Pear fire blight control tests 1973

Copper compounds were the only currently registered bactericides that controlled streptomycin-resistant strains of firelight bacteria in Bartlett pear trees, but they induced considerable amounts of fruit russet. An anti-transpirant material reduced the amount of russet caused by the copper materials when applied alternately, or in conjunction with copper sprays. A new organic bactericide, MBR 10995, provided excellent control of fireblight in a limited trial but is not currently registered. Biological control of fireblight with application of bacteria antagonistic to Erwinia amylovora was somewhat effective. The efficacy of bactericides can also be determined by their effect on epiphytic populations of E. amylovora in blossoms.