Defoliation of Oak, Maple,and Other Woody Plants with 2-Chloroethylphosphonic Acid and Potassium Iodide.

摘要

This investigation determined the defoliation response of red maple (Acer rubrum L.),pin oak (Quercus palustris Muenchh.),and several other actively growing deciduous woody plants to 2-chloroethylphosphonic acid (68-240) and potassium iodide (KI). Applications of 68-240alone were made at 2,500, 5,000and 10,000mg per liter and each concentration in combination with 2.0% KI to 6-year-old red maple and pin oak. Treatments were made in July and included one,two,or three sprays at 1-week intervals. The best defoliation occurred with three sprays of 68-240alone at 10,000mg per liter. When 2.0% KI was added to 68-240,complete desiccation occurred before abscission could take place. When KI was applied alone on 1August at 0.5, 1.0,and 2.0%,all concentrations caused 100% desiccation on red maple. With pin oak, 1.0% KI was needed to obtain 100% desiccation. Ten woody plant species from 5to 10feet tall were sprayed in early July with 5,000mg per liter of 68-240. During a period of 3weeks,black locust,tree of heaven, sycamore,and sweet gum were almost completely defoliated (80to 100%);six other species were defoliated to a lesser extent in descending order from 60to 20%. (Author)