Production of cellulase (Cx) by different species of Erwinia.

The tested isolates of Erwinia chrysanthemi (corn pathotype) and E. carotovora constitutively produce high levels of cellulase(s) (Cx) in presence or absence of carboxymethyl-cellulose (CMC) as substrate in the medium. The tested isolates of E.

Identification of Erwinia sp., causing stalk rot of maize in Egypt.

The physiological characteristics, pathogenic propensities, and the sensitivity towards certain antibiotics of the causal bacterium of stalk rot of maize, isolated in Egypt, were studied. Different isolates of Erwinia carotovora and E. atroseptica were included for comparative studies.

Production of adventitious root primordia on hypocotyls of castor bean seedling, infected with Agrobacterium tumefaciens.

The development of sterile secondary tumours on hypocotyls of castor bean seedlings, inoculated with any of the ten isolates of Agrobacterium tumefaciens tested, were observed below the site of the primary tumours. Histopathological studies performed in the present work indicate that the observed secondary tumours were adventitious root primordia and not the ordinary type of secondary tumours. According to the available literature such findings are reported here for the first time.

Tests in vitro and in pots with certain chemicals for inhibition of Pseudomonas solanacearum.

Twenty one isolates of Pseudomonas solanacearum E. F. Smith (Race 3) from various parts of Egypt were inhibited in vitro by Ampicillin, Chloramphenicol, Kanamycin, Oxytetracycline.

Race identification of Pseudomonas solanacearum E. F. Smith in Egypt.

Twenty one isolates of Pseudomonas solanacearum E. F. Smith, which does not occur on hosts other than potato in Egypt, obtained from diseased potato tubers, were collected from different localities in Egypt and used in this study.