New insecticides give grape growers more options for 2008

Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included.  

In the past few years, the grape industry has received registration of many new insecticides. This is good news for grape growers who must maintain insects below economic injury levels in a time of increasing restrictions on conventional insecticides.

The grape entomology program at Michigan State University evaluates insecticide performance in our Concord, Niagara and hybrid vineyards at the Trevor Nichols Research Complex. Each year, we run these trials against grape berry moth, Japanese beetle, and in recent years, potato leafhopper, testing the new products against each other and against a standard insecticide program. Our results have helped convince manufacturers and the EPA to register some of the new insecticides listed below, and they help provide information on which to base our recommendations. These products vary in their performance across different types of insect pests, the residual control they provide, and their safety to biological control agents. We have described their performance below to help growers integrate these products into their IPM programs.

Reasons to consider new insecticides as part of a grape IPM program include: 1) Some are more effective against key pests than current standard products; 2) Using new chemical classes can prevent insecticide resistance, 3) Reduced impact on biological control agents of some of these products can reduce the risk of pest outbreaks, and 4) Greater safety to workers and the environment.

This is a great time to learn about new pest management tools, including insecticides, to prepare for the busy growing season ahead. Talk to other growers who might have tried some of these products, attend grape grower meetings organized by the Extension service in your area, and read the new Extension grape management guides for your region. You can also see the labels for these products at the website.

Actara 25WG (Syngenta) is a neonicotinoid insecticide that is locally systemic, so it spreads in the foliage, protecting it against wash-off. This insecticide is labeled at 1.5-3.5 oz and is very effective on leafhoppers, beetles and other foliage feeders.

Admire Pro (Bayer CropScience) is labeled for leafhoppers, scale, mealybugs and phylloxera. This is the same insecticide as Provado, in a different formulation for soil application. The label states that application can be made using a chemigation system or through soil application followed by irrigation. In our trials, this product provided three weeks of control of potato leafhopper when chemigated on vines grown on a drip system at the first sign of leafhoppers. However, performance was poor when we applied it as a band under irrigated or non-irrigated vines. This suggests that sufficient uptake of this insecticide (and most other systemic insecticides we tested) is only possible on vines with roots trained to emitters. A later application, in late June, in a drip-irrigated vineyard was also shown to protect leaves from Japanese beetle feeding. This product has a 30 day PHI.

Assail 30SG (Cerexagri) is a neonicotinoid insecticide with activity on leafhoppers and other leaf-feeding insects. It also has performed very well in vineyard trials against rose chafer (equivalent to Sevin) and it provides vine protection against Japanese beetle feeding. Assail is also labeled for use against the foliar form of phylloxera.

Avaunt 30WG (DuPont) was registered in mid-2007 and is a member of a new class of insecticides called the oxadiazines. It is labeled for Japanese beetle at 3.5-6 oz/acre. This insecticide has shown good activity on grape berry moth in our small plot trials, providing a high level of control after bloom and in the mid-season, but lower control after veraison when berry moth infestation increases. The label directs growers to use a 5-6 oz rate for berry moth control. It should also have broad activity on other pest types, including leafhoppers, making it useful for growers aiming to control multiple insect types.

Baythroid XL (Bayer CropSciences) has high activity on a broad range of insects. At the 3.2 oz rate, our trials have shown excellent activity against grape berry moth and Japanese beetle. This product is also very active on Asian ladybeetles, providing a week of control of this harvest-time pest at a 2.4 oz/acre rate. This has a 3 day PHI.

Brigade 2EC (FMC) is the same material as Capture 2EC (FMC), labeled from 3.2 to 6.4 oz per application, with a 6.4 oz limit. These products are pyrethroids with high activity on a broad range of insects. At a 3.2 oz rate, Brigade has excellent activity against grape berry moth with higher rates giving longer residual control. Control of beetles and leafhoppers is also expected to be high. This product was very active on Asian ladybeetles at a 2.4 oz/acre. This has a 30 day PHI.

Delegate 25WG (Dow AgroSciences) was registered in the past few months, and is a member of the spinosyn class of insecticides. It has activity on moth pests and we expect it to have high activity on grape berry moth. However, we have not yet had a chance to test this in Michigan for insect control, and will run our first trials with it during 2008.

Intrepid 2F (Dow AgroSciences) is a selective insecticide with high activity on grape berry moth and safety to natural enemies. Intrepid acts by disrupting the molting process in moths. Labeled at 4-8 oz/acre, there is a 16 oz seasonal limit. Grape berry moth eggs treated with this insecticide have low rates of hatching, and larvae that ingest residue die during molting. For these reasons, excellent coverage of clusters with spray is needed to achieve control. This product has long residual activity and is relatively resistant to wash-off. It has a 30 day PHI.

Mustang Max 0.8EC (FMC) was registered in 2007 on grapes. At a 4 oz rate this pyrethroid gave excellent control of grape berry moth, Japanese beetle and multicolored Asian ladybeetle. It has a 1 day PHI.

Venom 20SG (Valent) insecticide is in the same class as Admire Pro, and can be applied as a foliar or soil application. Foliar application provided excellent control of potato leafhopper in Traverse City vineyards during 2007, and it is also active on Japanese beetle. Venom has also shown high activity against potato leafhopper when applied through chemigation, and activity against other soft-bodied insects such as mealybugs or other leafhoppers is expected. Our tests of Venom have also demonstrated reduced grape berry moth infestation when used against the first generation of this pest. Venom is not recommended for late-season control of berry moth, but it showed excellent activity against Asian ladybeetle infesting ripe grapes at 2 oz/acre in our 2007 trials. It has a 1 day PHI.

An important label change that may not have been noticed by all grape growers is the extension of the Re-Entry Interval for Imidan 70WP to 14 days in vineyards. The pre-harvest intervals have changed too: if more than 1.3 lbs is applied per acre, there is a 14 day PHI, compared with only seven days if a lower rate is used. To get the maximum activity from this insecticide, it should be applied in water with pH 5.5. If you don’t know the pH of your water supply, be sure to test it to find out if buffering is required.

A final note: Our evaluations of insecticides are conducted with an airblast sprayer in mature juice grape vineyards that have vigorous growth. For this reason, our applications after July are conducted using 50 gallons of water per acre. This is especially important when the layers of leaves can block the clusters from spray material. If the insecticide doesn’t cover the cluster, grape berry moth control will be minimal, so we recommend growers pay attention to cluster coverage after bloom and make the necessary adjustments to maintain coverage through the last application. This effort will be rewarded with improved pest control.

The insecticide testing program of the grape entomology program at Michigan State University is supported by the Michigan grape industry through the Grape and Wine Industry Council and National Grape Cooperative, by the agrochemical industry, and by the IR-4 Project.

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