- Author: Thomas J Getts
I have gotten quite a few calls about blister beetles this year. There was a newspaper article up in Modoc that caused some stir, and was picked up by a lot of social media pages. So, what are blister beetles and why do we care?
Blister beetles get their name for a reason. They contain the toxin cantharidin, which can be excreted when they are threatened, or crushed which causes bad blisters on the skin. While this is problematic they typically are not drawn to humans, and blisters can be avoided by not handling them. Where they pose a larger problem is as a contaminant of hay, where they can be crushed/killed and incorporated into a bale posing as a potential toxin to be consumed by livestock.
Photo One:...
- Author: Michael Rethwisch
- Editor: Ian M Grettenberger
This Grade Chart represents the average Insecticide Efficacy Grade against alfalfa weevil larvae from experiments conducted in the Palo Verde Valley over the past five years, with applications being approximately 18-20 gallons/acre to ensure excellent foliar coverage. Some products and rates are represented by only a single data point, while others have multiple year/rates of data. Data shown are from experiments which had weevil larvae numbers at or above economic threshold levels, providing high confidence in data.
Efficacy of pyrethroid insecticide products has changed through this period due to the development of insecticide resistance in this area's alfalfa weevils. Resistance has shifted multiple pyrethroids from...
- Author: Madi Hendrick
- Author: Ian M Grettenberger
- Author: Michael Rethwisch
Insecticide resistance in alfalfa weevils is spreading across California
- Author: Ian M Grettenberger
- Author: Kevin Goding
- Author: Rob Wilson
During the 2021 season, we conducted an insecticide trial evaluating a new insecticide being developed for a range of crops. It could be a very good fit for alfalfa weevil given the efficacy we saw as well as the critical need for novel modes of action for alfalfa weevil management. The need for more modes of action comes from the growing issue with pyrethroid resistance in alfalfa weevils. Across the US (an in California), there are now populations of pyrethroid-resistant alfalfa weevils. We are addressing this in a separate project, focusing primarily on resistance to lambda-cyhalothrin. New modes of action could allow for rotation, something that is very difficult given that currently, effective options are mainly limited to...
- Author: Ian Grettenberger
- Author: Rachael Freeman Long
- Author: Madi Hendrick
A virtual forage and alfalfa field day - our insect pest contribution
This year, the Kearney Research and Extension Center Alfalfa and Forage Field Day went virtual. Attendees did not get the chance to look out over lush fields of alfalfa or towering plantings of sorghum, but they get did an update on ongoing work in alfalfa and other forages. Our team put together a rapid-fire video to discuss what are typically the key insect pests in California alfalfa: summer worms, alfalfa weevils, and aphids.