TY - JOUR
T1 - Relative toxicity of nC24 agricultural mineral oil to Tetranychus urticae Koch (Acari: Tetranychidae) and Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae) and its possible relationship to egg ultrastructure
AU - Xue, Yingen
AU - Beattie, G. Andrew C.
AU - Meats, Alan
AU - Spooner-Hart, Robert
AU - Herron, Grant A.
PY - 2009
Y1 - 2009
N2 - The relative toxicity (LCâ‚…â‚€ values based on mg oil/cm2) is evaluated of aqueous nC24 agricultural mineral oil (AMO) emulsions to the egg, six-legged nymph (larva), eight-legged protonymph and adult stages of two-spotted mite (Tetranychus urticae) and its predator, Phytoseiulus persimilis, on French bean leaf discs, using a Potter spray tower to apply of the oil. The egg of P. persimilis was the least susceptible stage (LCâ‚…â‚€ 444.84) and its LCâ‚…â‚€ was significantly higher than all other stages tested of either P. persimilis or T. urticae. The LCâ‚…â‚€ for adult female T. urticae (LC50 63.89) was significantly lower than the larva (LCâ‚…â‚€ 93.86); however, there was no significant difference in response between the protonymph (LCâ‚…â‚€ 70.44) and the larva, which were both higher than T. urticae eggs (LCâ‚…â‚€ 17.55). LCâ‚…â‚€s for P. persimilis larva (LCâ‚…â‚€ 43.87), protonymph (LCâ‚…â‚€ 41.55) and adult female (LCâ‚…â‚€ 53.34) were similar. Scanning electron microscopy showed that the egg surface of T. urticae is usually well covered with fine silk that may trap more oil and increase AMO efficacy. Other possible differences in AMO efficacy between T. urticae and P. persimilis may be due to differences in egg size, egg incubation period, egg surface structure and the presence of vulnerable respiratory cones in T. urticae eggs. Dose of 0.2-0.3% (w/w) is considered to be the most appropriate for nC24 AMOs use against T. urticae in combination with P. persimilis in integrated pest management programs.
AB - The relative toxicity (LCâ‚…â‚€ values based on mg oil/cm2) is evaluated of aqueous nC24 agricultural mineral oil (AMO) emulsions to the egg, six-legged nymph (larva), eight-legged protonymph and adult stages of two-spotted mite (Tetranychus urticae) and its predator, Phytoseiulus persimilis, on French bean leaf discs, using a Potter spray tower to apply of the oil. The egg of P. persimilis was the least susceptible stage (LCâ‚…â‚€ 444.84) and its LCâ‚…â‚€ was significantly higher than all other stages tested of either P. persimilis or T. urticae. The LCâ‚…â‚€ for adult female T. urticae (LC50 63.89) was significantly lower than the larva (LCâ‚…â‚€ 93.86); however, there was no significant difference in response between the protonymph (LCâ‚…â‚€ 70.44) and the larva, which were both higher than T. urticae eggs (LCâ‚…â‚€ 17.55). LCâ‚…â‚€s for P. persimilis larva (LCâ‚…â‚€ 43.87), protonymph (LCâ‚…â‚€ 41.55) and adult female (LCâ‚…â‚€ 53.34) were similar. Scanning electron microscopy showed that the egg surface of T. urticae is usually well covered with fine silk that may trap more oil and increase AMO efficacy. Other possible differences in AMO efficacy between T. urticae and P. persimilis may be due to differences in egg size, egg incubation period, egg surface structure and the presence of vulnerable respiratory cones in T. urticae eggs. Dose of 0.2-0.3% (w/w) is considered to be the most appropriate for nC24 AMOs use against T. urticae in combination with P. persimilis in integrated pest management programs.
KW - agricultural pests
KW - biological control
KW - mineral oils
KW - predatory mite
KW - two-spotted spider mite
UR - http://handle.uws.edu.au:8081/1959.7/549788
U2 - 10.1111/j.1440-6055.2009.00713.x
DO - 10.1111/j.1440-6055.2009.00713.x
M3 - Article
SN - 1326-6756
VL - 48
SP - 251
EP - 257
JO - Australian Journal of Entomology
JF - Australian Journal of Entomology
IS - 3
ER -
