| title: | Delayed effects of sublethal doses of natural insecticides on pest and beneficial insects |
|---|---|
| reg no: | ETF6722 |
| project type: | Estonian Science Foundation research grant |
| subject: |
4.2. Crop Sciences (inc. Horticulture) |
| status: | accepted |
| institution: | Estonian University of Life Sciences |
| head of project: | Külli Hiiesaar |
| duration: | 01.01.2006 - 31.12.2009 |
| description: | The mechanisms of the lethal effect of natural insecticides have generally been much studied. The later and indirect effect of weak or sublethal doses (concentrations) on pests has, on the contrary, been undervalued and thus less studied so far. Nevertheless, weak doses may cause later functional changes in insect organs, for example, by decreasing the lifespan of the insect, its reproduction ability and winter susceptibility, sparing, at the same time, its natural enemies. Studying of such changes is one goal of the research. The indirect effect of the preparations is revealed in the chain of interconnected species and factors within one agrocynosis: e.g. pollinators, pest insects, their parasitoids and diseases. Elucidation of mutual relations between pest insects, their parasitoids, disease spreading and pollinators provides new and necessary information on the direct and hidden effect of the preparations. The later and indirect effect of sublethal doses may, in the long term, prove more effective than the instantly killing doses, which are also expensive and may restrict pest control in nature. The named indirect effect is studied in the chain of model species, which includes: the cabbage butterflies (Pieris brassicae and P. rapae), the cabbage moth (Mamestra brassicae ), their parasitoids and diseases. At the same time, the effect of natural insecticides on the feeding behaviour and physiological state of the bumblebee (Bombyx terrestris) is studied. The presumed importance of the research is in elaboration of scientific bases for the use of low doses of some natural insecticides, where it is essential to direct and favour the natural pest control. |
| project group | ||||
|---|---|---|---|---|
| no | name | institution | position | |
| 1. | Külli Hiiesaar | Eesti Maaülikool | ||
| 2. | Aare Kuusik | |||
| 3. | Luule Metspalu | |||
| 4. | Priit Põldma | |||