The never ending problem of dealing with greenfly and whitefly on the Botanics collection of plants under glass is now being tackled with biological control. Wasps that parasitise these troublesome pests are being released to deal with the problem the natural way. The advantage of this approach is that it is much safer for both the public and staff as no potentially harmful chemicals are used. Instead, two species of tiny parasitic wasps fly around looking for their favourite hosts. When the wasps find what they are looking for an egg is laid and the greenfly or whitefly is destined to have a very short life from them onwards. The species being used are Encarsia formosa and Aphidius ervi. The eggs of the parasitic wasps are either placed on damp tissue in a plant pot or hung on plants attached to small squares of cardboard.
Next time your in the glasshouses keep your eyes peeled. You won’t see the wasps, but may see the evidence that their eggs have been introduced.