VIEW ARTICLE

Disease Control and Pest Management

Dosage-Response of Root-Knot Nematode-Infected Grape Roots to cis-1,3-Dichloropropene. M. V. McKenry, Assistant Research Nematologist, San Joaquin Valley Agricultural Research and Extension Center, Parlier, CA 93648; I. J. Thomason(2), and P. Naylor(3). (2)(3)Professor of Nematology, Department of Nematology, University of California, Riverside, CA 92502; (3)Staff Research Associate, San Joaquin Valley Agricultural Research and Extension Center, Parlier, CA 93648. Phytopathology 67:709-711. Accepted for publication 3 December 1976. Copyright © 1977 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-67-709.

Field and laboratory populations of Meloidogyne spp. within roots of Vitis vinifera ‘Thompson Seedless’ were exposed at 20-23 C to various dosages (concentration-time) of gaseous cis-1,3-dichloropropene. Roots then were bioassayed on tomato plants. The resulting LD₅₀ value for nematodes within roots 3.2 to 13 mm in diameter was calculated to be 85 μg ml^–1 day in the soil water. The LD₉₅ value was approximately 170 μg ml^–1 day. Dosages of less than 60 μg ml^–1 day resulted in greater infectivity than in the nontreated control roots. The LD_99.9 value was extrapolated to be approximately 180 μg ml^–1 day, or a dosage of eight times that required to kill soil populations of infective juveniles at the same soil temperature.