Sawfly and willow trees

Last Summer (2012) I noticed the foliage of my 2 willow trees (next to each other) were being suddenly consumed by Sawfly larvae (absolutely confirmed). It was all too late and despite spraying them with washing up liquid solution and trying to pick them off, I lost the battle and the tree was left almost bare (except the very tops).

We've had a cold winter and I had hoped this might mean that I might not get a repeat. But it appears I'm wrong. Both trees have had sawflies hovering about (especially when it was very warm for a few days last weekend). And now they're covered in green eggs. This is May 11th 2013.

I've tried removing as many of the leaves with eggs on them but this is not very practical. And let's face it, I'm never gonna remove every egg!

Does anyone recommend a fool proof attack to win the war this Summer? They haven't hatched from eggs yet, so, at the moment, I have the high ground! lol.

Is there an insecticide I should use? This might be a shame though because I have loads of berries nearby. I wouldn't want to eat them if there was any chance of them being tainted. Help...


  • nutcutletnutcutlet Posts: 24,050

    That's a tricky one Joshy. I spend hours picking sawfly larvae off the solomon's seal but a tree is a different game. Can't see how you could spray a whole tree even if you didn't worry about other casualties - the bees, other insects, yourself.

    That's not very helpful, sorry.

  • JoshyDJoshyD Posts: 4

    Last year everything started on the bottom leaves and worked upwards. So I would imagine that the sawflies (which are quite delicate little wasps really) prefer to lay eggs on the lowest branches. So I think if I hit them with something now (or as they all start hatching), I could stop them. But it's a question of with what? I'm not keen on using chemicals in my garden generally and would prefer a friendly solution, if there is one. I haven't got much time...

  • FairygirlFairygirl Posts: 19,692

     I sympathise Joshy- only experienced them on S's Seal as well, but I did catch one many years ago which was huge-must have been a queen. Have you tried googling an RHS site- or one of the govenment agencies that deal with the environment? Can't think of anything else.

  • JoshyDJoshyD Posts: 4

    Thanks for your replies. Unfortuantely are US based. I'll have to visit my local garden centre and see what they say. They're out in force today. There's always a few bussing around. Better get down there soon!





  • Like all insects, sawflies probably have good and not-so-good years. This might be a good period for them (but bad for you). I think you will either have to live with it or start zapping everything in sight, which seems a little unfair on the already depleted insect world.

    There are many different sawflies that are hosted by different plants or groups of plants. Willows wouldn't have survived all these thousands of years if the attacks were fatal.

  • trifid housetrifid house Posts: 101

    I get bad problems with sawflies too.they attacked gooseberries, roses, dahlias last year. I have just bought grow your own nematodes from the nemaslug company. They say that they are meant to do sawflies. dont knownif they will work but only cost about a fiver so thought I would give it a try. I used nemaslug last year with great success.

  • JoshyDJoshyD Posts: 4

    Thanks. A few clutches of eggs have already hatched. So the onslaught begins. Will have to take a before and after shot for comparison. 'Grow your own nematodes' doesn't list all sawflies as dealt with so...

  • nutcutletnutcutlet Posts: 24,050

    The solomon's seal type are just moving in.

  • BobTheGardenerBobTheGardener LeicsPosts: 6,357

    The adult soloman's seal sawfly is quite attractive - completely black with black wings - reminds me of a stealth fighter.  It's a pity the larvae are so damaging - they make a right mess of my clumps every year.

    A trowel in the hand is worth a thousand lost under a bush.
  • nutcutletnutcutlet Posts: 24,050

    Mine are almost defoliated in spite of my picking effort. For the first few years we didn't see any and I know what a lovely yellow the leaves turn in autumn.

  • Hi,

    Did anything work Josh?  i have three willows (one 3.5 years old and two only a year old)  the two little ones are covered in sawfly larvae.  i sprayed the washng up liquid solution over but the trees went brown.  When the leaves came out again, so did the little critters.  i bought some "Bugsoff" spray that lists sawfly on the back.  one hour after spraying, the sawfly larvae were back to eating.  would love to know if there is anything organic i can use but they seem to be immune to everything - advise please.......  thanks in anticipation

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