I always say that vigilance is the key to combatting plant pest and diseases, so keeping your eyes peeled for the very first signs of a problem will serve you well in your attempt to get rid/control the effects.
Imagine my horror the other day when deadheading some roses in my front garden that I found that a lot of the top leaves had just vanished, with only the mid-rib left behind, telling a sad sorry tale.
What had happened was an attack of the rose sawfly larvae. These little horrors had crept up on me, and had nibbled their way through complete leaves before I had time to turn around..
But you have to look quite closely to see them!
Often called the skeletoniser due to the larvae’s habit of eating all the leaf except the prominent ribs, this small caterpillar-like larvae is well camouflaged and difficult to spot.
The adult sawfly is noticeable for its bright yellow abdomen, but causes no harm to the plants.
The larvae have voracious appetites and rapidly denude rose bushes of their foliage. There is usually several generations following in quick succession but the damage done is usually more of an annoyance than significant.
The best treatment is to wait until the flush of flowers is over, then prune fairly hard, removing all the larvae in the process. Insecticide sprays will also rid the bushes of their unwelcome hosts, but may kill the beneficial predator insects as well.