Sapping the Life from your Trees

To me every plant has its place. Just because I think its place is in the bin doesn’t necessarily mean you should feel the same. Every garden should be as diverse as its owner.  Take pride in expressing your individuality in your garden.  Just because Jamie Durie likes it doesn’t mean you have to.

 Some plants though do not deserve anyone’s TLC.  These plants make up Australia’s Most Wanted Weed List or Weeds of National Significance.  Lantana would have to be number one.  This plant has successfully taken over nearly every rainforest and bushland along the east coast of Australia as well as some areas in West Australia and Northern Territory.  As a way to help combat this evasive weed a Bio-control called Aconophora compressa (Lantana Treehopper) was introduced in 1995 throughout Queensland and New South Wales.

 Bio-control is importing a natural enemy to combat pests. It has been very successful in controlling a range of introduced plants that are pests to agriculture, the environment, and human health. Bio-control methods also help reduce the need for pesticide use. The decision to use a Bio-control is not gone into lightly. The lantana treehopper was screened as a bio-control agent from 1990 to 1994 and its release was unanimously supported by 22 state and federal agencies.

 The Lantana Treehopper camouflages itself very well against the bark of the tree. The insects are brown in colour and can grow up to 8mm long.  It has a horned body so it makes the plant look like it has thorns.  It sucks the sap out of the host plant and exudes large amounts of honeydew, a sugary solution in which black sooty moulds can grow. The treehopper can cause die back, stunted growth and flowering, unhealthy leaves and eventually death of the plant.

 Unfortunately this bio-control hopped onto some of our ornamental shrubs and trees.  This is ok though as this bio-control can be controlled through spraying with an insecticide and trimming or removal of affected plants. The two most viscously attacked plants are fiddlewoods and duranta but it has been seen on other ornamentals as well such as Jacarandas and Pandoreas.

 Fiddlewood a West Indian native is now considered an undesirable introduced tree as their roots are very invasive.  The Department of Primary Industry (DPI) recommends removing the affected fiddlewood and replacing it with a desirable native tree. Duranta – Sheenas Gold or Geshia Girl are so extremely fast growing and resilient that a severe trim, a fertilise with Organic Link (a good quality organic slow release fertiliser) and a follow up spray is all that is necessary. 

 If spraying is necessary the chemical Imidacloprid (Searles' ConGuard) is recommended by the DPI.  I have found Pyremuythum based sprays are also effective.

 This weekend give your life some TLC by getting dirty and making sure you have no nasty critters hiding in amongst your flowers.

 Department of Primary Industry Information Guide