Preliminary Studies On The Bioactivity And Mechanisms Of Octadecyl Trimethyl Ammonium Chloride Against Magnaporthe Grisea

Octadecyl trimethyl ammonium chloride (1831) is a novel fungicide. Due to theinformation on the bioactivity and application of the compound is not available, thefungicidal activity, pot experiment, field trial and action mechanism experiment werecarried in this study. The main results are as follows:1. 1831 strongly inhibit the mycelium growth and spore germination of Magnaporthegrisea in vitro. Toxicity regression equations of 1831 inhibition mycelium growth ofMagnaporthe grisea are y=1.8608+1.5592x(r=0.9829), y=1.4247+1.7986x (r=0.9975), y=0.3542+2.3276x (r=0.9928),y=0.2775+2.4108x (r=0.9913) andy=0.3443+2.4165x (r=0.9828). Average EC₅₀ is 94.97mg/L. Toxicity regressionequations of 1831 inhibition spore germination of M.grisea are y=2.3889+1.1624x(r=0.9914), y=2.4143+1.1432x (r=0.9938), y=2.3775+1.1518x (r=0.9864),y=2.269+1.2001x (r=0.9878),y=2.2037+1.2254x (r=0.9910). Average EC₅₀is 185.6mg/L. Its inhibition effect on the mycelium growth is better than that on thespore germination.2. Pot experiment results show that 1831 has a good preventing and cure effectagainst rice blast. Toxicity regression equations of its prevention to rice blast are y=4.6416+0.1489x (r=0.9954), y=4.6316+0.1529x (r=0.9958), y=4.6267+0.1538x (r=0.9972), y=4.6219+0.1567x (r=0.9976) and y=4.6136+0.1616x(r=0.9976). Average EC₅₀ is 256.9mg/L. Toxicity regression equations ofits cure to rice blast are y=4.6457+0.1382x (r=0.9932),y=4.6409+0.1411x (r=0.9961), y=4.6352+0.1442x (r=0.9938), y=4.6300+0.1466x (r=0.9918)and y=4.6238+0.1483x(r=0.9892). Average EC₅₀ is 346.8mg/L. Its preventioneffect against rice blast is better than the cure effect.3. Field trial results show that 12% 1831 SP has a good efficiency against rice leafblast and panicle blast. Its efficiency are 80.38% and 82.46% respectively using 270g.ai/hm², Which is better than 75% tricyclazone WP (281 g.ai/hm²)and 4%kasugamycin WP(30 g.ai/hm²). 12% 1831 SP is safe to crop.4. The action mechanism experiment shows that 1831 can induce PAL, POX and PPOactivity in rice. PAL, POX and PPO activity in rice increased rapidly after treatmentby 1831. 9 days after 400 mg/L 1831 treatment, PAL, POX and PPO specific activities in rice seedlings are 76.2, 25.7 and 44.8 U/g.h more than the controlrespectively.