Sep 3, 2020
Another challenging pest has made Pennsylvania its home

A few weeks back, you were alerted that the Swede midge was found on a Pennsylvania farm. We now warn you about another invasive pest, jumping worms.

Jumping worms (Amynthas spp., also known as Asian jumping worms, crazy worms, Alabama jumpers, and snake worms) were identified on a farm in Montour County this week.

So, what’s the big deal? Jumping worms are highly destructive to soil quality; they grow fast and reproduce quickly, and consume large amounts of organic matter. The plant nutrients in the worm castings are unavailable for a considerable time, and the castings themselves form a dry pellet. Soils tend to dry out quickly as organic matter is depleted, and soil structure degrades, resulting in a soil structure that some have described as resembling coffee grounds. In the forest, they can destroy the mulch layer on the forest floor, making it impossible for many plant species to germinate and establish themselves.

How widespread are these jumping worms in Pennsylvania? We just don’t know.

The Montour County growers believe they have been on their farm for at least two years. As you can see from the picture, the adults are about 5 or 6 inches long. They are more active than nightcrawlers. They appear to jerk or jump when disturbed. One characteristic that distinguishes them from a nightcrawler is the clitellum (the narrow band around their middle). The clitellum on the jumping worm is flush with the rest of the body, while on a nightcrawler, it is slightly raised. The clitellum on the jumping worm goes all the way around the body while it does not go around a nightcrawler’s underside. It is creamy white to grey on a jumping worm. The jumping worm has only one generation a year. The adults lay their eggs in the soil then die when the ground freezes. The egg cocoons can survive winters worst and hatch out in the spring.

Note the clitellum around the middle is flush with the body. On a nightcrawler, this would be slightly raised. 

Do they damage crops in ways other than reducing soil quality? It has been documented that they will feed on roots. The Montour County grower had the beet and carrot seedlings eaten off shortly after emergence within the last week. We found an abundance of jumping worms in the area and no other potential pests.

What should you do if you find jumping worms? First and foremost, be careful not to spread them around on your farm or to other farms. They move with soil. Keep in mind that soil can contain eggs even if adults are not present—clean soil from equipment and even shoes before moving to the next field. There are no insecticides labeled to control jumping worms. If found on a small scale, the worms can be collected, destroyed, and disposed of. Do not use them for fishing or in a compost bin. We currently know very little about this pest, but that will change. Keep your eyes and ears open for now.

John Esslinger, Penn State University

Jumping worms are highly destructive to soil quality. Photos: John Esslinge/Penn State

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