| Psammotettix striatus L. is an important pest in arid and semi-arid regions of Northern China. It made serious damages and caused great loss to agricultural products by transmitting wheat blue dwarf disease and wheat red dwarf disease as well as causing direct damage to wheat and maize.The ecology and wheat blue dwarf Transmission of Psammotettix striatus L.were studied in this paper in order to provide some scientific proofs to control Psammotettix striatus L.and the diseases.It drawn some conclusions through keeping and continuous observation of Psammotettix striatus L. in lab:the shortest development duration of instar 1,2,3,4,5 on wheat is 1.88d(35℃),1.75d(35℃),2.03d(30℃),2.31d(30℃),3.27d(30℃) respectively.With temperature increased, the development duration of instar 1～5 decreased at 15℃～30℃,but increased at 35℃. The highest survival rate of instar 1,2,3,4,5 is 80.78%(20℃),83.86%(15℃),84.41%(15℃),84.15%(15℃),82.86%(20℃) respectively.The developmental threshold temperature of instar 5 is highest(12.6572℃),instar 1,2,3,4 is lower and no notable difference.The required lowest effective accumulated temperature is from instar 2 (42.6907 degree-days),the highest is from instar 5 (62.5084 degree-days).With temperature increased,the longevity of female adults is Shortening.The mean oviposition per female adult is highest at 20℃(24.11eggs),the lowest at 35℃(2.00eggs).There are no obvious peak of the spawning at 15℃,20℃,the peak of the spawning is respectively 10 days,9 days,13 days of adults at 25℃,28℃,30℃.The net reproductive rates(6.1067),the intrinsic rate of increase(0.0523) and the finite rate of increase(1.0537) are the largest when reared at 25℃. The survival curve of Psammotettix striatus L. is the typeⅡof Pearl(1928)and Deevey(1950)at 15℃,20℃,25℃,but it is typeⅢat 28℃,30℃,35℃. It can be conclude above analysis that the most suitable temperature for the development and reproduction of Psammotettix striatus L. was 25℃.By continuous observation and keeping of Psammotettix striatus L. in different host plants,the result indicated that the insect could develop and reproduce on all three test host plants(wheat,corn and green foxtail). The development duration from egg to nymph of Psammotettix striatus L. on wheat was the shortest (23.33d),then on corn (26.39d),and the longest on green foxtail (27.50d). The survival rate (17.22%) of the nymph reared on green foxtail were lower than those reared on the other two host plants,its survival curve is typeⅢ.The net reproductive rates(6.1067),the intrinsic rate of increase(0.0523) and the finite rate of increase(1.0537) are the largest,whereas the mean generation times (34.5807d) and the doubling times (13.2533 d)is the shortest when reared with wheat,the survival curve is typeⅡ; Mean Oviposition per female(17.63eggs) is least on corn,and no obvious peak of spawning.Based on the life-table parameters and survival curves,the most suitable host plants for the development and reproduction of Psammotettix striatus L. was wheat,followed by corn and green foxtail.This paper also discussed the effects of maize varieties on the development,survivorship and fecundity of Psammotettix striatus L.The result indicated that Psammotettix striatus L. is able to lay eggs but not hatching when feeding on Yedan 12 and Zhengdan 958;It is unable to lay eggs when feeding on Shendan 16.It can develop to adult when nymph fed on Yedan 12 and Zhengdan 958,whereas all nymph died at instar 3 on Shen dan 16.The leafhopper can co- mplete the development cycle when feeding on Xundan 20.Compared to feed on Yedan 12,Shendan 16 and Zhengdan 958, it is the shortest,higher,the longest and the most on the duration of nymphs, egg hatchability, survival rate of nymphs, life expectancy and oviposition when feeding on Xundan 20.The experiment also studied the wheat blue dwarf transmission of Psammotettix striatus L.,the result indicated that the disease rate rised with time-extended of acquisition and transmission of virus in the experimental conditions.The shortest acquisition time of Psammotettix striatus L. is 6 min,and the shortest transmission time is 1h.The shortest latent period of the pathogens in wheat is 8d and the longest is 44d,24.36d on average.The female,male and nymph all could make wheat infected by diseases,and female had much more ability in transmission virus. |
