Submitted to: Florida Entomologist
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/27/2001
Publication Date: 12/1/2001
Citation: Mckenzie, C.L., Lapointe, S.L., Duncan, L.W. 2001. Landscape fabric as a physical barrier to neonate diaprepes abbreviatus (coleoptera: curculionidae). Florida Entomologist. 84(4): 634-635. Interpretive Summary: There are few options available to Florida producers of citrus and ornamentals for control of root-feeding weevils such as the Diaprepes root weevil, Diaprepes abbreviatus (L.). Increasing damage from D. abbreviatus and the recent failure of a commercial entomopathogenic nematode product underline the precarious situation for growers. Adult D. abbreviatus and other weevils such as species of Artipus and Pachnaeus, oviposit by cementing eggs in a layer between leaves or other surfaces. Neonate larvae fall to the ground, burrow into the soil and feed on progressively larger roots as they grow. A physical barrier to prevent neonate larvae from reaching tree roots could be an effective, nontoxic control of root weevils as well as potentially providing a number of collateral benefits to citriculture. If technically viable in groves, a properly designed barrier could offer multiple returns on initial investment over several years including effective, long-term, non-chemical control of root-feeding weevils; reduced use of irrigation water and pump energy; non-chemical weed control; and reduction of soil erosion. In this study we determined the ability of neonate D. abbreviatus larvae to penetrate a range of commercially available weed cloth fabrics in controlled laboratory experiments. The spun polyester/polyolefin bi-layer products acted as a physical barrier to Diaprepes by preventing downward penetration by neonate larvae in laboratory experiments. If issues of cost and field deployment can be resolved, landscape fabric has potential as a component of an integrated approach to control of root weevils.
Technical Abstract: In this study we determined the ability of neonate D. abbreviatus larvae to penetrate a range of commercially available weed cloth fabrics in controlled laboratory experiments. The spun polyester/polyolefin bi- layer products were very effective barriers to neonate penetration. These products are continuous films designed to be water permeable but without large pores that would allow neonate passage. The plastic films have varying densities of perforations (0.5 mm diam) equal to or slightly larger than the width of the head capsule of neonates that permitted penetration of 50 to 75% of neonate D. abbreviatus. Two products were intermediate in that they reduced penetration compared with the control of the perforated plastic films, but allowed some neonates to pass through them. One of these (Commercial Landscape Fabric) consisted solely of spun-bonded polyester. This product is a mesh of polyester fibers that allowed neonates to burrow through. The second (Lumite 994GC) was a surprisingly efficient barrier compared with the continuous film products even though Lumite 994GC is woven with openings of varying size between the plastic strands. Issues of cost and methods of field deployment remain to be addressed. These will determine whether landscape fabrics are economically viable alternatives for control of root weevils.