LOWVILLE Experts are recommending a two-pronged approach to combatting alfalfa snout beetles, both by introducing predator worms and by planting more resistant strains of alfalfa.
We need to get the pressure down before we introduce resistant alfalfa, Elson J. Shields, professor of entomology at Cornell University, Ithaca, told more than 50 area farmers during the inaugural Lowville Farmers Co-op winter forage forum Tuesday at the Lowville Elks Lodge.
Mr. Shields, who has conducted research on the beetle since the late 1980s, said that trials and research continue to produce more resistant strains of the plant, but a large concentration of snout beetles will still decimate even the hardiest of crops. Thats why he is pushing farmers to apply microscopic roundworms called nematodes, which feed on the larvae of snout beetles and other insects, to their alfalfa crops.
We think weve gotten it down to where its pretty economical, Mr. Shields said.
Nematode applications have cost farmers about $30 per acre to do it themselves or $60 per acre to have Cornell staff do it for them, he said.
However, research has indicated that the predator worms because they will move to find larvae may be spaced out in rows from six to 11 inches apart and still achieve full-field coverage, Mr. Shields said. That drops the per-acre cost for do-it-yourselfers to between $5 and $10, depending on how heavily the field is infested, he said.
How many ways do we blow five bucks? Mr. Shields said. In contrast, the beetle costs farmers an estimated $350 to $500 per acre each year, he said.
The alfalfa snout beetle, an invasive species that likely came to Oswego in boat ballasts in the 19th century, has marched through the north country ever since. The insects lays eggs at the root of alfalfa plants. Larvae feed on plant roots, severely damaging the vital forage and rotation crop critical to dairy and other livestock farmers.
This is not a dainty insect, said Julie L. Hansen, senior research associate in the department of plant breeding at Cornell. It doesnt nibble. It takes big bites.
Since undertaking greenhouse research in 2002, Ms. Hansen said, beetle resistance in alfalfa has improved dramatically, and the newer varieties started to be tested in field trials a few years ago.
However, even the most hardy strains would still be classified only as moderately resistant, she said.
Research since 2007 on 189 fields throughout Northern New York has shown success in controlling the snout beetle with a single application of nematodes, preferably done a couple of weeks after a cutting during the fields second year of alfalfa, Mr. Shields said.
The worms also appear to survive in fields through crop rotations to corn and even soybeans, with at least one field showing a high nematode concentration in a year when corn had been planted, he said.
The Cornell professor speculated that in that instance, the predator worms were feasting on corn rootworm larvae, noting they are generalists that will devour almost any grubs they come across.
Nematodes can be purchased through Cornell, but Mr. Shields suggested that farmers request them before cutting alfalfa to allow time for breeding the worms.
Joseph R. Lawrence, a former educator at Cornell Cooperative Extension of Lewis County who now works for the Lowville Farmers Co-op, said interested farmers could contact either him or Extension Field Crops Educator Michael E. Hunter for more information.
The forum also included presentations on corn pests and traits, silage inoculants and state Department of Environmental Conservation pesticide regulations.