Formulation Of ME And EW Of Hexaconazole And Its Application In Controlling Against Sphaerotheca Fuliginea

Sphaerotheca fuliginea is a main pathogen which caused cucumber powdery mildew in greenhouse, but there have no good fungicide to prevent Sphaerotheca fuliginea. At the same time.the formulation of fungicide preventing Sphaerotheca fuliginea usually are EC and WP, so the quality of cucumber is badly affected and it empoison the environment.This research try to choose the efficient germicide to prevent Sphaerotheca fuliginea, and raw fungicide can be formulated to environment friendly formulation. Main contents is as follows:1.In this paper a new inoculating and testing method - cotyledon-brushing with spore suspensions in the bioassay of fungicides to Sphaerotheca fuliginea in cucumber was introduced. In the preparing of spore suspension, emulsifier was used to make sure the consistency of spore suspension. And when the density of spore is 30-40 per visual field (microscope, 15×10 times), the cotyledon suffered the disease uniformity. Comparing this new method with spore spraying inoculating method, it showed the former method could increase the incidence of disease and uniformity than the latter one. Using the numbers of powdery mildew spots replaced the disease index in calculating the toxicity effect could reduce the artificial errors. Used cotyledon-brushing with spore suspensions and leaf dipping method, the EC50 values of hexaconazole, mycolbutanil, triadimefon, thiophanate-methyl and chlorothalonil to Sphaerotheca fuliginea was tested, the results showed that this method was reliable.2.For the screening the formulation of hexaconazole 5% ME, the appropriate solvent and emulsifier was selected, the best solvent was the mixture of cyclohexanone and N'N-dimethylformamide (3:1, m/m ), which was 20% weight of total composition; the emulsifier was the mixture of 1602#, EL-10 and 500# (2: 2: 1, m/m/m), occupied 20% weight, the other conponent was water. The main specifications of hexaconazole 5% ME made with water of different content of calcium i on, including physical and chemical stability were tested after storage under 0℃ and 54 ℃. All of them were up to grade and there was no significant difference with deionized water.3.Study on cold storage stability of pesticide ME,it is showed that the composition of ME have effets on cold storage stability:the times of cold storage stability of hexaconazole ME and content of solvent is direct proportion, the higher solubility of solvent, the shorter cold storage stability time , the lower solubility of solvent, the longer cold storage stability time; the times of cold storage stability of hexaconazole ME and content of surfactant is direct proportion, in same type surfactant, the lower of HLB, the longer cold storage stability time;if the number of alcohol carbon nc<5 add in ME, cold storage stability time will be become lower, if the number of alcoholcarbon nc≥5 add in ME, cold storage stability time become longer; Inorganic salts adding in ME will low the time of cold storage stability.4. Study on transparent temperature range of pesticide ME,it is showed that the composition of ME have effets on transparent temperature range :the effect of solvent on transparent temperature range is relate to it's dissolve capability and polarity, the higher solubility of solvent, the wider transparent temperature range , and transparent temperature range will be move to high temperature area along with polarity coming bigger; ME with hydrophilic surfactants have wide transparent temperature range in high temperature area, and ME with lipophilic surfactants have wide transparent temperature range in low temperature area;if the number of alcohol carbon nc<4 add in ME, transparent temperature range will be move to high temperature area and become wider, if the number of alcohol carbon nc≥4 add in ME, transparent temperature range will be move to low temperature area and become narrow; Inorganic salts adding in ME will low transparent temperature range; transparent temperature range will be lower along with Harder of water.5.For the screening the formulation of hexaconazole 5% EW, the appropriate solvent and emulsifier was selected, the best solvent was the mixture of cyclohexanol and toluene (1:1, m/m ), which was 30% weight of total composition; the emulsifier was the mixture of EL-80 and NP-6-P(3:1,m/m),Tween-60 and NP-6-P(3:1,m/m), L61 and NP-6-P (9:1, m/m), occupied 30% weight, the other conponent was water. The All of them were up to grade and there was no significant difference with deionized water.6.The quantitative analysis method of hexaconazole with GC and HPLC was studied. In gas chromatographic method, a 3%OV-101 on Chromosorb AW DMCS 150-177μm, 1 m×3mm (i.d.) glass column was used at column temperature of 195℃ and detector temperature of 230 ℃. The internal standard was n-eicosane, dibutyl o-phthalate and dibutyl o-phthalate respectively. This method had a recovery of 99.3%~100.7%, their coefficients of variation were 0.21%, respectively. Operating conditions by HPLC were C18 column (250mm×4.6mm), V(methanol):V(water)= 85:15 as mobile phase, spectrum length UV-223nm. This method had a recovery of 99.9%~101.2% and their coefficient of variation were 0.47% for hexaconazole respectively.7.The control efficiencies of hexaconazole 50 ME and EW at the dose of 25, 12.5 and 8.3mL/667m2 were all over 80%, and equaled to the same active dose of hexaconazole 10% EC. Their effect were better than that of 50g of thiophanate-methyl 70 WP, Those otherness is marked. The result showed hexaconazole 5% ME was a safety and better fungicides in the control against Sphaerotheca fuliginea on cucumber. The security appraise efficiencies show that , security dosage is less than 6.25mg/kg inseeding growth period, security dosage is less than 12.5mg/kg in three leaves period, security dosage is less than 25mg/kg in grown period.