Should you use tea seed meal to eradicate Amynthas jumping worms?
My lawn and raised bed garden have been infested with the Amynthas jumping worm that I first noticed in 2021. I’ve read that applications of tea seed meal will eradicate these worms. I realize that Tea Seed Meal will also kill the good worms are there any other downsides?
We do not recommend using the tea seed meal as a treatment. While there are some reports of it being effective at killing earthworms (jumping and, as you note, normal beneficial ones), it is also lethal to other organisms in the food chain, particularly molluscs and fish if it gets into the groundwater. You can read more in this UMass-Amherst Q&A on Amynthas and Metaphire worms. Unfortunately, there isn’t yet a consensus on a safe and effective management technique, other than removing them by hand using the mustard soaking explained in my included links. Obviously, if your infestation is on a larger scale than that allows, that idea may not be feasible for you, but it could work in a garden bed or two. That said, there is some evidence that biochar and diatomaceous earth may mitigate the pests when mixed into the soil (read about the use on the UPenn Extension page on jumping earthworms)–this will affect beneficial earthworms, too, but is presumably less harmful when added to the soil.