General Information | Chemical News | Insects | Credits
Volume 7, No. 1 March 23, 1998
43F 50F Current DD accumulations (Geneva 1/1-3/23): 39 11 Coming Events: Ranges: Green fruitworm 1st catch 41-143 9-69 Pear psylla adults active 2-121 0-49 Pear psylla 1st oviposition 25-147 1-72 McIntosh at silver tip 56-137 17-58 Phenologies: All dormant
by Art Agnello
Now that we've made it through such a bizarre winter, it's nice to start out the spring with a more conventional foot-and-a-half snowfall, just so we know that all is right with the world. As they always do, the mild winter temperatures have elicited a number of hopeful inquiries to our department from the general public, anxious to know whether the warm January and February will translate into worse than average insect problems. Although we don't pretend to have a psychic connection with the multi-legged world, it's been our experience that the spring weather is a much more predictable determinant of pest populations. Warm winters generally only predict lower overwintering mortality of things like mite eggs and young OBLR larvae snoozing in their hibernaculae. However, even a larger than normal spring flush of mite nymphs or leafminer moths don't have an easy time getting started if April and May are cold, wet, rainy, and windy (in other words, normal).
As usual, we are always happy to consider contributions (particularly from NY sources) in the form of articles on topics in any of the fruit crop protection or crop production areas, as well as NY field observations, trap data, etc. We generally do not send the mailed version of this newsletter to growers, homeowners, or other private individuals not having some fruit extension, commercial, university or governmental affiliation. This is not only for economic reasons, but also because of "turf" considerations having to do with growers' relationships with their local Cooperative Extension programs. There are a few exceptions, mostly for people who were "grandfathered in" before this policy was instituted, and we prefer to keep this number low. Unless things get too out of hand, the e-mail version will be sent to anyone who requests it. As before, we also post this newsletter to the CENET Tree Fruit Discussion Group BB, at: CCE-TREE-FRUIT-L@CCE.CORNELL.EDU
On Friday the 13th, we received word that the Pyramite state label for apples and pears was approved by the New York State DEC. The label allows use of Pyramite 60WP on apples to control European red mite, apple rust mite, and twospotted spider mite in a maximum of 2 applications per year, with at least 30 days between sprays, and a 25-day PHI (REI is 12 hours). On pears, use is allowed to control ERM, pear rust mite, twospotted spider mite and pear psylla, with a maximum of 2 applications per year, 30 days between sprays, and a 7-day PHI.
by Art Agnello
For the first time in a long time, European red mite management has finally reached the point of not having to be an endless game of catch-up. Although we call the approach we are promoting resistance management, the more appropriate term would really be susceptibility management, and the apple (and pear) industry is now in a position to show its ability to exercise some responsible stewardship of the tools available to this end. Perhaps the single most useful piece of advice we can offer to apple growers looking to preserve the effectiveness of the miticides available to them is: Rotate! That is, whatever mite control program was used last year, and regardless of even how well it worked, wise resistance management practice dictates a change to a different one in 1998. The rationale behind this advice is that the time to manage pesticide resistance is before it starts to show up, and the options that now exist for mite control make this a practical, if somewhat controversial strategy for ERM.
Apollo and Savey should be regarded as essentially the same material for purposes of resistance development, considering the well-known incidences of cross-resistance between these two products in the world fruit industry. There is not yet any evidence of ERM resistance to Agri-Mek, but there is also no reason to expect it not to occur at some time in the future. Nevertheless, with a number of early season products to choose from, it's not difficult to formulate a few different rotation programs to begin using, and most growers have already used one of these rotations last season.
One such program could be a prebloom spray of Savey or Apollo, and then a summer rescue application of Pyramite, Carzol or Kelthane, if needed. Admittedly, some of these summer materials have certain limitations, but the effectiveness of the early season products should work to minimize the severity of any late-season outbreaks that do occur.
A possible 2nd-year rotation would be to use Agri-Mek at (or immediately after) petal fall; an oil spray before bloom could be elected, but this has actually proven not to be necessary in several field trials we have conducted with Agri-Mek, which has provided season-long control with a single well-timed application. If a summer rescue treatment is needed, rotate among the three products available for this use. In the 3rd year a return to Apollo or Savey could be recommended, etc. Implicit in the provisional need for a rescue treatment is the practicality of once again taking leaf samples in the summer to determine how close to threshold (remember that concept?) the population is. The presence/absence charts for this simple exercise can be found on pp. 98-100 of the 1998 Recommends, and also in the IPM Scouting Manual.
Ideally, these rotation programs should be used on a farmwide basis, or on as large a scale as is practical; although we have no evidence to indicate that mites from one block will "contaminate" (for resistance purposes) an adjacent block that has received a different miticide program, the chances of such an event occurring are obviously less if the entire farm is treated with the same program during the season.
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