Leaf disc and whole plant assays of bt corn against ostrinia furnacalis (Guenee) for regulatory requirements and resistance monitoring

Issue Date

10-2017

Abstract

As part of the responsive regulatory system for all Bt corn applications prior to commercialization, formulation or midification of science-based risk assessment protocols to comply strictly with biosafety guidelines is needed. Bioefficacy testing is one way to determine whether Bt transgenic products will be approved for release and use. Direct, simple, cost-effective, and environment-friendly methods would be recommended as standard protocols for Asian corn borer (ACB) resistance management strategies and regulation of Bt-protected maize lines. Leaf disc and whole plant assays have been used for efficacy testing of Bt transgenics. Successive trials were done both in the laboratory and field in 2015-2017 which demonstrated their effective use in determining effects of Bt corn on either neonates or early instars of ACB. For each leaf disc trial, optimum laboratory conditions were maintained and acceptable threshold larval mortality strictly monitored. Petri dish, plastic cup, and assay wells were compared as containment of leaf discs. The effects of test leaf discs (Bt againts non-Bt) can be discriminated at different periods from 1-5 days. Whole plant assays using developed artificial infestation techniques have been employed both for caged and uncaged (field) conditions. Under favorable conditions, at different corn stages and multiple sites, bioefficacy of Bt corn can be easily evaluated on the basis of larvae and pupae recovered from Bt and non-Bt plants. The 100-whole plant assay was the most effective. These tests can be further improved and recommended for efficacy testing especially for Bt corn family lines.

Source or Periodical Title

The Philippine Entomologist

ISSN

0048-3753

Volume

31

Issue

2

Page

158-159

Document Type

Article

College

College of Agriculture and Food Science (CAFS)

Frequency

semi-annually

Language

English

En – AGROVOC descriptors

MAIZE, TRANSGENIC PLANTS; OSTRINIA FURNACALIS; BACILLUS THURINGIENSIS; INSECTA; PESTS; PEST OF PLANTS; PEST INSECTS; PEST, RESISTANCE TO; INFESTATION; BIOSAFETY; BIOSAFETY REGULATIONS; BACTERIAL PESTICIDES

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