Dorte Heidi Højland Castberg

PhD, Postdoc

Dorte Heidi Højland Castberg
Se relationer på Aarhus Universitet


Present (Post doc):

Managering pyretroid resistance in insect pests of winter oilseed rape

The increasing number of people on the planet means more mouths to feed and trustworthy yields in agriculture is becoming a worldwide demand. Oilseed rape play a major role in securing a cheap food source/crop with high nutritional value. Likewise, the use of oilseed rape in biofuel production has further increase the importance of this crop.There is an ever growing need to effectively fight pest in agriculture to obtain this, and an effective way has so far been use of insecticides. This need is further increased and complicated by emergence of resistance to commonly used insecticides, which leads to more insecticide use, ultimately ending in a never ending circle. Through many years the trend has been towards development of better and more specific insecticides, which target only the pest and do not affect the beneficial insects or mammals. 

Several pests of oilseed rape occurs throughout the season causing verious forms of damage, primarily on the seed buds. Damage due to insect pests is a costly afffair for growers. The primary form of control is by applying chemicals on the seeds or directly on the plants. Recently, coating seeds with neonicotinoids has been prohibited in Europe due to possible harmful effects on bees. This leaves few alternatives for control, which leads to higher selection pressure and increases the risk of resistance developing in insect pests.
Within his project, I aim to determine the resistance level of Danish psylliodes populations and compare my findings with similar tests for British an German populations. This will serve as the first of a line of smaller projects within the big project to elucidate development of resistance in Danish oilseed rape fields.


Former (PhD):

Cytochrome P450 monooxygenase-madiated resistance in the house fly Musca domestica
The insectide spinosad has been introduced for housefly control within the last decade and plays an essential role in pest management strategies of multiple insect pests. However, resistance can be due to alternations in the nicotinic acetylcholine receptor as well as increased expression of metabolic enzymes, the so called cytochrome P450s. During a collection of field strains from Danish farms prior to the introduction of spinosad, one population proved 27-fold and 5-fold resistant to spinosad for females and males, respectively.
Despite not being to contact with the insecticide, female flies of this strain still proved resistant, while male flies are within the range of expected resistance levels for a field collected strain.

The aim of the project is determine the mechanisms behind this sex dependent difference in spinosad resistance, causing the females to be considered resistant and males susceptible. Linkage of sex determining factors as well as analysis of gene expression will be part of this project. This project will hopefully shear some light on some of the mechanisms behind insecticide resistance in the common houseflies and helps us to better manage the use of insectides.

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