Preliminary Formula Study On 20% Wettable Powder Combined Chito-oligosaccharide·tricyclazole

Caused by Pyricularia grisea Sace.(teleomorph Magnaporthe grisea Yaegash),rice blast disease is a typical multi-circulation disease,which occurs during the whole rice growth season.It is one of the most damaging and wide-spread diseases in the world,and brings great economic loss.It is so important to control. Tricyclazole has a good effect on the disease in the application over more than 20 years.People devote many efforts to the active principle and dosage form.The research creates a new wettable powder prescription by mixing chito-oligosaccharide and tricyclazole.Main results are as follows:The results indicate that the seeds dipped in the aqueous solution of chito-oligosaccharide with an average molecular weight 3000 has great improvement in germination rate,plant height and bud length.The result indicates that chito-oligosaccharide can induce rice-plant to express PAL and POD,enhancing its defease reaction.With plant growth rate method,testing rice blast disease biologically ensures that optimal proportion between tricyclazole and chito-oligosaccharide is 18 to 2.Its virulence regression equation is Y=-0.7880+ 2.7561X,and the combined toxicity coefficient is 120.27.After choosing carders and surfactants,a wettable powder was developed,which contains 20% chito-oligosaccharide and tricyclazole(2%chito-oligosaccharide and 18%tricyctazole),2%wetting agent BX, 2%dispersant NNO,1%CMC,diatomite carrier to fill 100%.Refered to GB,the wetting time,suspensibility,degree of fineness,pH,moisture and cold / hot storage were tested and the results indicated this new wettable powder containing 20%chito-oligosaccharide and tricyclazole met the national standards.The result indicated that the new developed agent is obviously higher than 20%Jinggangmeisu and Tricyclazole wettable powder in spore germination suppression rate.Field trials showed that the new agent could prevent and cure rice blast disease efficiently.The effect to the disease is 72.11%with 40g/667m~2,equal to 75%tricyclazole WP(71.52%) in measure as 20g/667m~2 The effectiveness to the disease in measure as 40g,80g/667m~2 is better than 20%Jinggangmeisu and tricyclazole 80g/667m~2,and is still above 70%after 15 days.It indicates that less medicament has the same effect.The mixture of the new agent(600～900g/hm~2) and water(40～50kg) is recommended to spray in field.The fact mentioned above demonstrates that the new agent is qualified,satisfy the requirements of pesticide products,has a good synergized action and long term of validity,can prevent and cure rice blast disease effectively,so it is worthy of popularizing.