Effects of simultaneous, or sequential, application of two different insecticides on the reproduction of Laodelphax striatellus
英文摘要:
[Objectives] The purpose of this study was to investigate the effects of
simultaneous, or sequential, application of two insecticides on the
reproduction of the Grey planthopper, L.
striatellus. [Methods] Jinggangmycin inhibits reproduction in the
Grey planthopper, whereas Carbendazim and Triazophos stimulate reproduction.
Third instar nymphs sprayed with either Jinggangmycin & Carbendazim (JGM
and CBM), Jinggangmycin followed by Carbendazim (JGM + CBM), Jinggangmycin and
Triazophos (JGM and TZP), or Jinggangmycin followed by Triazophos (JGM + TZP).
The interval between successive pesticide applications was 48 h. After adult
eclosion, female fecundity, preoviposition period, oviposition duration, female
lifespan, female weight, female body length, oviposition valve length, ovarian
protein content and triglyceride content, were measured. [Results] Compared to the control group, the female
fecundity, oviposition duration, female lifespan, female body weight,
ovipositor valve length, ovarian protein content and triglyceride content of
the JGM and CBM group increased by 28.9%, 29.5%, 19.1%, 34.6%, 35.2%, 20.0% and
30.4%, respectively. There was, however, no significant difference in the pre-
and post-oviposition body length of adult females. The JGM + CBM treatment
group had significantly lower female fecundity, pre-oviposition period,
oviposition duration, ovarian protein content and triglyceride content values
than the control group (23.3%, 28.9%, 18.6%, 12.1% and 15.0%, respectively),
but there was no significant difference in female longevity, female weight,
female body length or oviposition valve length. The JGM and TZP treatment group
had significantly lower female fecundity, female body weight, female body
length, ovarian protein content, triglyceride content and a shorter
pre-oviposition period (57.4%, 8.5%, 21.4%, 33.8%, 26.2% and 56.5%,
respectively) than the control group. There was, however, no significant
difference in oviposition duration, female longevity and ovipositor valve
length. The JGM and TZP treatment group also had significantly lower female
fecundity, oviposition duration, female body weight, female body length,
ovipositor valve length, ovarian protein content, triglyceride content and
pre-oviposition period values (19.6%, 32.6%, 7.2%, 14.8%, 7.6%, 31.5%, 36.8%
and 79.7%, respectively) than the control group. There was, however, no
significant difference in female life span. [Conclusion]
Spraying paired combinations of Jinggangmycin, Carbendazim and
Triazophos, simultaneously or sequentially, had significant, different effects
on reproductive parameters of the grey planthopper.