Pathogenicity of Philippine populations of Steinernema abbasi and Heterorhabditis indica to major lepidopterous pests of corn and sweet sorghum
2015
Caoili, B.L. | Mercado, C.D.M. | Sandoval, R.F.C. | Latina, R.A.
Recent interests on the use of entomopathogenic nematodes (EPNs) showed their great potential as one of the alternative biological control agents against above ground insect pests especially those that already developed resistance against chemical insecticides. Preliminary bioassay studies on seven indigenous populations of entomopathogenic nematodes identified two highly virulent local entomopathogenic nematode species. Morphological and molecular analyses identified these EPNs as Heterorhabditis indica PBCB2 and and Steinernema abbasi MBLB2. The potential of these EPNs against major lepidopterous pests of corn and sweet sorghum was evaluated against larvae of Helicoverpa armigera, Ostrinia furnacalis and Spodoptera litura. Laboratory bioassay studies showed an LC 50 values of 10.52 IJs/20 ul, 9.86 IJs/20 ul and 4.64 IJs/20 ul and LT 50 value of 23.32 hours (H), 33.92 H and 28.29 H for H. indica PBCB2 at 200 IJs/150 ul to O.furnacalis, H. armigera, and S. litura, respectively. Meanwhile, S. abbasi MBLB2 exhibited LD50 values of 10.99 IJs/20 ul, 11.44 IJs/20 ul and 9.145 IJs/20 ul and LT 50 values of 24.45 H, 33.89 H and 28.83 H at 200 IJs/150 ul to O. furnacalis, H. armigera, and S. litura, respectively. This is the first report on local EPNs exhibiting high virulence against the three lepidopterous pests tested. Their efficacy under greenhouse conditions is currently being evaluated.
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