GardenBanter.co.uk - View Single Post

zxcvbob · 27-05-2007, 04:39 AM posted to rec.gardens

wrote:
On May 26, 1:51 pm, zxcvbob wrote:
I have a rather extensive collection of old bottles of pesticides, but
I'm out of Kelthane. :-( Also, I think "Black Leaf 40" (nicotine
sulfate) is not approved for roses.

What other insecticides are *effective* against mites? Some are listed
but don't work very well because mites are not insects. How about
horticultural oil? I have a bottle of dormant oil spray that I can mix
half-strength for a summer oil spray... Will that work? Thanks.

Bob

Bob, control of mites is possible with Neem oil, insecticidal soap or
a high purity horticultural oil. If you prefer chemicals, miticides
such as abamectin (Avid) or bifenthrin (Talstar) may help. If you use
a miticide, frequent chemical applications may be necessary and not
very effective if plants are not also washed with water.

Periodically washing plants reduces numbers of mites while preserving
their predators. When hosing off the plant, make sure to rinse the
entire plant, top to bottom, as well as the undersides of the leaves
using a hard spray of water. Once spider mites are knocked off of the
plant, they can't crawl back. The watering should be done in the
morning or early evening so that the leaves can dry before nightfall.
You don't want to trade the mite problem for fungal problems!

Hope that helps...

Daniel

Thanks. I don't have any miticides. I think I'm gonna go with the
horticultural oil, alternating every few days with spraying the plants
with high pressure water. I have several insecticides that /might/ work
(diazinon, dursban, and cygon), but more likely they'd just kill any
predatory insects and ultimately make the mite problem worse.

Once the roses are healthy and growing good, the mites will lose
interest in them. But the roses are just now coming up and some are
still stressed-out from last winter.

Bob