| Bipectilus zhejiangensis Wang is an important pest in Fujian bamboo growing areas, but also is a new bamboo shoot pest in Fujian Province, which has been spreading to disaster in the northwest Fujian. According to statistics the damaged rate of winter and spring bamboo shoots which caused by B.zhejiangensis, reached as high as 26%-68%. The B.zhejiangensis does not only destroy shoot, results in its nutrient loss and quality deterioration, but also poses a threat to the growth of the bamboo forests, and then causes serious economic losses. In this paper, through the measurement of the damaged bamboo shoot contain substances to judge its nutritional quality change characteristics. Also via the application of Metarhizium anisopliae for toxicity test in laboratory and forest control, screening out high-virulence strains to carry out an effective biological control to B.zhejiangensis larvae, and then to promote a large-scale use in production.1 Effects of B. zhejiangensis damage on secondary substance of Bamboo shootsAn experiment to test tannins, flavonoids, total phenolic material contents among mild, heavily-infested harmful and healthy bamboo shoot showed that the contents of tannins, flavonoids, total phenolic material in the damaged bamboo shoots were less than health ones, respectively, a decrease of 13.350,4.575,14.255 mg·g-1. Analysis on the change of variance showed that tannins, flavonoids, total phenolic material content was remarkable, when the bamboo shoot was destroyed by B.zhejiangensis. With the damage increasing, tannin, total phenol material contents assumed a downward trend. In comparison with the healthy bamboo shoots, reduction in volume of heavily-infested about tannin, total phenol material contents was mild reduced amount 7 times and 4 times. It also showed that heavily-infested bamboo shoots flavonoids was more than mild one, their difference is significant.2 Effects of B. zhejiangensis damage on nutritional quality of Bamboo ShootsAn experiment was adopted to test on their quality that the B.zhejiangensis damage fresh and dry bamboo shoot, as well as with Pharmacy controlling of health fresh and dry bamboo shoot. The results showed that the crude fiber content of fresh and dried bamboo shoots damaged by B.zhejiangensis was more than those in healthy ones, respectively, higher than 0.602%, 9.533%; also the total sugar, total acid and vitamin C contents of fresh and dry bamboo shoot after the damaged had shown a significant reduction, in which fresh bamboo shoot substances reduced the amount of 0.471%, 0.164%, 4.893 mg·(100g) -1, dried bamboo shoots reduced amount of 0.196%, 0.004%, 0.86 mg·(100g) -1; damaged fresh bamboo shoot of the sugar-acid ratio, soluble solids lower than that in health fresh bamboo shoot, respectively, a decrease of 0.712,0.713%. Spraying treatment, in addition to the crude fiber content of dried bamboo shoots increased significantly, the fresh and dry bamboo shoot contents of several other different material were not significant compared with non-spraying. Visible nutritional quality of damaged bamboo shoots has been a significant impact, of which nutritional and edible decline in value than healthy ones; but the health bamboo shoots had not shown those situation after using biological pesticides to control the pest, so we could promote the use of production of biological agents to combat the B.zhejiangensis.3 Experiment of B. zhejiangensis larvae Metarhizium anisopliae controlIn order to ensure the quality of bamboo shoots and to protect the ecological environment, this paper carried out a test on using M. anisopliae to control B.zhejiangensis. In indoor experiments, from 5 different strains of M. anisopliae (MaWP-01, Ma1775, MaYDTR-010, MaFzzL-01, Ma1291-2) were screened out Ma1291-2 strains, which had the most significant effect on B. zhejiangensis larvae, and corrected mortality rate reached 76.67%, LT50 value of 5.4d, and that the strain with increasing the concentration of pathogenicity to strengthen, 10d within the LC50 of 1.98×105 spores·mL-1. Forest control tests showed that broadcast application of M. anisopliae Ma1291-2 and shallow ploughing could effectively control the B.zhejiangensis larvae destroying the bamboo shoots, which caused the average corrected mortality of larvae was 58.07% and average control effects of bamboo shoots reached 65.64%. In the different treatment methods, the control effects of broadcast application of strains on ground was higher than broadcast application of strains around bamboo shoots, which is more than16.25%. In addition, there were significant differences of control effects by broadcast application of different strains around bamboo shoots, broadcast stain Ma1291-2 was higher (16.19%) than strain YT-04-01. Integrated throughout the process of protecting and controlling in the forest, it indicated that there was a better control effect to B.zhejiangensis larvae with broadcasting strain Ma1291-2 and then shallow ploughing,as well as extended and be applied to this method in producing practice. |
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