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Biological Control

Pest control

The Department of Bioscience conducts research in the field of pest control. Biological control means using live organisms to control other harmful organisms. The best known example of this is probably ladybugs that are used for control of aphids.

One of the areas in which Aarhus University is ahead of the game is in the use of ants in pest control. Studies are being conducted in Africa and Australia, and recently we started up in Denmark as well with the project ANTAID and MothStop, which respectively studies whether the common black garden ant can be used to control aphids and whether forest ants can be used to combat winter months in organic apple orchards. As far as the black garden ant  goes, it is necessary to change its behavior so that it does not help the aphids, but eat them instead.

In addition to working in Denmark, we work in Australia, Benin, Tanzania, Thailand and Vietnam.

New results and project-hightligts

Antaid

The project is active until 2019.

For more information, contact Joachim Offenberg

Ant Biocontrol in Afrika (DANIDA)

The projektet was active in the period 2011 - 2015. More reports are written and you will find a summary here.

Cashew and Mango Integrated Pest Management Using Weaver Ants as a Key Element:

See some of the results here as well as a manual on how to manage weaver ants in tropical plantations. Download the guide here

For more information, please contact Jørgen Aagaard Axelsen

 

 

 

Mothstop

Mothstop

Danish fruit is in short supply. Among other things, this is due to the fact that organic fruit growers have a battle against pests and diseases that are hard to fight without the use of pesticides. Therefore, the result is a more unstable production in organic farming than in conventional. 

If it is possible for MothStop to find new organic methods for pest control, it will improve and stabilize the organic outcomes from growers, and thereby improve the competitiveness of organic fruit production. More fruits without pesticide residues will then be available for the Danish supermarkets and the production method is more environmentally friendly than the conventional. 

 

Wood ant has captured a winter moth larva on an apple tree. Photo: Jesper Stern Nielsen

Project is active in the period 2016-2017.

For more information, contact Joachim Offenberg

Antmanure

The project was active in the period 1/4 2012 - 30/9 2015. Read the summary here:

Plants cooperate with ants because ants remove pests from plants. However, ants may also fertilize plants, as the pests they eat are processed and remains of them are deposited on ant-plants as ant manure.

We have found that ant manure contains important plant fertilizers, e.g. nitrogen, in chemical compositions that plants can absorb directly through their leaves.

Also, we have shown that coffee plants are able to absorb nitrogen from ant manure, and that ant-plants reach higher nitrogen contents than plants without ants. In other words, pests are not just removed, they are also converted into plant fertilizer.

Manure is mainly deposited on actively growing plant parts, such as buds, flowers and fruits, which means it is deposited where nutrients are most needed for the plant. This also means that nutrients are delivered to the canopy of ant-plants, bypassing the soil layer where plants otherwise would have to compete with other plants for these vital nutrients. This may cause better growth of ant-plants.

Our results also showed that ants are a very rare example of a biocontrol agent being more efficient than pesticides in outdoor crops. These results support the use of ants as a sustainable plant protection method that is acceptable in organic production.

The five most significant publications from the project:

  1. Vidkjær, N. H., Wollenweber, B., Gislum, R., Jensen, K. M. V., Fomsgaard, I. S. (2015) Are ant feces nutrients for plants? A metabolomics approach to elucidate the nutritional effects on plants hosting weaver ants. Metabolomics 11:1013-1028.
  2. Pinkalski, C., Damgaard, C., Jensen, K.M.V., Peng, R. & Offenberg, J. (2015) Quantification of ant manure deposition in a tropical agroecosystem: Implications for host plant nitrogen acquisition. Ecosystems, 18: 1373–1382.
  3. Offenberg J. (2015). Review: Ants as tools in sustainable agriculture. Journal of Applied Ecology. 52: 1197-1205.
  4. Vidkjær, N.H., Wollenweber, B., Jensen, K.M.V., Ambus, P.L., Offenberg, J., Fomsgaard, I.S. (2015) Urea in weaver ant feces: Quantification and potential uptake and translocation in Coffea Arabica. Journal of Plant Growth Regulation. Accepted.
  5. Pinkalski, C., Jensen, K.M.V., Offenberg, J. Foliar uptake of nitrogen from ant manure: a novel pathway in ant-plant nutrient transfer. Not yet published, but report is based on some of the most important results.