Three Asian corn borer, Ostrinia furnacalis (Guenee) (Lepidoptera:Crambidae) isofemale lines from Isabela [Philippines] survive after screening for Cry1Ab resistance allele
2015
Caoili, B.L. | Sapin, G.D. | Alcantara, E.P. | Cayabyab, B.F.
Bt corn has been currently grown in the Philippines for almost a decade as a management strategy against the Asian corn borer, Ostrinia furnacalis (Guenee). Hence, Cry protein resistance development monitoring in O. furnacalis is necessary to prolong the usefulness of this technology as well as for designing a proper insect resistance management program. In the study, the authors utilized F2 screening to select for O. furnacalis Isofemale lines harbouring the Cry1Ab resistance allele. O. furnacalis populations were collected from two Bt corn sentinel sites in Isabela province, namely, Barangay [village] Alicaocao, Cauayan (ACI) and Barangay San Felipe, Ilagan (SII) in September 2014. Bioassay was conducted for each Isofemale line by feeding newly hatched F2 larva with Bt corn leaf disc for 24 hours (h). Twenty-four and 18 Isofemale lines were bioassayed in the laboratory for ACI and SII populations, respectively. Percent larval survival of isofemale lines from ACI ranged from 9.09% to 84.78%, while those from SII ranged from 40.66% to 80.95%. Highest successful adult survival rate of the isofemale lines from ACI and SII were 20.19% and 38.10%, respectively. At present, two isofemale lines collected from San Felipe, Ilagan (SII 236 and SII 268) and one from Carabatan Bacareno (CBC13) are in their F12 generation. Percent larval and lines were screened at F8 generation. Percent larval and successful adult survivals for SII 236, SII 268, and CBCI 3 were 65.08%, 32.14%, and 81.82% and 32%, 3% and 70%, respectively.
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