Airdrie & Coatbridge Advertiser
The aphids are coming... so get ready to fight for your plants
Late June is a wonderful time of the gardening year – my home plot is full of flowers and lush green growth. However, among the spectacular displays, there’s still work to be done.
Inspecting my borders the other evening I came across foliage which was twisted, blistered and deformed. I turned over a couple of affected leaves and found the culprits – an extended family of aphids had moved in.
Aphids come in a number of shades. There is the classic greenfly, there are creamyyellow coloured aphids, pink ones (which are quite pretty to look at), black ones, even woolly ones, to name but a few.
They all reproduce prolifically and if you neglect to notice the beginnings of a colony they may have produced a number of generations before you spot the damage. Plants commonly affected by them generally have a lot of soft green growth.
At this time of the year aphids will be emerging and multiplying in huge numbers on lime trees. Aphids exude a sugary, sap-like excretion which will make the ground sticky and discoloured underneath. If there are plants underneath they tend to get a sooty mould growing on the honeydew.
But many other plants can also be affected. Recently I noticed a Choisya ternata had blackening leaves which appeared to be dying.
Choisyas are normally robust shrubs but this was covered in a sooty mould and the honeydew was coming from aphids on an overhanging lime tree.
Aphids not only distort and stunt young growth and cause secondary problems such as sooty mould – they can also be a disease carrier as they move from one plant to another. Because they are sap-sucking insects they can carry viruses or bacteria to the next plant.
It is very tempting to pop into a garden centre or hardware shop, buy a chemical insecticide and spray them into oblivion. But insecticides should really be avoided as they will often kill other beneficial insects, including those which eat aphids.
If you wish to spray aphids, just use a liquid made up of soft soap and warm water. It will clog their spiracles (through which they breathe) and kill them.
You will need to wash the soapy residue off the plants afterwards.
An alternative is to buy a biological control, such as ladybirds or lacewings, and release them into your garden.
Their larvae are voracious eaters of aphids. This doesn’t mean you should watch and wait while your plants are destroyed either. Get a hose out and spray the aphids off the plant. Many of them won’t survive the blasting and those that do will hopefully be eaten.
If there aren’t so many, you can pick or rub them off the leaves with your fingers.
I had a blackcurrant bush years ago which was badly affected. I picked the worst leaves off the plant and destroyed them and sprayed the remaining leaves with the hose whenever I was out watering. The leaves improved hugely.
With any pest or disease problem, vigilance is very important – especially with aphids.
You can also place sacrificial plants in the garden near your precious ones to lure aphids away. For example, grow Calendula officinalis (pot marigolds) under apple trees and plums as they will draw away any blackfly.
Pot marigolds serve a dual purpose as they attract hoverflies, whose larvae also feed on aphids.
French marigolds ( Tagetes patula) and the poached egg plant (Limnanthes douglasii) also attract hoverflies and make great companion plants for your endangered specimens.
Another good decoy is Tropaeolum majus, commonly called nasturtiums.
Birds will also eat aphids, so it makes absolute sense to do what you can to extend a big welcome to our feathered friends!