" To plant trees is to give body and life to one's dreams of a better world " Russell Page

Thursday, September 6, 2012

Pests & Beasts

Dear folks! this post is more a help request than a proper post.
Actually it will also open a chapter dedicated to pests and diseases that affect plants in general and especially the ones I grow and care for...

I guess all of us have their own horror stories about that fungus or that type of bug that has wretched (I dare say with an incredible time planning) a crop or a plant just a couple of days before it reached perfection or it opened that first bud we were so eager to see. I guess this is part of the game and since I took the firm resolution to reduce to an absolute minimum all toxic treatments, well the war is bitter and sometimes the losses are sensible!

The past winter has been particularly mild and the result was, against my expectations, a proliferation of nasty little buggers. A pretty severe attack of red spider mites was just one of them. 
But what really annoyed me was a massive presence of sawflyes!

The rose sawfly - Arge Pagana with its quite poetic Latin name, is I am told, a plant eating wasp that deposits its eggs in the tender shots of roses. From there, little (so tiny you can barely see them until it's late!) larvae  develop and in no time devoure the leafs of your healthy rose.
Most books and experts tend to say that the Arge is no serious threat to your rose and that you should eliminate the hungry caterpillars by hand - well and that's all!

The Arge has a saw like cutter on its abdomen with which it stiches the eggs into the tender branches. It leaves a mark on the branch that looks very much like a machine stitching... very neat and regular.

 Sawfly larvae devouring leaves and the ugly scorch the emerging larvae have left behind.

Quite unsightly leaf damage after the larvae have left...

Well, the problem is that all young branches which are supposed to bear blooms, have been attacked by sawflies... The damage is not killing the plant but obviously the blooms are heavily compromised and the rose looks ratty! Furthermore the left scars grow and open as the branch ripens and I suspect that it can fragilise the plant on long term since it can facilitate other fungus or insects...
Now the hamletic quest is - there possibly any type of deterrent capable to prevent the sawfly infestation? Relying on birds and the like has so far, had no impact!  It might work on larger scale in a proper garden in the country, but in the urban environment the results are rather scarce.

No reasonable pest bible gives a clue in how to prevent the sawfly from visiting the roses. I do not mind loosing a couple of leaves, or cutting off one or two affected branches but if I have to chop down an entire plant on the expenses of the flowers, well I get quite mad....

Rosarians out there, do you have any experiences with this bug? I would be glad to get your advice and share your experiences...

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