Effects of Selected Fungicides, Insecticides, and Adjuvants on In Vitro Germination of Highbush Blueberry Pollen. Peter R. Bristow, Associate Plant Pathologist, Washington State University, Western Washington Research and Extension Center, Puyallup 98371-4998. Gwenyth E. Windom, Agricultural Research Technologist III, Washington State University, Western Washington Research and Extension Center, Puyallup 98371-4998. Plant Dis. 71:326-328. Accepted for publication 3 November 1986. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/PD-71-0326.

Pollen from highbush blueberry (Vaccinium corymbosum) readily germinated on 9% sucrose agar but was inhibited by more than 50% (ED₅₀) when the medium contained 50 µg a.i./ml of captan, benomyl + captan, captafol, ferbam, triforine-EC, diazinon, or X-77. Some pollen still germinated with acephate, captafol, triforine-WP, triforine-F, Triton B-1956, and Tween 20 at a concentration of 5,000 µg/ml. For most chemicals, the ED₅₀ value was less than the concentration in spray suspensions at recommended rates. At very low concentrations (0.1 and sometimes 0.5 µg/ml), all chemicals except the combination of benomyl + captan stimulated germination. The emulsifiable concentrate (EC) formulation of triforine was markedly more toxic to pollen than either the wettable powder or flowable formulations, with complete inhibition by the EC formulation at 100 µg/ml. Virtually all of the toxicity of the EC formulation was accounted for by one of the inert ingredients and not triforine.

Keyword(s): phytotoxicity.