| Oryza sativa L.is the most important food crop in our country.The rice pests are various in types and may cause serious consequences.Numerous studies have shown that the continuous application of pesticides can make the rice pests have a resistance to drugs.Therefore,the technology of using pest ecological regulation to control the rice pests is bound to be a tendency in the future.According to the principle of eco logical regulation,since 2015,through a series of field trials that aim to select a reasonable and effective ecological control method,we had formed an ecological control system of "push-pull" in Xinhui District,Guangdong Province.The system was as fo llowing: the tobacco and perilla that used to expel plants were placed on one side of the rice field to form a force of "push";While the vetiver grass,light trap and sex attractant that used to seduce plans were placed on the other side,forming a force of "pull".Except the method above,the control area had the same condition of drug delivery and water and fertilizer.We got the following results by indoor measurement and field investigation:(1)Planing tobacco and perilla in the rice field can expel t he white backed planthopper and brown planthopper.According to indoor determination,the number of the WBPH(Y-tube olfactory response)to chose "tobacco+rice" was 30.12%,to "rice" was 69.88%,to "perilla+rice" was 38.7%,and to "rice" was 61.3%.In the enveloped experiment,there were 34.74% chose the "tobacco+rice",65.26% chose "rice",33.90% chose "perilla+rice",and 66.10% chose "rice".As for the BPH(Y-tube olfactory response),the number to chose "tobacco+rice" was 39.65%,to "rice" was 60.35%,to "perilla+rice" was 33.87%,to "rice" was 66.13%.In the enveloped experiment,there were 39.00% chose the "tobacco+rice",61.00% chose "rice",38.10% chose "perilla+rice" and 61.90% chose "rice".As we could see,the proportion of the group of "tobacco+rice" and "perilla+rice" was lower than the group of "rice".In addition,field survey found that the number of planthoppers that 1-4m far from tobacco and perilla was significantly lower than that in control.And as the distance increases,the number of planthoppers increased.Studies had shown that within a certain range,tobacco and perilla had some effect to expel the WBPH and BPH.Nicotine is the major component of alkaloids in tobacco,so we conducted a further test on nicotine and the result showed that in all kinds of cases,the number of the WBPH chose nicotine(25mg/L)was 16.7±0.9aB,the control was 22.0±1.2bA;nicotine(50 mg/L)was 14.7±0.9bB,the control was 22.7±1.8bA;nicotine(75 mg/L)was 12.3±1.2a B,the control was 26.0±1.0bA;nicotine(100mg/L)was 7.0±1.0aA,the control was 31.0±0.6bB;nicotine(125mg/L)was 6.7±1.5aA,the control was 31.3±1.2bB.O n the other hand,the number of the BPH selected nicotine was 18.4±1.0a B,the control was 21.0±0.7bA;nicotine(50mg/L)was 15.3±0.8a B,the control was 23.9±1.6bA;nicotine(75 mg/L)was 13.3±1.5aB,the control was 24.7±1.2b A;nicotine(100 mg/L)was 8.0±0.9aA,the control was 31.0±0.3bB;nicotine(125 mg/L)was 7.7±0.9aA,the control was 30.7±0.9b B.This study showed that the number of the WBPH and BPH chose nicotine was significantly lower than that in control.So we could say that nicotine had certain repellent effect on the WBPH and BPH,in which the concentration of nicotine 100 mg/L was the most appropriate.(2)Vetiver could attract spiders.Indoor measurement showed that the number(Y-tube olfactory response)to selected "vetiver+rice" was 67.55%,to "rice" was 32.45%.In the enveloped experiment,there were 66.07% chose for "tobacco+rice",33.93% for "rice".We could see that the ratio of "vetiver+rice" was higher than that of "rice".Vetiver planted on rice fields could provide spiders a place to spawn and inhabit.The average number of spiders in the rice field that planting vetiver grass and the control area were respectively 237.33±74.92 b and 133.33±56.37 a,from which we could clearly see that the number of spiders in test field was higher than that in control area.This study showed that planting vetiver grass in rice field could attract spiders and increase their number.(3)The number of WBPH,BPH,rice stem borer and rice leaf roller could be greatly reduced by insect-trapping lights and sex attractant.The average number of the WBPH(per 100 plants)in the test feild with light trap and sex attractant and that in the control area was respectively 229.33±73.42 a and 322.67±82.00 b.By contrast the number of BPH(per 100 plants)were respectively 216.00±61.75 a and 246.67±38.59 b.The average dead tillers rate(%)were respectively 6.80±0.80 a and 11.60±0.82 b,and the average the rate of roll leaves were respectively 8.80±1.50 a and 12.60±3.21 b.We could see that the number of plant hooper,dead tillers rate,the rate of roll leaves in the test field were significantly lower than that in the control area.These studies showed that the insect-trapping lights and sex attractant could play a role in controling the appearance of the WBPH,BPH,rice stem borer and rice leaf roller.The indoor studies and field trials above had shown that the "push-pull" ecological control system that constructed mainly b y tobacco,perilla,vetiver grass,insect-trapping lights and sex attractants could provide a scientific guidance for protecting natural enemies and reducing the main pests of WBPH,BPH,rice stem borer and rice leaf roller. |
PDF Full Text Request