The life-stage variations in insecticide resistance of western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), to selective insecticides (acrinathrin, formetanate, and methiocarb) were studied using resistant laboratory strains. In each strain, the second-instar larva was less susceptible to the insecticides tested than the adults. The lower the resistance level of the adults, the higher the difference between larva and adult susceptibility: 32-fold to methiocarb, 15.4-fold to formetanate, and 180-fold to acrinathrin in the reference strain. In laboratory-selected resistant strains, these differences were much lower: 5.8-fold to methiocarb, 4.8-fold to formetanate, and 2.0-fold to acrinathrin. In selected strains, higher resistance levels for each insecticide were found, both for larvae and adults, compared with the reference strain. These results show that after insecticide resistance selection in adults, the resistance is carried over to the larvae, but at lower levels.
"However, this ratio was lower for larval stage compared with adults in YZ strain. Variation in resistance at different developmental stages has also been reported in different insects (Contreras et al. 2010, Leonova and Slynko 1996). Several factors including difference in enzyme activity level and rate of cuticular penetration could account for these variations between larval and adults stages (Leonova and Slynko 1996, Yu 2008). "
[Show abstract][Hide abstract] ABSTRACT: Control of Frankliniella occidentalis (Pergande) is a serious problem for agriculture all
over the world because of the limited range of insecticides that are available. Insecticide resistance
in F. occidentalis has been reported for all major insecticide groups. Our previous studies showed that
cytochrome P450-mediated detoxification is a major mechanism responsible for insecticide resistance
in this pest. Degenerate polymerase chain reaction was used to identify P450 genes that might be
involved in acrinathrin resistance, in a laboratory population of F. occidentalis. Associated sequences
were classified as belonging to the CYP4 and CYP6 families. Real-time quantitative polymerase chain
reaction analyses revealed that two genes, CYP6EB1 and CYP6EC1, were over-expressed in adults and
L2 larvae of the resistant population, when compared with the susceptible population, suggesting their
possible involvement in resistance to acrinathrin.
[Show abstract][Hide abstract] ABSTRACT: The monitoring of the susceptibility of fleas to insecticides has typically been conducted by exposing adults on treated surfaces. Other methods such as topical applications of insecticides to adults and larval bioassays on treated rearing media have been developed. Unfortunately, baseline responses of susceptible strains of cat flea, Ctenocephalides felis (Bouchè), except for imidacloprid, have not been determined for all on-animal therapies and new classes of chemistry now being used. However, the relationship between adult and larval bioassays of fleas has not been previously investigated. The adult and larval bioassays of fipronil and imidacloprid were compared for both field-collected isolates and laboratory strains. Adult topical bioassays of fipronil and imidacloprid to laboratory strains and field-collected isolates demonstrated that LD50s of fipronil and imidacloprid ranged from 0.11 to 0.40 nanograms per flea and 0.02 to 0.18 nanograms per flea, respectively. Resistance ratios for fipronil and imidacloprid ranged from 0.11 to 2.21. Based on the larval bioassay published for imidacloprid, a larval bioassay was established for fipronil and reported in this article. The ranges of the LC50s of fipronil and imidacloprid in the larval rearing media were 0.07‐0.16 and 0.11‐0.21 ppm, respectively. Resistance ratios for adult and larval bioassays ranged from 0.11 to 2.2 and 0.58 to 1.75, respectively. Both adult and larval bioassays provided similar patterns for fipronil and imidacloprid. Although the adult bioassays permitted a more precise dosage applied, the larval bioassays allowed for testing isolates without the need to maintain on synthetic or natural hosts.
Journal of Medical Entomology 05/2014; 51(3). DOI:10.1603/ME13240 · 1.95 Impact Factor
Note: This list is based on the publications in our database and might not be exhaustive.
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.