Twenty-one years of research and field testing have paid off for New York’s alfalfa growers. Cornell University students are introducing growers across the state’s six northernmost counties to the protocol for rearing and applying native nematodes that look to be a solution to the destructive invasive species alfalfa snout beetle.
The Rearing and Applying Nematodes to Control Alfalfa Snout Beetle manual that condenses the Cornell research that led to an on-farm biocontrol method is online in the Field Crops: Alfalfa section of the Northern New York Agricultural Development Program Web site at www.nnyagdev.org.
More than 13% (500,000 acres) of the state’s agricultural land has been infested by snout beetles that can destroy entire fields in one year. The flightless insect likely arrived in the Port of Oswego in the ballast of sailing ships in the 19th century. It has walked and hitchhiked from Oswego County to eight other counties (Cayuga, Clinton, Essex, Franklin, Jefferson, Lewis, St. Lawrence and Wayne) and southeastern Ontario.
In 1989, Cornell University entomologist Elson Shields and plant breeder Donald Viands began work at Peck Homestead Farm in Jefferson County, where snout beetles had destroyed 70-100% of the alfalfa year after year since they arrived in 1985. Snout beetle larva feed on alfalfa taproots, causing fields to look winterkilled (patchy with yellowed, leafless plants).
Damage at the Peck farm also manifested in the milk check. “We saw 25-30% loss in our milk production and as much as a 25% increase in production costs with the added expense of replanting every year or two,” says John Peck.
Over time, treating the Peck fields with native insect-attacking nematodes that feed on snout beetle larvae caused the beetle populations to drastically diminish.
“The nematodes naturally recycle within the alfalfa snout beetle host, persist in the soil and effectively self-disperse, creating the opportunity for sweeping and perpetual control across treated fields,” says Tony Testa, Cornell research support specialist.
In 2009 and 2010, Cornell students Joshua Knecht and Allyson Jones-Brimmer helped more than a dozen farmers raise the beetle-battling nematodes.
The treatment combines two types of northern New York-native nematodes that co-exist well. One prefers shallower soil; the other burrows deeper, broadening the effectiveness of the treatment.
The farmers working with the students mass-produced the native nematodes using small fish-bait cups filled with sawdust and wax worms. Each cup, inoculated with roughly 15,000 nematodes, produced about 25 million juvenile nematodes for field release. The newly emerged nematodes were separated from the sawdust mix using screens and water. The rinse water containing the nematodes was applied to field surfaces through a variety of sprayers.
Two starter cups per nematode species produced enough nematodes to start eight additional cups. Nematodes from those eight cups were sufficient to inoculate one 15- to 25-acre field at a cost of about $75.
“Growers are able to inoculate their fields just one time to achieve long-term control,” Testa says. “This eliminates the cost of annual applications of the more costly commercially produced nematodes that persist in the field for less than a single growing season.”
A step-by-step rearing and application manual developed by Jones-Brimmer was field-tested and finalized with farmer input.
“The protocol is easily implemented, and this inexpensive and field-effective result is the perfect payoff for the patience and funding the Northern New York Agricultural Development Program invested in finding a solution to protect a highly valuable crop,” says Bernie Gohlert at Hilltop Dairy in Lowville.
At Sheland Farms near Belleville, Jones-Brimmer worked with 15-year-old Erik Shelmidine, who raised the nematodes as his FFA project. Fields there are showing a strong return to full alfalfa production after more than 40 years and up to 80% field loss at times.
At Mapleview Dairy in Madrid, Lou Ann King says, “Raising the nematodes on the farm was a great project for my 14-year-old daughter and we have seen positive results that benefitted our farm and helped us help a neighbor who lost his alfalfa to the beetle and needed to buy some in.”
While Shields and Testa worked on biocontrol solutions, Viands was selectively growing resistant alfalfa varieties, using varieties native to New York and Hungary. Sixth- and seventh-generation selections were field-tested at Sheland Farms with good results.
“Control with snout beetle-resistant varieties is quite possible,” says Viands. “We have seen root damage scores consistently drop and believe we can achieve even better results with subsequent selections. Seed companies participating with the northern New York research project now have alfalfa with some alfalfa snout beetle resistance in commercial seed production for potential use.”
Farmers interested in learning more about controlling alfalfa snout beetles and FFA and other students interested in participating in control efforts can contact Tony Testa at 607-591-1493 or at28@cornell.edu.