| Chemical control is the main way to control the spread harm of Alternanthera philoxeroides. The commonly used chemical herbicides,such as glyphosate, fluroxypyr and bispyribac-sodium, has some control effect to overground part of A.philoxeroides. However, these chemical herbicides cannot control the regeneration of A. philoxeroides effectively. A.philoxeroides has poor absorption and conduction to chemical herbicides is the main reason that chemical herbicide eradicates Alernanthera philoxeroides difficultly. Moreover, wetting and spread property of solution on the blade surface is one of the most factors that impact the absorption of A. philoxeroides to chemical herbicides. Surface-active agents can enhance wetting and apread property of solution on the blade surface, increase the osmolality of solution, improve efficacy. A. philoxeroides is used as control object in this thesis, measure the sensibilities of A. philoxeroides to common herbicides through laboratory tests. We also research the synergistic effect and synergistic mechanism of three surface-active agents (azone, methyl oleate and organosilicone), which can control Alernanthera philoxeroides and inhibit A. philoxeroides regeneration, We verified the control effect of fluroxypyr add organosilicone to A. philoxeroides through field trial furtherly,which can provide the basis for the effective contol of A. philoxeroides hazards. The results are as follows:1. Sensitivity measurement of A. philoxeroides to herbicide25 d after treatment,on the basis of EC90 value of herbicide to A. philoxeroides,wo, can find that the herbicide activity of glyphosate is less than fluroxypyr and more than bispyribac-sodium, the herbicide activity of bentazon is more than halosulfuron methyl and less than bispyribac-sodium.2. Synergies of different surface-active agents for herbicides to A. philoxeroidesAzone, methyl oleate, and organosilicone(0.030%(w/w)) have synergise to fluroxypyr(45 g a.i./hm2)and bispyribac-sodium(30 g a.i./hm2).Synergise of azone is more than methyl oleate and less than organosilicone. Control effects of fluroxypyr(45 g a.i./hm2) obtaining organosilicone(0.030%(w/w)) or bispyribac-sodium(30 g a.i./hm) obtaining organosilicone(0.030%(w/w)) is higher than single dosage significantly. (The control effect of fresh weight increased from 69.66%,33.21% to 85.94%,59.39% respectively. The inhibition rate of renewable branch was from 75.16%,25.60% to 83.23%,42.33% respectively. The inhibition rate of regenerative stem length were from 43.52%,27.39%to 59.07%,37.27% respectively). This result was considerable to 0.030%(w/w) cattle ester sulfonamide which was added on glyphosate.3. Mechanism of different surface-active agents for herbicides to A. philoxeroidesAzone or organosilicone(0.030%(w/w)) can reduce the surface tension and contct angle of fluroxypyr(45 g a.i./hm2),enlarge its diffusion area and allowance.Effect of organosilicone is better than azone. After adding 0.030%(w/w) organosilicone (0.030%(w/w)), We found that the surface tension lowered from 52.53mN/m to 25.09mN/m while the diffusion area and retention increased from 0.167cm2,1.245g/cm2 to 0.195cm2, 1.891g/cm2 respectively.After adding azone(0.030%(w/w)), We found that the surface tension lowered from 52.53mN/m to 42.00mN/m while the diffusion area and retention increased from 0.167cm2,1.245g/cm2 to 0.190 cm2、1.443 g/cm2 respectively. So we can see that the physical properties change rule of fluroxypyr obtaing azone or organosilicione was similar to the glyphosate obtaining cattle ester sulfonamide.4. Synergies of different concentration of organosilicione to fluroxypyr in controlling A. philoxeroides.After adding organosilicione(0.024%～0.060%(w/w)), the control effet of fresh weight of fluroxypyr (45 g a.i./hm2) to A. philoxeroides increased from 69.85% to 76.06%～90.91%, while the inhibition rate of renewable branch and regenerative stem length increased from 72.58%,46.45% to 83.87%-100.00%,54.98%～100.00% respectively. We also found that there is no significant difference of control effect of fresh weight and inhibition of regeneration when the dosage of organosilicione was more than 0.042% (w/w).5. Synergies of different concentration of organosilicione to fluroxypyr in controlling A. philoxeroides.The surface tension and conduct angle of fluroxypyr(45 g a.i./hm2) decreased with increasing organosilicione, retention and diffusion area increased with increasing organosilicione. After adding organosilicione (0.018%～0.042%(w/w)), the surface tension of fluroxypyr 45 g a.i./hm2 lowered from 52.53mN/m to 33.05-21.76mN/m while the diffusion area and retention increased from 0.167cm2,1.245g/cm2 to 0.177～0.208cm2, 1.537～2.130g/cm2 respectively.6. The field trial that synergies of different concentration of organosilicione to fluroxypyr in controlling A. philoxeroides.The field trial (August 2013 in Yancheng, Jiangsu Province, Fang Qiang Farm (20000m2), Yangzhou City Baoying City(13340m2), Yancheng Funing City (13340m2)) showed that after adding organosilicione (0.042%(w/w)), the control effet of fresh weight increased from 70%～80% to over 90%, which was correspond to 0.042%(w/w) cattle ester sulfonamide which was added on glyphosate(The control effect of fresh weight increased from 70%～80% to 85%～90%). |
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