FIRST REPORT OF ENTOMOPATHOGENIC NEMATODE HETERORHABDITIDAE (RHABDITIDA) IN ORGANIC VEGETABLE FARMS IN CEBU, PHILIPPINES

Abstract

In the Philippines, there is little or no information on indigenous Entomopathogenic nematodes (EPNs) occurring in different habitats. Its significance can be more emphasized in Cebu, Philippines, due to reports of high biodiversity index in the area. Thus, a study was conducted to identify indigenous EPNs from different organic vegetable farms. Soil samples from 17 farms within 10-15cm deep during wet and dry season were collected from eight municipalities across south, central and northern Cebu for EPN morphological characterization and identification. Some ecological factors such as soil type, temperature, and pH and land elevation were noted. All samples were positive of EPNs. These EPNs were found in elevations ranging from 22-884 m above sea level, under low light intensity, in wet soils with slightly acidic to slightly basic (6-8.0) soil pH. EPNs were found in all soil types surveyed (loam-clay). All isolates collected belong to genus Heterorhabditis of the family Heterorhabditidae. From these, four species were identified: H. bacteriophora, H. indica, H. marelatus and H. taysearae. H. indica was found to be widely distributed across south, central and northern Cebu. On the other hand, both H. bacteriophora and H. marelatus were found only on samples taken from central Cebu, while H. Taysearaewas found in southern and central Cebu.This shows that Cebu, Philippines, holds indigenous EPNs and their distribution are influenced by environmental factors.