Effects of genetically modified Bt-rice on non-target rice insect pests

This study was conducted to assess the potential effects of Bt-rice line expressing CryIAc1 on non-target rice insect pests under laboratory conditions. Transgenic Bt-rice line (japonica rice cultivar Nakdong) with a synthetic cryIAc1 gene, C7-1-9-1-B, which was developed to express insecticidal activity derived form Bacillus thuringiensis Berliner and highly active against all larval stages of Cnaphalocrocis medinalis (Guenee) (Lepidoptera: Pyralidae), and non-Bt isoline were used for the experiments. Test insects were non-target herbivore, Oxya japonica japonica (Thun berg), Scotinophara lurida (Burmeister), Nilaparvata lugens (Stål), which are important rice pests, and direct feeding tests were conducted using 50 days old rice seedlings. For S. lurida and N. lugens, no significant differences were found in total immature development time and immature survivorship, and adult physical characteristics such as weight, and body length and width. For o. japonica japonica,immature development time was significantly prolonged but immature survivorship and adult physical characteristics were not different.

Key word: Bt-rice, CryIAc1, Cnaphalocrocis medinalis, non-target insect pests, adverse effect, Oxya japonica japonica, Scotinophara lurida, Nilaparvata lugens