| Diplecoptera bilinealis(Plecoptera bilinealis),lepidoptera,noctuidae,whose larva is one of the main leaf-eating pests of the precious tree species pterodactyl.In recent years,there has been a serious outbreak of the moth in sandalwood forest in hainan.In order to find a kind of effective and green and pollution-free control method,we tried to find a kind of insecticidal fungus from the soil or insect carcasses of sandalwood forest in hainan province.he most widespread and common insecticidal fungus in nature is beauveria bassiana.Beauveria bassiana(Bals.Beauveria bassiana is widely used in pest control in China.Doctrine of literary talent in the from dalbergiae cocobolo cocobolo wood dead insect pests in the forests of soil and dalbergiae separation filter for dalbergiae cocobolo defoliator of insecticidal fungi,through preliminary biology research on them(after virulence studies),further through the means of its induced by ultraviolet mutagenesis,from secondary screening irulence is strong,jiang worm of high rate of insecticidal fungus mutation strains.Then,it was compared with the insecticidal fungi products on the market,and the differences in morphology,biology and gene were compared to analyze and judge the superiority of the selected insecticidal fungi mutagenesis.The main research results were as follows:1.Screening and identification of insecticidal fungi and determination of pathogenicity of leaf-eating pests.From a total of eight areas of hainan province screen separation strains,through morphology observation,9 strains similar to colonies and spore morphology of beauveria bassiana strains,after through DNA sequencing,found two strains with beauveria sequence similarity is as high as 99.8%or more of the strain:HNCM and HNCM-S-S-02-07,are from hainan chengmai peaceful forest farm dalbergiae cocobolo forests in the soil.Through systematic analysis of the lethal effect of hncm-s-02 and hncm-s-07 on the larvae of night moth with double lines after inoculation for 3,5 and 7 days,the pathogenic strength of the two strains on 3,5 and 7 days was compared.On the seventh day,the cumulative death rate of ncm-s-02 reached the maximum of 73.00+0.099b,while the cumulative death rate of hncm-s-07 reached 27.10+0.271b.The LT50 of hncm-s-02 was 4.627d,the LT50 of hncm-s-07 was 6.881d,and the rigor rate of hncm-s-02 on the 7th day was 54%,while that of hncm-s-07 was only 16%Together,the above results showed that the lethal effect of vermilion bassiana hncm-s-02 on nightmoth larvae was stronger than that of vermilia bassiana hncm-s-07.3.Ultraviolet mutagenesis and screening of two strains of beauveria bassianaAfter the two strains of beauveria bassiana were mutagenized by ultraviolet,the optimal bacteria were screened out by comparing the adjusted mortality and the beauveria bassiana rate.The cumulative mortality of beauveria bassiana hncm-s-02(UV30)reached 83.33%,the beauveria bassiana rate reached 73.33%,and the LT50 was 3.241d(7d).Through the contrast analysis of the spore production of each strain in the light experiment,it can be seen that the spore production of each strain is not affected by the light.4.Comparison between beauveria bassiana hncm-s-02(UV30)and market beauveria bassiana products(1)morphologicalThe colonies,spore morphology and mycelium morphology of each strain were observed under a microscope,and it was found that the colonies of the three strains of beauveria bassiana were round or quasi-round,white,with a little concave in the center and colorless in the base.Conidium conidium may bifurcate many times at right angles and aggregate into clusters.Conidia are mostly spherical,with a diameter of 2.00-2.15 microns.There was no significant difference in morphology between the three strains.(2)biologicalBy comparing the four aspects of the adjusted mortality,the stiffness rate,LT50 and LC50 of the strains with different concentration gradients in each group,it can be found that bassiana hncm-s-02(UV30)is better than the other two strains,with the adjusted mortality of 92.12%,the stiffness rate of 82.22%,the LT50 of 4.327d and the LC50 of 6.194×107/mL.The adjusted mortality,stiffened insect rate and half-lethal time of each group all changed with the increase of concentration.There was a positive correlation between the adjusted death rate and the stiffened insect rate and the concentration of spore solution.(3)geneBeauveria bassiana A is closely related to the optimal strain hncm-s-02uv30 of beauveria bassiana,and beauveria bassiana D is closely related to beauveria bassiana hncm-s-07.Relative to the whole,the four strains of beauveria bassiana are closely related to each other,but their pathogenicity is significantly different,which indicates that the pathogenicity of beauveria bassiana on the larvae of the night moth is related to genes. |
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