Population Regulation Of Ocimum Gratissimum L.Volatile On Apolygus Lucorum And Natural Enemies In Tea Plantation In Shandong Province

The tea industry in Shandong Province has developed rapidly in recent years,and has become a characteristic industry.With the increasing expansion of tea planting area in Shandong Province,the problem of pests in the tea plantation has become increasingly prominent.The piercing and sucking mouthparts pests,such as A.lucorum,had a serious threaten to tea plantation.A.lucorum is an omnivorous insect.Because of its wide host range,strong migration ability and small size,control of A.lucorum has become difficult in the tea plantation.At present,the control of A.lucorum is mainly based on chemical pesticides.However,the long-term use of chemical pesticides has led to increased pest resistance to chemicals,reduced the numbers of natural enemies,and weakened the ecological regulation ability of tea plantation.Therefore,research and development of an ecological control of A.lucorum is the current research direction of pest control in the tea plantation.Trap crop is a kind of biological control plant.In recent years,the control of insect pests by trap crop supplemented by chemical and physical control methods has achieved remarkable results,providing a new idea for pest control.In this study,seven basil varieties were intercropped in tea plantation.The result of field investigation showed that Ocimum gratissimum had the best effect on attracting A.lucorum.Therefore,O.gratissimum was selected as the trap crop in tea plantation.High-density and low-density intercropping modes were adopted to explore the regulation on Apolygus lucorμm in tea plantation.At the same time,the volatiles of O.gratissimum leaves and flowers were collected,identified,and dynamically tracked.The types and contents of compounds in volatiles of O.gratissimum and the release dynamics of the main components were determined.Field and laboratory experiments were conducted to verify the behavior regulation ability of O.gratissimum on A.lucorum and screen out the compounds with regulating effect on A.lucorum.The main results were as follows:1.Among the seven basil varieties intercropped in tea plantation,O.gratissimum attracted the largest population of A.lucorum and had obvious attraction effect on A.lucorum.The difference in aroma of seven basil varieties were analyzed by using electronic nose,and the result showed that there were significant differences in volatile matter of O.gratissimum and other basils varieties,and the highest volatile matter was found in O.gratissimum.Therefore,O.gratissimum were chosen as a trap crop for A.lucorum in tea plantation to evaluate the regulation effect.2.After autumn flowering,O.gratissimum in the high-density intercropping mode had significant regulation effects on the A.lucorum,while those in low-density intercropping mode had no obvious effecst.Therefore,high-density intercropping mode of O.gratissimum was recommended for the control of A.lucorum in tea plantation.In addition,O.gratissimum during the flowering stage had the significant behavioral regulation ability on A.lucorum.It was speculated that the volatiles from the flower of O.gratissimum played a role in positioning the best host selection for A.lucorum.3.The volatile compounds and release amount of O.gratissimum flowers are much higher than O.gratissimum leaves.The volatile species and release amount of O.gratissimum flower is much higher than O.gratissimum leaf.Identification and analysis of the volatiles of O.gratissimum by GC-MS,flower volatiles contain 58 compounds,which are divided into alcohols,aldehydes,benzene,esters,hydrocarbons,ketones,and terpenes.Among them,eucalyptol and(±)-limonene are the relatively high-release compounds in flowers.Combining the results of previous studies and the dynamic analysis of the volatiles of O.gratissimum flowers.Twelve compounds were screened out: eucalyptol,beta.-ocimene,linalool,dodecane,2-propenoicacid,methyl cinnamate,tetradecane,(±)-limonene,nonanal,1-octen-3-ol,beta.-myrcene,terpineol,camphor.4.Field compound control experiment results show:(±)-limonen has a significant lure effect on A.lucorum in the field.eucalyptol and beta.-myrcene have a lure effect on A.lucorum,but they did not reach a significant difference.Terpineol has a repellent effect on A.lucorum in the field,but it did not reach a significant difference.In terms of natural enemy control,(±)-limonene has a significant attract effect on syrphid flies and Taenia vespa,Tendency experiment shows: dodecane and eucalyptol have a significant attract effect on A.lucorum.The attract trend of(±)-limonene and nonanal to A.lucorum was greater than the repellent trend,but did not reach a significant difference.Terpineol has a very significant repellent effect on A.lucorum.In summary,it is preliminarily clear that volatile species of(±)-limonene and eucalyptol have an attracting effect on A.lucorum,and terpineol has a repellent effect on A.lucorum.