Two University of California (UC) researchers have interesting results to share from trials conducted on the efficacy of the new insecticide Movento for vine mealybug control in table grapes and insects that target California citrus.

Movento is a new, two-way systemic foliar insecticide from Bayer CropScience designed to kill sucking insects. Movento enters the leaf vascular tissue and then moves up and down the plant to protect leaf and root tissues.

Table grapes

David Haviland, UC Cooperative Extension entomology farm advisor, Kern County, has studied Movento and other insecticides in table grape field trials in commercial vineyards in Kern County, Calif., for two years.

Haviland gives Movento high marks for vine mealybug control.

“Movento was very effective for vine mealybug control in table grapes,” Haviland said. “The product performed best when applied in April, but it also did well in May and June.”

A single application is typically sufficient for early varieties including Flames. Movento can be used in combination with other products for late-season varieties, Haviland says.

Over the years the vine mealybug has earned a bad reputation in the grape industry. The pest generates honeydew that drops onto grape bunches and vines creating a black sooty mold that makes grapes unfit for consumption.

Mealybug control is crucial to table grape exports from California, Haviland said. “For those exporting fresh market fruit, there’s no tolerance for mealybugs in the grape clusters.”

Haviland’s trials showed surfactants (wetting agents) improved the effectiveness of Movento. Each surfactant tested performed similarly.

Kern County, located at the southern end of California’s San Joaquin Valley (SJV), is among the first table grape-growing areas to get vine mealybug infestations each year. Infestations are heavy with five to seven pest generations. Haviland says the insect is present in at least one vineyard in each table grape-growing region in the county.

Haviland kicked off the trials with Jennifer Hashim-Buckey, UCCE viticulture farm advisor, after several growers noted they had adopted UCCE vine mealybug control techniques, but were “were still getting their tails whupped by the pest.”

The in-season trials included 20 vines per plot; a total of 2,400 vines. Movento was tested with the insecticides Venom, Applaud, Assail, Clutch, and Platinum.

Foliar-based products were applied with an air blast sprayer. Bamboo sticks, cups, and drip irrigation were utilized for soil-applied products.

“Movento provided excellent control of vine mealybug in Flames grapes,” Haviland said.

In Crimson (late season) table grape variety field trials, 8 ounces of Movento per acre were applied in April, May, or June. Crimson grapes are typically harvested from October to early November.

Haviland said, “If a grower has a high mealybug infestation in Crimson grapes late in the season, the stacking of different insecticides is recommended during the growing season.”

Haviland says the best options are Lorsban in February, Applaud in April, Movento from April to June, Admire in May or June, Clutch a little later, and possibly a Lannate application close to harvest. In some cases a grower can get away with one or two of these options. In others, many will be needed to prevent damage.

Movento also did well in Summer Royal and Thompson grape variety post-harvest trials (one each) sprayed in August. Movento outperformed the grower standard Lorsban when evaluated the following May.

Movento doesn’t harm beneficial parasitoid insects that tackle mealybugs in the fall vine canopy, Haviland said.

“Movento is becoming the standard by which mealybug treatments in grapes are measured,” Haviland said. “The product has that much potential.”

Haviland’s trials were financed by the grower-funded Kern-Tulare Consolidated Pest and Disease Control District, Bayer CropScience, and other companies.

Citrus

Beth Grafton-Cardwell, UC research entomologist and integrated pest management (IPM) specialist, Kearney Agricultural Center, Parlier, Calif., conducted trials on Movento’s efficacy against six citrus pests from 2006-2008.

• California red scale: Movento’s best success in citrus pest control was against the California red scale. Its long, filamentous mouthparts attack plant tissue in citrus twigs, leaves, branches, and fruit. Heavily infested fruit can be downgraded in quality at the packinghouse resulting in lower returns to growers. Serious tree damage can occur during late summer and early fall infestations.

Grafton-Cardwell’s laboratory tests with Movento provided a 99 percent mortality rate of the first, second, and third instar scales.

In a 2006 field trial in a commercial orange orchard, Grafton-Cardwell studied whether Movento could be applied with less water and still do a good job. Traditionally California red scale is controlled with 750 to 1,500 gallons of water per acre. The application of high water amounts can cause application costs to be higher than the pesticide cost, Grafton-Cardwell says.

Movento, mixed with the surfactant Silwet, was sprayed on individual trees using 250, 500, and 1,000 gallons of water.

“The water volume could be reduced while attaining similar levels of red scale control with Movento,” Grafton-Cardwell said. “A Movento application in July with an oil adjuvant in 500 gallons of water offered the best control of California red scale in oranges.”

She calls Movento a “good fit” for California red scale control. The insecticide works well with natural enemies including the wasp parasite Aphytis melinus.

“Growers need an insecticide to rotate with Esteem to avoid pesticide resistance in California red scale control,” Grafton-Cardwell said. “A single Movento application between May and August works best.”

• Citricola scale: This serious citrus pest causes sooty mold problems and reduced yield when insect levels are high. Citricola scale produces a single generation per year. Crawlers emerge in the spring and move to the leaves.

“Movento didn’t provide significant control for citricola scale control,” Grafton-Cardwell said. “Lorsban remains the standard for citricola scale control.”

•Citrus red mite: This spring-time insect causes pale stippling (lightening) on the upper leaf surface. Severe infestations can cause leaf drop, twig dieback, plus fruit sunburn in hot weather.

“Movento did a nice job of reducing citrus red mites to low levels for several weeks,” Grafton-Cardwell said. “It’s equivalent to the product Envidor.”

• Cottony cushion scale: The scale reduces plant vigor by removing sap from leaves, twigs, and branches. Leaf and fruit drop plus twig dieback can occur in heavy infestations.

Insecticide treatments for this pest in the SJV are occasionally needed since the vedalia beetle, a natural predator, does a yeoman’s job of cottony cushion scale control.

“Trial results showed little cottony cushion scale control from Movento,” Grafton-Cardwell said. “The product was friendly on vedalia beetles; good news for integrated pest management compatibility.”

• Citrus leafminer: This insect primarily targets citrus nurseries and new plantings; tunneling inside young leaves causing curling and distortion.

Grafton-Cardwell’s experiments exposed citrus leafminer eggs to citrus seedlings. A 10-ounce Movento application per acre killed the eggs in five days. Grafton-Cardwell will repeat the experiment with larvae and adjuvants.

“We want to come up with alternative products so nurserymen can rotate different types of insecticides to better manage resistance issues,” Grafton-Cardwell said.

• Cotton aphid: This aphid picks up citrus tristeza virus (CTV) in citrus and pomegranates and moves it to other trees. CTV causes girdling at the bud union which halts the transport of starch to the roots.

While CTV has killed millions of trees around the world, the virus is generally a mild strain in the San Joaquin and the southern desert valleys.

In a commercial pomegranate orchard trial, Movento applied in April reduced aphid numbers after several weeks for a short period with the assistance of natural enemies.

“Movento helps reduce cotton aphid populations and the natural enemies can finish the job.” Future trials will study adjuvant and irrigation use.

Grafton-Cardwell conducted the leafminer and scale lab work at the Kearney Ag Center and the citrus field trials at the Lindcove Research and Extension Center where she serves as the director. Funding was provided by the California Citrus Research Board and the chemical industry.

Movento’s active ingredient is spirotetramat; the mode of action is a lid biosynthesis inhibitor. Movento received registrations from the U.S. EPA and the California Department of Pesticide Regulation in the summer of 2008.

Haviland and Grafton-Cardwell shared their findings with pest control advisers attending a Bayer CropScience tree and vine seminar in Monterey, Calif., in January.

email: cblake@farmpress.com