Defoliation of Oak, Maple, and Other Woody Plants with 2- Chloroethylphosphonic Acid and Potassium Iodide
FORT DETRICK FREDERICK MD
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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 68-240 alone were made at 2,500, 5, 000 and 10,000 mg 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 68-240 alone at 10,000 mg 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 1 August 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 5 to 10 feet tall were sprayed in early July with 5,000 mg per liter of 68-240. During a period of 3 weeks, black locust, tree of heaven, sycamore, and sweet gum were almost completely defoliated 80 to 100 six other species were defoliated to a lesser extent in descending order from 60 to 20.
- Anatomy and Physiology
- Chemical, Biological and Radiological Warfare