二种拟除虫菊酯对桔全爪螨繁殖的影响

STUDIES ON THE EFFECT OF TWO PYRETHROIDS ON THE DEVELOPMENT OF CITRUS RED MITE

Results show that the LC₅₀ of Sumicidin and Decis are 15 and 1.8ppmon the citrus red mite Panonychus citri Mcy.,respectively.The responses of nymphs,imagoes and eggs to different concentrations have been shown in the different effects.With same dosage,the effect of Decis is greater than that of Sumicidin.The higher concentrations of the pyrethroids inhibit,and the lower concentrations stimulate,the development.The treatment on the second instar nymphs of the mite may extend the influence to the roat of the life-span of female imagoes,and increase the egg production,and hatching rate of eggs.Though the treatment on eggs may increase the hatching speed of the initial and middle stage of incubation,yet not effect the total hatching rate has been observed;the treatment on the female imagoes may increase their egg production.In greenhouse,the treatments on the mite population pre-ponderating in 1-2 instar nymphs,on the potted citrus trees with the two pyrethroids,would increase significantly the quantities of imagoes,nymphs and eggs after 14 days,showing the stimulating effect on the development of this citrus red mite.