STUDIES ON LATE WILT DISEASE OF MAIZE

Abstract

Maize is considered to be the second important cereal crop in the world . late wilt disease is the most important stalk rot disease in Egypt, which causes severe losses in maize yield reached to 40%.

To study certain factors that reduce loss due to such disease consequantly increase yield corp, the present work was carried out taking in consideration pathological, biological, electrophorotic (PCR) RAPD and serological studies.

The pathological studies concemed with isolation of the late wilt pathogen as well as ce1tain microorganisms antagonistic to Cephalosponum maydi.1 , detennining the virulence of the obtained isolates in addition to evaluating certain maize inbred lines, hybrids and cultivars against inoculation with a mixture of C. maydis isolates. The obtained results could be summarized as follow :

1- Fourteen isolates of C. maydis , which were isolated from 6 govemorates differed in their mycelial colours on PDA medium . Isolates no. 1,7,9,10,11 and 13 were white, while no's. 2,3,4,6 and 8 were gray and no's. 5,12 and 14 were dark gray.

2- Twenty five soil samples which were collected from the rhizosphere of healthy maize plants from different govemorates , resulted in isolates of 71 1choderma spp i.e. T.harzianum ; T viride ; T. roseum ; T. hamatum . .• Gliocladium virnes : G .