Why have caterpillars stripped our Twisted Willow trees?
By Kris
United Kingdom 
A swarm of small yellow/green and black caterpillars have completely stripped the foliage off our established Twisted Willow trees within a 4-day period.
Will the trees die, or is there a spray or wash we can use to save them from a repeated attack?
13 Jul, 2009
Answers
The caterpillars have stripped your tree because they were hungry, and probably liked the taste of the leaves, there is little that you can do if it is a very large tree as it would take gallons of treatment, to eradicate them, you will just have to let nature take its course, and hope the tree can recover, and maybe produce more foliage.even if it is a smaller tree there is very little on the market that you can use effectively, although a good gallon of water and some fairy liquid can shift quite a lot of pests as the don't like fairy liquid being sprayed over them, and it doesn't harm the plant, I sprayed it over black fly on my runner beans and broad beans and it soon shifted them and they are supposed to be difficult,even ants don't like it.
13 Jul, 2009
Willows are one of the most popular food plants for several difffent Caterpillars, What do is keep a careful watch over the new growth and at first signs, pinch out the shoots which are being eaten, second growth is often left uneaten.
13 Jul, 2009
Probably a sawfly larvae rather than a Lepidopteran (Moth/Butterfly).
14 Jul, 2009
Not necessarily I've seen both at work on a tree
14 Jul, 2009
We have a potted weeping willow. There has been a growth on the leaves and some of the branches of a yellow patch, it looks like sulphur. Does anyone know what it is and how to treat it?
12 Aug, 2009
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The trees will survive but will need t.l.c. next year look for the eggs before they hatch
13 Jul, 2009