The Feasibility of Creating a Bio-Based Slug Control Product from Quackgrass

In 1980, USDA weed scientist Roger D. Hagin identified quackgrass as a potent slug deterrent in no - till corn. Subsequently, he and coworkers identified the active ingredient as 6-hydroxy 1,2,3,4-tetrahydro-B- carboline-3-carboxylic acid (6-HT C-3COOH), demonstrating very significant toxicity (LD50 of 5 ¿g per gram). The compound exhibits little or no mammalian toxicity and no effect on one species of worm and three species of worm and three species of freshwater snails. If we can show that quackgrass leaves carry enough toxicity to kill slugs, it will be possible to create a new specialty crop and a new slug control product. Two requirements for using quackgrass as a raw material for slug control are: 1) Slug mortality must be linked to the active ingredient concentration in quackgrass, 2) Active ingredient concentration must be high enough in quackgrass leaves to justify its use. In Phase I, we will analyze the concentration of active compound in harvests of different growth stages of quackgrass formulate baits with concentration of active ingredient that bracket the lethal dose observed by Hagin and Bobnick (1991). Subsequently, the two most promising bait formulations will be assessed for slug control in field trials. Additionally, the effect of moisture on the baits' effectiveness will be documented in laboratory bioassays.