Biological control of leafy spurge with introduced flea beetles (Aphthona spp.)

Abstract

AstractFlea beetles ( Aphthona spp.) were introduced into leafy spurge (E u p h o r b i a e s u l a L.)-infested rangeland in east-central North Dakota. The study objectives were to evaluate the effects of the introduced insects on leafy spurge cover, density, and yield, and grass and grass-like yield of associated plant communities. A p h t h o n a spp. were released in 1988 and 1989 at 2 sites near Valley City, N.D. Aboveground vegetative sampling for leafy spurge cover, density and yield, and grass and grass-like yield was conducted between 1993 and 1995. Belowground sampling of root density, dry weight and root buds was conducted between the release date and 1995. A p h t h o n a spp. reduced aboveground cover, density and yield of leafy spurge and increased yield of grass and grass-like species. Leafy spurge root density, weight, and number of root buds decreased on insect release sites between release dates and 1995. Reduced stem density of leafy spurge and increased grass and grass-like yield, should enhance cattle use and production from these sites.Key Words: biological control, leafy spurge, insects, flea beetles, range improvement Biological control of introduced noxious weeds using insects has received limited use on rangelands (Vallentine 1989). Successful biological control efforts using insects has been reported for St. John's-Wort (H y p e r i c u m p e r f o r a t u m L.) (Huffaker and Kennett 1959), pricklypear (O p u n t i a spp.) (Goeden et al. 1968), and tansy ragwort (Senecio jacobaea L.) (Hawkes 1968). Efforts to control leafy spurge (E u p h o r b i a e s u l a L.) with insects has been ongoing since the 1960s with significant expansion in the 1970s and 1980s (Harris 1984, Pemberton 1985.Leafy spurge is an introduced plant from Eurasia that is extremely persistent and competitive in grazed rangelands (Dunn 1979). It is considered a prime candidate for biological control because of its propensity to invade a variety of habitats such as grasslands, woodlands, riparian areas and waterways where alternative control efforts may be limited and it is a perennial weed providing a continuous source of food to organisms capable of utilizing portions of the plant. Unfortunately, leafy spurge's defense mechanisms such as the milky latex make utilization of the plant difficult except for well adapted insects that have evolved means to overcome these defenses (Best et al. 1980). Eight insects have been released to control leafy spurge in North Dakota since the 1980s (Lym and Zollinger 1995). Of these, flea beetles (Aphthona spp.) have been the most successful for establishment, reproduction and redistribution. However, limited quantitative information is available regarding the impact of Aphthona spp. on leafy spurge and the associated plant community. The objectives of this study were to evaluate the effects of Aphthona spp. on leafy spurge cover, density and yield, and grass and grass-like yield of associated plant communities. University, Fargo, N.D. 58105; professor, Entomology Department, North ...

The Biology and Integrated Management of Leafy Spurge (Euphorbia esula) on North Dakota Rangeland

“…Also, an unexpected finding of current research is that herbage production has not returned to normal even after leafy spurge density has been reduced by Aphthona spp. feeding for several years (Kirby 1996). For example, Kirby (1996) found leafy spurge density was reduced threeto fivefold at two locations in North Dakota 5 yr after the initial flea beetle release, but little or no increase in graminoid production compared to the control was observed.…”

“…feeding for several years (Kirby 1996). For example, Kirby (1996) found leafy spurge density was reduced threeto fivefold at two locations in North Dakota 5 yr after the initial flea beetle release, but little or no increase in graminoid production compared to the control was observed. The reason for the lack of response by the graminoid species is not known.…”

Seedlings of the Invasive Strawberry Guava Psidium cattleianum Were More Sensitive to Defoliation Than the Closely Related Malagasy Native Eugenia goviala in a Simulated Herbivory Experiment

“…This hypothesis suggests that non-native plant species may experience less herbivory damage allowing them to outcompete native plants (Cappuccino & Carpenter, 2005; Keane & Crawley, 2002). If non-native plants are less susceptible to herbivory than native plants, it might be possible to control the expansion of non-native plants by introducing their natural herbivores in the new range (Kirby et al., 2000). However, such an operation is risky because these herbivores may also have detrimental effects on native plants (Fowler et al., 2000).…”

Detection of Leafy Spurge (Euphorbia esula) Using Multidate High-Resolution Satellite Imagery

“…Leafy spurge is well adapted to a broad range of habitats and is difficult to control because of its extensive root system (Kirby et al 2000;Lym 1998;Lym et al 1998). Single patches of the weed typically vary from a few square meters to many square kilometers, where it often spreads up to 1 m/yr (Lym et al 1998).…”