Thesis (BS Biology) -- University of the Philippines Mindanao, 2003

Strip survey and mapping were done to determine the distribution of the exotic weed Helianthus cucumerifolius from it was first reported in 1996. Survey along roads revealed that the weed is concentrated in Davao City, Davao del Sur. The mapping revealed that weed infestation has so far reached five districts of Davao City, namely, Calinan, Tugbok, Talomo, Toril and Marilog. Weed population decreased as distance radiated outward from the point of origin. Bago Oshiro, the place where the weed was first spotted, had the highest population density at 401.7 hills/m2. This was followed by Mintal (279.5 hills/m2), Sto. Nino (103.4 hills/m2), Catalunan Pequeno (95.5 hills/m2), Catalunan Grande (70.4 hills/m2)), Tugbok (66.2 hills/m2), Dumoy (23.6 hills/m2), Baliok (17.4 hills/m2), Bago Gallera (4.3 hills/m2), Tacunan (1.7 hills/m2), Los Amigos (1.4 hills/m2), Bangkas Heights 90.88 hills/m2), Riverside (0.46 hills/m2), Ula (0.18 hills/m2), and Mulig (0.12 hills/m2). Patches of weed infestation were recorded in Rizal, Bansalan and Astorga, Sta. Cruz in Davao del Sur. The reported occurrence of the weed along oil palm plantations in Sultan Kudarat was also confirmed. Rainy periods provided better vegetative and reproductive growth for the weed. Dry period, on the other hand, caused retardation of their growth