Insects| Chemical News | Credits
Volume 6, No. 19 July 28, 1997
43F 50F Current DD accumulations (Geneva 1/1-7/28): 1934 1271 (Highland 1/1-7/28): 2296 1537 Coming Events: Ranges: Peachtree borer flight peaks 864-2241 506-1494 American plum borer 2nd flight peaks 1648-2612 1037-1840 STLM 2nd flight subsides 1773-2514 1148-1818 Oriental fruit moth 2nd flight subsides 1806-2783 1164-1963 Apple maggot flight peaks 2033-2688 1387-1804 San Jose scale 2nd flight peaks 2136-2591 1479-1874 PEST FOCUS Highland: Spotted Tentiform Leafminer tissue feeders present; numbers high. Codling moth 1st flight began 5/19. DD (50 F) since then = 1300. Geneva: Spotted Tentiform Leafminer 2nd flight began 6/23; DD (43 F) = 958. American Plum Borer 2nd flight began 7/25. San Jose Scale 2nd flight began 7/28. Codling moth 1st flight began 5/19. DD (50 F) since then = 1079. TRAP CATCHES (Number/trap/day) Geneva: 7/14 7/17 7/21 7/24 7/28 Redbanded Leafroller 5.6 4.0 3.0 1.1 0.7 Spotted Tentiform Leafminer 470 732 976 800 665 Lesser Appleworm 1.0 1.2 1.4 1.3 0.5 Oriental Fruit Moth (apple) 3.0 2.5 2.0 2.5 2.3 Oriental Fruit Moth (peach) 0 0 0 0 0 San Jose Scale 0.1 0 0.3 0.1 23.2 Codling Moth 0.3 4.2 4.5 2.9 2.3 American Plum Borer 0.1 0.2 0.8 1.5 1.7 Lesser Peachtree Borer 2.0 5.0 2.9 0.8 0.7 Peachtree Borer 0.6 0.5 0.1 5.8 7.7 Pandemis Leafroller 0 0 0 0 0 Obliquebanded Leafroller 0 0.2 0 0 0 Apple maggot 0.06 0.08 0.1 0 0.3 Highland (Dick Straub, Peter Jentsch): 6/27 7/7 7/14 7/21 7/28 Redbanded Leafroller 0.9 5.1 9.1 2.3 2.4 Spotted Tentiform Leafminer 39.4 85.3 59.7 46.0 28.4 Oriental Fruit Moth 0.9 1.3 1.3 0.3 0.6 Lesser Appleworm 2.0 0.2 0.4 0.9 1.2 Codling Moth 2.6 1.9 0.6 1.2 1.0 Fruittree Leafroller 0 0 0 0 0 Tufted Apple Budmoth 2.9 1.3 0.4 0 0.4 Obliquebanded Leafroller 0.3 0.6 0.2 0.1 0.1 Sparganothis Fruitworm 1.4 3.9 0.7 0.1 0.3 Apple Maggot 0 0 0.1* 0.9 1.1 Variegated Leafroller - - 0 0.4* 0.2 * = 1st catch
by Harvey Reissig & Art Agnello
Even though apple maggot flight is not particularly strong in most N.Y. orchards this season, we are entering the traditional period of peak emergence. Following is some general information on the biology and life history of this well-known insect.
The apple maggot overwinters as a pupa in the soil. Adults from the single generation of flies begin to emerge in late June to early July. Females cannot lay eggs until they become reproductively mature, 7-10 days after emergence. Females lay eggs in fruit and larvae develop there, emerging in the autumn after the fruit has fallen and entering the soil to pupate. Flies are active from July to mid-September, but commercial orchards generally require protection only from about mid-July through August. Flies do not reach orchards in large numbers until mid-July, and before this date fruit remaining on the tree is unfavorable for larval development, so early infestations do not cause sustainable populations in the orchard. In addition, for unknown reasons, fly activity between about August 20 and September 15 does not usually cause serious damage in commercial orchards in New York.
Larval tunneling inside the fruit causes it to become rotten and unmarketable. Early stings caused by punctures from the female's ovipositor may severely deform the fruit of some varieties, even though no larvae survive.
Monitoring to determine whether control sprays are necessary is recommended primarily in orchards that are not near large sources of outside infestation (such as abandoned orchards), and those with no indigenous infestations of flies. Theoretically, there is absolutely no tolerance for AM damage in fruit. In practice, AM damage is not usually detected in normal fruit inspections unless there is approximately 5 percent fruit damage.
Small wasps parasitize AM larvae in fruit, and predators such as birds and crickets may eat larvae or pupae in or near the soil. In natural, unsprayed apple and hawthorn trees, AM populations are not regulated by natural enemies. Parasites and predators are also ineffective at controlling AM in commercial orchards.
AM flies have a limited migratory capability, so all apple and hawthorn trees within 1/4-1/2 mile of commercial orchards should be removed if possible. Do not allow dropped fruit to remain beneath the tree for more than one to two days. Eliminating fruit drops will break the life cycle of flies in an orchard by preventing larvae from exiting the fruit and entering the soil.
AM flies can be "trapped out" in small, well-pruned trees that are not near large sources of outside infestations. A relatively high density of sticky red spheres (plain or volatile-baited) is required, approximately 1 trap per 100 apples. Mass trapping is usually less effective than chemical control, and AM may still damage 1-5% of fruit from mass-trapped orchards.
Most commercial orchards have no indigenous populations of flies. Therefore, chemical control sprays are usually directed against flies immigrating into orchards from outside, unsprayed hosts, including both apples and hawthorns. Most insecticides, particularly organophosphates, are remarkably effective in controlling adults. Insecticides must kill females before they oviposit in the fruit. Residual effectiveness of insecticides is particularly important in controlling AM in commercial orchards when flies are continuously immigrating.
Insecticides can be applied according to trap catches as described in the 1997 Pest Management Recommendations for Commercial Tree-Fruit Production (p. 84), or on a standard or modified IPM schedule. The standard schedule requires an initial spray 7-10 days after the first emergence of flies, followed by additional sprays at 10-14-day intervals until August 15-20. (The first AM fly in Geneva was trapped on 7/7.) The modified IPM schedule requires only three sprays, on approximately July 15, August 1, and August 15. We would suggest that growers in high maggot-pressure areas maintain a standard spray schedule, or at least be vigilant in checking traps twice a week, in order not to be caught unprotected during this peak flight period.
A few words may be in order here about when to terminate sprays for apple maggot in late summer. Most people are aware that each year in N.Y. orchards, substantial numbers of AM flies are captured on monitoring traps late in the season, and growers are naturally concerned about potential fruit infestation from these late season survivors. For the past few years, we have conducted trials in a heavily infested research orchard of McIntosh and Cortland trees by applying bi-weekly applications of Guthion beginning in early July and continuing for 2, 3, 4, and 5 total sprays. New oviposition punctures were checked weekly on "scout" apples clipped to the trees, and female AM flies captured throughout the flight period were dissected to check for the presence of eggs. The results of these studies can be summarized as follows:
We regard these results as corroboration of our long-standing recommendations that a final spray be applied around the middle of August to effectively control apple maggot in most commercial orchards.
by Dave Kain & Art Agnello
Things are a little slow this week so we thought we'd catch you up on our comparison of events so far this year with last season and the "normal":
DD (base 43°F) Normal 1996 1997 DD43 to date (7/28) 2096 1998 1934 PPS 1st oviposition 82 48 124 GFW flight peak 137 206 234 ERM egg hatch begins 284 - 266 RBLR 1st flight peak 305 379 234 STLM 1st flight peak 330 379 360 OFM 1st flight peak 423 379 464 CM 1st catch 487 505 426 LPTB 1st catch 588 602 464 APB 1st flight peak 701 625 733 SJS 1st flight peak 674 - 646 OBLR 1st catch 922 962 847 PTB 1st catch 1084 851 646 STLM 2nd flight begins 1068 1034 1005 OBLR 1st flight peak 1164 1034 1005 AM 1st catch 1350 1481 1384 APB 2nd flight begins 1616 1748 1760 CM 2nd flight begins 1881 1847 1654 CMB 1st adult catch 1440 1396 1402 LAW 2nd flight begins 1630 1748 1442 OFM 2nd flight begins 1436 1481 1296 RBLR 2nd flight begins 1503 1305 1296 SJS 2nd flight begins 1696 1748 1934 STLM 2nd flight peak 1642 1748 1760
We have just been informed of the approval of Pyramite's 24(c) label for apples. One application is allowed against mites this season, and a copy of the label (available from distributor) must be in the applicator's possession.
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:
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Photographs courtesy of New York State Integrated Pest Management Program