June 3, 2002 Volume 11 No. 12 Update on Pest Management and Crop Development
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TRAP CATCHES (Number/trap/day)
Highland: 1st Obliquebanded Leafroller caught 6/3.
Roundheaded Appletree Borer
Oriental Fruit Moth
San Jose Scale
Roundheaded Appletree Borer
Oriental Fruit Moth
San Jose Scale
(Art Agnello, Entomology, Geneva)
Despite the regular procession of unseasonably chilly nights, we are now officially into the summer phase of the fruit pest management season, and if past trends are any indication (and even if they aren't, which is more likely), our assorted insect pests are continuing along their regularly scheduled developmental paths. If there's such a thing as a normal schedule, they're probably a bit behind it, but that doesn't eliminate those points in time, like about now, when a lot of them might pop up all at once. The following are updates on some of the more noteworthy players in this season's lineup. Dates in parentheses, where present, are the mean date of occurrence according to our recent records.
Obliquebanded Leafroller (June 10)
We have yet to catch the first obliquebanded leafroller adult in western N.Y., but it won't be too much longer before the first moths start showing up. Depending on the location, larvae can be found now in many stages of development, from the relatively small to the pupal stage in some of the more advanced sites. This would therefore be an advisable time to hang a pheromone trap in problem apple blocks, to fix the date of first emergence in your specific area. Recall that we recommend sampling at 600 DD (base 43°F) after the first adult catch, to determine the need and timing for treatment. It pays to keep an eye on the daily highs and lows for your area if you are doing your own trapping, as it's likely that our "normal" first sampling date of July 5 won't turn out to be necessarily appropriate this year.
Stone Fruit Aphids
Although green peach aphids are not always a serious pest every year, colonies of these greenish, smooth-looking aphids may have already started showing up in peach blocks. They cause curled leaves that may turn yellow or red in severe cases, and more importantly, they are vectors of Plum Pox Virus, which still has not been documented in N.Y., fortunately. The young aphids begin to hatch about the time of peach bloom and remain on the trees for 2-3 generations, until early summer, when they seek other hosts (mainly vegetable truck crops). Green peach aphids suck the sap from the new fruits and twigs, and are also found on plum, apricot, cherry, and many ornamental shrubs. These insects are difficult to control; Provado has another Section 18 label this year, and Lannate and Thiodan are also options, but are probably less effective. Applications are recommended before excessive leaf curling occurs, in order to maximize the spray's effectiveness. Also, keep an eye out for black cherry aphid in your cherry trees after shuck fall. If colonies are building up on the foliage, recommended materials include Provado, Sevin and Imidan (tart cherries only).
Cherry Fruit Flies (June 16)
No adults have been reported caught on sticky board traps yet, but because of the zero tolerance in cherries for insect damage or presence, it's prudent to begin sprays in your cherries now (for this pest as well as for curculio). Guthion, Imidan (tart cherries only), Sevin, Diazinon or the pyrethroids are all effective treatments. Sevin and Imidan will also control black cherry aphid.
Lesser Peachtree Borer (May 25)
The first adult catch in Geneva was noted on May 23. Remember to get your trunk and scaffold sprays on peaches and cherries during the first 10 days of June if borers are a problem in your blocks. If you're planning to use Isomate-L pheromone disruption this year, now is the time to hang the ties (125-150/acre will disrupt both species -- Peachtree Borer appears about mid-month -- in our region). This pest increases the severity of Cytospora canker infections in peaches and is often found within the canker; by feeding in the callous tissues, it interferes with the tree's natural defenses against the disease. Infestations can be determined by the presence of the insect's frass, which resembles sawdust, in the gum exuded from the wound. In peaches, you can use Lorsban 4E, Thiodan, Asana, Ambush, or Pounce for this application. In cherries, use Thiodan 50WP, Asana, Pounce, Ambush, or Lorsban 50WP (tarts only) or 4E, as a trunk spray ONLY; do not spray the fruit.
Summer Oil for European Red Mite
In situations where European red mite pressure or the crop's sensitivity to them haven't necessarily justified an early season treatment with Agri-Mek, Apollo or Savey, this is the time of year when a summer oil program might be considered as an alternative preventive approach. Field research trials conducted in commercial and experimental apple orchards in western N.Y. have shown the effectiveness of using a highly refined oil in a seasonal program to control mites throughout the summer. Some examples of these products are Sunspray Ultra Fine Spray Oil (Sun Refining & Marketing, Philadelphia), Stylet-Oil (JMS Flower Farms, Vero Beach, FL), and Omni Supreme (an ExxonMobil product formulated using Orchex 796 and distributed in our area by Helena); others are labeled and may be available, although we haven't tested all brands.
Our approach is to make three applications, on a preventive schedule, immediately after the bloom period, before mite populations have a chance to build. The first application can be any time from petal fall to 1-2 weeks later, followed by two additional sprays at 10-14-day intervals. The oil is not concentrated in the tank, but rather mixed on the basis of a rate per 100 gallons of finish spray solution; in most cases, we recommend 100 gal. per acre. A rate of 1-2 gal/100 should maintain control of most moderate populations. Don't apply without leaving at least a 10-14-day interval before or after a captan spray.
San Jose Scale (June 19)
Minute SJS adult males emerge in the spring from beneath scale covers on the trees, usually during bloom, and mate. We have not yet caught any adult males in our traps this season. On average, the first catch occurs at 481 DD (base 50°F). The females produce live crawlers within 4-6 weeks of mating; these make their way to new sites and insert their mouthparts into the tree, secreting a white waxy covering that eventually darkens to black. SJS infestations on the bark contribute to an overall decline in tree vigor, growth, and productivity. Fruit feeding causes distinct red-purple spots that decrease the cosmetic appeal of the fruit. Insecticidal sprays are most effective when directed against the first generation crawlers, specifically timed for the first and peak crawler activity, which are usually 7-10 days apart.
The most reliable method of determining first appearance of the crawlers in your specific area is by putting sticky-tape traps on the tree limb near encrusted areas and checking them at least twice a week, starting about the second week of June. Alternatively, a degree-day accumulation of 310 (50°F base) from the date of first adult catch has also been shown to be reliable if the degree-days are known with some accuracy. In the Geneva area, first crawler emergence has tended to occur sometime around mid-June, but as we have not yet caught any adult males, or even reached the average date of first catch, as of this writing, we still have some time to wait. Lorsban used to be the standard recommended treatment for scale, and since it's no longer labeled for summer use, we're fortunate to have a new product available that is reportedly quite effective against this pest. Esteem 0.86EC can be applied at 13-16 oz/acre at first crawler emergence; a low rate (0.25% or 1 qt/100) of a highly refined summer oil (see above) has been shown to improve penetration and, therefore, control. The remaining OP's such as Guthion, Imidan, diazinon and dimethoate, are the conventional standby choices.
Plum Curculio. Not tremendous movement toward the 340 DD (base
50°F) spray cutoff for this pest. However, the 10-day forecast calls
for uniform highs in the 70's, so these can add up fast (we hope). Some
Oriental Fruit Moth. In Niagara Co., using May 6 as the biofix for first flight, the 242 DD (base 45°F) accumulation puts us at 10% first brood larval hatch. Growers should be somewhere between their first (at PF) and second (14 days later) applications of a pyrethroid for this insect (plus curc).
Codling Moth. Also relatively behind recent years. With 250
DD (base 50°F) as a first spray date, we currently have:
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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