Thesis (BS Biology) -- University of the Philippines Mindanao, 2000

Isolates of Phytophthora Butler obtained from rot-infected durian (Durio zibethinus L.) fruits were inoculated on healthy fruits of six durian cultivars (Alcon Fancy, Arancillo, Native, Puyat, Seri Kembangan Original and Seri Kembangan F2). Inoculation was done by applying 1 ml isolate suspensions on the mid-section rind of each fruit (10 per cultivar). Seri Kembangan F2 and Alcon Fancy showed to be the most susceptible to fruit rot in terms of percent infection and lesion development. Puyat and Seri Kembangan Original had the least infection. In two other tests, two inoculation methods were tried, namely wounded (making a very tiny scratch on the surface in between the spines of the rind at the mid-portion of the fruit, slightly exposing its inner epidermal tissues) and unwounded, prior to application of 1 ml of the inoculum. The methods were applied on durian fruits of two age-groups (young and full-grown) and on two entries (Seri Kembangan Original and Puyat) that manifested least infection in the varietal test with a susceptible entry (seri Kembangan F2) as check. In the age-group test, wounded fruits contracted infection earlier than unwounded fruits, regardless of age-group and younger fruits developed rot symptoms earlier than older fruits in the wounded inoculation group. On the test involving the two least infected cultivars and the susceptible entry, all wounded fruits (except those that ripened) succumbed to fruit rot and one in the unwounded group. This apparently suggests that bruises or abrasions can serve as favorable avenues for infection regardless of cultivar