Benefit Analysis Of Bt Rice And Insecticide Spray On Non-Bt Rice To Control The Rice Stem Borer

With rice varieties transgenic Bt rice Minghui63 and non-transgenic rice Minghui63 as test materials, this paper studied the effects of Bt rice and non-Bt rice on pest control, arthropod community and yield of grain, and evaluated the effects of Bt/non-Bt rice pollen to silkworm. The main results were showed as follows:1. The results of field tests in two years showed that, the transgenic rice exhibited high resistance against the stem borers. The percentage of rolled leaves and dead hearts in Bt rice paddy were significantly lower than them in other treatments.2. The yield of grain in two years were quite different. In 2005, the yield and output/input of non-Bt rice with insecticide spray were lower than Bt rice. In 2006 the yield of rice with insecticide spray was higher than Bt rice, and their output/input were similar. So it is possible that the grain yield will decrease when growing Bt rice year after year. It is very important to control the non-target pest. The quantity and frequency of insecticide spray have much relationshiop with input. Sometimes they could reduce the output/input. The insecticide reduction should be proposed for environment protection and profit.3. The stability of arthropod community in transgenic Bacillus thuringiensis rice (Bt rice) paddy and insecticide sprayed rice paddy were investigated and evaluated in terms of community indices and community similarity. No significant differences were found between the Bt and non-transgenic rice without any insecticide paddy in community indices. The similarity of arthropod community between them was quite high. The diversity indices in the treatment with Methamidophos and with Regent were significantly lower than it in the control treatment without any insecticide. The similarity of arthropod community between the control and the treatments with insecticide spray were relatively lower. Such results suggest that the growing of Bt rice has not decreased the stability of arthropod community, and spraying methamidophos or regent can decrease the stability of arthropod community in various degree.4. The transgenic Bt rice pollen had no negative effects on the growth of silkworm, but reduced the enzymatic compare energy of protease, diastasum and esterase.