CHEMICAL CONTROL OF ERWINIA AMYLOVORA BURRILL WINSLOW ET AL. IN PEAR ORCHARDS.

T. Deckers, W. Porreye
In 1980, the Research Station of Gorsem started investigations on the possibilities for chemical control of fire blight in pear orchards with following compounds : streptomycin sulfate, CGA 78039, Copac E, MBR 10995, FSB 8332; inoculation with a strain of Erwinia herbicola was also tried for controlling the disease. These compounds were sprayed weekly in the orchards during the vegetative period which started at the beginning of June and lasted until the end of August. The experiments were carried out on heavily infected pear trees of the variety Durondeau on Quince A rootstock which is known to be very sensitive to Erwinia amylovora.

A weekly application of streptomycin sulfate at 100 ppm in one orchard did not prevent further infections during the vegetative period. A weekly CGA 78039 treatment was also not sufficient for a real control of the fire blight disease. Weekly applications of Copac E, an ammoniacal coppersulfate formulation, at 0.5% reduced the number of infections seriously but was not able to prevent all infections. Control of the epiphytic flore of Erwinia amylovora on the leaves, by counting the number of Erwinia bacteria under IF-microscope, confirms the reduction in the number of bacteria in the plots treated with Copac E. An experiment was done for the biological control of fire blight using a strain of Erwinia herbicola : a weekly spray of the antagonist was not effective in reducing infections of fire blight in the treated plot. The experience with FSB 8332 and MBR 10995 is still limited, but some results are promising. Good results were obtained in 1983 with MBR 10995.

Deckers, T. and Porreye, W. (1984). CHEMICAL CONTROL OF ERWINIA AMYLOVORA BURRILL WINSLOW ET AL. IN PEAR ORCHARDS.. Acta Hortic. 151, 215-222
DOI: 10.17660/ActaHortic.1984.151.28
https://doi.org/10.17660/ActaHortic.1984.151.28
Fire blight - Chemical control

Acta Horticulturae