Gy. Zhao et al., CLOFENTEZINE TOXICITY AND FATE IN THE BULB MITE RHIZOGLYPHUS-ECHINOPUS (ACARI, ACARIDAE), Experimental & applied acarology, 20(4), 1996, pp. 215-222
Clofentezine was toxic to bulb mite, Rhizoglyphus echinopus (Fumouze a
nd Robin), eggs and larvae; however, it was not toxic to adults alone
or in the presence of piperonyl butoxide. When adults were exposed to
radioactive clofentezine, the acaricide was absorbed, metabolized and
excreted. After 48 h exposure, 49.8% of the recovered radiocarbon was
parent compound with 37.1, 9.1 and 3.6% detected in the container rins
e, mite rinse and internal fraction, respectively. Homogenates of adul
ts extensively metabolized clofentezine. The most active fraction was
the 12 000 g supernatant plus glutathione followed in decreasing order
by the supernatant, supernatant plus NADPH and the whole homogenate,
each of which metabolized at least 16% of the acaricide. In the presen
ce of piperonyl butoxide, in vitro metabolism of clofentezine by each
of these active fractions was increased approximately 10%. Although it
is possible that rapid metabolism could have contributed to the lack
of toxicity of clofentezine to bulb mite adults, it is more likely tha
t another major mechanism was involved. Perhaps adult bulb mites lack
the sensitive target found in immature mites.