| Arhopalus rusticus(Linnaeus)is main stem borer,mainly harms Pinus massoniana,Pinus thunbergii,Pinus densiflora and so on,have a strong ability to carry Bursaphelenchus mucronatus Mamiya et Enda and B.corneolus Massey.The biological characteristics and prediction of Arhopalus rusticus research have not detail found at present in our country.In this experiment,we have been further study on biological characteristics and prediction of Arhopalus rusticus.Results are as follows:1.Arhopalus rusticus(Linnaeus)were 1 generations per 2 years in Taian,and over winter as larvae in boring tunnel of xylem.the overwintering larva started activity in March the next year.The adults started emerging in mid to late May,adult stage lasted from mid September,The imagoes had one peak emergence:mid to late June and mid august was a little peak emergence.The larval hatching period was from early June to early October.Arhopalus rusticus(Linnaeus)started pupating in late April,peak pupation in mid June and finish in mid September.2.Arhopalus rusticus(Linnaeus)bite an oval emergence hole for climb out,feeding fresh pine needle for feeding materials.After the adults feeding materials,pine needles remain green,but there are obvious point-like marks.The adults were mating when climbing out,the next day can spawn.The main mating way of Arhopalus rusticus(Linnaeus)was the backpack mating.Adult mating from late May to late September.The maximum number of life can be mating 8 times,the average mating period was about 4d,the peak mating was 10:00-11:00 and 19:00-20:00 every day.The average life-span of female and male adults is 12.24 ± 0.264 d and 18.83 ± 0.560 d respectively,there are significant differences between the them.Adults in the early spawning period was long time than the length of eggs,average spawning was 8.05 d,and the average spawning period was 3.15 d,the maximum number of daily oviposition can be up to 217 capsules/heads,the average single female spawning amount of 157.6 grains/head,the maximum of single female spawning amount of 440 tablets/heads.The egg starts hatching from the 3rd day,the 8th day reached the hatching peak,the 14 th day hatch was over,the average hatching rate was 68.13%.Newly-hatched larvae started feeding bark,and then continue to gnaw the xylem,forming a straight line or "L" type cylindrical worm road,there were obvious defecation holes,the harmful discharge of a large number of finely crumbs.The mature larva of before cocoon had two states: activity slowly,or along the insect body vertically.The pupa of indoor feeding was 0.21 ± 0.012 g,and the pupa of outdoor was 0.34 ± 0.010 g,which had significant difference between the two.The pupa period of indoor and outdoor feeding was 6.56 ± 0.341 d and 6.38 ± 0.320 d respectively,and the difference between the two was not remarkable.3.Supplementary nutritional materials have a certain influence on mating,fecundity and egg hatching rate of adults.It was found that the feeding way of Arhopalus rusticus(Linnaeus)was a dot-like bite.The feeding source of the experiment had some effect on the mating time,but it was not obvious.Arhopalus rusticus(Linnaeus)bite of Pinus tabuliformis,egg hatching rate of up to 98.86%,the average hatching rate of 78.13%,the average single female egg-laying rate of 320 tablets/head,was currently single-female spawning and egg hatching rates the highest treatment.The fecundity were amount of different nutrition sources is: Pinus tabuliformis> Sugar,Pinus thunbergii,Vinegar,Cedrus deodara> Pinus armandii,Pinus densiflora> Water,Nothing>Sugar-vinegar mixture.And the fecundity of sugar-vinegar mixture is 84 tablets /head.The hatching rate of different nutrition sources was as follows: Pinus tabuliformis> Pinus thunbergii,Pinus densiflora,Sugar-vinegar mixture> Pinus thunbergii,Vinegar,Pinus armandii,Water> Sugar,Nothing.And the hatching rate of sugar and nothing were 57.88% and 57.28% respectively.4.In this study,three variables were measured,including the head capsule width、the protergum width and the body length of larvae.Based on Dyar’s law,the larvae of Arhopalus rusticus(Linnaeus)were divided into 6 instars.Verified the measured value of the head capsule width、the protergum width and the body length by Crosby growth rules,the result of Crosby index is less than 0.1,so it is possibile to use the data divided instar as a standard。Of the three variables measured,the head capsule width provided the best division of instars.5.Measuring female pupa weight and counting fecundity of Arhopalus rusticus(Linnaeus),it was found that the maximum female pupa weight is 0.67 g,the minimum value is 0.17 g and the mean is 0.4374±0.0076 g.The maximum male pupa weight is 0.37 g,the minimum value is 0.1g and the mean is 0.2547±0.0065 g.The correlative regression forecast was conducted,of weight of pupa(x)and number of ovum(y)of Arhopalus rusticus(Linnaeus),and its regression equation is y=-177.621+866.469 x and correlative coefficient is r=0.963.The maximum fecundity of Arhopalus rusticus(Linnaeus)is 440 granule,the minimum value is 7 granule.6.The effective accumulative temperature of A.rusticus pupal stage K=(143.988±35.33)degrees,the developmental threshold temperature C=(9.475±3.36)℃.The fitting result of SSI indicates that the developmental threshold temperature is about 10 ℃,the optimal temperature of pupa development is 28℃,had a high fitting degree.The forecast of adult emergence period by effective accumulative temperature(start was May 20,start peak was June 15,peak was June 27,final peak was July 27,final was September 28)were later than measured value(start was May 20,start peak was June 14,peak was June 25,final peak was July 26,final was September 26),when the error range was 0~2 d.7.The formula of A.rusticus adult emergence period by periodical method were that Start Peak:F=Hi+(15.31±2.88);Peak :F=Hi+(10.53±2.57);Final Peak:F=Hi+(13.26±2.93).The forecast of adult emergence period by periodical method(start peak was June 15,peak was June 25,final peak was July 27)were later than measured value(start peak was June 14,peak was June 25,final peak was July 26),when the error range was 0~2 d.8.The flowering time of 15 kinds of plants such as Lagerstroemia indica,Magnolia grandiflora and Albizia julibrissin were predicted for phenology of adults,and observed: The beginning of the adult was coincide with the late flowering of Viburnum macrocephalum,Rosa rugosa and Rosa multiflora blooming and the beginning of Melia azedarach.The beginning of the adult was coincide with the beginning of Ligustrum lucidum of privet bloom,Albizia julibrissin flowering period,Punica granatum and Castanea mollissima flowering at final peak,Magnolia grandifloraflowering,Sorbaria kirilowii flowering ending.The peak of the adults was coincide with Firmiana platanifolia and Ligustrum lucidum flowering starting,Albizia julibrissin flowering and Magnolia grandiflora ending.Adults at final peak was coincide with the flowering of Rosa chinensis,Lagerstroemia indica,Koelreuteria integrifoliola and Hibiscus syriacus. |
