By Iank1958
United Kingdom 
I have a small olive tree in a pot in my Bootle back garden which has been there for 3 years or so. I've noticed in the past that if I see new, young leaves stuck together, on parting them there will always be a small green grub in there usually about 1cm long. Not only do these grubs eat the leaves but, whatever it is that they use to stick the leaves together also harms them, leaving them dried and scarred.
Since discovering this I've kept on top of the problem by looking for the problem each day and picking the grubs off before they do too much harm.
This summer I thought they had been leaving the tree alone but, only when it was too late did I discover they'd turned their attentions to the many blossoms which were on the tree, something I noticed because the blossoms weren't developing properly. So this pest has wiped out whatever crop of olives I was going to get even before they've got started.
To add to the problem, just last week I bought another Mediterranean plant, an Oleander, also in a pot. It stands next to the olive tree and suffers from the same problem.
None of the many other shrubs in the garden are affected.
I'm also reasonably sure that this grub can produce a thread of silk like a spider, because after knocking one off the tree, it appeared to stop in mid air before suddenly crawling back up the thread it had produced.
I'm assuming something lays a series of single eggs in different places on these 2 plants.
Any idea what it can be? Also, any advice on how I can prevent this happening in future would be much appreciated.
Ian,
Bootle,
Merseyside.
9 Jul, 2014
Answers
Thanks, much appreciated.
Being as I intend to eat the olives, just as I did last year, (though not this time round obviously after what this pest has done) I will stick to looking out for the caterpillars and remove them as soon as growth starts next spring, rather than treat the tree with any kind of pesticide.
At least I'll know exactly where to look next time, ie in the blossoms as well as the leaves.
I now think the Oleander was affected simply because it was standing next to the Olive tree and, the grubs must have abseiled down the thread they produce.
I've moved it elsewhere now.
Thanks again,
Ian.
10 Jul, 2014
This is the bungee caterpillar, Characoma nilotica. The young larvae start eating the flowers in the upper canopie of the olive tree and then rappelle down to the flowers on the lower part of the tree (hence the common name bunge caterpillar). They can do some leaf damage by skeletalizing them. You have to inspect the trees early on to control the problem for once they start stringing down to new locations it's too late. If I may, a little flyfishing side note: I have a great affection for little green bungee jumpers of this type, the reason being that when they string down from the branches of trees overhanging my favorite trout streams and hit the water trout take them in short order. Therefore I fly tie imitations of these caterpillars using deer hair died green and I take trout in short order using this fly. I will also add that I am a catch and release fly fisher, reason? After playing eighteen holes of golf does one burn the golf ball?
10 Jul, 2014