Bugweed - Solanum mauritianum

This invasive alien species is present in the Mount Moreland Conservation area

Solanum mauritianum commonly known as Bugweed is a small tree or  shrub belonging to the potato and tomato family Solanaceae which is native to Northern Argentina, Southern Brazil Paraguay and Uruguay. It has become a widespread invasive weed in many countries including South Africa.

Bugweed - Solanum mauritianum

 

The plant has a life of up to thirty years, and can grow up to 10 m tall. Its large greyish oval leaves are covered with felt like hairs. The flower is purple with a yellow centre. It is tolerant of many soil types and quickly becomes established around plantations, forest margins, scrub and open land. Solanum mauritianum can form dense stands that inhibit the growth of other species through overcrowding and shading. 

 

All parts of the Solanum mauritianum plant are poisonous to humans, especially the berries, handling the plants can cause irritation and nausea. The dust from the plant can cause respiratory problems. 

 

In our area birds in particular the Speckled Mousebird (Colius striatus) eat the fruit and spread the seed far and wide 

  

Solanum mauritianum is a category 1 invasive plant 

 

Control 

The best form of invasive species management is prevention. If prevention is no longer possible, it is best to treat the weed infestations when they are small to prevent them from establishing, controlling the weed before it seeds will reduce future problems. 

Small plants may be hand-pulled but mature plants will re-sprout if they are cut down. Solanum mauritianum is easily killed with herbicides applied as foliar, basal bark (painting herbicide onto the bark at the base of the trunk) or cut stump applications. When using any herbicide always read the label first and carefully follow all instructions and safety requirements. If in doubt consult an expert. 

 

Manual control

Cutting down, or removing seedlings by hand. The stumps of trees that have been cut down must be treated with an application of herbicide otherwise they will rapidly re-sprout.

 

Chemical control

Solanum mauritianum is easily killed with herbicides so very low dose rates, Glyphosate and triclopyr are registered in South Africa for foliar, basal stem or cut stump applications. A 0.5-1% solution of either glyphosate or triclopyr mixed with water has given me good results. 

 

Michael Hickman 

19.04.12