| Oriental fruit fly Bactrocera dorsalis(Hendel) is a serious quarantine pest in fruits and vegetables,is widely distributed in tropic and its temperate zone is from south Asia,south-east Asia to south Pacific.In the past ten years,B.doarsils out broke and spread in south and southwest of China,cause great lose to these local fruit production.And,the population of this pest trended to move north and to spread wider.Chongqing is located on the upstream of the Yangtze,has complicated three-dimensional climate,abundant of rainfall,warm in winter and hot in summer, which is the most suitable citrus-growth areas of the World.The construction of the Industrialized-citrus-plant-area and non-infested area were undertaking.Till the end of 2007, Chongqing had more than 4 million hectares of citrus with plenty of varieties,which provided the great and efficient condition for the invasion of B.dorsalis.In order to complete the construction of non-infection area of B.dorsalis,the mechanism of adjustment and its disaster-mechanism need to be known.Based on the results from both domestic and foreign research,knowledge of insect ecology,insect physiology,biochemistry and bio-statistics,the effects of humidity,temperature pressure,and host to B.dorsalis were studied.1 Extreme temperature to B.dorsalis1.1 Survivals of adults of B.dorsalis under high temperature pressureThe tolerance of male,female both sexually mature or immature to high temperature are tested under 42±1℃.The results showed that B.dorsalis would appear heat shock response in the 42℃for 135.20～163.40 mins.The heat shock time of mature females was remarkably longer than that of immature females to 163.40±14.06 mins.There were no remarkably differences between immature male and male sexual maturation on the heat shock time.The B.dorsalis adults had heat shock would revive under 28±1℃for 321.40～479.60s.The time from heat shock to revival in immature females was remarkably longer than that of mature females,the females and remarkably longer than that of males.The results showed that heat resistance of mature female were significant higher than immature females,females and males.The adults with heat shock were heat to death for 16.00～22.40mins under 42±1℃constantly.The immature females with heat shock are dead with 16.00 min under 42±1℃constantly and the time which the immature females needed was remarkably shorter than other times.1.2 Low temperature on pupal survival rate of B.dorsalisThe effect of low temperature pressure to pupal survival rate of B.dorsalis was studied under the condition of 4±1℃,after 5,10,15 and 20 days.The results indicated that the pupa emergence rate was 6.7%under the 4±1℃on the 5th day,while others were 0%.1.3 Winter soil temperature in Chongqing on the survival rate of B.dorsalisIn the soil water content(SRWC)75%in the layers of 3,4 and 5cm outside after 60,80,100 d in winter,all the pupa were dead.The results indicated that B.dorsalis didn't overwinter as pupa in winter.2 High temperatures on the heat shock protein of B.dorsalisWhen mature females of B.dorsalis were heat shocked at 42℃for 0.5,1,1.5,2,2.5,3 h, Protein level was measured.The content of protein in B.dorsalis adults were increased initially and descended later with the time of high temperature simultaneouly.It was obtained maximum after B. dorsalis adults was under 42±1℃for 2h.The proteins of B.dorsalis adults with M.W 98.41,93.63, 70.80kDa were produced under high temperature stress.It reached maximum for 1.5～2h and descended after 2h.The content of protein with M.W 98.41,89.07 kDa became 0 when the adults died after exposing to 42±1℃for 3 h.The content of protein with M.W93.68,75.74 kDa became 0 after exposing to 42±1℃for 0.5～1h,and then raised with the time of high temperature increasing simultaneously.The content of the protein with M.W45.2,38.25 kDa didn't change.3 Relative sand water content on the pupa of B.dorsalis3.1 Relative SRWC on the emergence rate,development and survival of oriental fruit fly mature larva and pupaWhen SRWC attained to 100%,all of the pupae were failed to survive.In the other 4 sand water contents,there was not significant difference on beginning of emergence and peak of emergence.All the pupae arrived peak of emergence second day after the beginning of emergence. The emergence at three-day-old pupae' end at 75%SRWC significantly was longer compared that at 0%and 25%SRWC.The five-day-old pupaes' beginning of emergence and peak of emergence at 75%SRWC was significantly longer than that of other SRWCs.As the increasing of SRWC,the survival of oriental fruit fly pupae was increased.It was obtained maximum at 75%SRWC,then with the increasing of SRWC,the survival of B.dorsalis pupae was decreased.The survival of B. dorsalis pupae was reached maximum at 50%SRWC and minimum at 100%SRWC.The best SRWC was 50%for development and survival of oriental fruit pupa.3.2 Different SWRCs and soil depths on the pupa of B.dorsalisThe depth of soil was an important environmental factor of B.dorsalis emergence.Significant difference of pupal emergence rate was found at different soil depth.B.dorsalis are not emerged at the soil depth of 5cm.Significant difference was found at different SWRC with the same soil depth. Pupal survival rate at 3cm in soil was the higher under the 50%SWRC,100%SWRC and which showed extremely low pupal emergence rate that only 4.44%adults emerged.Pupa could emerge at the surface and 1cm deep in soil at the 0 SWRC.Pupa could emerged in the depth of 2～4cm in soil at the 50%SWRC.3.3 Water on the pupa of B.dorsalisHealthy pupa of 12,24,36,48,60 and 72h were watered 12,24,36,48,60,72,84 and 96 h, respectively,in order to investigate the effect of the time in water on the pupa of B.dorsalis.Result showed that the pupae survival rate decreased as the watering time extended.,The longer the pupal period,the survival rate higher at the same time in water,when the time was 96 h,the survival rate of period pupa was 14.44%with 12 h in water;the survival rate of period pupa was the highest,i.e. 91.11%with the time was 72 h and 12 h in water.4 Different fruit of citruses and vegetables on the oviposition and development of B.dorsalisThe effect on the oviposition was preferenced on different fruit of citruses and vegetables,such as the development and reproduction of B.dorsalis on the host of jinjiang glorious oranges,navel oranges,licheng glorious oranges,No.447glorious oranges and pumpkins,peppers,cucumbers, tomatoes.The results showed that on jinjiang glorious oranges,the fecundity was the most,the pupation time was the shortest and the emergence rate was the highest;the longest pupation time was on navel oranges;the pupation rate was the highest and the emergence rate was the lowest on licheng glorious oranges;the pupation rate was the lowest on No.447glorious oranges.Under the same condition,the fecundities on vegetables were all less than that on citruses.Larvae could not complete the life cycle on pumpkins,peppers,cucumbers,tomatoes. |
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