Symptoms Fire blight

fire blight on pear tree caused erwinia amylovora

tissues affected symptoms of erwinia amylovora include blossoms, fruits, shoots, , branches of apple (pomoideae), pear, , many other rosaceous plants. symptoms above ground , typically easy recognize. symptoms on blossoms include water soaking of floral receptacle, ovary, , peduncles. results in dull, gray-green appearance @ 1–2 weeks after petal fall, , tissues shrivel , turn black. base of blossom , young fruit show similar symptoms infection spreads. opaque white or amber colored droplets of bacterial ooze can seen on infected tissue when environment high in humidity. shoots show similar symptoms develop more rapidly. “shepherd s crook,” can seen when tip of shoot wilts, diseased shoot leaves typically have blackening along mid-vein , die. in number, diseased shoots give tree blighted appearance. initial infection of blossoms , shoots can spread larger tree limbs. branches darken , become water soaked. advanced infection develops cracks in bark , sunken surface. wood under bark become streaked black discoloration. immature fruit forms water-soaked lesions , later turned black. bacterial ooze can found on these lesions. severe infections result in fruit turning entirely black , shriveling.

a primary inoculum of disease typically cankers formed season before. factors determine whether or not cankers become active not known, thought cankers found on larger tree limbs more become active. thought age may factor.