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

Aphids

Some weekends start off perfectly - the slow and steady rise from sleep to wakefulness, the smell and taste of a fresh brewed coffee and the deliciousness of a cooked breakfast.  Finally as the sun starts to warm up the garden you get motivated to go outside and enjoy the day by being productive outside.

 You take a slow stroll around the garden creating a mental checklist of what needs to be done when you stop short.  What on earth has happened to my beautiful plants?  They were fine yesterday (or whatever day I was last out here!) Now suddenly they are in dire need of a little TLC. The perfect weekend is slowly spiralling downhill.

Even through the cold months insects and disease can play havoc in our gardens.  An easy way to keep insects and disease at bay is to keep our plants healthy.  Fertilising with a complete organic slow release fertiliser every three months or at the change of season is a great way of helping our plants stay strong and able to fight off disease and insects.  Sometimes though even the best laid plans go astray and plants unfortunately will get disease and insects, it even happens to the best of us green thumbs!

At the moment I am finding that aphids are having a feast in my garden.  With the warm days many of my plants have tender, yummy, new shoots appearing, just what aphids love.  There are many different species of Aphids; they are all small sap sucking insects that vary in colour from green to yellow and black. Aphids don’t just suck the life from your plants they also transmit virus diseases such as broad bean wilt. Natural predators are lady birds but if you don’t have enough of these you may need to spray with the chemical Imidacloprid.  The brand I use is Conguard by Searles.  

Azaleas will also benefit from a spray of Imidacloprid (Conguard) at this time of year.  If your azalea leaves have lost their colour and lustre (may look sandblasted) and have black spots on the underside of their leaves – you have Lace Bug. Severe infestations of lace bug can lead to reduced plant vigour and loss of leaves. You may need to spray a few times to control your infestation and unfortunately once the leaves have that sand blasted look they will stay that way.  A good trim and fertilise though will help promote nice new healthy growth to cover the unsightly affected growth.  If you don’t like spraying with chemicals a new range of azaleas have been released that are lace bug resistant. This is called the Encore Range.  My favourite is Autumn Twist.  It is mauve with a dark purple stripe thru the flower.

The Imidacloprid based sprays work on a Systemic action – absorbed through the foliage and moves throughout the plant to control insects.  They are safe to use on most plant types and you need very low concentrations to be effective.  The most important thing I find is that Imidacloprid based sprays are low toxic to beneficial insects such as ladybirds and bees.

Start and end your weekend perfectly by giving not only your garden but the birds and the bees some TLC.