July 1, 2002 Volume 11 No.16 Update on Pest Management and Crop Development
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TRAP CATCHES (Number/trap/day)
Geneva: Dogwood Borer 1st trap catch 6/25 in Wayne Co.
1st catch of Pandemis Leafroller and Obliquebanded Leafroller 6/10. DD (base 43°F) since then = 579. (Sample at 600 DD).
Highland: Apple Maggot 1st catch on 6/26.
High Aphid and Leafhopper numbers observed.
Spotted Tentiform Leafminer 2nd flight began 6/24. DD (base 43°F) since then = 588. (Sample sap-feeding mines at 690 DD).
Roundheaded Appletree Borer
Oriental Fruit Moth
San Jose Scale
Spotted Tentiform Leafminer
Roundheaded Appletree Borer
Oriental Fruit Moth
Spotted Tentiform Leafminer
(Art Agnello, Entomology, Geneva)
It shouldn't be long before we start seeing some adult Comstock mealybugs in pear foliage, followed by their invasive crawler offspring. The crawlers are the most susceptible stage for chemical control, which we expect sometime during the next couple of weeks, especially in the Hudson Valley. The following information is adapted from the Comstock Mealybug IPM Fact Sheet, No. 22:
There are two generations of Comstock mealybug in New York, each taking 60 to 90 days to complete, depending on seasonal temperatures. The egg is generally thought to be the primary overwintering stage, but some nymphs and adult females from the second (summer) generation may also overwinter, with eggs being laid in the spring rather than the previous fall. Adult females and males emerge at the same time, from late June to mid-July for the first (overwintering) generation, and late August to mid-September for the second (summer) generation. Adult females are present for a total of 4-6 weeks, and oviposit for about one week after mating. Males survive for only a few days after emerging.
The elongate, orange-yellow eggs are laid in jumbled masses along with waxy filamentous secretions in protected places such as under bark crevices, near pruning cuts, and occasionally in the calyx of fruit. The summer-generation eggs are laid from mid-June through late July, and the overwintering eggs from mid-August into October. The early larval instars of the CMB are similar to adult females (wingless and elongate-oval in shape, with a many-segmented body) except that they are smaller, more oval-shaped, lack the long body filaments, and are orange-yellowish because they have less wax covering. Later instars are similar in appearance, but become progressively browner and redder.
The overwintered eggs hatch from mid-April through May and the nymphs (crawlers) migrate from the oviposition sites to their feeding sites on terminal growth and leaf undersides of trees and shrubs. This hatch is completed by the petal fall stage of pears. Nymphs that hatch from these overwintered eggs are active from roughly early May to early July. As the nymphs approach the adult stage, they tend to congregate on older branches at a pruning scar, a node, or at a branch base, as well as inside the calyx of pears. Second- (summer) generation nymphs are present from about mid-July to mid-September.
The Comstock mealybug poses two major concerns for the pear processing industry of New York: First, the emergence of crawlers and adult females from the calyx of pears at the packinghouse creates a nuisance to workers. Second, pears to be made into puree typically are not peeled or cored by New York processors, so infestations can potentially result in unacceptable contamination of the product.
Another problem, of concern to apple growers in the 1930s and 1940s, and again in the Hudson and Champlain Valleys in the early 1980s, is that the honeydew secreted by the crawlers is a substrate for sooty molds growing on the fruit surface. This type of damage has also been noted on peaches in Niagara Co. and in Ontario, Canada. These molds result in a downgrading of the fruit, and are therefore an additional cause of economic loss.
To date, the Comstock mealybug has been a problem to growers of processing pears because of the contamination and aesthetic reasons noted. An infestation generally requires one or more insecticide sprays during the growing season, directed against the migrating crawlers. Examine the terminal growth for crawler activity periodically throughout the summer. Crawler and adult female activity can also be monitored by wrapping double-sided tape such as white carpet tape around low scaffold branches and inspecting for crawlers that have been caught by the tape. They can be recognized with a hand lens or, with some experience, by the unaided eye.
Sometime in early August, we'll advise an application of a material such as Provado, Diazinon, Lannate, or the newly available Actara to control this insect.
This is the time of the season when a second trunk application of a pesticide should be made against peachtree borers in cherries and peaches. A coarse spray directed at the trunk and scaffold branches gives the best protection against ovipositing adults; shutting off all but the bottom nozzles on a speed sprayer won't do an effective job. Use Lorsban 4EC, Thiodan, or a pyrethroid (Ambush, Asana, Pounce; Danitol is NOT registered in stone fruits). Do not spray the fruit.
On June 18, 2002, the EPA held a technical briefing on the Revised Cumulative Risk Assessment for the organophosphate pesticides (OP) in Alexandria, VA. This assessment, mandated by the Food Quality Protection Act (FQPA) considers the combined effects on human health that could result from exposure to such pesticides through various routes including food, drinking water and residential use.
Preliminary results from the assessment, which reviews more than 1,000 pesticide food tolerances, indicate that the regulatory actions already taken by the EPA during the past six years have substantially reduced the risk posed by these pesticides and will meet the tough standards set forth in the FQPA.
EPA suggested that there will be no wholesale cancellation of the organophosphate compounds as a result of this assessment. There are a few questions surrounding specific product/commodity combinations that may require further mitigation but these should not greatly affect the tree fruit community. EPA also indicated that OPs in drinking water are not a major source of cumulative exposure and neither is residential use given the recent cancellation of chlorpyrifos and diazinon for those purposes.
However, the risk assessment has not been finalized. EPA will meet with its Scientific Advisory Panel (SAP) June 26 and 27 to request input on several science policies used to conduct the assessment such as the method of incorporating safety margins and the appropriate percentile for regulation. There is also a 30-day public comment period, currently in effect, to allow for stakeholder input. In addition, there are seven OP compounds for which the individual risk assessments have not been completed and therefore are not fully incorporated into the cumulative assessment. Although the final outcome of this assessment may be altered somewhat when the results of the final organophosphate risk assessments are included and all science policy questions have been settled, the conclusions should support a high level of confidence in the use of these compounds and in the safety of our food supply system.
For more information, visit http://www.epa.gov/pesticides/cumulative
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
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