Environmentally-Friendly Pesticide To Combat Potato Cyst Nematodes

Potato cyst eelworms are normally hatched from their protective cyst in spring by a substance excreted by potato plants. Each cyst is in fact the swollen remains of a mature female and it contains several hundred fertilised egg cells. The young eelworms make their way to the growing roots of the plant, which they penetrate. From then on they live as a parasite on the plant. As a result, its growth is impeded and productivity falls.

The chemists at Amsterdam University, were looking for an environmentally-friendly way of confusing the eelworms. Their strategy for doing so is based on synthetic production of the substance solano-eclepin A, which young potato plants excrete via their roots.

Solano-eclepin A is however a complex chemical compound whose molecular structure was only identified in 1992. It has nine chemical stereocentres and contains seven rings, ranging from three to seven-membered rings.

The researchers were able to reconstruct the complex functionalised seven-membered ring. They also succeeded in synthesizing four of the seven molecular rings in the configuration of solano-eclepin A. They then tested its biological activity on substances similar to solano-eclepin A. Two derivatives showed a promising ability to hatch juvenile eelworms.

The team intend doing further research on a wide range of substances derived from solano-eclepin A. The tests are intended to produce a biologically active substance which can be simply prepared on an industrial scale and which will provide an environmentally-friendly means of protecting potato crops against eelworm infestation.

Farmers would then be able to combat the pest with the substance. They would treat fallow fields with it in order to awaken the eelworms in the ground. These would then die because there would be no potatoes to feed on. Next season, potatoes could be planted without any danger of their being infected by the parasite.

Tests both in the laboratory and in the field proved successful at eradicating potato cyst eelworms. Proper use of the newly developed substance will mean that potatoes can be planted in the same field every two years instead of every five as at present.

The research was funded by the NWO Technology Foundation, STW.