Study On The Bioecology Of Carpomya Vesuviana Costa And The Forecast Of Its Potential Geographic Distribution In China

The ber fruit fly(Carpomya vesuviana Costa),the important quarantine pest of jujube trees,was found in Turpan region of Xinjiang in China for the first time in 2007.In order to grasp the characteristics of the pest and the effective control measures,the biological and ecological characteristics of Carpomya vesuviana Costa was preliminarily investigated and studied in Turpan region from September 2007 to October 2008.According to the research,the potential geograph distribution of the pest in China was predicted.The results are reported hereinafter.The primary distribution area of Carpomya vesuviana in Turpan region locates in Sanpu township,Erpu township,Qiatekale township,Yaer township,Shengjin township, Aidinghu township,Yuanyichang administered by Turpan city,in Lukeqin township, Lianmuqin township,Dalangkan township,Dikaner township,Tuyugoutownship,Pizhan township,Qiketai township administrated by Shanshan county and in Xia township, Hedong township administered by Toksun County.Naturally it hosts all varieties of jujube including the wild ones,but not the other melons and fruits mainly planted in Turpan region.It occurs 2 or 3 overlapping generations one year and overwinters as pupae in the soil under the jujube crown.The overwintering adults emerge in mid-May,lay eggs in the surface of the ber fruit in mid-June.About five days later,the larva begins to eat the flesh of jujube once hatching.The final instar larvae wriggle out of the fruits,drop down into the soil to live through pupal stage.The puape live in the depth range of 15cm towards the surface in the soil.On late September,the late-maturing larva of the 2^nd generation and the mature larva of the 3^rd generation begin to pupate for wintering.The adults are sensitive to green,yellow and cyan.The adult emergence occurs in the morning.Both female and male adults need food for survival after eclosion.The honeydew on the leaf surface is the main food for the adults in the field.The adult can live for an average of 20 days and 45 days by the greatest extent given enough food,but it just can live for less than 24 hours without any food given.Only water provided,the adult can survive for an average of 3 days and 4 days by the greatest extent.Both female and male adults exhibit multiple mating behavor.The matting normally happens in the 6^th day after eclosion provided enough food for adults,but sometimes it happens in the 2^nd day.The matting time can last for an average of 4 hours and for 8 hours at most in the lab,but it always last for half an hour in the field.The mean egg amount of single female adult is 16 and the maximum amount could be 26.In the field,when the jujube fruit grows at the size of 21mm×16mm,female starts to oviposite under the fruit surface.The egg is long and oval,milky and glossy,layed flatwise in the fruit.There are always 1～2 eggs in every oviposition puncture.About 5 days later,the hatching shows.The larva of Carpomya vesuviana is maggot,3 instars,white and vermiform.The whole stage of larva lives through in the fruit.When matured,the larva gets out of the fruit with the pinch of abdomen muscle through the circular drop-out hole bitten by the larva.After landing,the matured larva pupates into the soil under the jujube crown.The pupa is ricelike,yellow and oval,with acuminate head and flat circular bottom.There are creases surrounding the puparium.The developmental threshold temperature and the effective accumulated temperature for the pupa of Carpomya vesuviana are caculated to be 13.63℃and 807.55 degree-days respectively.The confidence interval of mean monthly soil surface temperature in Turpan was calculated with the records from 1988 to 2007.According to the effective accumulated temperature formula and the confidence interval,we predict that the overwintering adult emergence would firstly occure from 13th to 22nd of May in 2008 in the field.Through comparing the forecasted emergence date with the practical emergence date in 2008,the forecasted result is proved to be accurate.Through experiments,the eclosion rate of the pupae is proved to have a relationship with the way of pupation.The results show that the eclosion rate of the pupae covered up in the soil in the three ways of flatwise,head up and head down is 78%,75%and 62%respectively,which has a significant difference.The eclosion of the first way is higher than the others.Another experiment result shows that the depth of pupation in the soil has an impact on the eclosion rate of the pupae.The eclosion rate is 80%,90%,30%,15%,0,0 respectively corresponding to the pupae buried in the soil in the depth of 5cm,10cm,15cm,25cm,30cm.Soil moisture can affect the pupae eclosion rate.The pupa is proved to adapt to the drought sandy soil.The eclosion rate of the pupa is 70%,40%,32%,22%,13%,3%respectively corresponding to the sandy soil moisture of 0%,20%,40%,60%,80%,100%.Put the pupae into the soil of -10℃for 5～30days,it shows that the combination of the cold temperature and the time span doesn't have an obvious impact on the pupae eclosion rate.The odor taxis experiment shows that the ault has some reflection to the smell of pear and plum. Through experiments and searching the correlative data,the biology and ecology about Carpomya veusuviana was obtained.Use the CLIMEX and GARP to predict the potential geographic distribution of Carpomya veusuviana in China.Integrating the results, it shows there is a wide potential distribution for the ber fruit fly in China.The high suitability regions include the most parts of XinJiang,Hebei,Henan,Anhui,Jiangsu, Yunnan,Shanxi,Shanxi,Shandong and Guangxi.The medium suitability regions include the several parts of Liaoning,Ningxia,Hubei,Hunan,Jiangxi and Fujian.The lowest suitability regions consist of a few parts of Sichuan and Gansu.The rest regions of China aren't the suitability place for Carpomya veusiana.According to the quantitive methods of the pest risk analysis,the risk level of Carpomya vesuviana to the potential geograph distribution was evaluated.The results show that besides the medium risk level to Hubei and Hunan,the fruit fly is at high risk level to the other potential suitable distribution in China.The danger of Carpomya vesuviana to jujube production in Xinjiang was also evaluated.The results show Turpan and Hotan are at moderate risk,and Kami,Bayangoleng,Aksu,Kashgar are at high risk. Based on the results,the suggestions are enhancing quarantine,taking effective measures to control the pest and improving the monitor methods to prevent the spread of Carpomya vesuviana in the other regions of China.