When using blended products:
- Know the pest that you need to control.
- Use an appropriate insecticide that will do the job with as little negative impact as possible.
- Avoid broad spectrum insecticides when possible.
- Avoid using redundant materials.
Over the past decade, the number of vegetable insecticides (both commercial products and insecticide classes) has increased significantly. Included in these are a number of materials with novel modes of action (MOA), and high degrees of pest specificity. For example, some newer materials have efficacy against caterpillars only, while others may control caterpillars and some fly larvae. Other examples are detailed in the chart, Combination Insecticide Products for Commercial Vegetable Crops. This article clarifies the options in the Commercial Vegetable Recommendations so that growers may make more informed choices as to the most useful product for specific pests.
The increasing number of choices for insect control in vegetable crops can lead to some confusion, but there is also great potential benefit if the options are understood – what the different compounds do, both to crop pests and beneficial insects. A number of newer compounds can manage important pests, while preserving beneficial insects, such as pollinators or natural enemies of other crop pests. These are positive factors if an integrated pest management (IPM) approach is desired by growers. Make best use of available insecticides by learning what each component of these compounds target and impacts. Be aware that products combining two insecticidal compounds may increase confusion when choosing the appropriate product for a specific pest situation. Frequently, only one component of the insecticide blend has activity against the target pest. In other instances, one component may result in secondary pest outbreaks. Still other blends are redundant, in that they combine similar products.
Remember, blended products are identified by trade name for ease of identification by the user. Components are listed by generic name, consistent with their appearance in the Commercial Vegetable Recommendations. Generic names are followed by the Insecticide Resistance Action Committee (IRAC) code for the compound. This assists in avoiding compounds with redundant MOA.
Know What the Insecticide Controls!
Example 1: If the pest is a caterpillar (European corn borer in pepper), you will see in the Commercial Vegetable Recommendations, the product Besiege. This product is the combination of chlorantraniliprole, IRAC-28, and lambda-cyhalothrin, IRAC-3. Both components of this blend are also listed separately for ECB control in peppers. Chlorantraniliprole is an excellent caterpillar material that will not harm beneficial insects. As a result, no secondary pest outbreaks would be expected from using it alone. Lambda-cyhalothrin will also control ECB, but this class of insecticide will kill predators and parasites of aphids. Use of this material as little as one time can result in an aphid outbreak. Further, this class of insecticide, IRAC-3, is acutely toxic to pollinators and contact with these beneficial insects should be avoided.
When looking in the Commercial Vegetable Recommendations Guide for insecticides, check to see whether one component insecticides are recommended. When a two component insecticide product contains a broad spectrum insecticide, its use may cause secondary pest outbreaks. In an IPM scheme, IRAC-3 insecticides are discouraged for caterpillar control because there are usually other choices that work very well without the negative impact on beneficial insects.
Example 2: A significant number of stinkbugs are found in a pepper planting, and fruit injury is appearing. Choices in the Commercial Vegetable Recommendations Guide include the same combination as in the previous example. In this case, the lambda-cyhalothrin, IRAC-3, component is the one with activity against the stinkbug. The second component (chlorantraniliprole IRAC-28) has no effect on the target pest. Lambda-cyhalothrin is recommended individually for stinkbug control in peppers. This product does kill beneficial insects, but in this instance, management of the stinkbug is the priority.
When only one component of a recommended blend controls the target pest, use the one component insecticide, instead of a blended product. There is no need to have a second material that has no positive impact on the pest situation.
When possible, avoid materials that are toxic to bees.
Example 3: The combination of thiamethoxam, IRAC-4A, and chlorantraniprole, IRAC- 28, is in the Commercial Vegetable Recommendations Guide for control of numerous caterpillar pests of tomato. For tomatoes, chlorantraniliprole (the component responsible for caterpillar control) is also recommended by itself. The second component, thiamethoxam (as are all IRAC-4A materials) is extremely toxic to bees and has no use against caterpillars.
This two component product should be avoided for caterpillar management in favor of products that specifically target them. Chlorantraniliprole would be one product with good efficacy on caterpillars and little impact on bees.
Example: A combination of zeta-cypermethrin, IRAC-3, and bifenthrin, IRAC-3, is in the Commercial Vegetable Recommendations Guide for control of cucumber beetle on summer squash. Both components are also recommended individually. They are in the same chemical class and do the same thing, as broad spectrum insecticides. Individually, either would be effective against cucumber beetle. There are many instances in the Commercial Vegetable Recommendations Guide where this combination is an option for specific pests while the components are also listed.
Why apply a redundant product, when the individual parts can perform the necessary task?
The Take Home Message
A number of newer compounds can manage important pests, while preserving beneficial insects, such as pollinators or natural enemies of other crop pests. However, as the numbers of commercial insecticide products and classes have increased, choices in vegetable crop protection has become more complex and potentially confusing. Blended products only add to that confusion if individual component impacts are not understood. Become familiar with products, their components, and targets to make best use of available vegetable crop protection insecticides.
Know the pest that you need to control.
Use an appropriate insecticide that will do the job with as little negative impact as possible.
Avoid broad spectrum insecticides when possible.
Avoid using redundant materials.