Synergistic Effect of Adjuvant Green Orange Peel Oil on Different Herbicides

Ru Li,Zhanzhi Xiong,Xiangqun Ni,Kai Zhang

Huaiyin Institute of Agricultural Sciences in Xuhuai Area,Huai’an 223001,China

Abstract [Objective]The paper was to explore the synergistic effect of a novel adjuvant green orange peel oil on different herbicides in direct sowing paddy field.[Method]The synergistic test of green orange peel oil on 10% cyanoflurate SC and 10% metamifop EC was conducted in 2019.[Result]The control effect of green orange peel oil 150 mL/hm2+10% cyanoflurate SC 1 275 mL/hm2on Echinochloa crusgalli and Leptochloa chinensis were significantly superior to that of 10% cyanoflurate SC 1 500 mL/hm2.The control effects of green orange peel oil 150 mL/hm2+10% cyanoflurate SC 1 200 mL/hm2on E.crusgalli and L.chinensis was equivalent to that of 10% cyanoflurate SC 1 500 mL/hm2.The control effect of green orange peel oil 150 mL/hm2+10% metamifop EC 1 275 mL/hm2on E.crusgalli and L.chinensis was equivalent to that of 10% metamifop EC 1 500 mL/hm2.[Conclusion]The green orange peel oil had certain synergistic effect on cyanoflurate and metamifop.

Keywords Adjuvant;Green peel orange oil;Herbicide;Cyanoflurate;Metamifop;Echinochloa crusgalli;Leptochloa chinensis;Plant control effect;Fresh weight control effect;Synergism effect

Rice and wheat crop rotation is the main planting pattern in the middle and lower reaches of the Yangtze River.Due to long-term use of single planting pattern,weeds have occurred severely in the fields,especially in direct sowing paddy field,dry and wet management in early growth stage of rice lead to complex and severe weeds in the field,so effective control of weeds in the field has become an important link for high and stable yield of rice[1-2].Chemical weeding is still the main weeding method at present due to large quantity of weeds in direct sowing paddy field and high cost of labor[3].With the extension of herbicide service time,weeds in the field develop certain resistance,and in order to achieve the ideal weeding effect,farmers further increase the amount of herbicide.Extensive use of pesticides not only causes high weeding cost,increased pesticide residues,and declined quality of agricultural products,but also easily leads to environmental pollution and destruction of natural enemies.Green orange peel oil is a kind of plant-derived adjuvant extracted by distillation after cold pressing of green orange peel based on pure natural plant essential oil,which does not block the stomata of leaves and has excellent performance when mixed with other pesticides;mixture with chemical agents can effectively improve the penetration rate and plate-out ability of liquid preparations,so as to improve the efficacy[4-5].In order to reduce the amount of herbicides for controlling weeds in direct sowing paddy field,the author studied the synergistic effect of green orange peel oil on different herbicides,and the results were summarized as follows.

1 Materials and Methods

1.1 General situation of experimental site The test was conducted in a direct sowing paddy field in Hongze District,Huai’an City,Jiangsu Province.The soil was loam,with medium to high fertility,pH 6.3,and the previous crop was wheat.The rice variety Huaidao 20 was broadcasted on June 10,2019,with a sowing quantity of 150 kg/hm2.The weeding test was carried out on July 10(three leaf stage of weeds).The main gramineous weeds in the field were Echinochloa crusgalli and Leptochloa chinensis.

1.2 Agents 10% Cyanoflurate SC(Qingdao Qingyuan Nongguan Resistant Weeds Control Co.,Ltd.),10% Metamifop EC(FMC Corporation)and green orange peel oil(Axeb Biotech SL)were all commercially available.

1.3 Experimental design A total of nine treatments were designed in this test(Table 1).Each treatment was repeated three times,and all treatments were in randomized block design.Each plot covered an area of 30 m2.Plots were ridged for isolation,with separate irrigation and drainage.Agents were sprayed on stem and leaves by 3WBD-16L knapsack electric sprayer with the water consumption of 450 kg/hm2.

Table 1 Experimental design of synergistic effect of green orange peel oil on different herbicides

1.4 Safety investigation The leaf color and growth of seedlings were observed irregularly after herbicide administration to investigate the safety of herbicides on rice.

1.5 Investigation of herbicide efficacy Four points were randomly selected from each plot,0.25 m2each point.The number of E.crusgalli and L.chinensis at survey points was investigated at 20 and 35 d post administration(since broadleaf weed control was not included in this test,all broadleaf weeds at survey points were artificially removed),respectively.The fresh weight of aerial parts of E.crusgalli and L.chinensis at survey points was measured at 30 d post administration.The plant control effect and fresh weight control effect of each treatment was calculated according to the following formulae:plant control effect=(number of weeds in control area-number of weeds in treatment area)/number of weeds in control area×100%;fresh weight control effect=(fresh weight of weeds in control area-fresh weight of weeds in treatment area)/fresh weight of weeds in control area×100%[6-9].1.6 Data analysis The significance of differences among different treatments was determined by Duncan’s new multiple range method.

2 Results and Analysis

2.1 Safety to rice The results showed that there were no symptoms of chemical damage such as yellowing,leaf shrinkage and rotten stem in different treatment areas,and the plant height and leaf color were consistent with that in blank control area.

2.2 Control effect on weeds The investigation results at 20 d post administration(Tables 2-3)showed that the plant control effects of treatment 1 on E.crusgalli and L.chinensis were 92.6% and 92.5%,respectively;the plant control effects of treatments 2-4 on E.crusgalli were 98.5%,93.3% and 88.9%,and those on L.chinensis were 98.1%,98.1% and 94.3%,respectively.The plant control effects of treatment 5 on E.crusgalli and L.chinensis were 94.8% and 88.7%,respectively;the plant control effects of treatments 6-8 on E.crusgalli were 94.1%,88.1% and 83.0%,and those on L.chinensis were 90.6%,84.9% and 81.1%,respectively.As shown in Table 2,treatment 2 had the best control effect on E.crusgalli,significantly superior to other treatments,and treatment 4 had the worst control effect on E.crusgalli;the control effect of treatment 1 on E.crusgalli was equivalent to that of treatment 3.The control effect of treatment 2 on L.chinensis was equivalent to that of treatment 3,which were all significantly superior to those of treatment 1 and 4.The control effects of treatment 5 on E.crusgalli and L.chinensis were equivalent to those of treatment 6;followed by treatment 7,and the control effect of treatment 8 was the worst(Table 3).

Table 2 Plant control effect of 10% cyanoflurate SC and its mixture with green orange peel oil on Echinochloa crusgalli and Leptochloa chinensis at 20 d post administration

Table 3 Plant control effect of 10% metamifop EC and its mixture with green orange peel oil on Echinochloa crusgalli and Leptochloa chinensis at 20 d post administration

The investigation results at 35 d post administration (Tables 4-5)showed that the plant control effects of treatments 1-4 on E.crusgalli were 93.2%,98.1%,91.9% and 87.6%,and the fresh weight control effects were 94.0%,99.0%,94.7% and 91.3%,respectively.The plant control effects of treatments 1-4 on L.chinensis were 92.1%,98.4%,96.8% and 90.5%,and the fresh weight control effects were 97.0%,98.8%,97.5% and 94.7%,respectively.

Table 4 Plant control effect of 10% cyanoflurate SC and its mixture with green orange peel oil on Echinochloa crusgalli and Leptochloa chinensis at 35 d post administration

Table 5 Fresh weight control effect of 10%cyanoflurate SC and its mixture with green orange peel oil on Echinochloa crusgalli and Leptochloa chinensis at 35 d post administration

The plant control effects of treat-ments 5-8 on E.crusgalli were 90.7%,94.4%,88.8% and 84.5%,and the fresh weight control effects were 94.8%,95.3%,91.1% and 88.1%,respectively.The plant control effects of treatments 5-8 on L.chinensis were 88.9%,90.5%,84.1% and 81.0%,and the fresh weight control effects were 93.9%,94.3%,90.1% and 87.5%,respectively(Tables 6-7).

Table 6 Plant control effect of 10% metamifop EC and its mixture with green orange peel oil on Echinochloa crusgalli and Leptochloa chinensis at 35 d post administration

Table 7 Fresh weight control effect of 10%metamifop EC and its mixture with green orange peel oil on Echinochloa crusgalli and Leptochloa chinensis at 35 d post administration

The plant control effects of most treatments on E.crusgalli and L.chinensis at 35 d post administration were better than those at 20 d post administration,and the fresh weight control effects of all treatments on weeds were better than those of plant control effects.The differences in control effects on weeds among treatments 1-4 or treatments 5-8 at 35 d post administration were similar to those at 20 d post administration.

3 Conclusions and Discussion

Within the range of guidance dosage,single use of 10% cyanoflurate SC and 10% metamifop EC or their mixture with green orange peel oil were safe to rice.No differences were found in growth,leaf color and plant height between treatments and control,and no symptoms of chemical damage were observed.

In this test,the control effect of 10% cyanoflurate SC 1 500 mL/hm2on target weeds was equivalent to that of 10% cyanoflurate SC 1 200 mL/hm2+green orange peel oil 150 mL/hm2,inferior to that of 10% cyanoflurate SC 1 275 mL/hm2+green orange peel oil 150 mL/hm2.The control effect of 10% metamifop EC 1 500 mL/hm2on target weeds was equivalent to that of 10% metamifop EC 1 275 mL/hm2+green orange peel oil 150 mL/hm2,significantly superior to those of 10% cyanoflurate SC 1 200 mL/hm2+green orange peel oil 150 mL/hm2and 10% cyanoflurate SC 1 125 mL/hm2+green orange peel oil 150 mL/hm2.Therefore,green orange peel oil had certain synergistic effect on cyanoflurate and metamifop,with varying synergistic effects on different herbicides.

Due to the limitation of conditions,only three gradients 15%,20% and 25% with the same dose of adjuvant were designed in the test to control the weeds of the same age,and the test was relatively rough.To grasp the synergistic effect of green orange peel oil comprehensively and objectively,more scientific and detailed test remains to be further designed,supplemented with relevant laboratory work.