Abstract:
Guava (Psidium guajava) a vitamin C enrich fruit tree is grown abundantly throughout Sudan. In fact, it is an important fruit in many parts of the world where the climate is suitable for its production. The present investigation was undertaken under laboratory conditions of Plant Protection Department, College of Agricultural Studies, Sudan University of Science and Technology to study the effect of different concentration of aqueous extracts of jatropha seeds and argel leaves concentrations, on the growth of the fungus Pestalotiopsis sp., under laboratory conditions in order to formulate promising disease management approach. The fungus used in this was first confirmed as Pestalotiopsis sp. associated with canker scab based on its morphological and cultural characters. Three concentrations of the jatropha seeds extracts as well as that of argel leaves (25%, 50% and 100 %) were used in addition to control. The assessment of their inhibitory effect against the pathogen was expressed as fungal growth inhibition percentage. The results obtained showed that all concentrations of the two higher plants (25%, 50% and 100 %) reduced significantly (P<0.05) the fungal growth (56.2%, 75%, 75 %) respectively compared to untreated control. Moreover, the jatropha at 100% concentration demonstrated the highest inhibition of fungal growth (86%) followed in descending order by 50, 25% concentrations. Among Argel concentrations, the highest one (100%) reduced significantly the growth of the fungus (90%). Generally, the results showed that the antifungal activity increase with increase in extract concentration. Obviously, the test fungus differs in its response to the different concentrations but on the whole, growth inhibition increased with the concentration.
* The causal agents were identified as Pestalotiopsis spp. The identification was confirmed by morphological and culture characteristics, mainly the growth patterns and pigmentation.
