Well that has come around quickly! We have just completed our 3rd and final rust release along our 11 Himalayan balsam sites across the Tees Catchment!
Although we don't have any more rust releases to do, we still have more monitoring to do both in September and in the Spring next year to monitor the success of the biocontrol. As we visited the sites, some seem to be more successful than others have been.
At this point nearly all of the Himalayan balsam is fully grown, varying in size from a meter tall to over 4 meters! Some of the leaves are small, and some are huge, and this has varied throughout the catchment area! As well as this, they all have flowers and a sweet scent (love it or hate it).
But the flowers aren't the only thing that varies, the rust seems to have varied throughout the releases. Some of the rust pustules are small and in large quantities, and some of them are large with only a few or just one on each leaf.
We can't wait to go out in September and see the success of the rust after 3 lots of releases. After this, the balsam will be dying back for the Winter, and the rust will move to its complicated overwintering stage ready for us to monitor in the spring.