The efficacy of eight plant extracts (garlic, clove, garden quinine, Brazilian pepper, anthi
mandhari, black cumin, white cedar and neem) in controlling leaf rust disease of wheat was
investigated in vitro and in vivo. In vitro, all treatments inhibited spore germination by more
than 93%. Neem extract recorded 98.99% inhibition of spore germination with no signifi-
cant difference from the fungicide Sumi-8 (100%). Under greenhouse conditions, seed soaking
application in neem extract (at concentration of 2 ml/L) resulted in 36.82% reduction in the
number of pustules/leaf compared with the untreated control. Foliar spraying of plant extracts
on wheat seedlings decreased the number of pustules/leaf. Foliar spraying of plant
extracts four days after inoculation led to the highest resistance response of wheat plants
against leaf rust pathogen. Spray application of wheat seedlings with neem, clove and garden
quinine extracts, four days after inoculation with leaf rust pathogen completely prevented
rust development (100% disease control) and was comparable with the fungicide Sumi-8.
Foliar spray application of wheat plants at mature stage with all plant extracts has signifi-
cantly reduced the leaf rust infection (average coefficient of infection, ACI) compared with
the untreated control and neem was the most effective treatment. This was reflected on
grain yield components, whereas the 1000-kernel weight and the test weight were improved
whether under one- or two-spray applications, with two-spray application being more
effective in this regard.Thus, it could be concluded that plant extracts may be useful to control
leaf rust disease in Egypt as a safe alternative option to chemical fungicides.