Use of herbicides for selective removal of Eragrostis curvula (Schrad.) Nees from a Pennisetum clandestinum pasture

1987 ◽  
Vol 27 (3) ◽  
pp. 359
Author(s):  
MH Campbell ◽  
HW Kemp ◽  
RD Murison ◽  
JJ Dellow ◽  
H Ridings

In 3 experiments near Candelo, New South Wales, the effectiveness of tetrapion, glyphosate and 2,2-DPA in selectively removing Eragrostis curvula (agronomic type Tall Chloromelas) from a Pennisetum clandestinurn pasture was determined by applying each at various rates in each season of the year in 1981-82 (experiments 1 and 2) and in 1983 (experiment 3). Experiment 4 examined the effect of the herbicides on 3 cultivars of P. clandestinum when applied in each season in 1983-84. Tetrapion (2.25 and 3.00 kg/ha a.i.) was the most effective herbicide in killing E. curvula and promoting P. clandestinum in experiments 1 and 2, but, in experiment 3, glyphosate and 2,2-DPA were equally effective in killing E, curvula at 3 (glyphosate) and 2 (2,2-DPA) of the 4 application times. The differences between the results of the experiments were attributed to the herbicide being leached faster by the higher rainfall and being immobilised by the greater amounts of dead foliage of E. curvula in experiment 3. Despite occasional success in killing E. curvula, glyphosate and 2,2-DPA could not be considered for selective use as both were much more phytotoxic to P. clandestinum than tetrapion (experiment 4). Time of application had little influence on the selectivity of tetrapion, the least effective being May-June. In experiments 1 and 2, E. curvula was still well controlled by P. clandestinurn 5 years after the application of tetrapion. Pennisetum clandestinum cv. Crofts was more tolerant of tetrapion than were cvv. Whittet or Common.


1985 ◽  
Vol 25 (3) ◽  
pp. 665 ◽  
Author(s):  
MH Campbell ◽  
JJ Dellow ◽  
MJ Keys ◽  
AR Gilmour

In the main experiment, the effectiveness of tetrapion, glyphosate and 2,2-DPA in selectively removing Eragrostis curvula from a Phalaris aquatica pasture was determined by applying each at three rates in July 1980, September 1980, December 1980 and March 1981 near Braidwood, New South Wales. Auxiliary experiments were conducted from April 1981 to April 1983 to determine the reliability of herbicide effect on E. curvula. Tetrapion (2.25 and 3.375 kg/ha a.i.) was the most effective herbicide in killing E. curvula and promoting P. aquatica and Trifolium subterraneum. It was more selective when applied in September 1980 and December 1980 than when applied in July 1980 or March 198 1. Re-infestation by E. curvula seedlings in the 3 years after spraying with tetrapion amounted to a maximum of 3% of ground cover. In the auxiliary experiments, tetrapion was effective on all nine occasions of application, which demonstrated its reliability and effectiveness at any time of the year. Glyphosate (1.08 and 1.62 kg/ha a.i.) was effective in killing E. curvula in March 1981 but this result could not be repeated in March 1982 or March 1983 or in nine other applications at other times in these years. 2,2-DPA (maximum rate 22.2 kg/ha a.i.) was ineffective in killing E. curvula at four times of application. Recovery of the P. aquatica pasture after treatment declined in the order: tetrapion >2,2-DPA>glyphosate.



1988 ◽  
Vol 28 (1) ◽  
pp. 53 ◽  
Author(s):  
WH Johnston

The palatability of 20 accessions of E. curvula collected from naturalised populations in New South Wales was compared on 7 occasions with 2 selected accessions previously found to be highly palatable. The experiment was conducted at Wagga Wagga, N.S.W., between January 198 1 and July 1983. The relative palatability of most accessions was substantially similar from rating to rating, despite differences in the extent to which the trial was grazed. Palatability was related to the agronomic group to which the accessions belonged. For the naturalised taxa, Curvula was ranked equal to Tall Chloromelas. but both were more palatable than Short Chloromelas. The naturalised accessions were all less palatable than the selected accessions. It was concluded that the selected accessions were sufficiently palatable to be well utilised in pastures by stock grazing at commercial stocking rates.



1988 ◽  
Vol 28 (1) ◽  
pp. 47 ◽  
Author(s):  
WH Johnston

Relative palatability of 12 previously selected taxa of Eragrostis curvula complex was assessed using a visual rating scale of 0 (not grazed) to 10 (completely grazed). Visual ratings were converted to ranks and the most and least palatable lines were compared over 19 grazing assessments in trials at Wagga Wagga, Temora and Orange, New South Wales. Three highly palatable and 2 acceptably palatable accessions were identified. The importance of palatability in the E. curvula complex is discussed.



2005 ◽  
Vol 45 (4) ◽  
pp. 401 ◽  
Author(s):  
W. H. Johnston ◽  
P. S. Cornish ◽  
V. F. Shoemark

A grazing experiment conducted in Wagga Wagga (New South Wales) from September 1993 to September 1998 compared the productivity of pastures containing 3 palatable types of summer-active Eragrostis curvula complex, with pastures containing either Medicago sativa or Phalaris aquatica. Issues relating to the management of E. curvula pastures were also investigated. Herbage growth rates of the P. aquatica and M. sativa pastures were highest in winter and spring; E. curvula pastures were most productive in summer and autumn. Stocking rates equivalent to 30–40 dry sheep were carried by the pastures during their growing seasons. Throughout the study, the pastures were dominated by their respective sown perennial species, however, a suite of desirable and undesirable annual grasses and annual legumes usually contributed >20% of total herbage mass in spring. The P. aquatica pasture contained a higher proportion of weedy species than the other pastures, especially C4 grasses and broadleafed species, and towards the end of the experiment it was also invaded by several native perennial grasses. Overall, the wool yield from the M. sativa pasture was 0.5–1.0 kg/animal.year higher than the other pastures. Management to minimise herbage accumulation on the E. curvula pastures was a key issue, and provided that pastures were grazed heavily, this was achieved by the rotational grazing strategy used in the experiment. It was concluded that palatable varieties of E. curvula have a useful and complementary role as perennial pastures in southern Australia. By increasing herbage availability in summer and autumn, E. curvula may improve management flexibility for a wide range of pastures that are commonly grown on farms.



1997 ◽  
Vol 10 (1) ◽  
pp. 77 ◽  
Author(s):  
M. Lazarides

Based on characters of gross morphology, a taxonomic revision is presented of the Australian taxa of Eragrostis Wolf, comprising 69 endemic and exotic species distributed in six groups. Seventeen species are proposed as new. Ten taxa are hereby reduced to synonymy. Lectotypes are designated for 11 species. New distribution records include E. atrovirens for Australia, E. schultzii for Western Australia, E. leptocarpa and E. pergracilis for Victoria, E. minor for New South Wales, and E. sterilis for New South Wales and the Northern Territory. Polymorphy and interspecific gradation are inherent problems in the taxonomy of the genus. Also, apparent evolutionary characters such as mode of spikelet disarticulation can be inconsistent and difficult to interpret. Features of the caryopsis relating to 3-dimensional shapes, compression, surface markings, and an adnate or free pericarp are among the most useful characters for identification purposes. Cleistogamy occurs in many species, but is not reflected in spikelet morphology. Eragrostis curvula is recorded as an apomict.



1989 ◽  
Vol 29 (1) ◽  
pp. 37 ◽  
Author(s):  
WH Johnston

Experiments established 30 km north and 30 km south of Urana N.S.W. in 1980 and 198 1, on areas heavily infested with spiny burrgrass, showed that lovegrass (Eragrostis curvula) varieties Consol and accession 4660 were more easily and reliably established than buffel grass or lucerne. Lovegrass persisted up to 1988 and continued to spread, despite 3 extremely dry summer periods and uncontrolled grazing. It achieved virtual control of spiny burrgrass after 4 years. Lucerne failed to persist in 3 out of 4 sowings, and only persisted where phosphorus had been applied. Lovegrass density was highest where fertiliser was not applied. Lovegrass can be recommended for controlling spiny burrgrass on infertile, sandy textured soils in low rainfall environments where the use of lucerne is uneconomic or its establishment and management are difficult.



2005 ◽  
Vol 45 (10) ◽  
pp. 1255 ◽  
Author(s):  
W. H. Johnston ◽  
P. S. Cornish ◽  
T. B. Koen ◽  
V. F. Shoemark

The productivity, carrying capacity and liveweight performance of wether sheep grazing pastures of Eragrostis curvula cv. Consol and Medicago sativa cv. Nova, which were also sown with annual grasses and Trifolium subterraneum, were compared under an intensive 4-paddock rotational grazing regime in a ‘put-and-take’ grazing experiment at Wagga Wagga, New South Wales from November 1993 to August 1996. The productivity of the pastures was broadly similar, with production peaks of >1000 kg/ha in winter and >3000 kg/ha in spring and summer in paddocks that had been spelled for 6 weeks. Although annual species contributed a high proportion of the total herbage mass in spring, over the remainder of the year, both pastures were dominated by their respective perennials. E. curvula maintained an average plant density of approximately 20 plants/m2. The density of M. sativa declined noticeably during the 3 years, and at the end of the experiment M. sativa plants in 1 replicate of the experiment were killed by rising groundwater and dryland salinity. The long-term average stocking rate of E. curvula and M. sativa pastures were similar (12.1 v. 12.5 sheep/ha) and both pastures were capable of sustaining high stocking rates for lengthy periods in spring and summer. Sheep grazing M. sativa tended to be heavier than animals grazing E. curvula, and they produced, on average, 1.1 kg (or 21%) more wool. However, M. sativa was more difficult to establish and its costs for weed and insect control were higher. Therefore, although it was more productive, it might not have been the most economically viable of the 2 pastures. The implications of the findings were discussed within a whole-farm context and it was concluded that E. curvula has a complimentary role to M. sativa for sowing on landscapes and in situations to which M. sativa is poorly adapted.





1979 ◽  
Vol 19 (99) ◽  
pp. 472 ◽  
Author(s):  
MH Campbell ◽  
AR Gilmour

The effect of three rates of glyphosate (1, 3 and 5 kg a.i. ha-1) and two of 2,2-DPA (21 and 33 kg a.i. ha-1), each applied in October 1972, January 1973, April 1973 and July 1973, on serrated tussock and associated improved species (Phalaris aquatics, Trifolium repens, T. subterraneum) was ascertained in an experiment near Bathurst, New South Wales. The effect of the herbicide treatments on the improved species was measured in October 1973 and the percentage kill of serrated tussock recorded in May 1974. Increasing the rate of glyphosate increased the percentage kill of serrated tussock (up to a mean of 77% with 5 kg a.i. ha-1) ; time of application had no significant effect on percentage kill. No glyphosate treatment resulted in a commercially acceptable kill of serrated tussock (above 90%). Thus the herbicide was inferior to 2,2-DPA which produced a 95% kill when applied in summer. P. tuberosa was more tolerant of glyphosate and 2,2-DPA than serrated tussock and recovered from all treatments. T. repens and T. subterraneum recovered from glyphosate and 2,2-DPA applied in summer. Thus it proved possible to selectively remove a large proportion of a serrated tussock infestation with 2,2-DPA or glyphosate, applied in summer, without permanent damage to the associated improved species.





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