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The white dust |
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Mealy bug is one of the hardest pests to control. Its body is covered
with white waxy threads, which often make a chemical pest control little
successful.
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Biology |
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Several species of mealy bugs are known to appear in greenhouses.
The most important ones are the citrus mealy bug (Planococcus
citri) and some Pseudococcus-species. The citrus mealy
bug can be found sporadically in cucumber, melon and aubergine. In
tomato
Pseudococcus affinis has become more and more widespread.
The bugs are covered with a white waxy secretion. A female can
lay 300 to 500 eggs in a cotton-like pouch made of wax threads.
After laying eggs, which takes 5-10 days, the female mealy bug dies.
The young bugs, which are most mobile, disperse to find suitable
feeding sites and then begin to feed on plant sap. There are 3
nymphal stages in the mealy bug's lifecycle. The length of the
lifecycle depends on temperature and takes 90 days at 18°C and 30
days at 30°C. |
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Damage |
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Mealy bugs cause nearly the same damage as aphids. Like
aphids, they suck plant sap and secrete honey dew, on which fungi can
easily grow. This dirtiness gives ornamental plants a loss of quality.
Viruses, however, are less transmitted by mealy bugs than by aphids.
Apart from yellowing, defoliation, and cosmetic damage, mealy bugs also
reduce the vigour of the plant.
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Beneficials |
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Responsibility and
copyright | |
