Failure of Canker Removal and Postharvest Fungicide Sprays to Control Nectria Twig Blight on Apples. D. A. Rosenberger, Department of Plant Pathology, New York State Agricultural Experiment Station, Geneva 14456. T. J. Burr, and J. D. Gilpatrick, Department of Plant Pathology, New York State Agricultural Experiment Station, Geneva 14456. Plant Dis. 67:15-17. Accepted for publication 10 May 1982. Copyright 1983 American Phytopathological Society. DOI: 10.1094/PD-67-15.

Experiments were conducted to test control measures for Nectria twig blight caused by Nectria cinnabarina. Both captafol at 1,200 μg/ml and benomyl at 300 μg/ml inhibited germination of N. cinnabarina conidia in vitro, but postharvest treatments in 1978 failed to reduce the incidence of twig blight in 1979. Spring applications of captafol were also ineffective. Neither captafol at 6,000 μg/ml nor the combination of benomyl at 300 μg/ml + 0.25% 70º spray oil applied 2 days after harvest in 1979 reduced disease incidence in 1980. Removal of infected twigs by pruning during July 1979 also failed to reduce 1980 disease incidence. No twig blight infections developed in two previously uninfected orchards following postharvest inoculation of broken fruit pedicels with conidia of N. cinnabarina.