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A new insecticide in the registration pipeline will give grape growers a chance to control sucking insects during the root-feeding stage, says a Washington State University entomologist.

Dr. Doug Walsh said he believes a new insecticide called Movento (spirotetramat) will be available within the next few years from Bayer Corporation to provide systemic control of sucking insects. The material has a unique mode of action that works throughout the entire plant system, from the young shoots to leaves to roots.

"Soon, we’ll be able to deliver a toxic insecticide during the root-feeding stage of insects, a stage that has been very difficult to control," he said, adding that the new insecticide will especially be of interest to California growers in their control of phylloxera and mealybugs.

Walsh, while updating growers on grape pests and insecticides at the Washington State Grape Society’s annual meeting last fall, said the pest issues of the state’s grape industry have been relatively stable. "The grape pest industry has been an exemplary example in terms of pest and mite control," he said.

Eliminated OPs

By using a targeted pyrethroid barrier spray for climbing cutworms, Washington’s grape industry has virtually eliminated the use of organophosphates from vineyards, Walsh said. The barrier spray, applied only to the base of the vine trunks, has worked well for controlling cutworms that climb up the vine and feed on grape buds in the spring. He noted that because the spray is targeted to the base of the trunks, it has not disrupted beneficial ­predators in the vineyard.

"Since the industry eliminated its use of Lorsban (chlorpyrifos), I’m not hearing of outbreaks of spider mites that were so prevalent ten years ago," Walsh said. Several miticides are now registered for grapes, providing a much more stable system than before. These include: Agri-Mek (abamectin), Acramite (bifenazate), Fujimite (fenpyroximate), Zeal (etoxazole), Omite (propargite), and petroleum oils.

However, he cautions growers to pay attention to the type of miticide they choose, because some synthetic pyrethroids like Brigade or Capture (bifenthrin), Baythroid (cyfluthrin), Danitol (fenpropathrin), and Mustang (zeta-cypermethrin), list spider mites on the label as a target pest. "I would strongly recommend against ever using any synthetic pyrethroids for control of spider mites because history has shown that you’ll wind up with a ­bigger problem than what you started with."

Three relatively new materials are registered for control of thrips, including the spinosad products of Success, Entrust (organic spinosad), and Reliant, which he calls a "super" spinosad because it contains a more toxic form of spinosad. Reliant may be more effective in cool spring conditions, he said. Though the spinosad materials offer fairly effective control, spinosad used against thrips in WSU tests in Washington vineyards have not been effective during cool spring conditions. He did note that a summer treatment of Success was effective against thrips in a Concord block.

Grape leafhoppers or Virginia creeper leafhopper have not been the problems in Washington that they have been in California, where Walsh recalls "biblical clouds of leafhoppers" in vineyards that were in large enough numbers to irritate workers. Several years ago, he screened numerous materials in a leafhopper outbreak at Cold Creek Vineyard in mid-August and found effective control of leafhoppers within two weeks of application from all seven of the tested materials.

These insecticides included: Provado (imidacloprid); Applaud (buprofezin); Assail (acet-amiprid); Danitol; Fujimite; Avaunt (indoxacarb); and Actara (thiamethoxam). The block had an infestation level of about 35 nymphs per leaf.

Glassy-winged sharpshooter, a vector of Pierce’s disease, has yet to show up in Washington, but the sucking pest has caused significant problems in California vineyards, where it has spread throughout grape-producing regions. Millions of dollars have been spent on research to develop control methods.

Walsh said there is some speculation that the insect could survive in Oregon’s Willamette Valley and Washington’s Columbia Basin, but he thinks it may be the lack of citrus (an alternate host of the sharpshooter) in the Pacific Northwest that is keeping the pest from moving north.

Researchers also doubt that the Pierce’s disease ­bacterium can survive the cold winters of the Northwest.

A new pest he warns growers to be on the watch for is the light brown apple moth. The pest was first detected in California last spring and has spread rapidly to about a dozen of the state’s more populated counties. Although it is native to Australia, and has found its way to other parts of the world including Hawaii and England, this is the first detection on the U.S. mainland.

State and federal officials are working together to ­control and eradicate the pest. Quarantine areas have been imposed, and restrictions to movement of regulated articles enacted.

While the pest doesn’t do well in hot climates, it has done well in England, Walsh said. "Cooler areas like the Willamette Valley and western Washington may have potential for the pest."

Washington and Oregon growers need to keep their eyes open for the pest because it has a wide host range of about 250 plants, he said. Thus far, most of the finds have been on ornamental plants, but the Pacific Northwest brings in a lot of ornamentals and food products from California. "There’s a pretty good chance that Washington will pick it up here soon."

Light brown apple moth is not to be confused with other leafrollers from the tortricidae family that are in the Northwest, such as pandemis leafroller, he said. Growers should look for egg masses, and if they see a suspicious moth, take it to WSU entomologists for identification.

"I have the feeling that their spray program is too little too late, and the pest will eventually make its way up the coast," he said, but added he does not know if the pest can make it across the mountains and persist in eastern Washington.