Bug Control (Aphids)
With the recent arrival of British summertime which ‘typically’ heralded the start of a pretty gloomy period of weather (well, it is only April), gardening attention is unlikely to be focusing on garden pests. But it’s worth giving some thought at this time of year to pests that you’re likely to experience in the summer. One of the worst are Aphids and how to deal with the ‘little suckers’ when they arrive and the consequences if you choose a chemical approach.
In my Essex garden I’ve banned all forms of chemical weapons, so at all cost I avoid reaching for the “gun” (‘bug gun’ that is) and look for alternatives and there are quite a few ways you can deal with Aphids.
Before I launch into some organic methods, I think a word on why I hate using pesticides might be useful.
One pesticide that comes to mind and is aptly named is “Bug Gun Ultra”. Although there are many that claim to do the same thing this is quite a big brand and is a typical ‘contact and systemic’ insecticide. You simply and conveniently spray it onto the plants at the first sign of Aphid infestation. The chemical kills on contact but is also absorbed by the plant, so as new Aphids feed, usually by sucking the sap from plants, they ingest the insecticide resulting in their death.
The insecticide, derived from a synthetic organic compound, contains acetamiprid, which is one of several Neonicotinoids. In the same way nicotine is addictive to humans, acetamiprid targets the nerve receptors in the brain, spinal cords, ganglia and muscle junctions in the insect resulting, initially, in ‘excitement’, followed by paralysis and finally death (I’ve often wondered what an excited aphid looks like?). It is deemed safe to humans, as the nerve receptors apparently react differently in vertebrates…
The advantages (if you can call it that) of this type of control is that vegetables can be harvested just ‘14 days’ after its use and is doesn’t damage the plant itself, although it should be tested on a small sample of young plants first. Where vegetables are concerned, Personally, I just can’t get past the fact that you’re spraying a chemical on something you’re going to eat!.. ?
The other big disadvantage of using this type of insecticide is that it’s a bit of a ‘scorched earth’ policy and will kill garden friendly insects such as Lacewings and Ladybirds as well as Aphids. So, for me it’s a non-starter. I’d actually rather see the plant go to waste than risk killing all the other invertebrates.
Cultural option
In contrast to the advantages of using an insecticide, the most obvious control is to provide an environment which attracts the Aphids natural predators. This is not just fashionable it actually works but needs planning and a bit of patience. Planting mint, fennel and achillea will help attract the garden friendly insects and Aphid predators, as will providing over wintering sites for these insects, (bug hotels etc.).
One of the problems with aphids is that they have a natural defender too in the form of ants, which harvest the honeydew produced by the aphids, so it’s important to limit the ants’ access to the infestation to allow the predators to do their work. This can be done if you’re able to coat the base of the stem in a sticky substance which ants cannot pass. I’ve never tried this but apparently Neem Oil is supposed to work well, although this is likely to discourage beneficial predators too. Ultimately my experience of ants is that they are ingenious insects and always find other ways to get to the aphids. Probably best to try and deter the aphids in the first place.
More recently (although the method has been around for years), I’ve started growing companion plants to repel aphids and other pests. This I can testify, works really well. Last year I grew large amounts of Basil spaced in between my Tomatoes and, ‘as if by magic’, my tomato crop was untouched by Aphids. I also grew Nasturtiums as a sacrificial plant and planted them next to my Runner beans and these too avoided being attacked by aphids. (The Nasturtiums didn’t look too good, but I wasn’t planning to eat the Nasturtiums, even though they’re great in salads) So I’m a bit of a convert to companion planting.
Onions, garlic, and mint will also help deter pests due to the aromatic scent given off by the plant, as will Nepeta, although if you’re not a cat lover the latter may introduce other pests in the form of neighbouring cats. The good thing (certainly in my neighbourhood) is that cats aren’t too fond of vegetables.
A whole list of companion plants can be found on Thompson & Morgan’s website and many other sources. So, if companion planting to deter pests is your main plan of attack you need to start sowing seeds now!