Scientist Profile


Alfredo R. Rabena

Chemist, OutstandingTeacher of Vigan City Tertiary Level (2006)

Expertise: Chemical Sciences, Natural Products Chemistry, Forest Products Chemistry, Natural Products and Wood

Dr. Alfredo R. Rabena, is recognized for his important contributions in the field of head of the Research and Development Office of the University of Northern Philippines in Vigan City, Ilocos, has discovered a solution. He found that the leaves of kakawate tree or Mexican Lilac (Glinicidia sepium) contains coumarins, an effective botanopesticide. To prepare the solution, chop the kakawate leaves and let these soak overnight to extract coumarins. Using a strainer, separate the leaves from the solution. Spray the solution to the ricefields. The best time to apply it is from eight o’ clock to nine o’clock in the morning and from five o’clock to six o’clock in the afternoon as worms and pests are coming out from the leaves at these times. So the solution would be more effective to use. If applied early, it wouldn’t be that effective as pests are still hibernating. And if used when the sun’s heat is too hot, it wouldn’t be that effective also as pest would hide. Since kakawate is a legume, says Rabena, its leaves are rich in nitrogen, an important soil nutrient. Hence, the discarded leaves can be applied to the field as an organic fertilizer. He also recommends fanners to put several leafy branches of kakawate tree in between rice plants two days after planting to prevent pests from attacking the crop. To prove this research finding, Rabena and Flora Cely Rodilias did a demonstration in Naglaoa-an, Sto. Domingo, Ilocus Sur as well as in Vigan City and Lidlidda, Ilocus Sur where the kakawate leaves botanopesticide effectively eliminated rice weevils, rice bugs, and worms in ricefields. To make the chopping of leaves easier, Rabena and Dr. Manuel Bajet Jr. designed a chopper. Called Dual Power Operated Foliage Chopper, the device can either be operated electrically or manually as it has a pedal. It costs P21,000 and there are units at the University. OTHER USES OF KAKAWATE LEAVES Coumarins in kakawate leaves are also effective termites and bed bugs neutralizer. Rabena presented this finding through his paper “The Isolation, Characterization and Identification of Active Botano Chemicals of Kakawate Leaves Against Termites” that he presented during the 5th International Congress of Plant Molecular Biology in Singapore in 1997. His study was also included in the book “The International Society for Plant Molecular Biology” published by the National University of Singapore and Institute of Molecular Agrobiology. Kakawate leaves are also effective anti-fungus. It can cure Trichophyton Metagrophytes that causes skin diseases like eczema. Crumple several leaves and apply to affected area of the skin for a salicylic acid-like effect. This year, Rabena and Dr. Nelia Aman, and Engr. Franklin Amistad have discovered that the ash of kakawate can be a good concrete mixture for ceramics. Its charcoal is a good moisture and odor absorbent, too. Kakawate leaves can be used also to deworm pigs. Just have the swine eat ample leaves and the parasites wouldn’t live long. If these uses are not enough, then remember that kakawate’s flowers can be made into salad or into dinengdeng, a delicious Ilokano veggie dish. So farmers, why don’t you plant kakawate this rainy season? So that next year, you will have a good source of botanopesticide, termites and bed bugs neutralizer, and anti-fungus.