Hops growers in the
Northwest – as well as sweet cheery, apple and other fruit growers around the
nation – may soon have a new tool to combat Prionus
beetles thanks to research funded in part by the Western Integrated Pest
Management Center.
The research identified a
sex pheromone produced by female Prionus
californicus beetles and developed a synthesized version to be used in a
commercial mating-disruption product that will be in large-scale trials as soon
as next year. Pacific Biological Control is developing the commercial product.
“Every year, the Western
IPM Center supports new pest-management research in the West, and this is
exactly the kind of impact we’re looking to make,” said Jim Farrar, the
director of the Center. “There really was no good way to manage this pest, and
now it looks like we’re close to an effective solution.”
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| Adult Prionus beetles. |
The adult Prionus californicus beetle is a
fierce-looking longhorn beetle about two-inches long. The adult beetle doesn’t
eat or drink and has a short three-to-four-week lifespan devoted to finding
other beetles to mate with. The damage is done by the larvae.
“The larvae are
root-feeders,” said Jim Barbour at the University of Idaho who co-led the Center-funded
research team with Jocelyn Millar of the University of California, and Lawrence
Hanks of the University of Illinois. “They grow to about three inches long, and
one or two of them really make a mess of hop roots and the roots of some fruit
trees. In fact, one old name for the beetle was the Giant Apple Root-Borer.”
Once a hop yard is
infected, the only effective control strategy has been pulling up the plants
and leaving the field fallow for two or three years. Fumigation with various
organophosphates is sometimes used, but its effectiveness is questionable.
“In Idaho, they are the
most serious hop pest,” Barbour said. “They are also a problem in Washington as
well, which is the largest hop-producing state with about 25,000 acres in
production.”
The team determined the
female Prionus beetle produces a sex
pheromone, then identified and synthesized the compound.
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| The larvae do the damage in hops and orchards |
“Since then, it’s been
shown to attract a number of Prionus
beetles, not just Prionus californicus,”
Barbour said. “It works with at least eight different species in North America
and one in Europe.”
The team tested its
compound in both mass-trapping strategies and mating-disruption approaches. In
the former, the bait scent is placed in traps that beetles fall into and can’t
escape and they die in the traps. In the latter, enough of the scent is
released to saturate an area so the beetles can’t follow it back to a female
and they die naturally without having mated.
“Mating disruption is
easier in some respects because you don’t have traps to manage,” Barbour said.
“It takes more work up front to show that the beetles are not finding each
other to mate.”
The team’s tests showed
both approaches can work, but have focused on mating disruption.
Barbour’s current research
team is working with Pacific Biological Control and Western Region IR-4 to get
the compound labeled by the EPA as a mating disruption agent for use in hops
and sweet cherries. Since both are small-acreage crops, expanding the approved
use to other crops like apples and pecans could help make the product more
economically viable.
“We hope that by 2014
we’ll have large-scale trials going with it,” Barbour said. “This certainly
will be welcome news in hop yards and to the hop commissions in various states.”
It's been a busy week couple of weeks for bees.
Are you planning new IPM research, or applying for a Western IPM Center grant, and want to know how to assess the impact of your project?
The Western IPM Center promotes integrated pest management practices not only in agriculture, but also for managing pests in natural lands as well as homes, schools and communities. One principle of IPM is prevention - keeping pests from taking hold to begin with. Now there's a new reference devoted to pest prevention in buildings.
In the past week, both Landscape Management and Green Industry Pros, two of the top trade publications in the industry, have published stories about the training material and links to the slide sets.
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