A PEST OF ROSES

Anoplophora malasiaca is the most dreadful pest of roses in Japan.  Most of gardeners have a experience of its damage to large rose stems.
A larva of it is called 'Teppo-Mushi' in Japan, which means 'rifle worm' in Japanese.  Eggs of Anoplophora malasiaca are laid into stems of various trees including roses.  A larva eats pith of stem and make a tunnel within it, just like the way stem borers do.  It looks like a bullet in a barrel of a rifle.

They come to gardens in June and July to lay eggs.  They usually fly to the top of roses with a height of more than 1.7 meter, and move down to a large part of branch or stem, most often to the point several inches from the ground.

Roses, especially climbing ones, often wither due to this pest.  We had lost a Rosa 'Pierre de Ronsard' several years ago.  Fortunately  Rosa 'Paul's Himalayan Musk' and Rosa 'François Juranville' had withstood attacks to their large branches.

Yesterday my wife found and caught it (below).

Anoplophora malasiac

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Four pictures below are situations of damage and precautionary measures in our garden.

Fine wood particles are attached on the surface of a rose stem.  This is a sign of a larva of Anoplophora malasiac. (Rosa 'Summer Snow, September 2012)

After removing the wood particles, holes of the back side of stems were found using a mirror.  By using a wire, larvae had been squashed.  (Rosa 'François Juranville', July 2012)

In order to prevent the damage, we used a fine net.  (Rosa 'Paul's Himalayan Musk') 

Another method is to coat the surface of large stems with special emulsion of resin.  (Rosa 'Summer Snow', April 2013)

Every two weeks from spring to autumn, we must check the signs of Anoplophora malasiaca about all of the roses in our garden.  (But we often forget it!)