Question Corner
Q. A.
with Richard Fenwick
Why is soft plant material more prone to aphid damage? Soft plant material is formed either when a plant is under stress; e.g. poor light levels and/or when high levels of nitrogen a present in the compost e.g. over feeding. The cuticle is reduced and this allows a sap sucking insect like an aphid to easily feed upon the plant material.
Some background information.
Aphids have been in ecosystem for 280 Million Years, there are 500+ aphid species in Britain and they can be found in many colours including; green, black, white, pink, yellow or mottled. Also included in this group are; Woolly beech aphid & woolly aphid which cover themselves with a fluffy white waxy secretion, this is mainly used for protection. Size is approx 1-7mm long and they feed on many [if not all] ornamental plants, fruits, vegetables glasshouse plants & houseplants. Some aphids also have the ability to transmit viruses; this is a particular problem on strawberries, raspberries, tomatoes, cucumbers, dahlias, tulips and sweet peas. Aphids are very inefficient feeders losing +80% of there intake this they excrete as a sticky substance (honeydew) on the foliage. This encourages the growth of sooty moulds reducing photosynthesis and weakening the plant further.
Control
Daily monitoring the main key for controlling pests including aphids. Using the yellow sticky cards can be an advantage; because you can use these for monitoring [aphid count each day] and also for control especially in an organic system.
Garden Tripod 14 ~ page 88