We have a slight invasion of possible Sawfly caterpillars invading the rear yard. I have tried to see where they are heading, but have not been successful. I have found one in a cocoon, but it has not altered in the week I have been watching it. There is a bottle brush tree in the next door garden on our fence, but cannot see any indication of their presence. We only get three or four crossing our backyard each day, and they seem to travel towards the house. The spray that Bunnings suggested only causes them to swim through, and also the Rose spray seems to have no effect. The only control I have found is Mortien spray, which certainly stops them in their tracks. Is there anything we can do to get rid of them, and where would they be heading? They are not interested in the soil I have placed for them, or in the leaves. When squashed, they are very juicy. Would like to know what they are doing, or going to do.