Phone: 61 2 46406471 Address: NSW Department of primary Industries, Elizabeth MacArthur Agricultural Institute, private bag 4008, Narellan NSW 2567, Australia
Western flower thrips, Frankliniella occidentalis (Pergande), has developed a high level of resis... more Western flower thrips, Frankliniella occidentalis (Pergande), has developed a high level of resistance to pyrethroid insecticides in Australia. Biochemical examination of those pyrethroid-resistant populations shows esterase activity 2.0-to 6.5-fold higher in six of the seven resistant field populations compared with the susceptible population. This increase in esterase activity in the resistant populations was further supported by native polyacrylamide gel electrophoresis and inhibition studies with the orga-nophosphate insecticide profenofos. The polyacrylamide gel electrophoresis analysis showed differences in the banding pattern and intensity of the esterase isozymes between the pyrethroid-resistant and susceptible F. occidentalis populations. Glutathione S-transferase activity was significantly higher (up to 1.7-fold) in five of the seven resistant field populations when compared with the susceptible populations. Esterases appear to be an important mechanism that contributes to pyrethroid resistance. Glutathione S-transferases may also play a role in pyrethroid resistance in Australian F. occidentalis populations.
With the introduction of transgenic cotton, sucking insect pests have become more troublesome, so... more With the introduction of transgenic cotton, sucking insect pests have become more troublesome, so requiring increased targeted insecticide control and resistance development. Pre-emptive baseline data proved critical to the successful management of cotton aphid because resistance could quickly be confirmed. However, no baseline data for mirids currently exists, preventing an early confirmation of resistance and subsequent resistance management. For this reason methods were developed to breed mirids under laboratory conditions and test them to insecticides. Cotton aphid and two-spotted mite were collected from Australian cotton growing regions and tested in the laboratory for insecticide resistance. Two-spotted mite was tested against Propargite (Comite®), chlorfenapyr (Intrepid®), abamectin (Agrimec®) and bifenthrin (Talstar®) and resistance detected but high frequency resistance was restricted to bifenthrin (Talstar®) only. Molecular testing is now used to detect Pirimicarb (Pirimo...
• WFT were collected from each of the two major Australian processing tomato production districts... more • WFT were collected from each of the two major Australian processing tomato production districts early and late in the season and tested for resistance. • WFT numbers collected were very low and better described as a minor contaminate in a tomato thrips sample, a confusing result because WFT should dominate a sprayed environment. • Low WFT numbers may be indicative of suboptimal spray application that should be investigated. • Insecticides tested included Suprathion®, Maldison®, Lancer®, Vantal®, Success®, Actara® and Thimet®. • A discriminating dose to determine Thimet® resistance was determined experimentally prior to testing and was set at 3.0 g active ingredient / L. • Suprathion® only did not have resistance, Maldison®, Lancer® and Thimet® showed a small (<4%) proportion of resistant WFT in some strains, Vantal® and Actara® had up to 9% resistant WFT with Success® having >70% resistant WFT in some strains. • This is the first detection of Actara® resistance in Australia;...
Aphis gossypii Glover (cotton or melon aphid) is an important pest of cotton due to its ability t... more Aphis gossypii Glover (cotton or melon aphid) is an important pest of cotton due to its ability to reduce yield through feeding damage. Until the introduction of Bt-cotton to Australia in the mid 1990s cotton aphids were considered late season secondary pest because they were suppressed by insecticides used against other pests. However, from 1998-1999 season aphids have been more troublesome initially with control failures against pirimicarb (Pirimor®) and omethoate (Folimat®) making sticky cotton a real possibility and subsequently nearly a decade later more failures with neonicotinoids. Chemical control failures necessitated a complete re think and modification of the aphid IRMS that is still developing and evolving to this day. The strategy is underpinned by resistance monitoring and mitigation methods based on chemical alternation and no sequential use. This is augmented by a series of adjunct methods of aphid control that help put the resistance gene(s) at a selective disadvant...
• The frequency of neonicotinoid resistant Aphis gossypii Glover populations has markedy decrease... more • The frequency of neonicotinoid resistant Aphis gossypii Glover populations has markedy decreased from a high of 94% to a moderate 22% in a single season. • The decrease in the frequency of neonicotinoid aphids likely relates to a subtle change in the way foliar neonicotinoids are being used against pests other than aphids and where aphids are accidently being selected by that use rather than a reduction in neonicotinoid seed dressing consumption or an increase in seed dressing efficacy (it was shown not to completely control resistant A. gossypii). • Pirimicarb resistant A. gossypii remain infrequent and the chemical continues to be a relaible IPM compatible method of aphid control. • A new quantitative real-time PCR (qPCR) method under development to estimate pirimicarb resistance in A. gossypii will potentially increase assay accuracy and decrease test cost.
ABSTRACT Cotton aphid, Aphis gossypii Glover, has emerged as a prominent pest in Australian cotto... more ABSTRACT Cotton aphid, Aphis gossypii Glover, has emerged as a prominent pest in Australian cotton production, and monitoring pesticide resistance including pyrethroids in field populations is crucial for its sustainable management. We examined the distribution of kdr resistance in 35 field-collected A. gossypii populations and used TaqMan qPCR assays with pooled samples. The study demonstrated proof of concept that pooled insect qPCR methodology provided effective detection with better sensitivity than individual PCR-RFLP genotyping techniques for the kdr resistance allele. The practical outcome is that routine resistance monitoring can examine more sites while increasing the likelihood of detecting incipient resistance at those sites. More importantly, the method is adaptable to any genetically caused resistance and so not limited to A. gossypii or even insect control. It cannot be overstressed that the ability to detected resistance at very low frequencies is critical to all sustainable resistance management. Early detection of resistance provides critical time for the modification of chemical use prior to potential insecticide control failure.
The successful use of chemical rotations to manage insecticide resistance requires reversion betw... more The successful use of chemical rotations to manage insecticide resistance requires reversion between alternate chemical applications. We tested a tebufenpyrad resistant population of Tetranychus urticae Koch after some 55 months laboratory culture without pesticide selection and found LC50 level resistance had dropped from 63.29- to 2.41-fold. However, the population was still heterogeneous with LC99 level resistance at 38.03-fold. It is likely that a lack of reversion contributed directly to the initial tebufenpyrad control failure.
J. Econ. Entomo!. 88(5): 1106-1112 (1995) ABSTRACT Field populations of the twospotted spider mit... more J. Econ. Entomo!. 88(5): 1106-1112 (1995) ABSTRACT Field populations of the twospotted spider mite, Tetranychus urticae Koch, were collected and tested to determine levels of resistance. Resistance was detected to fen-butatin-oxide (resistance factor [HF], 2.6-464 at LC9s), propargite ...
Spinosad has been widely used in Australia to control western flower thrips Frankliniella occiden... more Spinosad has been widely used in Australia to control western flower thrips Frankliniella occidentalis (Pergande) but spinosad usefulness is now compromised by resistance. Here we studied a highly spinosad resistant strain of F. occidentalis to explore if esterases had a role in spinosad resistance. Enhanced esterase activity in pressured spinosad-resistant F. occidentalis was confirmed via PAGE electrophoresis and estimated to be approximately three times higher than that in a susceptible strain. Spinosad-esterase inhibition data in the resistant strain, showed a concentration effect with significant esterase-spinosad binding occurring at spinosad concentrations from 6.2× 10(-7) to 1.5× 10(-5) M. Similarly, a spinosad-piperonyl butoxide (PBO) inhibition curve showed a concentration effect, with significant esterase-PBO binding occurring in the resistant strain at PBO concentrations between 3.3× 10(-5) M and 8.4× 10(-4) M. No binding of esterase to spinosad or PBO occurred in the susceptible strain. Results of bioassays in which spinosad resistant F. occidentalis were sprayed with a 4h delayed release formulation of cyclodextrin-complexed spinosad with immediately available PBO demonstrated that spinosad resistance was significantly reduced from 577 to 72-fold. With further development the PBO synergism of spinosad using a delayed release formulation, similar to that used here, may provide effective control for spinosad resistant F. occidentalis. Temporal synergism of spinosad may prove to be effective tactic for the control of spinosad resistant F. occidentalis where the main resistance mechanism involved has been confirmed to be esterase based.
Western flower thrips, Frankliniella occidentalis (Pergande), has developed a high level of resis... more Western flower thrips, Frankliniella occidentalis (Pergande), has developed a high level of resistance to pyrethroid insecticides in Australia. Biochemical examination of those pyrethroid-resistant populations shows esterase activity 2.0-to 6.5-fold higher in six of the seven resistant field populations compared with the susceptible population. This increase in esterase activity in the resistant populations was further supported by native polyacrylamide gel electrophoresis and inhibition studies with the orga-nophosphate insecticide profenofos. The polyacrylamide gel electrophoresis analysis showed differences in the banding pattern and intensity of the esterase isozymes between the pyrethroid-resistant and susceptible F. occidentalis populations. Glutathione S-transferase activity was significantly higher (up to 1.7-fold) in five of the seven resistant field populations when compared with the susceptible populations. Esterases appear to be an important mechanism that contributes to pyrethroid resistance. Glutathione S-transferases may also play a role in pyrethroid resistance in Australian F. occidentalis populations.
With the introduction of transgenic cotton, sucking insect pests have become more troublesome, so... more With the introduction of transgenic cotton, sucking insect pests have become more troublesome, so requiring increased targeted insecticide control and resistance development. Pre-emptive baseline data proved critical to the successful management of cotton aphid because resistance could quickly be confirmed. However, no baseline data for mirids currently exists, preventing an early confirmation of resistance and subsequent resistance management. For this reason methods were developed to breed mirids under laboratory conditions and test them to insecticides. Cotton aphid and two-spotted mite were collected from Australian cotton growing regions and tested in the laboratory for insecticide resistance. Two-spotted mite was tested against Propargite (Comite®), chlorfenapyr (Intrepid®), abamectin (Agrimec®) and bifenthrin (Talstar®) and resistance detected but high frequency resistance was restricted to bifenthrin (Talstar®) only. Molecular testing is now used to detect Pirimicarb (Pirimo...
• WFT were collected from each of the two major Australian processing tomato production districts... more • WFT were collected from each of the two major Australian processing tomato production districts early and late in the season and tested for resistance. • WFT numbers collected were very low and better described as a minor contaminate in a tomato thrips sample, a confusing result because WFT should dominate a sprayed environment. • Low WFT numbers may be indicative of suboptimal spray application that should be investigated. • Insecticides tested included Suprathion®, Maldison®, Lancer®, Vantal®, Success®, Actara® and Thimet®. • A discriminating dose to determine Thimet® resistance was determined experimentally prior to testing and was set at 3.0 g active ingredient / L. • Suprathion® only did not have resistance, Maldison®, Lancer® and Thimet® showed a small (<4%) proportion of resistant WFT in some strains, Vantal® and Actara® had up to 9% resistant WFT with Success® having >70% resistant WFT in some strains. • This is the first detection of Actara® resistance in Australia;...
Aphis gossypii Glover (cotton or melon aphid) is an important pest of cotton due to its ability t... more Aphis gossypii Glover (cotton or melon aphid) is an important pest of cotton due to its ability to reduce yield through feeding damage. Until the introduction of Bt-cotton to Australia in the mid 1990s cotton aphids were considered late season secondary pest because they were suppressed by insecticides used against other pests. However, from 1998-1999 season aphids have been more troublesome initially with control failures against pirimicarb (Pirimor®) and omethoate (Folimat®) making sticky cotton a real possibility and subsequently nearly a decade later more failures with neonicotinoids. Chemical control failures necessitated a complete re think and modification of the aphid IRMS that is still developing and evolving to this day. The strategy is underpinned by resistance monitoring and mitigation methods based on chemical alternation and no sequential use. This is augmented by a series of adjunct methods of aphid control that help put the resistance gene(s) at a selective disadvant...
• The frequency of neonicotinoid resistant Aphis gossypii Glover populations has markedy decrease... more • The frequency of neonicotinoid resistant Aphis gossypii Glover populations has markedy decreased from a high of 94% to a moderate 22% in a single season. • The decrease in the frequency of neonicotinoid aphids likely relates to a subtle change in the way foliar neonicotinoids are being used against pests other than aphids and where aphids are accidently being selected by that use rather than a reduction in neonicotinoid seed dressing consumption or an increase in seed dressing efficacy (it was shown not to completely control resistant A. gossypii). • Pirimicarb resistant A. gossypii remain infrequent and the chemical continues to be a relaible IPM compatible method of aphid control. • A new quantitative real-time PCR (qPCR) method under development to estimate pirimicarb resistance in A. gossypii will potentially increase assay accuracy and decrease test cost.
ABSTRACT Cotton aphid, Aphis gossypii Glover, has emerged as a prominent pest in Australian cotto... more ABSTRACT Cotton aphid, Aphis gossypii Glover, has emerged as a prominent pest in Australian cotton production, and monitoring pesticide resistance including pyrethroids in field populations is crucial for its sustainable management. We examined the distribution of kdr resistance in 35 field-collected A. gossypii populations and used TaqMan qPCR assays with pooled samples. The study demonstrated proof of concept that pooled insect qPCR methodology provided effective detection with better sensitivity than individual PCR-RFLP genotyping techniques for the kdr resistance allele. The practical outcome is that routine resistance monitoring can examine more sites while increasing the likelihood of detecting incipient resistance at those sites. More importantly, the method is adaptable to any genetically caused resistance and so not limited to A. gossypii or even insect control. It cannot be overstressed that the ability to detected resistance at very low frequencies is critical to all sustainable resistance management. Early detection of resistance provides critical time for the modification of chemical use prior to potential insecticide control failure.
The successful use of chemical rotations to manage insecticide resistance requires reversion betw... more The successful use of chemical rotations to manage insecticide resistance requires reversion between alternate chemical applications. We tested a tebufenpyrad resistant population of Tetranychus urticae Koch after some 55 months laboratory culture without pesticide selection and found LC50 level resistance had dropped from 63.29- to 2.41-fold. However, the population was still heterogeneous with LC99 level resistance at 38.03-fold. It is likely that a lack of reversion contributed directly to the initial tebufenpyrad control failure.
J. Econ. Entomo!. 88(5): 1106-1112 (1995) ABSTRACT Field populations of the twospotted spider mit... more J. Econ. Entomo!. 88(5): 1106-1112 (1995) ABSTRACT Field populations of the twospotted spider mite, Tetranychus urticae Koch, were collected and tested to determine levels of resistance. Resistance was detected to fen-butatin-oxide (resistance factor [HF], 2.6-464 at LC9s), propargite ...
Spinosad has been widely used in Australia to control western flower thrips Frankliniella occiden... more Spinosad has been widely used in Australia to control western flower thrips Frankliniella occidentalis (Pergande) but spinosad usefulness is now compromised by resistance. Here we studied a highly spinosad resistant strain of F. occidentalis to explore if esterases had a role in spinosad resistance. Enhanced esterase activity in pressured spinosad-resistant F. occidentalis was confirmed via PAGE electrophoresis and estimated to be approximately three times higher than that in a susceptible strain. Spinosad-esterase inhibition data in the resistant strain, showed a concentration effect with significant esterase-spinosad binding occurring at spinosad concentrations from 6.2× 10(-7) to 1.5× 10(-5) M. Similarly, a spinosad-piperonyl butoxide (PBO) inhibition curve showed a concentration effect, with significant esterase-PBO binding occurring in the resistant strain at PBO concentrations between 3.3× 10(-5) M and 8.4× 10(-4) M. No binding of esterase to spinosad or PBO occurred in the susceptible strain. Results of bioassays in which spinosad resistant F. occidentalis were sprayed with a 4h delayed release formulation of cyclodextrin-complexed spinosad with immediately available PBO demonstrated that spinosad resistance was significantly reduced from 577 to 72-fold. With further development the PBO synergism of spinosad using a delayed release formulation, similar to that used here, may provide effective control for spinosad resistant F. occidentalis. Temporal synergism of spinosad may prove to be effective tactic for the control of spinosad resistant F. occidentalis where the main resistance mechanism involved has been confirmed to be esterase based.
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Papers by Grant A Herron