Tree lucerne seeds

Today it has been wet, so no excuse to put off a job that has been waiting for a while now.

These are tree lucerne (also known as tagasaste) seeds. The plant is a legume used for forage in some areas of New Zealand, although it has also become weedy. After a small beetle was introduced into New Zealand to feed on broom seeds (as a biological control agent) we found that some tree lucerne seed was also attacked. Laboratory and field tests have shown that the beetles strongly prefer broom over tree lucerne, and we wanted to check this out in the field.

So in January we visited several sites where broom and tree lucerne grow together. We collected pods from 5 plants of each species at each site, and put them in separate fine mesh bags. These bags were then put into a bigger bag which has been hanging in our garage to allow the pods to burst and the beetles to complete development. Then we check through all the seeds to find out whether they have beetles in them or not, and count the seeds to compare infestation rates.

So far we aren't finding many beetles in the tree lucerne seeds. You can see here that these are healthy looking seeds that don't have beetle emergence holes in them. We're not quite half way through our samples, so will report back later when we have all our results.