Aphid infestation and virus infection of peas and beans on the Central Tablelands of New South Wales

1972 ◽  
Vol 12 (59) ◽  
pp. 668 ◽  
Author(s):  
NE Grylls

Field Studies were made of aphid infestation, population behaviour and virus incidence on Pisum sativum, Vicia faba and Phaseolus vulgaris at Bathurst, New South Wales, from November 1969 to June 1970. The relative importance of the aphids Aphis craccivora, Macrosiphum euphorbiae, Myzus persicae and Aphis gosypii as vectors of subterranean clover stunt virus (SCSV) and bean yellow mosaic virus (BYMV) was obscured by the overwhelming incidence of A, craccivora. On the first two plantings, virus incidence exceeded 90 per cent and yields were almost nil. Virus incidence was low on peas and canning beans on the third planting. Late infection on broad beans was 82-96 per cent. BYMV incidence, negligible on the first two plantings, was 16 per cent on the third planting of broad beans. Migrating alate aphids were trapped and tested on subterranean clover; c. 10 per cent of A. craccivora carried SCSV, and about 10 per cent of M. eybhorbiae, late in the season, carried BYMV. Three species of coccinellids attacked A. craccivora but did not control aphids until plants matured. Spraying with fenitrothion reduced aphid populations in control plots but had little effect on virus incidence and greatly reduced coccinellids. Aphidiid parasites were few and had little effect on aphid populations.

1969 ◽  
Vol 20 (1) ◽  
pp. 37 ◽  
Author(s):  
NE Grylls ◽  
JW Peak

A study was made of subterranean clover plants from areas of New South Wales where clovers were not re-establishing. Eight field isolates of diseased plants were collected in central and southern New South Wales and in the Australian Capital Territory. Mixed infections of strains of subterranean clover stunt virus (SCSV) and a bean yellow mosaic virus (BYMV) were transmitted from the isolates. Four species of aphids, Aphis cvaccivora (Koch), A. gossypii (Glov.), Macrosighum euphorbiae (Thomas), and Myzus persicae (Sulz.), transmitted strains of SCSV and the BYMV and a mixture of these to a number of legumes. Four stable strains of SCSV were separated after a large number of transfers and selections. BYMV was isolated by mechanical inoculation. One Australian cultivar, four Mediterranean introductions, and one intersubspecific hybrid of subterranean clovers were highly resistant to two strains of SCSV and to BYMV. Mixed infection with SCSV and BYMV and infection with one severe strain of SCSV seriously reduced pod formation and seeding in peas and canning beans as well as in subterranean clover.


2001 ◽  
Vol 41 (2) ◽  
pp. 187 ◽  
Author(s):  
R. Aldaoud ◽  
W. Guppy ◽  
L. Callinan ◽  
S. F. Flett ◽  
K. A. Wratten ◽  
...  

In 1995–96, a survey of soil samples from subterranean clover (Trifolium subterraneum L.) paddocks was conducted across Victoria, South Australia, New South Wales and Western Australia, to determine the distribution and the prevalence of races of Phytophthora clandestina (as determined by the development of root rot on differential cultivars), and the association of its occurrence with paddock variables. In all states, there was a weak but significant association between P. clandestina detected in soil samples and subsequent root rot susceptibility of differential cultivars grown in these soil samples. Phytophthora clandestina was found in 38% of the sampled sites, with a significantly lower prevalence in South Australia (27%). There were significant positive associations between P. clandestina detection and increased soil salinity (Western Australia), early growth stages of subterranean clover (Victoria), mature subterranean clover (South Australia), recently sown subterranean clover (South Australia), paddocks with higher subterranean clover content (Victoria), where herbicides were not applied (South Australia), irrigation (New South Wales and Victoria), cattle grazing (South Australia and Victoria), early sampling dates (Victoria and New South Wales), sampling shortly after the autumn break or first irrigation (Victoria), shorter soil storage time (Victoria) and farmer’s perception of root rot being present (Victoria and New South Wales). Only 29% of P. clandestina isolates could be classified under the 5 known races. Some of the unknown races were virulent on cv. Seaton Park LF (most resistant) and others were avirulent on cv. Woogenellup (most susceptible). Race 1 was significantly less prevalent in South Australia than Victoria and race 0 was significantly less prevalent in New South Wales than in South Australia and Western Australia. This study revealed extremely wide variation in the virulence of P. clandestina. The potential importance of the results on programs to breed for resistance to root rot are discussed. in South Australia.


1975 ◽  
Vol 15 (77) ◽  
pp. 795 ◽  
Author(s):  
JA Thompson

A range of temperate annual and perennial legumes, naturalized or commonly sown in the area, was examined at three field sites in low fertility soils derived from granite on the south western slopes of the New England Region, New South Wales. They were compared over a four year period in terms of their persistence, dry matter and nitrogen production and their compatibility with associated temperate perennial grasses, The response of sown grass to nitrogen fertilizer application was also examined in the absence of legume. Ten legumes were examined at one site and six of these at the other two sites. In general, nitrogen yields were ranked similarly to total dry matter yields of all treatments, including grasses in the absence of legume. However, the legumes were ranked differently in terms of productivity of the legume component and productivity of associated grass. At all sites lucerne gave the highest yields of total dry matter and of legume and the lowest yield and persistence of associated grass-comparable to grass growing in the absence of legume or applied nitrogen. Subterranean clover was ranked second or third in total dry matter yield, depending on site, but provided the highest yield of associated grasscomparable to grass receiving high levels of applied nitrogen. Under this legume soil nitrogen levels tended to be highest. Rose clover, sown at one site only, yielded more legume dry matter than subterranean clover but grass yield was comparable to that with lucerne. The results suggest that subterranean clover is the superior legume for successful mixed sowings although inclusion of white clover could be justified. Lucerne appears to be best sown as a pure sward.


1988 ◽  
Vol 28 (5) ◽  
pp. 561 ◽  
Author(s):  
HL Davies ◽  
E Devaud

A March-April joining of Merino ewes was compared with a June-July joining in central New South Wales at a low stocking rate on subterranean clover based pastures over 3 years. In all years, ewes joined in June were heavier (P < 0.05) than ewes joined in March (55 v. 52 kg). Liveweights at the start of lambing and liveweight change from joining to lambing were also high and favoured the later lambing group. The proportion of ewes lambing (97% March v. 93% June) and proportion of ewes twinning (29% March v. 20% June) were not significantly different between the 2 groups, but consistently favoured the March-April joining. Perinatal mortality was low (9.4% March v. 7.1% June) and not significantly different between the 2 groups, but was consistently lower in the June joined group. Number of lambs weaned per 100 ewes joined was also not significantly different, but was higher each year in the March joined group (1 13% March v. 105% June). The growth rate of the lambs (both singles [24% greater, 248 v. 200 g/day] and twins [37% greater, 2 13 v. 155 g/day]) was consistently in favour of March joined ewes. Mean greasy fleece weights of the ewes were not significantly different between the 2 groups, but were in favour of the late joined group (4.83 v. 4.50 kg). Time of joining significantly affected liveweights and greasy and clean fleece weights of the progeny at the shearing in the year following their birth in favour of March joining. These data suggest that, despite a nutritional advantage to the ewes in late pregnancy and milder weather at lambing with a June-July joining, a March- April joining is the preferred option on the Central Tablelands of New South Wales.


2004 ◽  
Vol 44 (12) ◽  
pp. 1165 ◽  
Author(s):  
A. M. Bowman ◽  
W. Smith ◽  
M. B. Peoples ◽  
J. Brockwell

Total productivity and legume nitrogen fixation (N2 fixation) in dryland pastures were examined in a 2 year study (1999–2001) on 118 farms in central-western New South Wales. Pasture exclosure cages, placed at 217 on-farm sites, were harvested on 7 occasions and the foliage hand-sorted according to species in order to measure shoot dry matter (DM). The separated legume shoot material collected in spring 1999 (52 different legume samples) and 2000 (76 different legume samples) from a subset of representative pastures (41 cages on 28 different farms in 1999, 32 cages on 25 different farms in 2000) was also analysed for concentration of nitrogen (%N) and 15N natural abundance. These data were subsequently used to calculate the proportion of the legume shoot N derived from atmospheric N (%Ndfa), comparative measures of the relative efficiency of N2 fixation (kg N fixed/t DM accumulated) and the amounts of shoot N fixed (kg N/ha). The survey encompassed 8 common pasture types, and 5 others that were less common, ranging from native perennial grass pastures with little legume content to lucerne (Medicago sativa L.) pastures with and without companion clovers. Fifteen legume species were found in the pastures, some only occasionally. Lucerne and white clover (Trifolium repens L.) were the only perennials. Mean spring estimates of %Ndfa were similar in 1999 and 2000 for lucerne (72 and 81%, respectively), rose clover (T. hirtum All., 82 and 77%) and annual medics (Medicago spp., 89 and 86%). For the remaining 12 legume species, measures of %Ndfa ranged from 64 to 95% and averaged 83%. Shoot %N contents were greater for lucerne than for the other 14 legumes and this was reflected in the comparative measures of N2 fixation which ranged from 14.5 kg N/t DM for rose clover to 25.7 kg N/t DM for lucerne in 2000. The most productive pasture type comprised lucerne plus balansa clover [T. michelianum Savi var. balansae (Boiss.) Azn.], white clover or arrowleaf clover (T. vesiculosum Savi), but all pasture types that contained lucerne were highly productive. Spring was the most productive season and summer the least. Lucerne was overwhelmingly the most productive legume and was responsible for >83% of the fixed N in those pastures that contained both lucerne and other legumes. Lucerne productivity was approximately uniform throughout the year whereas, for other pastures, especially those based on rose clover or subterranean clover (T. subterraneum L.), there were sharp peaks in spring and little or no dry matter production over summer. The presence of lucerne in pastures significantly (P<0.05) reduced broadleaf weeds. It was concluded that, where there are requirements in central-western New South Wales agriculture for uniform forage production throughout the year and a high input of fixed N, lucerne is substantially superior to other species.


2000 ◽  
Vol 27 (5) ◽  
pp. 531 ◽  
Author(s):  
Peter J. S. Fleming ◽  
David Choquenot ◽  
Richard J. Mason

An experiment that held the density of feral pigs constant while varying the effective density of aerially distributed baits was conducted at three sites in north-western New South Wales. Meat baits, containing one of the biomarkers iophenoxic acid, tetracycline or rhodamine B, were distributed at different intensities over each site, and a sample of pigs was shot from a helicopter at each site to determine bait uptake. Serum and tissue samples taken from each pig were analysed for the occurrence of the biomarkers; the proportions of pigs exhibiting biomarkers represented the proportions of the feral pig populations that had consumed baits at different baiting intensities (expressed as baits per unit of pig density). The maximum percentage of sampled pigs that had eaten baits varied from 31% to 72% across the three sites. Bait uptake was regressed against baiting intensity. For two of the trials, the quantity of bait hypothetically required to eliminate a population of feral pigs was extrapolated to be 1577 baits per unit of pig density, while for the third trial 1874 baits per unit of pig density would have been required. Bait-uptake by non-target animals was substantial, posing potential hazards to birds and reducing the availability of baits to feral pigs. Most likely, seasonal conditions affected bait-uptake by feral pigs. We discuss the implications of these results for exotic disease contingency planning.


2003 ◽  
Vol 43 (6) ◽  
pp. 539 ◽  
Author(s):  
G. M. Lodge ◽  
S. R. Murphy ◽  
S. Harden

An experimental site was established in 1997 on the North-West Slopes of New South Wales to further investigate the use of strategic grazing management to improve the persistence of phalaris (Phalaris aquatica cv.�Sirosa) and subsequent effects on animal production and soil water content. The pasture was sown in 1992 to Sirosa phalaris, subterranean clover (Trifolium subterraneum var. subterraneum cv. Seaton Park) and lucerne (Medicago sativa cv. Aurora). Four grazing treatments were applied in a randomised 3-replicate design. Treatments consisted of continuous grazing at 12.3 sheep/ha (C12 or control); continuous grazing at 6 sheep/ha (C6), and 2� spring and autumn strategies of either resting from grazing for 6 weeks in each season (SAR0), or reducing stocking rate from 12.3 to 4.0 sheep/ha (SAR4). Despite annual applications of fertiliser and high clover content, Sirosa phalaris herbage mass in plots continuously grazed at 12.3 sheep/ha declined from a mean of 3300 kg DM/ha in spring 1997 to < 700 kg DM/ha by May 1998. At the end of the study (February 2001), Sirosa mean herbage mass in these plots was 670 kg DM/ha and lower (P < 0.05) than for the other treatments (mean value 5400 kg DM/ha). These marked changes in herbage mass, and the degradation of the Sirosa-based pasture to an annual pasture by continuous grazing at 12.3 sheep/ha, were not generally reflected in either short-term animal production or substantial differences in soil water content. Wool production (kg/head) was not significantly different among treatments each year. Compared with continuous grazing at 12.3 sheep/ha, sheep liveweights were higher (P < 0.05) in plots continuously grazed at 6.1 sheep/ha from November 1997 to February 1999. However, from February 1999 to 2001, sheep liveweights in the 2 treatments with the highest Sirosa phalaris content were lower (P < 0.05) than those continuously grazed at 12.3 sheep/ha. Only the soil water content for the C6 and SAR4 treatments at 0–30�cm was significantly different to the control treatment, but the differences were predicted to be < 2.5 mm/year. In the root zone (0–90 cm), mean soil water content ranged from 159 to 309 mm (mean 220 mm), while plant available water (soil water content – soil water content at –1500 kPa) was a mean of 79 mm, ranging from 11 to 168 mm.


1968 ◽  
Vol 8 (33) ◽  
pp. 470 ◽  
Author(s):  
MH Campbell

The effects of herbicide, inoculation, and nitrogen on establishment, growth and survival of Trifolium pratense, T. repens, T. subterraneum, Lolium perenne, Dactylis glomerata, and Phalaris tuberosa were recorded at Rockley, New South Wales. Seed was surface sown on unploughed land dominated by tussock grass (Nassella trichotoma). All clovers established on unploughed land but only T. subterraneum survived successfully two years after sowing. Establishment of L. perenne and D. glomerata was three to four times as high as P. tuberosa, but two years later there were more P. tuberosa plants than either L. perenne or D. glomerata. Herbicide treatment increased establishment and growth of all grasses and was essential for their survival ; it was not essential for establishment or nodulation of the three clovers nor for regeneration of T. mbterranew, but did have beneficial effects. Nitrogen decreased the establishment of D. glomeratb but increased growth of all grasses and survival of L. perenne and D. glomerata; it depressed the establishment, nodulation, and growth of clovers. Three-step inoculation gave successful nodulation and proved essential for growth of all clovers and regeneration of subterranean clover.


2001 ◽  
Vol 41 (4) ◽  
pp. 497 ◽  
Author(s):  
G. D. Li ◽  
K. R. Helyar ◽  
M. K. Conyers ◽  
P. D. Cregan ◽  
B. R. Cullis ◽  
...  

Potassium (K) deficiency of wheat and pasture species was found at a site in the south-western slopes of New South Wales. The soil was a subnatric yellow sodosol. Subterranean clover (Trifolium subterraneum) was found to be less competitive for K in the soil compared with its associated grasses. Higher soil K concentrations were required to achieve the same subterranean clover K concentration in the grass–legume mixtures than in a subterranean clover monoculture. For wheat (Triticum aestivum) production, a soil exchangeable K (Kex ) below 0.25 cmol(&plus;)/kg appeared to be deficient for the limed treatments, but there was no obvious critical value for either limed or unlimed treatments. The critical K exvalues for the grass &ndash;legume mixtures could not be simply specified because the values were affected by competition between species growing in swards of variable botanical composition. An annual rate of 20 kg K/ha for the pasture–crop rotations (50/50%) and 29 kg K/ha for the permanent pastures was estimated to be sufficient to replenish the K losses from product removal and animal excreta transferred to campsites at this trial site.


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