July 22, 2002 Volume 11 No. 19 Update on Pest Management and Crop Development
Return to top
TRAP CATCHES (Number/trap/day)
Geneva: Spotted Tentiform Leafminer 2nd flight coming to an end; began 6/24. DD (base 43°F) since then = 867. (Begin sampling sap-feeding mines at 690 DD).
San Jose Scale 2nd flight beginning.
American Plum Borer 2nd flight under way.
Highland:Potato and Rose Leafhopper adults present, nymph numbers below threshold.
European Red Mite and Twospotted Spider Mite populations building.
Obliquebanded Leafroller 1st flight coming to an end.
Roundheaded Appletree Borer
Oriental Fruit Moth
Spotted Tentiform Leafminer
White Apple Leafhopper
Roundheaded Appletree Borer
Oriental Fruit Moth
Spotted Tentiform Leafminer
White Apple Leafhopper
(Art Agnello, Entomology, Geneva)
Hot and dry weather tends to encourage arthropod pests, so here's a brief overview of some of the pickins in the various orchard crops right now.
The 2nd brood flight of this peach and apple pest started some 7-10 days ago in most WNY sites, and the dates for peak flight are all over the place, but in general, we are now somewhat past the 6-day post-peak flight date for beginning the second round of sprays in peaches. We recommend Asana in two applications, spaced 14 days apart. If you haven't begun treating for this generation of OFM, this week is still not too late to start. Shoot-flagging injury from the first brood larvae is evident in the western county peach orchards by now, but those orchards relying on pheromone mating disruption seem to be holding their own. Also, a little attention to orchard weed management now can help minimize later season catfacing injury from tarnished plant bugs and their kin.
We have been noticing infestations of this nuisance pest in apple orchards for some time now. The woolly apple aphid (WAA), Eriosoma lanigerum, colonizes both aboveground parts of the apple tree and the roots, and commonly overwinters on the roots. In the spring, nymphs crawl up on apple trees from the roots to initiate aerial colonies. Most nymphs are born alive to unmated females on apple trees during the summer. Colonies initially build up on the inside of the canopy on sites such as wounds or pruning scars and later become numerous in the outer portion of the tree canopy, usually during late July to early August. Their presence now can serve as an indication of potential trouble spots later on.
Aerial colonies occur most frequently on succulent tissue such as the current season's growth, water sprouts, unhealed pruning wounds, or cankers. Heavy infestations cause honeydew and sooty mold on the fruit and galls on the plant parts. Severe root infestations can stunt or kill young trees but usually do not damage mature trees. Large numbers of colonies on trees may leave sooty mold on the fruit, which annoys pickers because red sticky residues from crushed WAA colonies may accumulate on their hands and clothing.
Water sprouts, pruning wounds, and scars on the inside of the tree canopy should be examined for WAA nymphs, and new growth around the outside of the canopy should be examined for WAA colonies. No economic threshold has been determined for treatment of WAA. Aphelinus mali, a tiny wasp, frequently parasitizes WAA but is very susceptible to insecticides (particularly pyrethroids) and thus does not provide adequate control in regularly sprayed commercial orchards. Different rootstocks vary in their susceptibility to WAA. Resistant rootstocks such as MM.106, MM.111, and Robusta are the only means of controlling underground infestations of WAA on apple roots; M.9 rootstock is very susceptible. WAA is difficult to control with insecticides because of its waxy outer covering and tendency to form dense colonies that are impenetrable to sprays. This insect is resistant to many commonly used materials, but insecticides that are effective include Diazinon and Thiodan.
The 2nd brood flight of STLM is pretty much over now, but it will be followed very closely by the 3rd, and of greater importance, its larvae are entering the stage of growth that makes them worthy of concern and timely assessment. The injury caused by the 2nd and 3rd generations is identical to that caused by the 1st, but second-generation injury is most damaging to the tree. Third-generation STLM is usually not a problem if the 2nd brood was controlled properly. Proper timing is essential for both the assessment of STLM densities and control, if required. Sampling for sap-feeding mines should be done at approximately 690 degree-days (base 43°F) after the start of the flight of the second generation. This flight began on June 24 in Geneva (which puts the DD tally at 867). Sampling guidelines can be found in the Recommends at: http://www.nysipm.cornell.edu/publications/apple.man/STLM_Sum.GIF. A decision regarding the third generation is generally not required unless the density of the second brood exceeded two mines per leaf. In recent years, an average of only 8% of sampled orchards have required a treatment for second-generation STLM.
Several insecticides are effective against this pest, including Provado, Vydate, Lannate, Danitol, Asana, and Actara. All of these products except for Provado and Actara are detrimental to predatory mites. Depending on the product chosen, application can be made anytime from initial egg deposition until larvae enter the tissue-feeding stages. Sampling is, of course, recommended before any spray is applied. If Provado is chosen, the manufacturer recommends aiming for the period 10-14 days after the flight starts. Unfortunately, if mines haven't yet begun to show up, this approach requires that you predict the need for a treatment based on either moth numbers or past field history, neither of which has been shown to be a very reliable indicator of actual pressure. According to our experience with this material, waiting until the appearance of early sap-feeding mines will give a better picture of problem blocks, and is still timely enough to effectively manage economic populations.
Apple maggot catches have not been terribly high yet, although they did seem to start up somewhat earlier than normal in our statewide research blocks. If you aren't monitoring in specific orchards and haven't yet applied a protective spray against AM (and aren't using SpinTor for OBLR), prudence would suggest a bit of attention to this insect. Growers on a SpinTor program should be somewhere between the first and second spray of this material for leafrollers, which will provide protection against moderate AM pressure.
Very few orchards we have seen are in trouble from European red mites so far, but this kind of weather can boost twospotted mite levels in a hurry. Inspect your leaves using the 5 mite/leaf form on p. 66 of the Recommends, but be aware that two-spot populations increase more quickly than ERM, so be conservative in your interpretations. We don't yet have Acramite in N.Y., and Pyramite works better against red mites, so we would counsel Vendex for problem twospotted mite infestations.
1) The Cornell 2002 Fruit Field Day will take place in and around Orleans Co. on Thursday, August 1, from 8:15 a.m.-4:30 p.m. During the tour, two new sweet cherries, 'BlackGold' and 'WhiteGold', will be released by stone fruit breeder Bob Andersen. The two cherries are the first of four new cherry varieties and two new plum varieties that Andersen expects to release within the next six months. Other topics covered by Cornell researchers and fruit extension educators and consultants during the tour will include new rootstocks, producing big 'Gala' apples, thinning trial results using new thinners, strategies for preventing apple russet, planting systems for apples and peaches, new insecticides, mating disruption strategies, on-farm propagation of trees, promising new apple varieties, storage tips, on-farm equipment demonstrations, and more. The event is sponsored by Cornell University and the New York State Horticultural Society.
The tour starts at the LaMont Fruit Farms, on Stillwater Road, in the town of Carlton, NY, at 8:30 a.m. A link to the complete schedule and a tour map is available on the Cornell Fruit home page at http://www.cornellfruit.com. Pre-register by July 25, by contacting Kim Hazel at 585-589-5561 or Mary Durham at 315-331-8415. Lunch will be provided. NYS DEC Recertification credits will be available. Bring your applicator ID card.
2) Further down the road, it's not too early to mark your calendar for the annual N.Y. Fruit Pest Control Field Day, which will take place during Labor Day week on Sept. 4 and 5, as dictated by tradition. As usual, the Hudson Valley installment will take place on the first day, and then we shift to Geneva for the western NY perspective on the second day. Activities will commence in Highland on Wednesday, the 4th, with registration, coffee, etc., at the Hudson Valley Laboratory, 8:30 am. The tour will proceed to the orchards to view plots and preliminary data from field trials involving new fungicides, miticides, and insecticides on apples. On Thursday, the 5th, Geneva participants will register starting at 8:30 in the lobby of Barton Lab, after which we will view and discuss results from field trials on tree fruits and grapes. It is anticipated that the tour of field plots will be completed by noon. Save the dates.
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
Phone: 315-787-2341 FAX: 315-787-2326
Online at <http://www.nysaes.cornell.edu/ent/scaffolds/>