Wet summer brings on coleus-like weed
The heavy rains this season have resulted in a greater-than-usual outbreak of an alien weed that is part of the mint family, and related to the colourfullyleaved coleus plants one often has in one ' s garden and home. It is Plectranthus comosus, commonly known
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during autumn and winter Harlequin ladybirds typically gather in large numbers around urban developments. When disturbed, adults exude a fluid with an unpleasant smell that can also stain fabrics. If you encounter a site with high abundance of Harlequin ladybirds( eg, more than 20 beetles) or a large aggregation such as those typically found as Abyssinian coleus, or woolly plectranthus. There are about 350 members of the Mint family( Lamiaceae), occurring worldwide ranging throughout Africa, India, Australia and even Japan. Of the 53 species in South Africa and Namibia it is those
around households in window frames and doors, you can contribute to the project by collecting ten to 30 ladybirds per site. All that is needed is that you place these ladybirds in a small, clean container or ziplock bag, note the date and site of collection, and freeze them in your home freezer. Once you have collected them, you can email researcher Dr Minette Karsten at minettek @ sun. ac. za and from the Eastern Cape and KZN that are most suitable as garden subjects. Plectranthus is not only very easy to grow, the plants also tolerate a wide range of conditions, from full shade through to full sun and from damp to dry. Unfortunately Plectranthus comosus, from North Africa-
LADYBIRD
she will contact you with information on how to send your sample. The specimens that you collect will be highly valuable to answer key questions of the invasion biology and will be used in a genetic study to uncover the origins, route of invasion and spread of the Harlequin ladybird in South Africa.
* Traditional English nursery
ALIENS
hence its common name Abyssinian coleus- has become a problem in some areas of South Africa, and is particularly evident this year in Gauteng. Woolly Plectranthus is a Category 3 weed. It grows without any effort, is hardy and can make an eyecatching display when in flower, all of which contributes to making it a lowmaintenance favourite with gardeners. To its discredit is the fact that it readily outcompetes indigenous plants and is therefore detrimental to natural vegetation. Woolly plectranthus is a robust erect shrub up to 3m tall with a woody base. The stems and leaves are densely woolly. Leaves are large, sometimes more than 100mm
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