抄録
Pratylenchus spp. are among the pests most
frequently detected during quarantine inspections of
ornamental trees. Ornamental trees are treated with
nematicides to eliminate Pratylenchus before export
from Japan. Three nematicides, abamectin, fosthiazate
and imicyafos, have been registered for use against
Pratylenchus in ornamental trees; however, their effects
on Pratylenchus eggs have not been investigated. We
observed the hatching rate of P. penetrans eggs after
immersion in these nematicides. Benomyl, fenitrothion
and fluopyram were tested for comparison. Treatment
with abamectin, fosthiazate and fluopyram solution for
24 h at 25°C significantly decreased the egg hatching
rate; the lowest (5.9%) in fosthiazate compared to
52.3% in the control. However, when eggs were
immersed at 10°C the hatching rates of fosthiazate and
fluopyram treatment groups were significantly higher
than those at 25°C. Eggs treated with abamectin,
fosthiazate, fenitrothion and fluopyram concentrations
10 times lower than the registered concentrations for
14 days at 10°C significantly decreased the hatching
rates; however, the rate was 29.0% (fluopyram) or
more compared to 49.2% in the control. These results
suggest that the nematicide effect on eggs may be
limited under winter treatment conditions commonly
used for ornamental trees.
