Insect and Nematode Diversity in Upland Rice Farms and Traditional Methods for their Control in Barangay Batulaki, Glan, Sarangani Province

This study investigated interrelationships between insect/nematode diversity and environmental factors in upland rice farms in Barangay Batulaki, Glan, Sarangani Province. Additionally, the pest control strategies used by farmers to manage insect and nematode populations were documented. The total number of insects documented was 1,051 during the wet season and 433 during the dry season. The most abundant insect order was Coleoptera (known as beetles), while Aphelenchoides spp. from the family Aphelenchoididae was the most abundant nematode. Combined principal components analysis (PCA) and canonical correspondence analysis (CCA) resulted in the extraction of 2 principal components (PCs) which collectively accounted for 99.8898% of total variation in the species and environmental datasets. The triplot generated by CCA sorted the insects and nematodes on the bases of their distinct habitat preferences and their general habits (i.e. flying vs subterranean). For instance, hemipterans, coleopterans and isopterans thrived best in areas having relatively lower altitude while flying insects were seldom observed in exposed areas having high wind speed values. Furthermore, results of the study revealed that farmers had shifted to the use of synthetic pesticides in upland rice cultivation. These results do not bode well for insect and nematode diversity in these areas especially since synthetic pesticides do not discriminate between harmful and beneficial insects. Sustainable and integrated pest control strategies are thus warranted so that the insect and nematode species will be conserved in these areas.