SOUTHAMPTON — Ever seen a worm thrashing about? It was probably a jumping worm, an invasive species that’s spreading through the region. According to Joe Impoco, new manager at Tripple Brook Farm, that may be bad news for gardeners, farmers, plants and the soil.
Impoco and employee April Sabadosa are in an “experimental phase” because the energetic worms are in local soils and interspersed with the worms already on the farm. That’s a problem for identification, separating resident worms from the newcomers, which is the first step in preventing soil and crop damage.
“Identification … is the main thing we have had to do, make sure that we identify them correctly and don’t eradicate any other earthworm species,” Impoco said. “They can be such an issue, in terms of degrading soil and jumping on fresh roots.”
Jumping worms look much like the typical nightcrawler found in local dirt, with two key differences. The collar, known as the clitellum, is lighter in color than a nightcrawler’s collar. The clitellum also does not entirely encircle a jumping worm, as it does on nightcrawlers.
Jumping worms also wiggle and thrash. The unusual energy is a good sign it’s a jumping worm — but the problem with jumping worms lies not in how they dance, but in how they change the soil.
Nightcrawler castings, dirt like material left by worms digesting organic matter in the soil, is some of the best amendments for gardeners. Not so for jumping worm castings. Jumping worms, a native of Asia, deplete nitrogen from the soil and degrade its quality.
“Typically, what you want to see is that rich black crumbly soil,” Impoco said of worm castings. “But their biology removes a lot of nitrogen from the soil … So we’re seeing them go through and break down things, but in an unfavorable way.”
Nitrogen is an essential soil element that promotes the growth of most plants. Nitrogen is so important for plant growth that most soil additives and amendments, such as Miracle Gro™, list on the front label what percentage of the product is nitrogen. Jumping worms deplete nitrogen, however, so Impoco anticipates higher costs for commercial growers if the invasive species becomes entrenched.
The structure of the soil itself is changed by jumping worms. Impoco characterized jumping worm castings as more like coffee grounds, while nightcrawler castings are lumpy, with a finely grained texture. The difference in soil structure may impact growing conditions and results, but clinical information about the newcomers and their impact on soil productivity are in short supply.
Jumping worms may not be a major threat to farm and garden production. Conventional farming methods may yield an effective countermeasure, but Impoco foresees an organic approach will bring a good degree of control. A new invasive species is upsetting, though, and alarms are still sounding around the area.
“This woman was saying that when she first found them in her garden she thought it was going to be the end of the world,” Impoco said. “As she continued with organic gardening practices, constant layers of mulch, refreshing the soil with compost amendments, using natural fertilizers, especially chicken or horse manure, planting legumes around, all those practices were enough to mitigate the issues” caused by jumping worms.
Chicken droppings are especially high in nitrogen and legumes restore nitrogen to the soil as they grow. Restoring nitrogen to the soil will aid plant growth, but Impoco anticipates that choosing different plants for the garden will also reduce the possible impact of the newest invasive.
“We’re looking at a lot of annuals that have been impacted by this … anything that has small tender roots,” Impoco said. “If we were to make a shift toward perennials that serve the same function — there are trees with edible leaves that could be used in place of a big bed of leafy greens — [then] we have a perennial source of those greens as opposed to annuals that run the risk of failure, due to the worms.”
It takes years to grow a tree crop. Many home garden crops like chard and kale, popular annuals, have small tender roots, preferred forage for jumping worms. How can a landowner know if jumping worms have reached a home garden? More importantly, how are the newcomers controlled or eliminated?
According to the University of Massachusetts Extension Landscape, Nursery and Urban Forestry Program at the University of Massachusetts Amherst Extension School, one method that draws jumping worms to the surface is a mustard soil spray. Unlike nightcrawlers, jumping worms prefer the upper two or three inches of soil and tend to congregate just beneath the surface.
“The mustard, it’s a liquid version of mustard,” Sabadosa said. “We pour it into the soil and it irritates their skin, so they come to the surface. It’s a good way to find out if they’re around.”
Sabadosa, a longer term employee at Tripple Brook Farm, hasn’t noticed much damage from jumping worms, but also isn’t certain when they arrived. They are in her yard, at her home, but seem to be staying in one area. They may be taking a silent toll.
“We had some new plants, they were propagated and they were very small, they were a type of aster. Many of them did not make it,” Sabadosa said. “We noticed there was some jumping worms [so] it looks like they could’ve been feeding on the new roots.”
Another method for discovery and control of jumping worms is to lay down black plastic film before planting a crop. In full sunlight, the black plastic will trap solar heat and warm the soil as high as 150 degrees. That will kill any worms and any egg casings already laid.
Impoco noted the lack clinical information about jumping worms, but wanted to avoid blanket statements about what works. Each garden, each farm is different. Gardeners should try amendments and practices until they find something that works. Impoco has faith the community of growers in the river valley will figure out best practices for dealing with jumping worms, the newest invasive.
“Do some research and try some things out,” Impoco said. “There’s a deficit of academic research concerning controlling these guys [but] I think we can come up with something.”
More information on jumping worms can be found at ag.umass.edu/landscape/fact-sheets/invasive-jumping-worm-frequently-asked-questions. Tripple Brook Farm, which specializes in native perennial species, can be reached at info@tripplebrookfarm.com.
