Velvet tree pear trials over 2.75 yrs – Peates Road, North Star NSW
Commenced 19 June, 2013. Funded by the then Border Rivers-Gwydir Catchment Management Authority (now LLS) – project managed by Les Tanner (North West Weeds). Most of the actual treatment work undertaken by Southwell Contracting P/L (0400 402 949).
The purpose of these trials is to demonstrate and promote the value of including (environmentally-safe) biological control agents (cochineal insects) in the long-term management of velvet tree pear infestations.
Cochineal insects are already present throughout most tree pear areas in NSW and Qld. The insects continue to be effective at wiping out small plants (especially seedlings), but have minimal impact on large, healthy plants – unless the plants can be knocked over!
These trials were approached from four angles:
- Plots 1,3 and 5 – no herbicide – all plants taller than 60 cm were cut down – ceasing the plants’ nutrient intake from the ground and more importantly, providing a sheltered environment for proliferation of the cochineal insects.
- Plots 2,4 and 7 – low rates herbicide/water foliar spray to “cripple” the larger plants and make them more susceptible to the effects of cochineal insects already present (albeit in low numbers).
- Plots 6 and 8/9 – basal bark with Garlon/water and herbicide/diesel mix respectively to cause plants to collapse – plants affected and dehydrated from herbicide and cochineal
- There were hundreds of young seedling plants growing throughout this tree-line area. All plants less than 60 cm in height were left to the cochineal insects.
1. No herbicide – plants cut down with chainsaws and brushcutters as a start to the biocontrol program. Cochineal numbers were low on some of the large plants so “a couple of bags” of cochineal from another site were added (see Plant 1B below – bag used to deliver the cochineal, left there to cover and help create a protected “nursery” for the introduced insects). Over time, most plants in the trials were devastated by the cochineal (one notable exception, 3A, right next to the road – bugger!).
There are four (4) good examples here (view L to R):
2. Below – Low rates herbicide/water foliar spray to “cripple” the larger plants and make them more susceptible to the effects of cochineal insects. Two (2) good examples here, Plot D was 500 mL Kenzon (equivalent to Grazon DS) + 500 mL Uptake Oil per 100 L water (about $0.10 L), Plot 4 was 2.5 L Amitrole T + wetter in 100 L water ($0.30 L):
3. Plot 9 – basal bark with Garlon 600 – mix 800 mL in 60 L diesel – approx. $1.62 L (but only small quantity req’d per plant – with just the bottom 60-90cm circumference of each plant to be treated – one full knapsack spray goes a long way). This treatment rots the base and causes the plant to collapse – another, safer way to down the plants and therefore assist the build-up of cochineal insects. And, if no cochineal or it doesn’t do the job quickly enough, then at least the pear is on the ground and easy to re-spray later if necessary!
This method of controlling velvet tree pear, especially in thick timber/scrub situations, has a lot of potential. Three (3) good examples here:
Also on this website: main velvet tree pear page and new page covering some of the results of herbicide treat of velvet tree pear on the property “Baree” – both in the North Star area.
|Did you know? The cochineal (Dactylopious opuntiae) found on velvet tree pear is the same one that works on common prickly pear. Very convenient, because we often find these two plants growing side-by-side. But, this cochineal is NOT effective on rope pear or tiger pear – they each require totally different cochineal species!|
IMPORTANT: USE OF PESTICIDES – ALWAYS READ THE LABEL
Pesticides must only be used for the purpose for which they are registered and must not be used in any other situation or in any manner contrary to the directions on the label. Never use a herbicide in any way contrary to the label recommendations.
DISCLAIMER: The information contained in this web site is based on knowledge and understanding at the time of writing. However, because of advances in knowledge, users are reminded of the need to ensure that information upon which they rely is up to date and to check currency of the information with the appropriate officer of North West Weeds or the user’s independent adviser. Les Tanner 23/03/2016