FURTHER STUDIES ON DOWNY MILDEW DISEASE ON MAIZE IN EGYPT

Abstract

Maize is one of the most important cereal crops in many countries all over the world. In Egypt maize is considered the third cereal crops after rice and wheat.

Maize is liable to be attacked by several diseases, which can be considered the major disease i.e. late wilt, common smut and downy mildew. Recently the downy mildew of maize caused by Peronosclerospora sorghi (Weston and Uppal) shaw, has become a serious disease in Egypt.

The present investigation was carried out during 1997-

2000 growing seasons at Gemmeiza Agricultural Research

Station. The results obtained could be summarized as follows:

1-Histo-patholgical studies of the fungus showed that the hyphae are hyaline, branched, intercellular. The witdh of the hyphae ranged from 3.4-4.1 with an average of 3.81 ).l . The haustoria are hyaline, spherical, the measurements of haustoria ranged from 5.1-6.8 )1. with an average of 6.01 ).l. The haustoria formed as vesicles globos from thin measured branched hyphae of mycelium.

2- Conidia are hyaline with thin wall and oval of nearly spherical.The measurements of conidia ranged from 13.7 to 20.5 x 13.7 to 27.4 )1. with an average of 15. 4x18. 5 L