23 Jan Whitefly
Description: Whitefly can cause great damage in the vegetable garden, but are also a pest of some ornamental species. The adults are white with a wingspan of around 3mm and cluster on the underside of leaves where they suck on the plants sap system, as well as lay their eggs. When disturbed they will quickly take flight in a cloud of tiny insects, then resettle back onto the shelter of the plant.
Damage Caused: Whitefly suck on the plants sap system that weakens the plant considerably and gives leaves a mottled yellow appearance. Piercing and sucking insects can also be credited with the spread of plant viruses. They also produce honeydew, a food source for sooty mould a fungus that can blanket the leaves in a back, sooty film. Removal of the pest will remove the source of the honeydew and thus diminish the fungus.
Green: Horticultural soaps (eg. Natrasoap) and oils (eg. Eco-Oil) sprays are useful for both vegetable and ornamental gardeners. Soap sprays work by dissolving the exoskeleton of the pest killing it. Oils sprays work by smothering the pests, blocking their breathing (which they do through their body) and killing them. Application to the entire plant (including undersides of leaves is crucial when using these types of products, as they require you to get the spray onto each pest present for successful control.
NB Do not apply oil sprays in temperatures exceeding 25°C as this will likely burn foliage.
Yellow sticky traps work well in limiting pest numbers and as an identification tool to let you know when to start spraying with botanical oils, horticultural soaps.
Orange: Only ornamentals should be treated with systemic insecticides (eg. Confidor, Maxguard), which penetrate into the plants sap system that the pests feed on. They are highly efficient at killing these pests and last on average two weeks in the plants system. As they are systemic the spray does not have to make contact with the pest itself to work and insects can be killed in areas of the plant not reached by the spray (though thorough application is recommended)
NB Care should be taken when spraying these above chemicals is they harm foraging bees. As a rule I only use these on plants that are not currently in flower to avoid the risk to bees that are so vital in the garden.
Red: Not required for this pest.