Does anyone know how to deal with snowball aphid infestation?

[ErrolTheDragon]

My snowball bush (viburnum sp) has quite a lot of leaves distorted/black gunked) by what looks to be its own particular pest, the snowball aphid.

Is there anything I can usefully do at this point - is it worth pruning off affected branches/twigs (most have few if any flowers)? Any other treatment... it's too big to spray.

Thanks!

Hopeful bump...

when you say too big to spray, how much above 20ft tall is it?

and how near your house?

Its at the bottom of the garden...maybe 10-12 ft tall but I'm only 5'1" and it wouldn't be a good place to use a ladder so I don't see how spraying could be done at the moment.

Thinking of cutting out the crappy bits now, then giving it a really hard prune after flowering ... not sure what to do thereafter to try to avoid re-infestation next year,

this sort of sprayer will squirt a 20ft tree, if you turn the nozzle to "jet" and hold it above your head pointing upwards, so will easily do a 12-footer without needing a ladder. The jet will break up into droplets towards the top of the parabola, and will fall down into the tree. It helps to do it on a still day, or if there is a slight breeze, stand to the windward side. I prefer to wear a rain-proof coat with a hood. You can tinker with the nozzle so that it has as fine a spray as you can get while still reaching the top (practice with plain water).

You will have to mix up a fair amount, but if the overspray falls on nearby roses or other flowering plants it will not matter. If it is going to fall on fruit and veg you would need a safe-to-eat spray.

Oh right ... my old walking coat - goretex and full hood - is now my gardening coat and I sometimes even wear old overtrousers too just to keep the mud off! . I very rarely spray with anything other than a strong blast of water and the occasional small-scale aerosol can type thing so I'm ignorant of large-scale spraying! There's nothing edible nearby, what would you use please?

I just use a systemic greenfly chemical, whatever's cheap. I look at the big-name brands on the shelf to see what chemical they contain, then look at the own-brands and choose one which has the same. A systemic should last a few weeks, and maybe you will be past peak infestation time by the time is wears off. Systemics kill insects that suck the sap, so, once dry, are not very dangerous to beneficial insects. Morning and evening there are not many bees about.

I usually get a bottle to mix up with water, not powders. Wilkinsons and Dyas usually have a good range of garden chemicals. Killers for example

The small readimix sprayers work out very expensive.

www.wilko.com/grow-your-own/insecticides+pest-control/icat/insecticide-pest-control?sort=name&parentCategoryRef=insecticide-pest-control&order=ascend&q=*&pdxttype=Bug Killers

you might have to copy and paste. The word "killers" is needed.

www.wilko.com/grow-your-own/insecticides+pest-control/icat/insecticide-pest-control and click on bug killers

p.s.

if your neighbours have fishponds, most insecticides will be harmful to the fish. Some people use washing-up-liquid in water but I don't believe it can do more than wash off a few of the adults which happen to be standing on top of leaves.

Thanks Piglet! I knew you were our resident DIY expert, didn't know you were a gardening guru too.

No, I can't imagine detergent dealing with these beasties either. That's ok for small-scale wash-and-wipe, this is on a different scale.

I don't think its wise to spray with insecticide, as you can imagine they kill other (beneficial) insects too such as bees/wasps.
You can use just plain water from a hose to spray off aphids or just leave them.

I particularly suggested a systemic rather than a contact insecticide.

Spraying tall trees with insecticides is not viable, this came from the RHS website.

"During the growing season there are many insecticides that can be used. It is only feasible to control aphids on plants that are small enough to be sprayed thoroughly. Aphid infestations on tall trees have to be tolerated. Always read the label use pesticides safely."

Its better to encourage natural predators or use water to spray them off.

Out of interest piglet which insecticides do you use which are not harmful to other insects? Am not convinced on that score.

ErrolTheDragon Wed 07-May-14 12:10:40
"...maybe 10-12 ft tall"

easily within the reach of a 5l sprayer

I use a systemic aphid spray for greenfly. I occasionally use a wide spectrum spray for thrip, capsid and whitefly on some ornamentals, and I use Roseclear on roses.

Bees in particular are inactive early mornings and late evenings. Sometimes I kill lacewings and laybirds unwillingly if I need a broad spectrum spray.

I am not fundamentally opposed to chemicals.