溴甲烷配合二氧化碳对朱砂叶螨的熏蒸作用

EFFECT OF METHYL BROMIDE FUMIGATION COMBINED WITH CARBON DIOXIDE ON TETRANYCHUS CINNABARINUM (ACARI:TETRANYCHIDAE)

在25℃条件下,研究了溴甲烷20g/m3,25g/m3,30g/m3,35g/m3,40g/m35种剂量单独使用及分别配合10%,15%,25%,30%,40%二氧化碳对朱砂叶螨的熏蒸作用。试验结果表明,在处理时间恒定时,溴甲烷单剂对朱砂叶螨熏蒸作用随溴甲烷使用剂量的增加而增强,熏蒸处理1h,1.5h,2h的LD50分别为27.8828g/m3,21.4533g/m3,18.8758g/m3。溴甲烷配合二氧化碳对朱砂叶螨熏蒸处理结果显示,在溴甲烷剂量一定的条件下,朱砂叶螨的死亡率随着二氧化碳浓度的增加表现为先增加后下降的趋势,在二氧化碳浓度为25%条件下熏蒸处理2h,溴甲烷的LD50为16.0682g/m3,以剂量为40g/m3的溴甲烷与25%的二氧化碳配合对朱砂叶螨熏蒸作用效果最佳,死亡率达100%,表明在一定浓度范围内,二氧化碳对溴甲烷熏蒸处理朱砂叶螨的效果有增效作用。二氧化碳对朱砂叶螨有麻醉作用,熏蒸时间短于1h或者二氧化碳浓度大于30%时,反而使溴甲烷的熏蒸效果下降。

At 25℃, Tetranychus cinnabarinus was fumigated with methyl bromide alone at 20, 25, 30, 35 and 40 g/m^3 or in combination with CO_2 at 10%, 15%, 20%, 30% or 40%. Treatment duration being identical,fumigation toxicity increased with methyl bromide dosage and LD_(50)s were 27.8288,21.4533 and 16.0683 g/m^3,respectively,for 1,1.5 and 2 h fumigating.With the same dosage of methyl bromide,the mortality of the pest increased with CO_2 concentration to its maximum,followed by a decline.Combination of methyl bromide at 40 g/m^3 with 25% CO_2 gave the best result with a mortality rate of 100% for 2 h fumigating,suggesting that CO_2 could have a synergistic effect.Owing to a narcotism of CO_2 to the mite,toxicity of fumigation decreased when fumigation time was less than 1 h or when CO_2 was greater than 30%.