An explosion of billbugs reduced orchardgrass hay production by 40% in Virginia, Maryland and Pennsylvania last summer, says Randy Hays, field representative for Willard AgriServices in Frederick, MD.
Using National Agricultural Statistics Service numbers, that's a loss of $124 million for hay growers, many of whom target the premium horse hay market, he adds.
Matt Rose first noticed a problem last June in orchardgrass fields he manages. By the end of the season, Grassland Farm near Middleburg, VA, had lost 60% of the year's production and sustained close to a $20,000 loss. Nearly 300 acres of orchardgrass had been damaged.
“I cut the hay in mid-May and topdressed it with fertilizer. Then there was no growth after one month,” Rose says.
Grass on field edges started to turn brown. He called Hays, who identified billbugs as the problem. They tried a contact insecticide, but it did nothing. That's when Rose sounded the alarm, hoping to identify a solution.
Local extension agent Kenner Love and Virginia Tech extension entomologist Rod Youngman met with Rose, other growers and co-op and chemical company representatives.
“We tried to get a game plan together,” Rose explains. Other area producers found similar damage. An initial damage survey showed that 64% of 700 acres in northern Virginia suffered economic damage.
Billbugs are small weevils that have been known to attack several crops over a wide area. Hunting and bluegrass billbugs are the primary species found in Virginia. They often go undetected in orchardgrass until fields turn brown, seemingly overnight, says Youngman.
The insects, which have a one-year life cycle, overwinter along fence rows and wooded areas. But when soil temperatures warm, typically between late April and mid-May, females begin laying eggs in orchardgrass stems, just above the crown. Hatched grubs feed within the stems, eventually chewing their way out to feed on crowns and roots. The bases of stems near the crown stop growing, turn brown and are easily snapped off, producing a powdery sawdust-like material. “These symptoms are very indicative of billbug feeding,” Youngman says.
Once damage is visible, hay growers have no control options. “By the time you see that kind of damage, you may still have grubs inside grass stems or down in the soil, feeding on the roots.” But contact insecticides, the only products labeled for grass grown for hay or pasture, have little effect on grubs, which are protected by plants or soil.
A class of systemic insecticides called neonicotinoids is EPA-approved for use on similar infestations of root-feeding insects in corn and turf grass. But it isn't labeled for use on grass hay and pastures. Youngman hopes future research projects will show that systemic insecticides are both efficacious and cost-effective against billbugs in hayfields and pastures.
“We need a systemic insecticide,” Rose says, and not only for billbug control. “There is really nothing out there to help us combat these pests.”
Fields damaged by billbugs last year could be hit again this coming season and should be scouted. So should undamaged fields in regions that experienced similar pest problems in 2005, Youngman says.
Although billbugs can fly, they usually walk to plants to lay eggs. Youngman suggests using pit- fall traps to monitor billbug numbers when they become active in spring, because egg laying soon follows. And that's when growers should apply an insecticide.
Growers should install pitfall traps before soil temperatures exceed 67°. Place large plastic drinking cups into holes made every 5-10' along edges of orchardgrass fields. Make sure the lips of the cups are flush with the soil. Then add soapy water about 1” deep to each cup and check the traps at least weekly. According to Ohio State University entomologists who have studied billbug damage on Kentucky bluegrass, two to five adults in a trap justify insecticide use.
“The only insecticides currently labeled for use on grass hay fields and pasture are Sevin XLR Plus, malathion and methyl parathion (which is highly toxic to humans),” says Youngman. Even with stems removed, the bugs can still infest the lower 3-5” of stubble. So spraying immediately after first cutting gives the insecticide a better chance of reaching the egg-laying females. More research, however, is needed to validate this, he cautions.
Billbugs infested established orchardgrass fields and newly seeded stands. Youngman says the damage was so extensive that many fields had to be reseeded. Willard AgriService's Hays says many of his customers either reseeded orchardgrass or killed it and seeded a small grain in its place Rose reseeded some fields after the infestation, only to face unusually dry fall weather. He supplied hay to the farm's core group of customers, but had to turn away a number of new customers.
His customers stable high-performance horses, he explains. “We don't deal in quantity; we supply a premium product with test results to back us up. We usually make 10,000 square bales of a premium product. We can't afford to spend $100/acre/year to reseed. We just want to solve this problem.”
Insects And Diseases Cause Headaches For Grass Hay Growers
Insects and diseases are ganging up on grass hay growers in the East, resulting in painful economic losses with few control options.
Forage specialists in Virginia, Maryland, Delaware, New Jersey and Pennsylvania are documenting problems in orchardgrass and timothy fields caused by billbugs, white grubs, cereal rust mites and combinations of insects and diseases.
“Normally we think of our grass hay crops as being relatively disease- and insect-free, and now our two major hay grasses are getting clobbered,” says Les Vough, University of Maryland forage systems management specialist.
Cereal rust mites have infested timothy fields throughout Eastern and Mid-Atlantic states. In some cases, mites have reduced yield by half or more. Infestations also cause discoloration, which horse-hay buyers associate with rain damage. Brown leaves also have less nutritive value.
“Because of the color loss, the grower is likely to take a discount at the marketplace,” Vough states.
Cereal rust mite numbers start increasing in late fall, build over winter, and generally peak in April and May. If spraying is needed, it should be done in mid- to late April in Maryland with Sevin, available under special-use registration, says Vough. “Growers should start checking for cereal rust mites starting about late March.”
Neither billbugs nor white grubs are new to the Mid-Atlantic region. But outbreaks like those experienced last spring can cause significant problems for grass hay producers, says Rod Youngman, Virginia Tech extension entomologist. White grubs are Japanese beetle larvae that overwinter and feed on roots in the upper 6” of soil.
Hay fields in the more central part of Virginia were damaged significantly by white grubs last summer.
“Early August is the best time to treat for them,” Youngman recommends. None of the insecticides labeled for grass hay and pasture include grubs on their labels. But a high rate of Sevin will at least give partial control, because the grubs are small and close to the surface. “Hopefully, in a few years, one or more low-cost systemic insecticides will be approved for grass hay and pasture fields that provide effective control of both billbug and Japanese beetle grubs.”
Plant pathologists, entomologists, agronomists and other hay industry stakeholders will meet later this winter to discuss what can be done to solve the problems plaguing grass hay growers, Vough adds.
Alfalfa Training Seminar Set For March 7-9
All aspects of alfalfa production, management, forage quality, variety selection and development, animal nutrition and marketing and economics will be taught at the March 7-9 Alfalfa Intensive Training Seminar.
The seminar, sponsored by the National Alfalfa Alliance, will be held at the Hilton St. Louis Airport, St. Louis, MO.
This three-day course will bring in experienced instructors, including extension agronomists and forage specialists; the director of the Dairy Forage Research Center, Madison, WI; and a Monsanto Company dairy nutritionist.
The first day, starting at 1 p.m., participants will learn about genetics, variety testing and selection, seed and seed production, growth and development.
The morning of March 8, the role of alfalfa in animal diets, establishment, irrigation and pest management will be discussed. The afternoon session will include production management; harvesting options, losses and decisions; mowing and field drying; silage and hay preservation and grazing information.
Alfalfa in rotations; soils, fertility and manure management; custom harvesting; economics; and alfalfa as a crop of the future will be examined the morning of the third day.
The cost of the seminar is $550/person. Certified crop advisor credits can be earned as part of the course. For more information, visit www.alfalfa.org. After Feb. 21, a $50 registration fee is added.