VIEW ARTICLE

Disease Control and Pest Management

Evaluation of Disinfestant-Flotation Salt-Surfactant Combinations on Decay Fungi of Pear in a Model Dump Tank. R. A. Spotts, Professor, Oregon State University, Mid-Columbia Agricultural Research and Extension Center, Hood River 97031; L. A. Cervantes, Experimental biology technician, Oregon State University, Mid-Columbia Agricultural Research and Extension Center, Hood River 97031. Phytopathology 79:121-126. Accepted for publication 9 August 1988. Copyright 1989 The American Phytopathological Society. DOI: 10.1094/Phyto-79-121.

Several disinfestant-flotation salt-surfactant solutions were compared for effect on germination of spores of Mucor piriformis, Penicillium expansum, and Phialophora malorum and decay of pear caused by these fungi after exposure to a 7-hr dynamic circulation and spore addition phase, followed by a 16-hr static phase in a model dump tank. In aqueous systems without soil added to the tank, chlorine at 64 μg/ml inhibited germination from 90 to 100% in all salt solutions. Effectiveness of 4,000 μg sodium o-phenylphenate (SOPP) per milliliter was highest in calcium and sodium lignin sulfonate and lowest in sodium silicate solution. SOPP was less inhibitory to germination than chlorine during the first 1-3 hr of the dynamic phase. In flotation systems with 6.25 mg/ml of soil, chlorine in sodium sulfate and SOPP in sodium lignin sulfonate inhibited germination of spores and reduced decay of fruit more than in sodium silicate. Inhibition of germination of the three fungi was greater at the end of the static phase than during the dynamic phase in several tests with 10 combinations of disinfestant-flotation salt-surfactant.