STUDIES ON EAR AND KERNEL ROT OF MAIZE CAUSED BY ASPERGILLUS AND FUSARIUM SPP.

Abstract

Results obtained throughout this work can be summarized as follows:

1- Disease survey in 1997-1998 indicated that ear rot disease was prevalent in the maize growing Jlelds of 6 gavernorates, namly Dakahliya, Kafr El-Shiekh, Gharbiya, Qalubiya, Beni soef and El­ Beheira (Nubariya) and the following fungi were recovered from the infected ma1zc ears: f.'usarium moniltf{wme, Aspergillus flavus, A.niger, l'enicillium spp. l•if.mrium niva/e, Nigrospora rJJ:vzae, Botrvodip/odia theohromae. However F.moni/ijiJrme was the most common fungus followed by A. flavus, l'enicillum spp., Nigro.1pora spp. while B.theohromae was found only at Nubariya... 2- • A number of 21 Fusarium spp. and 14 isolates of A.lpergillusflavus

were pathogenic to mnizc enrs. Five out of the Fusarium isolates were less pathogenic. F.monilijimne was the most aggressive one giving the highest level of infection followed by Fsemitec/um, and F.nivale. The most virulent one of AJ!al•us was isolated fi•om Beni suef 3- Silk channel injection gave the highest degree of infection compared with the rest methods of inoculation with F.monilij(mne. Wherc:as, silk channel and pinbar inoculation techniques were similar in producing damage to ears when inoculnted with A.flavus. 4- Detection and determination of anatoxins in AJ!avus isolates indicated that 9 out of 14 isolates had highly intense blue nuorescence under UV. Yet, only . 6 isolates could produce aflatoxins when chemically analysed by TLC. 5- All isolats of Fusarium monilifimne and F.niva/e. under study could not produce zearalenone. 6- Screening maize genotypes for their resistance to infection with F