Thesis (BS Biology) -- University of the Philippines Mindanao, 2007

Leaf extracts of Chromolaena odorata as an inhibitory agent against Phytophthora and mosquito wrigglers was studied. The mitigating ability of C. odorata toxin against Phytophthora sp. using water extracts from dried leaves was studied. Under laboratory conditions, extracts were directly mixed into the potato-carrot media at different concentrations in Petri plates and onto the center of which a slice of Phytophthora growth was seeded. The different treatments based on extract concentration were: T1 (control), T2 (5%), T3 (10%), T4 (15%), T5 (a7.5%), T6 (20%), T7 (22.5%), and T8 (25%). Each treatment consistent of 5 plates, replicated 4 times. Experiment was based on completely randomized design. It was revealed that colony growth and spore production decreased as extract concentration was increased. In the second experiment, which involved the use of extracts directly from fresh leaves without drying, same techniques and similar plate replications and protocol as the first experiment was conducted. Seven protist and fungal contaminants were recorded, and there were: Syncephalastrum sp., Rhizopus sp., Aspergillus sp., A. Aspergillus niger., Aspergillus sp. B. Aspergillus sp. C, and an unidentified fungus. Finally, a test using Anopheles sp. larvae as test organism was done. The same concentrations of C. odorata extracts were used. As anticipated, it took the least time to effect total mortality of the 10 test wriggles at the highest concentrations and more number of hours to mortality as concentration decreased. The exploratory study showed that C. odorata has the potential to be tapped as a botanical pesticide