On 16/04/17 15:34, Bob Hobden wrote:
On 16 Apr 2017 10:22, (Nick Maclaren) wrote:
In article ,
Bertie Doe wrote:
A 5 year old bougainvillea is suffering rapid leaf loss. Close
inspection
shows aphids to be the villains. It's planted in the soil of the
allotment
greenhouse.
Main concern is preventing the aphids migrating to the newly sprouted
seedlings, in trays of compost, nearby. I need to spend some time
today with
soapy water and brush them off.
Q. Can anyone suggest a spray deterrent, to prevent future attacks?
I've
tried various insecticides in the past (can't remember their names)
with no
luck. TIA.
Bluntly, no. I use horticultural soap, which has the advantage that
you can spray until they drip, as often as you need, but you can
also use dilute washing-up liquid with a squirt of meths in it.
That doesn't stop anything invading, but works well on aphids, if
the plants are small enough to spray completely.
Whilst we are on about sprays, what do you all use against Scale
insect? Somehow they seem to have invaded a number of our house plants,
(lots of different orchids and and anthurium). They are also a pest on
our citrus trees but that is "normal".
I've given up growing a clementine as it seems to suffer all sorts of
things. Our plant ended up almost completely black with sooty mould, and
although it flowered, just didn't carry fruits to maturity. There are no
satisfactory systemic insecticides against scale insect (such as
dimethoate) left for the amateur, and on anything other than a small
plant it is just not feasible to remove the scale by hand.
One possibly satisfactory answer is total abscission. Once the scale's
substrate has gone, then there shouldn't be any reinfection /from the
same plant/. Of course, if you have widespread scale, there is no
satisfactory answer, but you could try biological control:
http://ladybirdplantcare.co.uk/scale.html
--
Jeff