Those Canna Leafrollers
Joe Shaw (Fri, 28 Jul 2006 11:26:23 PDT)
Hi Gang,
I suppose that familiarity can breed contempt; for a long time I didn't
bother growing cannas because they were such "ordinary" plants from my
childhood. However, I've come to learn they are really nice in certain
places and used in certain ways.
I've had good luck with the one called 'Praetoria' (or 'Bengal Tiger' and
maybe some other names) by growing in a large pot (about 16 inches across)
that is lined with 3 layers of 4 mil insulation plastic. I filled the pot
with soil and put the plant in and it thinks it is in a wonderful bog.
But then there are the leafrollers; I know of 2 types, lesser and larger.
Perhaps there is an in between size too. After trying Bacillus
thuringiensis, and encouraging birds to feed on the things, I tried
imidacloprid. It works wonders and seems to last for about 3 months.
Maybe the product would last longer in a climate with less rain or heat. I
put about 1 cup (per large clump) of the Bayer Advanced lawn granules on the
soil around plants in spring, summer, and fall. There are no more problems.
Do others out there use imidacloprid? I sometimes hesitate to use anything
on some plants if I think they will grow out of a problem, or if I don't
mind the problem. But, those leafrollers can quickly turn a canna clump
into a sodden, disgusting mess of rot, worm debris, and (or course) worms.
By the way, I always check any pesticide at EXTOXNET for toxicity profiles,
including danger to groundwater, etc. I encourage all to do the same.
EXTOXNET is a great source of information; after you read up you can make
informed decisions.
LINK: Larger Canna Leafroller
http://edis.at.ufl.edu/pdffiles/IN/IN28900.pdf
LINK: Lesser Canna Leafroller
http://ipm.ncsu.edu/AG136/cater12.html
LINK: EXTOXNET
Cordially,
Joe
Hot today in Conroe, some Amarcrinum still blooming and wonderfully
fragrant. I don't know their background; they are unnamed plants I've
picked up here and there. I love 'em even though they are not as grand as
Crinum.