August 12, 2002 Volume 11 No. 22 Update on Pest Management and Crop Development
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TRAP CATCHES (Number/trap/day)
Geneva: Oriental Fruit Moth and Lesser Appleworm trap catches increasing.
Highland: Stinkbug damage evident in pear border rows.
Aphids building on new growth.
Twospotted Spider Mite numbers above thesholds and Rust Mite numbers increasing.
Oriental Fruit Moth terminal feeding observed.
(Art Agnello, Entomology, Geneva)
Most of the season's pest control decisions have been made by now, and as growers prepare to make what will probably be their last turn through the orchard for crop protection purposes before seriously addressing harvest activities, here's a quick rundown of some of the more important players to keep in mind for these dog day duties.
Catches of adults continue to be quite respectable (even startling) around the state, particularly in sites adjacent to hedgerows, so the dry soil conditions appear not to be hindering their emergence. Mid-August is traditionally still fair game for a decent number of flies to be out and laying eggs, although numbers should begin tapering off a bit soon. This is yet another of those seasons when localized trapping can pay off in the event that some blocks are under greater pressure than others, even on the same farm, so please continue to monitor traps in representative blocks.
Trap counts for the 3rd flight of oriental fruit moth continue to be relatively high in many western orchards (both apple and peach), and some varieties of peaches still have a couple of weeks to go before harvest. In our eastern demonstration blocks (Champlain Valley, Capital District, and Hudson Valley), the same scenario is playing out with lesser appleworm (see following photo). as the primary pest.
Pheromone disruption results have been encouraging so far, but the edges of blocks are susceptible to some problematic fruit infestations. Options include Guthion or Imidan or Asana in peaches. In apples and pears, you can use Guthion, Imidan, Avaunt, or Danitol; the last two materials will additionally give control of white apple leafhopper. For control of OFM, alternate row middle applications will not be as effective as whole orchard sprays in high pressure blocks. Assess the pressure in your specific situations, check the pre-harvest intervals, and determine whether a full or border spray might be in order.
European Corn Borer
Recall that these moths have a final flight that extends to the middle of September, and that the offspring can inflict last-minute fruit feeding damage to later varieties. One or two late sprays of a B.t. product like Dipel can go a long ways toward minimizing this injury, and the 0-day PHI is compatible with any harvest schedule. Also, SpinTor applied against late season leafrollers will also provide corn borer control (PHI = 7 days).
The appearance of neat little (2 mm) holes bored into the side of apples in the late summer and early fall, similar in appearance to those caused by a stem puncture, may indicate an infestation of this relatively sporadic pest. Although this insect is a relative of the European apple sawfly, its appearance is quite different; the larva is a bright green worm with a light brown head (see photo), as contrasted with the EAS, which is whitish and feeds on young apples during the petal fall period.
Dock sawfly confines its feeding almost entirely to plants belonging to the buckwheat family (Polygonaceae), including numerous docks and sorrels, the knotweeds and bindweeds, or else wild buckwheat or alfalfa.
The injury to apples consists externally of the small round holes bored by the larvae, which after a few days show a slightly sunken, brownish ring around them and occasionally may be surrounded by a larger discolored halo. These holes may occur anywhere on the surface, but are most numerous around the calyx and stem ends, or at a point where the apple touches a leaf or another apple, since it is easier for the larva to obtain a foothold here. Since the dock sawfly must live on the above-mentioned weeds, it becomes an apple pest only where these plants are growing in or around the orchard. There is little danger from this insect in orchards where the food plants don't exist. Now would be a good time to assess the weed situation in your orchard and make plans for such selective herbicide applications as may be appropriate regarding this insect.
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.
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