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Stuy On Control Of White Grub By Beauveria Brongniartii And The Optimization Of Its Solid-state Culture Condition

Posted on:2014-01-03Degree:MasterType:Thesis
Country:ChinaCandidate:L T SongFull Text:PDF
GTID:2233330398453798Subject:Agricultural Entomology and Pest Control
Abstract/Summary:PDF Full Text Request
White Grubs are the pests which are long-term underground activities and difficulty to prevention and control.The long-term chemical control not only product resistance of grub, but also leading to problems of environmentalpollution and food hazards. The further study on biological control bring new breakthrough to the control andprevention of underground pest. Beauveria brongniartii is biological insecticide with products commercialization,application widely, safe and effect lasting characteristics, which is favorable prevention and control effect to grubs.Furthermore, that is high practical value in field because of widely host range and can kill the other underground pestcharacteristics.To provide theoretical basis and practical guidance for prevention and control of grub with Beauveriabrongniartii in Harbin, we investigation on the growth and decline law of main adult beetles at the horticultural stationof northeast agricultural university, the feasibility study on mixed use of Beauveria brongniartii and chemicalinsecticides, and optimization design in the condition of solid-fermentation with white muscardine fungi. The mainconclusions were as foiiows:1.The investigation result of growth and decline law of main adult beatles at northeast agricultural university inHarbin.The main species of beetles at northeast agricultural university in Harbin was Maladera ovatula Fairmaire,Anomala exoleta Faldermann,Holotrichi adiomphalia Bates, Holotrichi atitanis Reitter, Holotrichia parallelaMotschulsky, Serica orientalis Motschulsky, Anomala corpulenta Motschulsky et al..The maximum trapping amountwere Maladera ovatula Fairmaire and Anomala exoleta Faldermann, which were the dominant population. Theoccurrence period of adult Maladera ovatula Fairmaire was from the late June to the late July, and the full incidenceperiod was the middle July. However, the occurrence period of adult Anomala exoleta Faldermann was from the lateJune to the late August, and the full incidence period was from the last July to the beginning August. There was apositive correlation between the amount of Maladera ovatula Fairmaire and daily mean temperature, and a negativecorrelation between the amount of Maladera ovatula Fairmaire and total precipitation in the occurrence period.2. Defined the influence of germination and growth of by chemical insecticidesThe influence of germination and growth is clearly by the different spices and concentration of chemicalinsecticides. Beauveria brongniartii can’t be germinate with the300X,1000X phoxim and the300X Dursban; thegermination was not inhibited when the Beauveria brongniartii mixed with the3000X phoxim,the3000X phoximand the1000X,3000X Cyhalothrin. With the increase of pesticide concentration, the inhibition of germination wasstrengthening. there is the largest inhibition of the spore germination by phoxim, followed by Dursban, λ-Cyhalothrinminimum inhibitory. Three kinds of pesticides on Beauveria growth inhibition are present, but do not inhibit the growth of concentration on bassiana were no significant differences.3. Determination of the control effect of Beauveria brongniartii and rhe mixed with chemical insecticides forwhite grubsBioassay of Different concentrations of Beauveria brongniartii (NEAU30503) spore suspension on White Grub,And choose formulaic Beauveria brongniartii and Green b. bassianaas for reference. The results of toxicitydetermination in laboratory showed that Beauveria brongniartii (NEAU30503) at the dose of2.5×1010and1.25×1011conidia/L, was highly Correct mortality as67.3%and79.9%. Not lowe than the reference strain. Beauveriabrongniartii (NEAU30503) is effective, can be used for the biological control of white grubs.From the bioassay results of two chemical insecticides and mix with Beauveria brongniartii (NEAU30503),It`s known: the mixtures of Dursban (1000X) with Beauveria brongniartii shows the highest virulence whose LT50ofthe larvae was2.1d,and LT90was4.9d. It increased by22.2%Comparing the corrected mortality of the Dursban(3000X) treatment after5d, and more significant compared with fertilizer alone increased Beauveria brongniartii(NEAU30503) of1×109conidia/L.there is not synergism mixed by λ-Cyhalothrin and Beauveria brongniartii(NEAU30503).he field experiment showed that Beauveria brongniartii (NEAU30503) against grubs control have nosignificant difference between chemical control,so that Beauveria brongniartii (NEAU30503) is effective.4.The fermentation conditions for Beauveria brongniartii (NEAU30503) were optimized.At first,the optimal matrix formula, water contentration,inoculation,fermentation temperature andfermentation time were determined by single factor experiments. By using Box-Behnken experimental design andthe response surface analytical methodology the optimum fermentation conditions were obtained: Formulation D(vermiculite: wheat bran: corn flour) of sporulation highest, reaching3.08×109conidia/g, after drying was9.97×109conidia/g, a water content of55%, inoculum15ml/100g, culture temperature is27℃, culture time was7.5d, inthis condition Beauveria brongniartii (NEAU30503) before drying unit sporulation capacity of3.7×109conidia/g.
Keywords/Search Tags:Beauveria brongniartii, White Grub, Bioassay, mixed-using, Colony-inibition, Solid-state cultureCondition
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