Summary,

Institutt for plante- og miljøvitenskap

Molecular techniques have become important tools in several entomological fields. In a series of papers (I-V) we have applied some of these molecular techniques for species identification and for insecticide resistance detection and monitoring in three pest species.
Species-specific DNA primers (I) or RAPD PCR (II) were used for the identification of the polyphagus leafminers Liriomyza bryoniae, L. huidobrensis, L. sativae and L. trifolii. The species-specific DNA primers were derived from species-specific RAPD-PCR fragments or from species unique gene sequences. The leafminers are serious insect pests both in field and protected crops around the world, and the species-specific primers will give an effective tool for identification of the quarantine polyphagous Liriomyza species.
Insecticide resistance is a growing problem worldwide. Good detection and monitoring methods are important to reduce the problem. We have used a combination of molecular, biochemical and bioassay methods for identification of resistance in Liriomyza spp and Norwegian populations of Myzus persicae and Bemisia tabaci. The Liriomyza (III) populations were investigated for pyrethroid resistance through the target site mechanism, knock down resistance (kdr). Three point mutations in the voltage gated sodium channel linked to this resistance mechanism were identified in different populations and species. The Norwegian populations of M. persicae (IV) and B. tabaci (V) were investigated for resistance too several classes of insecticides. Three known resistance mechanisms were found in M. persicae, increased esterase production, Modified Acetyl Cholin esterase (MACE) and kdr. These resistance mechanisms will increase the tolerance for pyrethroids, organophosphates and carbamates. In addition an increased tolerance for imidacloprid was found in one population. Populations of B. tabaci were highly resistant to fenpropathrin, lambdacyhalothrin, chlorpyriphos and buprofezin, and less susceptible to imidacloprid than the susceptible strain. All the tested populations were highly susceptible to pyriproxyfen in a bioassay. One population of B biotype retested after about 20 generations without any insecticide applications, showed increased susceptibility to fenpropathrin and imidacloprid and stable buprofezin resistance.
Nordhus, E. 2005. Molecular methods in species identification of Liriomyza spp. and the study of insecticide resistance in Liriomyza spp., Bemisia tabaci and Myzus persicae. Norwgian University of Life Sciences, Ås, Norway. Doctor Scientarum Theses. 16, ISBN 82-575-0658-3, ISSN 0802-3220.

Oppdatert: 23.11.05
Utskriftsvennlig versjon : Arkiv : Tips en venn