With all their mites |
Back to PORTFOLIO | Next Story: ‘This is the future’ |
Heading into a new season, California pear growers now
have several new options for managing these costly pests
No one has compared them to kids in a candy store, but some California crop advisors can hardly contain their excitement when discussing the broad selection of treatment options they have available this year for mite control in pears.
“We’re really very fortunate,” says Tom Wiseman, a professional crop advisor (PCA) with John Taylor Fertilizer in Walnut Grove. “This year we’re enjoying quite a selection of miticides for pears, many with different modes of action and chemistries, which is something we haven’t had for a decade. They’re all relatively easy on the beneficials and, when used in the right way, complement each other very well.”
PCA Bill Knispel of United AgriProducts in Kelseyville has a similar view.
“You can never have enough bullets in your holster,” adds the PCA “With all the concern about resistance management and IPM, it’s nice to have all these new tools available to us.”
So broad are the choices that for the first time in eight or nine years, Knispel expects some PCAs to give some old standbys a much-needed rest.
Breaking the cycle
“Some PCA’s and growers I’ve talked to say they’re going to either limit Agri-Mek (abamectin, Novartis) to only one application per season or possibly not use it at all — something that would have been unheard of only a year ago,” he says. “It’s been a good product for us, but we’ve heard some reports of it not working as hard as it used to and we want to preserve it for future seasons. We need to break up the cycle of continuous use.”
One possible substitute for Agri-Mek is Pyramite (pyridaben, BASF), an adulticide/larvicide that was recently cleared for use in California pears. Its spectrum of activity is similar to Agri-Mek’s, but it has a different mode of action. “But even with a new product, I think we want to be careful when using some adulticides back to back,” says Knispel.
“Sometimes late in the season, when the trees leaves get almost leathery, you get a knockdown from these products but not much in the way of a residual. I think that’s where some of our performance problems begin.”
Another option — one that has been gaining popularity in Oregon, where
some of these newer products have been used commercially for several years — follow the adulticide with an ovicide/miticide in the second or third cover spray. The idea is to kill the eggs and emerging nymphs to reduce the need for adulticides.
California pear growers have used Apollo (clofentizine, AgrEvo) for this purpose in the past, but another ovicide/miticide is now also available.
New option for California
This past fall, Savey (hexythiazox, Gowan) ovicide/larvicide was cleared for use in pears in California. Like Apollo, it’s effective against three types of mites — European red mite, two-spotted spider and McDaniel spider. Savey’s residual activity in pears is generally about five weeks or longer. Savey has been shown to be more effective than other ovicide/miticides in controlling the immature mite stages.
“I wouldn’t write off Savey as a me-too product,” Wiseman says. “It is similar to Apollo in the way it works, but it has a different chemistry and we shouldn’t discount the importance of that. Having two different ovicides could prove to be very valuable.”
Gowan, the manufacturer of Savey, recommends using either product only once a year, but never both. “The rule is that if Savey has been applied, do not apply Apollo — and vice versa,” says Dr. Rod Kepner of Madera, Calif., an entomologist with Gowan.
‘Responsible choice’
The industry has reacted positively to the company’s cooperative labeling.
“A lot of companies say that growers should have the choice and then leave it at that,” says Rick Hilton, an entomologist at Oregon State University who has worked extensively with mite control in pears. “But growers are faced with a lot of other problems and conflicting information. The responsible choice is the one that Gowan made, putting the products longevity and effectiveness ahead of the bottom line.”
Last year, PCA Wiseman was involved in several test plots evaluating Savey in California pears. “We didn’t have a tremendous amount of mite pressure in our area last year, but all of the treatments stood up very well to the European red and two-spotted mites,” he says.
“If rust mite is also a concern, then you have to start with a product like Agri-Mek or Pyramite,” he adds. “If we have populations creeping up on European red or two-spotted mites, then it would be prudent to add Savey or Apollo to the first or second cover spray.”
Dr. Kepner explains that ovicides/larvacides such as Savey should be used primarily as preventives. “You don’t put out fires with these products,” he insists. “You want to get them out there during the early stages of egg deposition. If a significant number of adult mites is present, we recommend tank mixing Savey with an adulticide.”
Getting a jump
In Oregon, where Savey and Apollo have seen extensive usage, growers say they like the flexibility the ovicide/miticides provide. “Instead of having to wait for mites to appear, we can go in and spray when we have a high egg count, which results in much lower adult populations later on,” says Laura Naumes, who supervises pest control on 2,400 acres of pears at Naumes Farms, Medford, Ore. “It also gets the young mites shortly after they hatch.”
“Getting a jump on young mite populations is important, she says, because adults are more difficult to control later in the season. As the leaves become harder, the adulticides can’ t be absorbed as readily and they lose some of their effectiveness,” she explains. “But in our experience with Savey, we haven’t seen any difference in performance later in the season. If we have high mite pressure and don t want the trees to burn [from mite infestation], we’ll apply both Savey and an adulticide together.”
Oregon State’s Hilton agrees with this approach.
“Because of their residual activity, if you apply Savey or Apollo mid- to late-season, eventually the adults will cycle through and the mites are turning over at a very rapid rate that time of year and the adults will die,” he says. “And because of the ovicide, the eggs won’t survive, either, so it ends up being an effective tool throughout the whole season.”
Easy on predators
Hilton thinks the “soft nature” of these ovicide/miticides have made them the first choice among growers using mating disruption and relying on biological controls for pear psylla.
“Both compounds are very easy on predatory mites and other natural enemies,” he says. “The new mite products for California pears are also leaving room for creativity when setting up programs for different growers. We could be looking at some interesting brews,” Knispel says.
“You might want an organophosphate like Guthion, Pencap-M or Imidan for the codling moth, maybe a little oil in there as a carrier, Provado or Comply as a psyllacide, and then Savey or Apollo as a miticide/ovicide. If it helps to break the pattern of what you’ve been doing and accomplishes what you’re trying to do out there, you should go for it.”
Finally, Knispel thinks using an ovicide/miticide may have potential use for post-harvest cleanup in some seasons.
“The last two years we’ve had a pretty mild fall, which can cause mites to re-emerge,” he says. “We had some fields that looked like they were hit with a blow torch— the mites just burned up the leaves. If you can keep the populations down in the fall, it’s going to make it a lot easier to control mites the following season. Applying Savey with some oil will help with pear psylla.”
Back to PORTFOLIO | Next Story: ‘This is the future’ |