Description, Biology, Life Cycle, Damage, Common Names, Images
This highly polyphagous species is capable of living on 249 genera of plants. It attacks mainly vegetables, especially the tomato, aubergine (*) and Cucurbitaceae, but also ornamental plants, with a prediliction for Asteraceae.
In cold climates, this whitefly is found only in glasshouses, while further south, it is found in the open, on both wild and cultivated plants.
- Adults congregate on younger shoots at the tips of plants; they take flight rapidly if disturbed.
- The female may lay more than 500 eggs during her life which lasts 3 to 6 weeks. Eggs are laid in a circle on smooth leaves (*) ; on hairy leaves, they are more dispersed and less regularly situated.
Shortly after laying, the eggs darken in colour; they hatch about 9 days later at 21°C.
- Newly emerged nymphs are mobile for a short period before settling to feed, their stylets inserted in leaf tissue, passing through three instars. They then cease feeding, moult and remain in a pupa for about 18 days.
- Reproduction is essentially parthenogenetic.
- Overwintering occurs at all instars. In northern climates, this whitefly usually lives in glasshouses on wild plants, or in summer on adjacent plants outside. Further south, adults may also overwinter on wild plants growing outdoors if the climatic conditions are not too severe.
- Reproduction occurs throughout the year when conditions are favourable, with several generations overlapping.
Under optimum conditions at 21-24°C, a cycle is completed within a little less than three weeks.
This whitefly is responsible for very severe damage: sucking of sap, production of honeydew and the consequent formation of sooty moulds. Up to 2,000 nymphs may be found on a single bean leaf, each being capable of producing 20 drops of honeydew in an hour.
Affected tomatoes cannot be sold (*) .
The species may also transmit viruses.
- This species, originating from Central America, is essentially tropical and subtropical. Introduced accidentally into western Europe, it now constitutes a major pest in glasshouses.
- A certain resistence to synthetic insecticides has been observed, particularly amongst parthenogenetic strains.
- Populations of this whitefly are controlled by the action of entomophagous species: fungi, ladybirds, Neuropterae, chalcid Hymenoptera.
Among the latter, the endoparasite Encarsia formosa Gahan (*) is a commercially available biological control agent.
HYPPZ on line : Species (scientific name), Pests (common names), Glossary, Crops.