Thesis (BS Biology) -- University of the Philippines Mindanao, 2008

This study documented the degree of damage on durian fruits among cultivars caused by rodents, estimates the cost of yield losses; identify rodent species together with demographic information and noted the existing farm practices to control rodent infestation. Trapping, baiting and morphometric measurements on captured rodents were done from June 2007 to September 2007. A total of 210 fruits were attacked by rodents which approximately costs Php 21,075 as yield loss. The month of July had the highest number of fruits attacked. Cultivars Alcon Fancy had the highest number of attacked fruits having a total of 164 (78.09%), followed by Arancillo at 21 (10.00%), Puyat at 17 (8.01%), Chanee and Monthong at three (1.43%) and D101 and Oboza at one (0.48%). Alcon Fancy trees located along the edges are frequently attacked due apparently to its nearness to rodent habitats and its softer and thinner pericarp made easier for these gnawing mammals. Majority of the fruits were attacked only once (102) with Alcon Fancy topping the list with 77 fruits. Temporal (previous and new) differences based on colorations and spatial (perianth, middlemost or bottommost) distribution differences on the nature of attacks were also observed. Continuous attacks of the rodents were results of bait shyness, presence of suitable habitats and the carrying capacity of the farm. Three species were identified from the n29 captured rodents namely: Rattus exulans, Rathus argentiventer and Rathus norvgicus. Existing farm practices include rat baiting (coumatetralyl) and farm sanitation methods such as weeding