New fruit pest threatens soft fruit, berries, grapes
Originally published July 27, 2010 at 6:01 p.m., updated July 28, 2010 at 10:53 a.m.
WENATCHEE — There’s a new fruit pest in North Central Washington.
Larvae, likely those of the spotted-wing drosophila (Drosophila suzukii), were found Tuesday in a higher-elevation cherry orchard near Wenatchee, according to Tim Smith, tree fruit specialist for the WSU Chelan-Douglas Extension.
Smith said the fly came up the coast from California and hit the west side of the state last year, damaging berries and soft fruit, those which are vulnerable to the pest.
Adult suzukii flies, similar to the common fruit fly, have been found in orchard traps over the last couple of weeks in low numbers. To know for sure whether the larvae are those of the much-feared pest, Smith said he would have to see them grow into adult flies.
“We were thinking it didn’t come over to the east side because the weather wasn’t conducive to its lifecycle,” said Smith.
Smith said the emergence of a new fruit pest is unusual. “All the major ones have been around for a while.”
It is unknown how the fly will behave in a cold-winter area, said Smith, adding it could be a sporadic pest.
“We’re not sure anybody has the right to say they’re free of them unless they have the traps out and find no adults in the traps,” said Smith.
The damage the fly inflicts is different from most NCW pests, said Smith. The female fly lays its eggs in good fruit. The larvae then hatch and consume the parts of the fruit around where the eggs were laid. “It will form a kind of rotten pocket on the surface,” said Smith.
The pest is originally from Asia; Smith said researchers believe it entered California via Hawaii. It doesn’t pose any big quarantine issues for export since the pest is already in Asia and is rapidly spreading from state to state in the United States.
“People who own peach orchards should make sure they get it straight with their field managers what their plan is (to combat the pest),” said Smith, “same with any other soft fruit, maybe even grapes.
Smith noted that grapes hang on the vine for a long time in the fall and may be particularly susceptible to the fly.
“It is a new pest,” stressed Smith. “It doesn’t show carelessness but it shows we have something new that our old programs don’t necessarily control.”
Growers will have to change spray behavior to control the pest, he said, but added that growers already use the organic and conventional pesticides that will combat it. “It’s just a management change.”
Home growers of berries, who haven’t had to deal with such pests in the past, will also have to work on ridding their gardens of the flies.
“With berries you didn’t have to do anything but get them to grow. Now there’s a pest that will attack the raspberries just as they’re ripening.”
Rochelle Feil Adamowsky: 664-7153
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