| Pinus tabulaeformis, the unique evergreen species in China, belongs to Pinaceae. In north China and northwest China, it is one of the important tree species for conservation of water and soil, greening environment and wood production. In recent years, growing recession phenomenon is becoming more serious because of the growing disease and insect pest, such as pine shoot moth, bark beetles, pine spittle bugs, plexiform shoot dead disease and so on in many adaptive areas of P. tabulaeformis. The potential boring pests mainly harmed xylem or pith. It is difficult for general agents to reach the parasites and achieve the desired control effects. To solve the above problems, a fat-soluble penetrant "Rouzhitong" was designed and produced. In this study, the physicochemical properties, performance and the control effects were explored. The results are as follows:1. Physicochemical properties of “Rouzhitong”: It appeared as tan paste liquid at 0℃ and began to thaw with stratification at 20℃. The layers were obvious at 25℃ and disappeared at 28℃. The penetrating agent was transparent brownish yellow liquid at 28℃. When temperature fall to 20 ℃, the stratification did not appear, indicating the penetrating agent had a certain stability. The p H of 1% aqueous solution was 6.2, which accord with the national relevant specifications.2. The penetration properties of “Rouzhitong”: The canvas sheet method was used to measure the penetration properties. The results showed that the time for canvas sheet of 2 cm in thickness submerged in 100 times liquid of penetrating agent was 3.80 s. The time was 9.0 s, 8.9 s and 17.0 s respectively when the canvas sheets were submerged in recommended concentration of reference reagent acetamiprid, lorsban and carbendazim. And the time were 4.0 s、3.8 s、5.3 s respectively when the canvas sheets were submerged in the mixed solution of 100 times of “Rouzhitong” and the above reference reagents. It was indicated that “Rouzhitong” could significantly shorten the immersing time of canvas and display the performance of penetration.3. The de-fatting performance of “Rouzhitong”: The qualitative and quantitative tests were used to determine the de-fatting performance of “Rouzhitong”. The qualitative test results showed that the colophony powder could not be dissolved in the 200~6400 times liquid of the adjuvants “Hailiping”, “Beiyaogong” and “Zhusha”. When the “Rouzhitong” was added in above solution, colophony powder dissolved. It could be inferred that the “Rouzhitong” had a strong dissolve fat performance. The quantitative results showed that the time of soaking grease canvas sheet submerged in 100 times liquid of the penetrating agent was 9.0s. They were 62.7 s、34.3 s、152.7s respectively when the soaking grease canvas sheets were submerged in recommended concentration of reference reagent acetamiprid, lorsban and carbendazim. And the times were 13.0 s、9.3 s、24.1 s respectively when the soaking grease canvas sheets were submerged in the mixed solution of 100 times of “Rouzhitong” and the above reference reagents. It was indicated that “Rouzhitong” could significantly shorten the time of the immersing soaking grease canvas and display the performance of de-fatting.4. The penetration properties of “Rouzhitong” detected by GC: The concentration of chlorpyrifos on the xylem surface of P.tabulaeformis branches was 13.8 ppm after 24 hours treated by 500 times of chlorpyrifos. The concentrations were 30.5 ppm, 31.3 ppm, 27.5 ppm respectively when treated by mixed solution of 500 times of chlorpyrifos and Hailiping(100 times), Zhusha(300 times) and Beiyaogong(500 times). There were no significant differences between the three kinds of promoters. The concentration was 55.3 ppm when treated by mixed solution of 500 times of chlorpyrifos and Rouzhitong(200 times). It showed significant difference with the above three kinds of promoters. Rouzhitong, Hailiping, Zhusha and Beigongyao increased the penetration ability of chlorpyrifos in P.tabulaeformis branches to 4.0, 4.0, 2.2 and 2.0 times respectively. The results showed that the penetration ability and fat-soluble ability of Rouzhitong were better than the other promoters, and the performance of 200 times liquid reached the best.5. The control effect of Rouzhitong in P. tabulaeformis forest: In Beidaihe control region, the control area, test area including the simple pest control area and pathogen exclusion zone using reductio ad absurdum, and organosilicon control area were set. To simple pest control area, 800 times of Chlorpyrifos plus 800 times of Fenoxycarband 200 times of “Rouzhitong” was used in May 25 and August 25, 2013. To pathogen exclusion zone, A mixed formula including 500 times of chlorpyrifos, 500 times of acetamiprid, 200 times of Rouzhitong and different fungicide was used in July 20, 2013. To organosilicon control area, 500 times of chlorpyrifos plus 500 times of acetamiprid, 200 times of organosilicone were used. The rate of folded shoot of each district was investigated in May 25, 2014. The results showed that the rate of folded shoot was 53.8% in the control area. And the rates of folded shoot were 28.0%, 27.2%, 8.8% respectively in large area control area, simple pest control area and pathogen exclusion zone, and the average one was only 4.9%. It was indicated that when the pesticide was chosen correctly in types, concentrations and doses, “Rouzhitong” could carry the pesticides into the subcutaneous branches and effectively kill pine shoot moth larvae, and maintain a long residual period. |
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