USING EXTRACTS AND OILS OF SOME PLANTS IN CONTROLLING PLANT DISEASES

Abstract

As a part of environmentally safe system for plant disease control, natural plant• products have been widely used for controlling plant pathogens. The objectives of this study were to detetmine the effect of. certain plant extracts and oils of 40 higher plant species belonging to 22 plant families against some fungi causing seedling damping-off and root­ rot disease namely, Rhizoctonia so/ani, Macrophomina phaseolina, Sclerotium rolftii and Fusarium spp. The results revealed that:

1- Leaf aqueous extract of Bougainvillaea spectabilis inhibited the growth•

of Fusarium poae, F. oxysporum and F. moniliforme by 94.4, 94.4 and

76.4%, respectively. It decreased the dry weight of F. poae and F.

oxysporum by 85 and 67%, and their sporulation by 100 and 99.8%

• respectively.

2- Citrus auranticum extract inhibited the growth of F. so/ani by 87.1, when six extracts decreased the fungus dry weight by ratios ranged from 76.4 to 100%. 3- Extract of Agave siselana inhibited linear growth of M phaseolina by.

50.9% when 20 plant extracts decreased the dry weight of fungus by ratios ranged from 77.6 to 96%.

4- Seventeen plant extract inhibited the growth of S. rolftii by ratios ranged

• from 75.7 to 94.3% when all tested extracts decreased the fungus dry weight by ratios ranged from 76.5 to I 00%, except Portulaca aleracea extract which increased it.