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Published July 22, 2013, 10:35 AM

Manage leafy spurge beetles

Landowners are encouraged to collect and redistribute leafy spurge beetles in their pastures. The bugs are used to fight the invasive weed.

By: South Dakota State University Extension Service,

BROOKINGS, S.D. — South Dakota State University Extension and the South Dakota Department of Agriculture encourage landowners to collect and redistribute leafy spurge beetles in their pastures.

“With the late spring, beetles can reasonably be collected and moved through about July 15 or so,” says Pete Bauman, SDSU Extension range field specialist.

Bauman adds that it is important to realize the relatively inexpensive benefits of utilizing beetles in your leafy spurge control program.

“By simply taking a few hours every spring to move beetles around to new patches, landowners can keep their beetle populations going indefinitely, ultimately reducing their overall chemical expenses,” he says. “There is no advantage to hoarding beetles in one spot, the key to success is redistribution on your own land and sharing with your neighbor.”

The following are recommendations to assist landowners in spurge beetle management:

When: Collect bugs only between mid-June and early to mid-July. This is when the adult beetles will be out on leafy spurge plants. Avoid releasing the beetles in the dense center of a leafy spurge patch, rather release them in areas of moderate density toward the edge of the patch.

Weather: The most productive collection days are hot, still days. The beetles will be higher up on leafy spurge plants and easier to collect. When it’s cold and windy out, beetles stay closer to the ground. Collections can be very successful, however, on moderately breezy days.

Where:Beetles will be most abundant where you find “dead cane” (dead, brittle leafy spurge stems). You may also notice damage to the leaves of live leafy spurge plants. This is evidence that beetles are present. Sweep in the vicinity of any previous year’s release areas, as beetles often move away from the original release points.

Technique: Sweep back and forth with a pace slow enough to prevent the beetles from jumping to the ground before they are collected.

Collection should continue until there is a cluster of material the approximate size of a baseball in the net. Shake the beetles to the bottom of the net and grab the net above the beetles to prevent escape. While holding the beetles in the net, turn the net inside out and put your hand and the ‘wad’ of beetles into the pillow case or laundry bag. Empty the net and close the top of the storage bag or pillow case firmly.

Equipment:

• Sweep nets (canvas net with no holes).

• Silk laundry bags or light colored pillow case (to put the beetles in after sweeping).

• Coolers with blue ice (no freezer ice or ice cubes) and newspaper which prevents beetle containers from getting wet. Use coolers and ice if beetles are not to be released for several hours.

Transporting beetles

Short distances: If beetles will be moved only a short distance, they can be placed directly from the nets into a pillow case or large brown paper grocery bag. If the beetles will be moved within one hour, the pillow case or bag can be tied shut and placed in the shade until the beetles are released.

Longer distances one hour or more: Place two or three blocks of blue ice into a cooler and cover the ice blocks with newspaper. This prevents the beetles from getting wet.

Spread the bug-filled pillow case or bag out on top of the newspaper so the beetles are not piled on top of each other, and leave until released. Paper bags with seams taped shut can also be used. If storing beetles in the refrigerator, remove the blue ice, otherwise they will get too cold and die.

To facilitate collections, The Nature Conservancy has provided nets to the following counties to be loaned to producers: Brookings, Brown, Clark, Codington, Day, Deuel, Grant, Hamlin, Kingsbury, Lake, Marshall, McCook, Minnehaha, Moody and Roberts. Call your county weed office to coordinate borrowing nets within these counties. For more information, contact Bauman at 605-882-5140 or peter.bauman@sdstate.edu.

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