March 29th, 2004
War of the Roses
For the last two years, after I acquired a dozen or so heirloom roses, I’ve spent the thirteenth week of the year battling a little green inchworm–spring cankerworm. As the cedar elm and oak trees leaf out, it floats down on a silken thread until it finds the tenderest new leaves, mostly those on the roses or the flower buds of the lilies. It exudes a sticky web and curls the leaves around it, munching away happily. In stage 2, it acts rather like a hornworm, munching leaves along a branch, denuding it.
This year, I was looking for them and I’ve caught them in stage 1. As soon as I notice. leaves balling up, I began spraying. Last year I sprayed with insecticidal soap. But since I have to repeat the process every day for 7 to 10 days until the cycle is over, this year I’ve use diluted apple cider vinegar instead. Vinegar smells less toxic to me, but is like an acid bath for the soft inchworms.
The three hybrid musk roses, ‘Buff Beauty’, ‘Penelope’, and ‘Prosperity’ have suffered the most so far. Their leaves are not glossy and the buds form down in the new growth and so are quickly bitten off. ‘Blush Noisette’ and ‘Madame Joseph Schwartz’ (pictured) have bunches of buds which shoot out away from the new leaves, and so are initially less vulnerable. Although, as you can see, once these loopers get big they go anywhere for a bite.
‘Souvenir de la Malmaison’ which was so ravaged last year, bloomed early this year and is holding her own.
Zanthan Gardens History
2005-03-24. First spring cankerworm spotted.
2006-03-14. First spring cankerworm spotted. Are they earlier this year, or am I more vigilant?
by M Sinclair Stevens