The production of legumes such as broad beans and peas has increased in Norway. But so too has the extent of pest insects with negative impact on crop yields.
There is a rising demand for Norwegian-produced protein crops for both food and animal feed, which has resulted in increased production of broad beans and peas in recent years.
At the same time as production has expanded, the number of incidents of crops being lost due to damage by pest insects, among other things, has also increased. Ten years ago, researchers would receive two to three questions about pests in protein crops during the whole season, now they are receiving two to three a day.
Part of the reason is that climate change is providing better conditions for the pest species to develop, while at the same time fewer insecticides are becoming available each year. Norway is slightly behind when it comes to knowledge about growing protein crops, but in Europe, research on alternative measures to combat the pests are ongoing. As part of a larger research project, NIBIO has now started to test alternatives to insecticides under Norwegian conditions.
One of the biggest problems for producers of both broad beans and peas is the pea-leaf weevil (Sitona lineatus). The adult beetle lives on the leaves and lays eggs in the soil. The larvae are feeding on the roots and nitrogen-fixing nodules, which might reduce the crop yield. This beetle has always been present in Norway but has now become a major problem. There have been local infestations so extensive that entire crops have failed due to feeding on the root system. It is possible to use insecticides against the adult beetles, but if you find an adult, there will already be eggs in the soil.
It is considered wise to sow broad beans a little later and deeper than usual, but this can be difficult because of the short growing season in Norway. Therefore, NIBIO is testing an early variety combined with later and deeper sowing. So far, the results are promising.