Survival and Characteristics of Ice Nucleation-active Bacteria on Mulberry Trees (Morus spp.) and in Mulberry Pyralid (Glyphodes pyloalis).

Abstract

Survival and population proportion of ice nucleation-active (INA) bacteria on mulberry tree and in an insect, mulberry pyralid, were investigated. Two groups of epiphytic bacteria, Pseudomonas syringae and Erwinia herbicola group bacteria formed dominant bacterial floras on mulberry leaves. E. herbicola group bacteria also distributed in most larvae of mulberry pyralid, but P. syringae was detectable in only some of them. Population frequency of INA P. syringae against total P. syringae in mulberry trees was very high (48.1%), whereas that of E. herbicola group bacteria was low (0.5%). Two group of INA bacteria were identified as P. syringae pv. mori and as Erwinia ananas which has not been detected from mulberry. These two species of INA bacteria were also first found in the insect, mulberry pyralid. A relationship between population of the INA bacteria and frost damage of mulberry trees was discussed.