Studies On Basic Biological And Ecological Characteristics Of Cinara Cedri Mimeur

Cinara Cedri Mimeur is a new record species reported in 2014.Since then,the pest has been found on Cedrus Trew of many cities.In order to scientifically and effectively control the harm and spread of aphids and protecting the green fruits of cities,it is very necessary to clarify the basic biological and ecological characteristics of this aphid.In this paper,the biological and ecological characteristics of the Cinara Cedri Mimeur were systematically studied through field investigation and indoor breeding observation.The morphological characteristics of the different age were described and four morphological indexes were measured.The results of the present study are as follows:1.Morphological characteristicsThe first instar of the wingless offspring is yellowish brown,and the aphid of the wingless offspring is reddish brown.The two were slightly transparent,with waxy white powde and color gradually deepened.It is found that the difference between second instar is that there are two tumor processes on both sides of the aphis' s front chest back on the wingless of the aphis,and the abdominal tube of the aphid.There is a "?" shaped hollow in the center of the back of the third instar.The fourth instar with wingless offspring has obvious caudae.The results showed that the length of body,body width,width of the head and the length of the antennae between the aphids was not obvious and clear.It can not be used for identification of Cinara Cedri Mimeur.2.Life history of Cinara cedri MimeurThe Cinara Cedri Mimeur has four instar.In Tai'an,Shandong,the overwintering fertilized eggs began to hatch in late 3 months.The winged aphids began to appear in mid April.The number of aphids began to decrease in July,and the number of insects began to pick up in the middle of September.In the middle of November,alate male born,and female aphids spawned on needles.3.The response of Cinara cedri Mimeur to different temperaturesAt 10,15,20,25 and 30?,the developmental duration of the aphid was shortened with the increase of temperature.The developmental periods of aphids was 30.3d,24.3d,17.1d,14.5d and 13.3d at different temperatures.In the range of 10~30 C,the time of generation of Cinara Cedri Mimeur was shortened from 48.4d to 21.0d.The length of life cycle of aphid has a negative correlation with temperature.When the temperature is 10~30?,the life cycle is shortened from 66.1d to 25.6d.The relationship between developmental rate and temperature of different ages of cedar can be well fitted by the two degree curve model.Temperature had a significant effect on the late litter size,litter size and late litter size.At 20?,the litter size of the aphid was the largest,with an average of 25.7,which was significantly greater than that of other temperatures.The litter size at 10? and 30 ?was 13.2d and 8.6d,respectively.At 30?,the birth date is 7.8.When the temperature is low,the birth date is longer,and 24.5d and 14.4d are 10? and 15? respectively.After significant analysis,it was found that temperature had no significant effect on the prophase of litter.In the range of 10?~ 30 ?,the intrinsic growth rate increases first and then decreases with the increase of temperature.At 20?,the intrinsic rate of increase is 0.110,and the net proliferation rate is the largest and the population doubling time is the shortest.Therefore,20? is the most suitable temperature for experimental population growth.The developmental threshold temperature of the Cinara Cedri Mimeur is 4.5?.The effective accumulated temperature for the generation is 521.2d·?.It can be concluded that the theoretical generation of cedar is 7 generations in Tai'an,Shandong province.The over cooling points in April,May,October and November were-11.80?,-11.68?,-11.65? and-11.93?,respectively,and the average supercooling point was-11.66?.The four months had no significant difference in the over cooling point of the Cinara Cedri Mimeur.