The Velvet Hammer

The Velvet Hammer

The destructive nature of the codling moth is well known. When it comes to tree fruit pests, the proverbial “worm in the apple” has gotten the lion’s share of attention, and rightly so. It can indeed wreak havoc. But when it comes to pears, there is one pest that can top even codling moth: pear psylla. “In most situations in central Washington, pear psylla is more difficult than codling moth, and more expensive to control,” says John Dunley, an entomologist at the Washington State University Tree Fruit Research Center in Wenatchee. “Pear psylla is basically a poster child for resistance management.”

While any pest can develop resistance to a certain pesticide over time, few have proven so resourceful as pear psylla. In the nearly 70 years since it first spread to Washington, growers thought they had KO’d pear psylla many times. But each time they would watch in disbelief as the pest got up from the mat, ready to fight some more. You don’t have to look further than that mainstay of growers’ arsenals in recent decades, Guthion, which, incidentally, has long been the top choice for codling moth. “The OPs (organophosphates) like Guthion smoked pear psylla in the mid 60s,” says Dunley. “But resistance developed in two years.”

But the OPs were hardly the last challenger. In the mid-80s came the pyrethroids, especially Asana. Again, growers thought they had the problem licked. Again, pear psylla came back, sucking the juice out of the trees and leaving messy honeydew behind. Fruit would russet, or worse, get sooty mold. Serious infestations would, and still can, stunt, defoliate, or kill the trees. Again, resistance had developed in just two years.
Other excellent products have been tried with success over the years: Agri-Mek, Comply, Assail, Actara, Clutch, etc. However, in each case, pear psylla would develop a degree of resistance. What’s clearly needed as we head into the 2008 crop year is not a reformulation, but a completely new chemical. That’s where Delegate insecticide comes in.

Biological Heritage

Most growers are already familiar with the class of products from which Delegate comes, the spinosyns. Developed by Dow AgroSciences, they are derived from the fermentation of Saccharopolyspora spinosa. The products with which growers are familiar include Success, and its organic formulation, Entrust, both of which have spinosad as the active ingredient. Dow AgroSciences has chemically modified two other spinosyns to come up with a unique product, spinetoram, the active ingredient in Delegate.

Like some other products, Delegate affects the pest’s nervous system, only it does so with a completely different mode of action, quickly paralyzing and then killing insect pests. Insects are controlled two ways, through both contact and ingestion, providing both quick knockdown and residual control. Delegate also has translaminar ability, which is particularly important with a pest such as pear psylla, says Dunley, because in the nymph stage the pest is immobile, usually hunkered down on the undersides of the leaves. “You have to really get the material to them,” he says. “They won’t crawl across the tops of the leaves.”

Dunley says he’s optimistic about Delegate not only because of its unique new mode of action, but because it has the ability not only to neutralize per psylla, but the other major pest of pears, codling moth. There aren’t many products that take care of both, especially one to which pear psylla has no resistance. That makes it a lot easier on pear growers, notes Harvey Yoshida, the Product Technology Specialist for Dow AgroSciences in the Pacific Northwest. “In certain places, codling moth is worse than pear psylla,” he says. “With this, you can get two key pests with one spray of one product.”

Reduced Risk Registration

Besides the two key pests, Yoshida notes that Delegate also takes care of leafroller and thrips, pests which are also a problem on apples. (In addition to pears, the product is also labeled for apples, cherries, peaches, plums, nectarines, and apricots. See the label for a complete list.) But despite the wide spectrum of pests it controls, Delegate is generally soft on beneficial insects, such as lacewings and ladybugs, says Yoshida. Because of that, he says it fits nicely into growers’ Integrated Pest Management (IPM) programs.

Besides being soft on beneficials, Delegate is also registered under EPA’s Reduced Risk Pesticide Program. The re-entry interval (REI) is just four hours, whereas most other products used on pear psylla have an REI of 12 hours or more, says Yoshida. “That short re-entry lends a lot of flexibility to growers and consultants,” he says. “You can spray in the morning, and if you need to go back in and do any number of tasks, you’re free to do them that afternoon.”

Perhaps even more important to growers than the short REI is that in apple and pear orchards Delegate has a pre-harvest interval (PHI) of just seven days. That’s particularly important in Washington, says Dunley, because most pear plantings in the state are interplants of Bartlett and Anjou varieties. Bartlett harvest begins about three weeks before the Anjou harvest, which can lead to problems if pear psylla is present and the grower is using a product with a 28-day PHI. “At harvest, pear psylla is sometimes close to boiling,” he says. “Hopefully it has been suppressed by then, but if not, you need to get control.”

Another factor, which has become increasingly important in the past few years, is that pear psylla can produce copious amounts of sticky honeydew. Besides potentially leading to sooty mold, the honeydew is a real nuisance for fruit pickers. Growers can really use a product with a short PHI to get in and clean up pear psylla close to harvest. “Growers are becoming more and more interested in having a clean crop to harvest,” says Dunley, adding that if the fruit’s sticky, harvest crews might just opt to look for work elsewhere. “With the past two harvests, labor has become tight enough that growers need a clean crop.”

Leave a Reply

Featured Stories
Cannabis plant closeup
Citrus
December 6, 2016
Report: Florida Cannabis Business To Approach $2 Billion By 2020
Lofty projections include a compound annual growth rate of 140%. Read More
Growers participate in a real-time industry survey session at the 2016 Florida Citrus Show
Citrus
December 6, 2016
Florida Citrus Community Tasked To Unify For Stronger Future
A group effort is necessary to forge ahead. Read More
BlackPearl® is the best early season cherry, ripening 10 days before Bing and around Chelan. It has exceptional flavor and is extremely firm and crunchy. BlackPearl® is medium size with 20% sugar and keeps better that most other cherries. The tree is hardy and canker resistant. Early season bloom, S4 unknown.
Fruits
December 6, 2016
Fowler Nurseries, Inc. 2017 Variety Showcase [Slideshow]
For more information on these varieties, contact Fowler Nurseries, Inc. Fowler Nurseries, Inc. 525 Fowler Rd. Newcastle, CA 9565827 Phone: Read More
betternut-23
Vegetables
December 6, 2016
Rupp Seeds 2016 Vegetable Variety Showcase
For more information, contact, Rupp Seeds: 17919 County Rd. B, Wauseon, OH 43567 800-700-1199; WEBSITE www.RuppSeeds.com FAX 419-337-5491; EMAIL [email protected] Read More
NAFDMA 2015 gourds
Farm Marketing
December 6, 2016
Registration Is Open For 32nd Annual North American Farmers Direct Marketing Convention
The six-day event for agritourism operators heads to the Northeast with highlights including bus tours, educational sessions and workshops, and business exchange. Read More
sprayer applying bactericides to citrus trees
Insect & Disease Update
December 5, 2016
Best Practices For Bactericides Key To Vetting Citrus Solution
Approval finally cleared for antimicrobial applications, and now growers wait and hope to see positive results. Read More
Low-volume overhead irrigation system at Jones Potato Farm
Citrus
December 5, 2016
South Florida Endures Driest November On Record
Region has not experienced any significant rainfall since Hurricane Matthew. Read More
Meadowlark, a University of Florida release, is a popular Southern U.S. variety with machine-harvest characteristics and early ripening. The very large berries offer excellent firmness and flavor. Requires a pollinator. Fall Creek is licensed to sell Meadowlark in the U.S.
Fruits
December 5, 2016
Fall Creek Nursery 2017 Variety Showcase [Slideshow]
For information about these varieties, contact Fall Creek Nursery: Fall Creek Nursery 39318 Jasper Lowell Road Lowell, OR 97452 800-538-30015 [email protected] Read More
Chandra Roberts and Randy Dodds of Brandt Consolidated
Fruits
December 5, 2016
Team Coverage: Fruit And Nut Industry Conferences
Can’t make it to the biggest fruit and vegetable conferences? No sweat, we’ll take you there. Read More
sv3255-pb-fruit-4
Vegetables
December 4, 2016
Rispens Seeds 2016 Vegetable Variety Showcase
For more information, contact Rispens Seeds: 1357 Dutch American Way, P.O. Box 310, Beecher, IL 60401 708-946-6560; WEBSITE RispensSeeds.com FAX Read More
The Latest
Citrus
December 6, 2016
Report: Florida Cannabis Business To App…
Lofty projections include a compound annual growth rate of 140%. Read More
Citrus
December 6, 2016
Florida Citrus Community Tasked To Unify…
A group effort is necessary to forge ahead. Read More
Fruits
December 6, 2016
Fowler Nurseries, Inc. 2017 Variety Show…
For more information on these varieties, contact Fowler Nurseries, Inc. Fowler Nurseries, Inc. 525 Fowler Rd. Newcastle, CA 9565827 Phone: Read More
Vegetables
December 6, 2016
Rupp Seeds 2016 Vegetable Variety Showca…
For more information, contact, Rupp Seeds: 17919 County Rd. B, Wauseon, OH 43567 800-700-1199; WEBSITE www.RuppSeeds.com FAX 419-337-5491; EMAIL [email protected] Read More
Farm Marketing
December 6, 2016
Registration Is Open For 32nd Annual Nor…
The six-day event for agritourism operators heads to the Northeast with highlights including bus tours, educational sessions and workshops, and business exchange. Read More
Insect & Disease Update
December 5, 2016
Best Practices For Bactericides Key To V…
Approval finally cleared for antimicrobial applications, and now growers wait and hope to see positive results. Read More
Citrus
December 5, 2016
South Florida Endures Driest November On…
Region has not experienced any significant rainfall since Hurricane Matthew. Read More
Fruits
December 5, 2016
Fall Creek Nursery 2017 Variety Showcase…
For information about these varieties, contact Fall Creek Nursery: Fall Creek Nursery 39318 Jasper Lowell Road Lowell, OR 97452 800-538-30015 [email protected] Read More
Fruits
December 5, 2016
Team Coverage: Fruit And Nut Industry Co…
Can’t make it to the biggest fruit and vegetable conferences? No sweat, we’ll take you there. Read More
Vegetables
December 4, 2016
Rispens Seeds 2016 Vegetable Variety Sho…
For more information, contact Rispens Seeds: 1357 Dutch American Way, P.O. Box 310, Beecher, IL 60401 708-946-6560; WEBSITE RispensSeeds.com FAX Read More
GenNext Growers
December 4, 2016
New Loans Available For Small, Beginning…
USDA recently announced streamlined guaranteed Loans and additional lender category for small-scale operators. Read More
Crop Protection
December 4, 2016
Bio Huma Netics Opens New Lab Facility
Facility to improve quality control and help expand product line. Read More
Vegetables
December 4, 2016
Outstanding Seed Company 2016 Vegetable …
For more information, contact Outstanding Seed Company, LLC: P.O. Box 202, Monaca, PA 15061 PHONE 877-248-4567; WEBSITE OutstandingSeed.com FAX 724-775-1544 Read More
Apples & Pears
December 4, 2016
Easy Tips For Apple Pruning Demonstratio…
Seminar to be presented in both English and Spanish by Penn State University Extension experts. Read More
Fruits
December 4, 2016
Dave Wilson Nursery 2017 Variety Showcas…
Dave Wilson Nursery in Hickman, CA, presents a new interspecific apricot, clingstone nectarine, red-speckled pluot, and more. Read More
Fruits
December 3, 2016
TOMRA Acquires Compac Sorting Machine Ma…
Transaction to be complete in first quarter of 2017. Read More
More Vegetables
December 3, 2016
Johnny’s Selected Seeds 2016 Veget…
For more information, contact Johnny’s Selected Seeds: 955 Benton Ave., Winslow, ME 04901 PHONE 877-564-6697; WEBSITE JohnnySeeds.com FAX 800-738-6314 Read More
Grapes
December 3, 2016
You Need To Have Flexibility In Your Vin…
Prioritization and compromise are sometimes necessary in a challenging growing environment. Read More