BLM staffers Ryan Browning (left) and Eric Peterson (right) from Miles City collect flea beetles from a Fergus County leafy spurge infestation site for distribution to other Montana counties July 7, 2009. Approximately 1.526 million flea beetles were gathered from collection efforts this year and distributed to waiting list of recipients.
Flea beetles cover the flowering top of a leafy spurge plant at an infestation site near Grass Range July 7, 2009. The spurge-devouring beetles emerge during a brief period in the summer and are collected by BLM staff for relocation to other spurge sites in Montana.
BLM Rangeland Management Specialist Beth Klempel prepares cardboard containers to hold flea beetles for shipment during a beetle collection in Fergus County July 7. The containers were distributed to persons on a waiting list, who later released the beetles onto other Montana spurge sites.
Flea beetles cover the sides of the “bug-o-lator” –a homemade contraption used to concentrate collected flea beetles for measuring into shipping containers– during beetle collection efforts in Fergus County July 7. The spurge-eating beetles have been gathered at Grass Range for several years and shipped as far away as New York. Eleven counties in Montana received beetles from this year’s beetle harvest.
Visiting Brenda Witkowski, BLM weed control specialist at the Miles City Field Office, one quickly notices the dried and framed weed specimens tacked to the wall near her workspace. They draw attention like a batch of wanted posters.
A particularly devious specimen is included in the lineup: leafy spurge.
Witkowski noted that with the frequent rains this spring and summer, leafy spurge infestations have experienced a significant uptick. When she spoke about it, she sounded like a doctor relaying a grim prognosis.
“This year I’ve seen spurge like never before,” said Witkowski. “It’s not in small patches; it’s in big, big, patches. Some areas have just exploded with spurge.”
Witkowski and the BLM are looking for persons interested in receiving free spurge-devouring flea beetles to fight spurge infestations on public and private ground. A waiting list for the hungry insects has been compiled, but more cooperators are needed.
“They’re free and we can get a lot of them. In past years we’ve collected a million and this year we collected over 330,000,” said Witkowski. “A lot of people could be receiving bugs, if we knew who wanted them.”
Leafy Spurge a Challenging Foe
The phrase “truth is stranger than fiction” applies to leafy spurge, which behaves more like a hostile other-worldly alien than the Eurasian weed that it is. In North America --where its natural predators are absent-- life is good for spurge. It grows bigger, reproduces faster and sucks up more nutrients; out-competing native and beneficial plants. Wherever spurge finds the conditions right, that’s where it wants to be.
According to the Plant Conservation Alliance, leafy spurge caught a ride into the U.S. early in the 1800s. Transported unwittingly as a “seed impurity,” it was first recorded in Massachusetts in 1827; first labeled a “weed” in a 1921 New York Herald editorial, and by 1979 it was plaguing at least 30 states.
Currently the noxious invader has found a home across most of the northern part of the U.S. Unfortunately, Montana, the Dakotas, Nebraska and Wyoming have been awarded the dubious distinction of hosting the worst infestations.
Leafy spurge uses a variety of tricks to out-compete native plant species. Spurge also spreads rhizominously underground; horizontally enlarging the colony from deep, fibrous, extensive root systems capable of burrowing to depths of more than 30 feet. Spurge infestations enlarge their perimeters by several feet annually.
Spurge also jettisons seed capsules up to a radius of 15 feet –which can remain viable seven to eight years before germinating. The weed can hitchhike on water, by wildlife, or tire tread and will establish quickly on disturbed or burned ground.
Flea Beetles a Key Weapon against Spurge
Several control methods can be used against spurge, including spraying chemical, livestock (sheep and goat) grazing, or the cheapest method: flea beetles. The speck-sized bugs are a creature whose life cycle is linked to spurge, hailing from Eurasia where the plant evolved.
According to the North Dakota State University Extension Service, “flea beetle” is a common name for several beetle species that jump quickly with enlarged hind legs when disturbed. Two species, one black (Aphthona lacertosa) and one brown (Aphthona nigristus), were vetted via an extensive process and approved as bio control agents for spurge in the mid-1980s.
The beetles eat spurge exclusively and will die out once a colony expires if they can’t find their way to more spurge. It is thought that latex compounds in spurge are a key factor in the relationship between flea beetles and their exclusive dining, life cycle and habitat requirements.
Flea beetles --albeit slower than more expensive methods-- are an effective, year-long tool according to Mike Barrick, a BLM range technician and weed specialist for the Lewistown Field Office. Barrick has been supervising flea beetle collection efforts in Fergus County for several years. Working steadily, the beetles attack spurge stems and roots; remaining viable underground through the winter to emerge briefly in the summer as adults to mate. Eggs are laid in the soil and the larvae hatch to feed on spurge roots and rhizomes.
“Ninety percent of your control is in the larval stage with flea beetles on the root structure,” said Barrick. “You’ll see the leafy spurge start to disappear and every year it’ll be less and less and less; the plant above ground is actually being reduced because the root structure isn’t in the ground anymore.”
Montana Grown Flea Beetles Sent Far and Wide
This summer, BLM staff from Miles City and Lewistown collected beetles from several “super sites” and provided them to landowners for release. According to Barrick, a whopping 1.526 million of the Lilliputian-sized spurge-killers were butterfly-netted, measured out and dumped into cardboard containers for delivery to waiting recipients this year. The process is quick, and the flea beetles are scattered back onto new spurge plants soon after being captured.
“Our collection period is only about a month long,” said Barrick. “We usually start collecting the last week of June and finish about the end of the third week in July. Every year varies a little. We have a short collection time when the adult flea beetles are on the soil surface and plant tops.”
Spurge control efforts in Yellowstone, Bighorn, Fergus, Blaine, Musselshell, Cascade, Sweetgrass, Custer, Prairie, Powder River and Fallon counties received beetles this summer. In previous collections, the Montana-bred beetles have also been sent to Arizona, Utah, California, Washington, Oregon, Idaho and upstate New York.
“Our site in Grass Range is one of our main collections sites for Montana and for the western United States,” said Barrick. “In fact, it’s well known in the bio control world that Fergus County, Montana, is a good place to go and collect.”
Flea Beetles Only One Piece of the Puzzle
Barrick advised that even though using flea beetles is an inexpensive approach, landowners need to have a realistic expectation regarding the time it takes to produce results. It may take two or three years before the bugs reach high enough numbers to reduce the root structures enough for the effects to be visible.
“They’re not the silver bullet, they’re not the cure-all,” said Barrick. “We still need to graze with sheep and goats, we still need to apply chemical; flea beetles are just one of our tools in controlling noxious weeds. You still need an integrated approach with different things to see what works best in your particular site.”
Regardless of the combinations used on infested areas, the beetles are still a good bet and can get to work until more aggressive measures like spraying or grazing can be employed, said Witkowski.
“The bugs work really well in areas that are really rough and hard to get back into. At least it’s something instead of letting it go all over unchecked,” said Witkowski. “In years past we’ve dropped them from helicopter in really rough areas we couldn’t get into.”
In addition to flea beetles the BLM is offering chemical pesticide to persons with a current pesticide applicator’s license wanting to spray for noxious weeds on adjacent BLM land.
“All the applicant has to do is fill out the application record and we’ll provide the chemical to spray on BLM land,” said Witkowski. “It helps us stretch our dollars further. Folks know where the weeds are, too.”