|
Frequently Asked Questions
SERRATED TUSSOCK, CHILEAN NEEDLE GRASS, PARRAMATTA GRASS, RATS TAIL GRASSES & AFRICAN LOVEGRASS
Serrated tussock, introduced into Australia in the early 1900's, probably as a contaminant in hay imported from Argentina, was first identified as a weed in 1935. However, no control was undertaken in NSW until the 1950's by which time it had spread widely due to the destruction of pastures by rabbits. By 1975 it occupied 680,000 ha mainly in the central and southern tablelands where 32% of all properties were infested. By 1995 870,000 ha were infested with another 2,000,000 ha at risk. In Victoria 130,000 ha are infested with 4.2 million ha at risk. In total serrated tussock has the potential to infest more than 10 million ha.
Chilean needle grass is often found in the same areas as serrated tussock. It is spread by animals rather than wind and has a characteristic annular ring below the seed head. It is of little nutritional value and in areas where an infestation exists tends to be a monoculture. African lovegrass has a very wide range from Victoria through NSW into Queensland. Parramatta grass and rats tail grasses occur in northern NSW and Queensland. These weeds are of little nutritional value and cause productive pastures to run down with resultant loss of production as the pasture composition heads towards a monoculture of weeds.
Where these weeds occur in non pasture areas loss of native grasses and environmental diversity will result affecting the total ecosystem.
Q: What is the difference between TASKFORCE® and FRENOCK®?
A: None. Both herbicides contain the same active ingredient. The National Registration Authority (NRA) has approved
TASKFORCE® after rigorously examining assays of the product to ensure its purity conformed to the required standard. The product was then registered as a "mirror image" to
FRENOCK®. TASKFORCE® contains the same active ingredient, sodium flupropanate, at the maximum concentration allowed by the NRA.
Q: What is the recommended usage rate for the grasses mentioned above?
A: For spot spraying use 200mL per 100 L of water & for boom spraying use at the rate of 2.0 L per hectare except for african lovegrass where the rate is 300mL and 3 L respectively.
Q: Is a surfactant required?
A: No. The active is mainly absorbed through the root system of the serrated tussock. After a minimum of 5 mL of rain the chemical will start to be absorbed by the roots. Adding a surfactant will not improve the efficacy and may cause unwanted damage to other plant species. Chemical drying on leaves will dissolve readily when rainfall occurs and find its way to the root zone.
Q: Is this a safe chemical?
A: All chemicals need to be treated with respect and in accord with the label directions and good industry practice. That being stated sodium flupropanate
has been in use since about 1972 without adverse reports and the mammalian toxicity data indicate it is a very safe. Please feel free to ask your supplier for a MSDS.
Q: Glyphosate is cheaper than TASKFORCE®. Why use this more expensive chemical to boom spray paddocks?
A: The bottom line is that glyphosate will result in a virtual weed mono culture. The high rates needed to kill mature serrated tussocks and the other weeds will also "nuke" everything else in the paddock. The weeds will also die but due to massive seed banks a tremendous germination will occur and these seedlings will thrive without any competition. The result after 2-3 years will be a paddock where the dominant species is the weed. The carrying capacity will be negligible.
TASKFORCE® will kill selectively and many desirable native and introduced species will thrive after weed removal. Due to the chemical stability of the active, flupropanate,
TASKFORCE® will continue to kill emerging serrated tussock seedlings for up to three years and keep the paddock free of seeding serrated tussocks for up to five years. Therefore a treatment with
TASKFORCE® has a long term affect.
Q: How long does TASKFORCE® take to kill?
A: TASKFORCE® is a slow acting herbicide and can take up to 16 months to kill serrated tussock although brown out will be obvious after 3-4 months dependent on soil type, conditions etc. The other weeds brown out and die a little quicker.
Q: What is the fate of TASKFORCE® after the serrated tussock etc. has been killed?
A: The active ingredient, flupropanate, is slowly translocated from the soil into the growing plant. It inhibits a biochemical pathway which results in the brown out ( 3 months) and death ( up to 16 months) of the serrated tussock. The plant then decays and the residual flupropanate is released into the soil and together with remnant flupropanate will act upon and kill seedlings for the next 3-5 years.
Q: Does TASKFORCE® sterilise the seed?
A: No, but .... because of the residual affect the active remains in the soil for up to 5 years (dependent on rate, soil chemistry, rainfall etc.) and this residue will kill germinating seedlings. Research by Dr. Malcolm Campbell of NSWAg has demonstrated that pastures boom sprayed will be free of seeding serrated tussock for about 5 years.
Q: How long before new serrated tussock seedlings become a seed source?
A: Seedlings do not become a source of viable seed until they are 1-2 years old. At this stage they can be taken out with much lower rates of
TASKFORCE® than is necessary to treat mature serrated tussock.
Q: What's the effect of mixing TASKFORCE® and glyphosate on serrated tussock?
A: The addition of glyphosate will quicken brown out but reduce the overall kill. Research has shown that flupropanate on its own has the best kill. Small additions of glyphosate reduce the kill. For example, the addition of 1.5 L/ha of 450g/L glyphosate into mix containing the equivalent 2 L/ha
TASKFORCE® reduced the kill from 100% for flupropanate alone to 96%. The kill was determined 16 months after spraying. The more glyphosate is added to the mix the poorer the long term kill. Even smaller quantities of glyphosate such as 0.5L/ha will reduce long term kill.
Q: What is the best time to spray TASKFORCE®?
A: TASKFORCE® can be sprayed at any time. TASKFORCE® needs to be sprayed before August to stop seedhead production in serrated tussock. During summer the flupropanate is maximally affective in killing serrated tussock. Application in autumn and winter is less effective in killing the weed than application in spring and summer. In addition, subterranean clover is severely damaged by application in autumn and winter but is unharmed by application in spring.
Q: Will TASKFORCE® stop serrated tussock seedhead production if sprayed in Spring?
A: No. If it is necessary to stop serrated tussocks producing seedheads as well as kill it a mixture of
TASKFORCE® and glyphosate will be required.This mixture will not be as effective in killing serrated tussock as
TASKFORCE® alone. The reason for the poorer kill of the mixture is probably due to the slow translocation of the flupropanate ( three months to have a noticeable effect) whilst during this period the glyphosate has had severe phytotoxic effects on the plant restricting the ability of the serrated tussock to translocate flupropanate.
To reduce or stop seedhead production its recommended to spray at least 2 -4 weeks prior to seedhead emergence. 2L/ha
TASKFORCE® plus 1.0L/ha of 450g/L glyphosate sprayed 4 weeks before seedhead emergence resulted in a 91% reduction of seedhead production; spraying with the same mix 2 weeks before resulted in a 98% reduction but spraying 1 week AFTER emergence only achieved 58% reduction.
Q: Is there any advantage in burning the serrated tussock infestation the winter prior to spraying?
A: Although serrated tussock burns readily in winter it recovers while most associated species are killed. Burning before or after the application of
TASKFORCE® will reduce efficacy.
Q: Can grazing control serrated tussock?
A: Cattle and sheep cannot control serrated tussock by grazing even if supplemented with urea, molasses or blocks. Goats have been successful in controlling the weed when it constituted 10% of an improved pasture but failed when it occupied 50%. Stock forced to graze the weed will eventually die.
Q: Does soil type affect rate?
A: Research has shown that poorer rocky soils require maximum label rate application. On deep productive basalt soils it may be feasible to use lower rates. A specific recommendation cannot be made but it has been demonstrated that summer application is the most effective. If serrated tussock is infests poorer soils such as shallow shales consider a summer program.
Q: I want to kill the serrated tussock infestation and sow a pasture of sub clovers and perennial grasses. How long should I wait between spraying with
TASKFORCE® and sowing the new pasture?
A: Spray out the old infested pasture in late spring with TASKFORCE® and re-sow in the following autumn. Do not sow the new pasture unless 100 mm or more rain has occurred since spraying.
Q: An 18 month old new pasture is infested with 8-18 month old serrated tussock seedlings. What options are available?
A: This pasture at Berridale NSW was sprayed with rates equivalent to 0.75 L/ha TASKFORCE® and resulted in a 100% kill of the serrated tussock seedlings without damaging sown pasture species of subterranean and white clovers, phalaris, fescue and cocksfoot. It is necessary to spray in late spring or summer to avoid damage to the sub clover.
Q:What other herbicides are compatible with TASKFORCE®?
A: Any herbicide such as glyphosate or paraquat, although compatible, will reduce the effectiveness of
TASKFORCE®. Broad leaf herbicides such as MCPA are currently being evaluated and at this stage do not appear to affect efficacy.
Q: What restrictions are there on grazing stock or cutting hay from paddocks treated with
TASKFORCE®
A: Areas receiving blanket treatment ( that is, treatment other than spot spraying ) are not to be grazed or cut for stockfeed for at least 4 months. The withholding period on spot sprayed areas is 14 days. Stock should not be grazed in treated areas 14 days prior to slaughter and lactating cows and goats must not be grazed in these areas. This restriction is stated on the label. Although the active, sodium flupropanate, is regarded as a very safe chemical this withholding period ensures sufficient rainfall occurs to dissolve the chemical off the leaves and transport it into the soil so that it can be translocated by the weed and begin working. If the chemical ends up being eaten by grazing animals prior to a rainfall event then efficacy will be affected. Research has demonstrated that high levels of the active fed to cattle is completely removed in the urine within 3 days.
Q: I have serrated tussock and chilean needle grass growing in amongst kangaroo grass and wallaby grass. Will
TASKFORCE® kill these natives?
A: Although some native grasses ( e.g. kangaroo grass Themeda triandra, redleg grass Bothriochloa macra, poa tussock Poa labillardieri) tolerate 2 L/ha
TASKFORCE® others ( e.g. wallaby grass Danthonia spp, weeping grass Microlaena stipoides) are killed by rates of 1 L/ha.
Q: A Blue Gum plantation is growing adjacent to a paddock I want to boom spray with
TASKFORCE®. If spray drifts into the plantation will it kill the eucalypts?
A: No. TASKFORCE® has no affect on eucalypt species.
Q: Is any government body researching serrated tussock, african love grass etc.?
A: Dr. Malcolm Campbell of NSW Agriculture has been carrying out research into serrated tussock for more than 30 years. He has published many papers on serrated tussock and can be contacted on 02 6391 3828
DISCLAIMER
The Q&A's above are based on research available in the published literature as well as other published data and are believed to be correct however no responsibility for its accuracy or correctness is accepted by either Elders Limited or VeeDri ( Aust )Pty. Limited. If in any doubt about the use of
TASKFORCE® consult your agricultural advisor.
|
