Optimization Of The Artifical Rearing Technique Of Chilo Suppressalis(Walker)

Chilo suppressalis(Walker)belongs to Insecta,Lepidoptera,Acrididae,Calycanthidae.And it is one of the most severe pests in China.It causes damage in all growth stages of rice.In the tillering stage of rice,larvae will erode rice seedlings and cause rice seedlings to wither.During the booting and heading stages of rice,larvae erode rice stalks,causing rice booting to fail,producing dry and white spikes.During rice filling and milk ripening,larvae rot the rice stems,causing the rice to be unable to fill normally,and the occurrence of half-summer and insect-infested plants and pods increased,which has a great influence on the product and quality of rice.The rice stem borer,which is endangered by C.suppressalis,has pod boreholes.There are few insect excrement outside the pod boreholes.The worms are mostly distributed in the stems and are yellow,making the damaged rice stalks dry and easy to break.The plant species harmed by C.suppressalis are very extensive.Apart from rice,it can also cause damage to alfalfa,corn,sorghum,sugarcane,rapeseed,faba bean,wheat and weeds of reeds,cockroaches and clams..In recent years,with the global climate warming,the damage of C.suppressalis has become increasingly serious and it is urgent to prevent and control.However,the research on prevention and control of C.suppressalis needs a stable source.The use of natural feeds is extremely inconvenient for rearing,and the survival rate and egg production are low and can not be expanded.For this reason,it is imperative to carry out related research on artificial rearing of C.suppressalis.However,the establishment of a suitable system for rearing C.suppressalis need to consider many factors,each link will have different problems to solve,and different details need attention.In view of the above problems,this paper carried out research on the screening of artificial diet and the related conditions of feeding conditions.The main findings are as follows.1.Optimization of artificial diet(1)Screening of main conponentsUnder the same conditions as the auxiliary components,choose wild rice stem,corn and water chestnut as the main conponents to conduct comparative tests.The test results show that the survival rate of C.suppressalis is the highest and that of larvae is the shortest when using wild rice stem as the main conponent.It is conclude that the wild rice stem is the main component of the optimal artificial diet.(2)Experimental research on the auxiliary componentsAfter determining the main conponents,four auxiliary components(choline chloride,ascorbic acid,sorbic acid,sucrose)were selected to further optimize the artificial diet.Three logically-accurate horizontal data were selected from these four auxiliary components by orthogonal experimentation,and four-factor and three-lever data tests were conducted.The optimum content of these four auxiliary components is obtained through spss ata processing: 0.3 g choline chloride per 1 kg,2 g of ascorbic acid,2 g of sorbic acid and sucrose 25 g.2.Optimization of production procedure of the artificial dietIn the past,the production process of the artificial diet for C.suppressalis is often boiled,which is easy to cause loss of water during boiling.At the same time,boiling time too long can also cause feed aging.In order to solve these problem,the method of making artificial diet of the C.suppressalis was changed from boiling to cooking.The specific approach are as follows.First,adds ingredients to the beaker and cover with aluminum foil for high temperature sterilization.Second,adds the others ingredients,which are not resistant to high temperatures.Then keep stirring constantly.At last,store the artificial diet in a refrigerator at 4°C until use.3.Effects of temperature and humidity on rearing of C.suppressalisTemperature and humidity are important for the growth and development of insects.Therefore,this experiment screened the optimum temperature and humidity for artificial rearing of C.suppressalis.Temperatures were set at 25°C,28°C and 31°C respectively.The humidity distribution were set to 40%,60% and 80%.The results showed that when the temperature was 28°C and the relative humidity was 60%,the survival rate of C.suppressalis larvae was higher and the larval stage was shorter.It is concluded that the relative humidity of 60% at 28°C is the most suitable condition for artificial rearing of C.suppressalis.4.Study on the spawning deviceSpawning is a very important part of artificial rearing of C.suppressalis,which directly affects whether or not expand the reproduction.After researching,a suitable device for spawning of C.suppressalis was finally obtained.That is a square box,which has transparent plastic on the bottom and three sides.Install gauze on the top and front of the box.At the same time,sew a zipper on the front gauze for easy operation.Cover the box with a wet black cloth to keep it moist and dark,and simulated rice field environment at night in summer.5.Screening of spawning mediumArtificial feeding research of C.suppressalis so far,there are less research of spawning medium,so the spawning media used are generally rice leaves of natural media.However,artificial breeding pursues fast and convenient,and rice leaves need to be continuously planted as an oviposition medium,which does not meet the requirements of artificial rearing.Therefore,the test was divided into several steps to screen the spawning media.The first is the screening of different media,different medium such as rice leaves,filter paper and carbon paper are randomly placed in the spawning device for spawning selection.The number of oviposit is used as a standard.The results show that the number of oviposit on the filter paper are the most except that of rice leaves.Meanwhile,the hatching rate is also higher than that of other medium.In view of this,it is inferred that C.suppressalis may prefer a rough texture for spawning.Because the rice leaves can provide nutrition to C.suppressalis,the second test was compared honey water with rice juice were soaked and dried in filter paper.And placed in the spawning device for testing.The results show that the number of oviposit of C.suppressalis on the filter paper,which treated with honey water is more.During the experiment,it is also found that C.suppressalis was more willing to laying eggs in folds of medium.It is conclude that when artificial rearing of C.suppressalis,filter paper which is folded and stained with honey water may be used instead of rice for spawning.With data as support,this experiment optimized the artificial breeding technology of C.suppressalis,improved the survival rate of C.suppressalis,shortened the larval period,and explored its spawning medium to lay the foundation for the realization of full artificial breeding.