weren't adequately protected, and some bronzed trees were seen by late June. Then, a lot of populations seemed to subside (or else get rained off), and things seem fairly quiet right now. However, in view of the moisture stress evident in many orchards, a careful foliar inspection should be conducted now if you haven't had one in the past 7-10 days, at least in your problem blocks, to be sure a rescue treatment of some sort isn't needed where populations surpass this month's 7.5/leaf threshold. Pyramite is available, among the regular standbys, so there's no excuse not to avail yourself of a remedy where needed.

See mite sampling chart.

European Corn Borer
To repeat some words from an earlier issue, 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.

Eggs of both clearwing species are still able to hatch and get into your stone fruit trees. American plum borer moths are at their 2nd generation flight peak and are also laying eggs. Therefore, it's not too late to treat orchards that are on a seasonal control program of trunk sprays: cherries - Asana, Lorsban, Ambush, or Pounce; peaches - add Penncap-M and Thiodan to the above list (do not spray fruit).

Peachtree borer adult female

Some growers are fairly satisfied with the program they used to take care of the 1st summer brood of OBLR this year, and some are not sure there's anything that can do the job properly (a possibility we've considered ourselves). However, I've been seeing enough fruit damage to indicate that the 2nd summer brood larvae could easily become a real problem in some orchards this year, and early enough that PHI's might not even be an issue for some materials. The second flight started a good week ahead of schedule in Geneva, and new larvae could start showing up in favored varieties (Cortland, Idared, even Delicious) soon enough to consider nearly any option on the shelf. This assumes treatment of the small caterpillars, which might start hatching out as early as next week. Add this one to the list of trouble-makers to check on as you inspect your trees in the next 7-10 days.

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

NOTE: Every effort has been made to provide correct, complete and up-to-date pesticide recommendations. Nevertheless, changes in pesticide regulations occur constantly, and human errors are possible. These recommendations are not a substitute for pesticide labelling. Please read the label before applying any pesticide.

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Photographs courtesy of New York State Integrated Pest Management Program