Siphoninus phillyreae, or the Ash Whitefly, is a polyphagous species, meaning they can survive and breed successfully using a variety of food plants from different families. The plants most frequently affected are Hawthorns, Ashes, Apple, Olive, Apple and Pear. Read on to learn more about the symptoms of a whitefly infestation, as well as tips to resolve them.
Whiteflies are a nuisance pests and a common problem in gardens, greenhouses and agriculture in general.
Whiteflies possess many natural enemies to help us keep them under control!
Adults: The adults look a lot like tiny moths when they fly. They have pale yellow bodies and pure white wings. They form in aggregations beneath the host plant foliage. Nymphs: The nymphs are disc-shaped, and look a lot like scale. They are whiteish-yellow, with a scalloped outline. With older nymphs, it's possible to see a rectangular black region in the centre of the body. Eggs: Whitefly eggs are pale yellow, sometimes covered with white wax.
Together with aphids, whiteflies can transmit viral diseases to plants. Their feeding causes stunted growth, as well as curling leaves. Honeydew may be found on the upper surfaces of leaves. Honeydew can result in secondary infections in the form of black mould. Ants are attracted to Honeydew and can sometimes make an infestation worse. Whitefly eggs are typically laid in circles, beneath the leaves. Ash Whitefly is most frequently found on the leaves of the host plant. Leaf yellowing. Smaller trees may experience stunted growth.
Whitefly infestations tend to be more problematic indoors, for example, in a glasshouse setting. Planting rhubarb in greenhouses is thought to deter whitefly. Whitefly eggs can be found underneath the leaves of plants, so these areas should be inspected regularly. Remove Whitefly eggs with a cloth and soapy water or rubbing alcohol. Any spacing between plants should be kept clear of weeds and debris. The use of netting can sometimes improve protection with garden plants. For lighter infestations, plants can be gently hosed down to remove whitefly and eggs. Ant traps placed near affected plants will aid controlling any secondary infestations. Whiteflies are drawn to the colour yellow. You can use yellow cards or sticky traps to attract whitefly and monitor the infestation level. Homemade garlic or chilli-based insecticide, diluted with water is thought to be an effective repellent against pest insects. Insecticidal soaps, neem and other horticultural oils can give some control over whitefly, and it's less harmful to the environment when compared with pesticides. Bottle labels should be read carefully. Oils can react badly with high temperatures and burn the surfaces of plants. Beneficial garden creatures such as beetles, wasps, lacewings and spiders will eat whiteflies. These can be attracted into the garden using a few simple tricks, such as incorporating insect hotels or by letting parts of the garden grow a little wild.
There's an array of contact insecticides available for use on the market that is more environmentally friendly (e.g. Natural pyrethrum/pyrethrins and insecticidal soaps). More persistent products include synthetic insecticides with a contact mode of action (e.g. cypermethrin, phenothrin, lambda-cyhalothrin and deltamethrin). These can still be toxic to some wildlife and a pollutant to water bodies, so please take care to research products and read instructions carefully before using them. Whitefly can reproduce at significant rates, so for this reason, it's quite often they build a tolerance to pesticides. We suggest trying to remove them some of the ‘Biological Treatments’ before attempting chemical treatments.
Some of the popular genera that this insect will infest.