Can anyone tell me if I need to worry about these bugs? We have a few in our garden and I caught one laying eggs on a tomato leaf - which I destroyed to be on the safe side but I'd hate to kill anything that might have a hearty appitite for aphids ???
Do you mean shield Bugs?
Yes. Sorry about the typo!javascript:replaceText('%20:P',%20document.forms.postmodify.message);
They eat plant matter, but the native ones aren't regarded as a pest.
If the shield bug is native any damage to crops will be minimal but if it is the illegal immigrant Nezara viridula they can do significant damage and I believe they are a contributing cause to the recent severe blight attacks on tomato crops.
Photo left shows damage to runner beans. Right shows nymphal stages of Southern green shield bug.
(http://downtheplot.com/images/nezara_viridula_damage.jpg) (http://downtheplot.com/images/Nezara_viridula.jpg)
I've had the severe blight, but not the bugs. I think it was the weather last year myself.