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| Toxic effects of four insecticides on mealybug, Phenacoccussolenopsis Tinsley (Hemiptera: Pseudococcidae) fedon Hibiscus rosa-sinensis (Malvales: Malvaceae) |
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| DOI： |
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| Hits: 2012 |
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| Abstract: |
| Phenacoccus solenopsis has invaded Guangxi and successfully colonized on Hibiscus rosa-sinensis, and it
has caused some damage to H. rosa-sinensis. In order to provide references for emergency control of its outbreak, leaf
dipping method was used to test the toxic effects of profenofos, chlorpyrifos, imidacloprid and neem oil on mealybug fed
on H. rosa-sinensis, and toxicity regression equations were established by Probit Analysis to compare the susceptibility of
different instars to different insecticides in this paper. The results showed that the direct toxic effect of neem oil against
this pest was weak, after 3 days treatment, the corrected mortality rate of 1st instar nymphs for the highest concentration
(10 mL/L) was only 66.43%, and the highest concentration almost had no direct toxic effect on the other three instars.
The toxic effects of the other three chemical insecticides against this pest were powerful, after 3 days treatment, the
fatality rates of most doses were over 50.00%, and fatality rates of the highest concentrations were all over 90.00%. The
susceptibility order of different instars was 1st instar nymphs>2nd instar larvae>3rd instar larvae>female adult, and the
susceptibility order to insecticides was profenofos >
imidacloprid > chl orpyrifos. It suggests that the direct
toxic effects of chemical insecticides on mealybug are
significant, but the differences in the sensitivity of
different instars to different pesticides are obvious, so the
field application should select appropriate insecticide,
dose and right time based on the age structure of this
pest. |
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