Colorado potato beetle insecticide resistance management
Colorado potato beetles are emerging and migrating into potato fields. Find out how to slow insecticide resistance development in this insect.
Colorado potato beetles are notorious for developing insecticide resistance, therefore their management should follow appropriate guidelines to stop or slow this process. Our records show that between 1998 and 2010, the level of insecticide resistance to imidacloprid has grown exponentially in this insect.
The most common way to manage beetles currently in commercial potatoes is to apply neonicotinoid insecticides (imidacloprid or thiamethoxam) in furrow, at planting. In most cases, this treatment provides sufficient control for overwintered beetles and in some cases, for summer populations as well. If the summer generation of beetles needs to be managed, then foliar insecticides can be applied.
In order to slow down the resistance development of Colorado potato beetles, it is recommended that insecticide classes are rotated, meaning that insecticides with the same mode of action are not applied to Colorado potato beetles twice within a season. All of the insecticides in Table 1 are non-neonicotinoid, so they are good options for foliar beetle management if a neonicotinoid was applied at planting.
The National Potato Council has prepared the following guidelines for Colorado potato beetle insecticide resistance management. Manage insecticide resistance in the following ways.
- If a neonicotinoid insecticide (Group 4A) was applied at planting, either in furrow or as a seed treatment, do not use a foliar neonicotinoid insecticide later in the season.
- Crop rotation with a minimum of 0.25 of a mile between successive plantings is especially important for management of Colorado potato beetle.
- Apply insecticides only when necessary.
- Use scouting, sampling procedures and action thresholds.
- Do not treat all potato fields on one farm or in one localized area with products from the neonicotinoid class.
- Preserve natural controls by using selective insecticides when possible, like Rimon.
- Spot treat when feasible, such as field edges. This can also be done by using a potato trap crop – potatoes that are planted in field margins earlier than the main crop – and therefore will harbor large numbers of early emerging beetles that can be killed on the trap crop.
- Do not apply insecticides below labeled or recommended rates. Application of sub-lethal rates of any insecticide may result in poor product performance, insect damage to the crop and an increased risk of resistance development.
For further details on neonicotinoid insecticides and resistance management, go to the National Potato Council’s Neonicotinoid Insecticides website.
Table 1. Foliar options for Colorado potato beetle management if imidacloprid or thiamethoxam was used at planting.
|Group||Brand name||Chemical name||Rate (per acre)||PHI||Days between treatments||Recommended maximum use per season||Recommended maximum number of applications1|
|3 and 28||Voliam Xpress||lambda-cyhalothrin + chlorantraniliprole||6.0-9.0 fl oz||14 days||7 days||27 fl oz||3|
|5||Radiant SC||spinetoram||4.5-8.0 fl oz||7 days||7 days||16 fl oz||2|
|6||Agri-Mek 0.15 EC||abamectin||8.0-16.0 fl oz||14 days||7 days||32 fl oz||2|
|15||Rimon2||novaluron||6.0-12.0 fl oz||14 days||7 days||24 fl oz||2|
|28||Coragen||chlorantraniliprole||3.5-5.0 fl oz||14 days||5 days||10 fl oz||2|
|1 Limit applications to a single generation2 Only effective on larvae, time application when small larvae are most abundant|
For a more comprehensive potato insect management guide, go to MSU’s Potato foliar insecticide spray guide for insecticide resistance management website.
Dr. Szendrei’s work is funded in part by MSU’s AgBioResaerch.