Water stress and redlegged earth mites affect the early growth of seedlings in a subterranean clover/capeweed pasture community

2000 ◽  
Vol 51 (3) ◽  
pp. 361 ◽  
Author(s):  
R. Chapman ◽  
T. J. Ridsdill-Smith ◽  
N. C. Turner
Keyword(s):  
Water Stress ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Early Growth ◽  
Halotydeus Destructor ◽  
Redlegged Earth Mite ◽  
Environment Experiment ◽  
Mite Infestations ◽  
The Impact ◽  
Growth Of Seedlings

The impact of water stress and infestations of redlegged earth mite [Halotydeus destructor Tucker (Acarina : Penthaleidae)] on the early growth and botanical composition of a mixed subterranean clover (Trifolium subterraneum L.) and capeweed (Arctotheca calendula Levyns) pasture was investigated in a controlled environment experiment. Water stress and redlegged earth mite infestations both significantly reduced herbage production from both species. The yield of the subterranean clover was suppressed less by water stress than that of the capeweed. The differing sensitivities of the two species to water stress were attributed to differences in seedling size and growth rates at the onset of the drought. Redlegged earth mites caused greater feeding damage on cotyledons of the subterranean clover than of the capeweed. Despite this, the mites had a greater deleterious impact on the growth of the capeweed, which was suppressed both in the presence and absence of water stress. Redlegged earth mites in the presence of water stress did not significantly affect the growth of the subterranean clover. Furthermore, in the absence of water stress, the growth of the subterranean clover was greater when mites were present than when absent. The greater sensitivity of the capeweed to the effects of feeding by the redlegged earth mites was attributed to the smaller size of its seedlings at the time the redlegged earth mites were introduced. The increase in growth of the subterranean clover following the introduction of redlegged earth mites is more likely due to a change in the competitive relationships between the two plant species than to any direct effect of the mites’ feeding. Our observations indicate that the presence of water stress and redlegged earth mites significantly affects the competitive interactions between seedlings of subterranean clover and capeweed.

Mass rearing Halotydeus destructor (Tucker) (Acari : Penthaleidae) for use in summer screening of Trifolium subterraneum (L.) for mite resistance

1997 ◽  
Vol 37 (3) ◽  
pp. 343 ◽  
Author(s):  
D. J. Thackray ◽  
T. J. Ridsdill-Smith ◽  
D. J. Gillespie
Keyword(s):  
Subterranean Clover ◽  
Soil Surface ◽  
Trifolium Subterraneum ◽  
Mass Rearing ◽  
Screening Tests ◽  
Common Vetch ◽  
Halotydeus Destructor ◽  
Natural Pasture ◽  
Redlegged Earth Mite ◽  
First Time

Summary. Controlled environment experiments were conducted to establish some of the requirements for successful mass rearing of Halotydeus destructor (redlegged earth mite). Numbers of mites reared on Vicia sativa (common vetch) cv. Blanchefleur grown alone or on a mixture of vetch with Trifolium subterraneum (subterranean clover) cv. Goulburn, were significantly higher than those on subterranean clover or Arctotheca calendula (capeweed) alone. Populations reared on vetch grown in a sandy soil were significantly higher than those reared on vetch grown in a loamy soil, pure sand or pure loam. Covering the soil surface with a natural pasture mulch increased mite numbers compared with leaving the soil bare or placing plant pots inside ventilated cages. Subsequent changes in rearing methodology produced enough mites to enable summer screening of subterranean clover lines for resistance to H. destructorfor the first time. Over 20 000 mites can be produced from vetch at one time for screening tests throughout the year.

Responses and feeding damage of redlegged earthmite (Acarina: Penthaleidae) to seedlings of resistant and susceptible subterranean clover varieties

1995 ◽  
Vol 46 (5) ◽  
pp. 1091 ◽  
Author(s):  
TJ Ridsdill-Smith
Keyword(s):  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
The Other ◽  
Feeding Damage ◽  
Halotydeus Destructor ◽  
Pot Experiments ◽  
Resistant Varieties ◽  
Redlegged Earth Mite ◽  
Single Variety

Responses of redlegged earth mite (Halotydeus destructor) to seedlings of three resistant and four susceptible varieties of subterranean clover (Trifolium subterraneum) were measured after 7 or 14 days in pot experiments in the glasshouse. With a single variety/pot, mites on resistant varieties (DGI007, EP145SubD and Rutherglen B) produced 45% of the progeny that were produced by mites on the susceptible varieties (89838G, Dalkeith, Junee and 70088B). Number of stages completed and survival were little affected by varieties. Feeding damage (silvering of cotyledons) on resistant varieties averaged 45% of that on susceptible varieties with a single varietylpot. H. destructor fed less on resistant varieties in choice than in single variety experiments. On Junee and 89838G seedlings, feeding damage was similar to that on other susceptible varieties, but there were about half as many H. destructor progeny as on Dalkeith and 70088B. Mites laid more eggs on soil away from Junee plants, compared to the other three susceptible varieties. Different factors adversely affected the number of progeny produced on resistant varieties and on Junee.

The foraging behaviour of redlegged earth mite, Halotydeus destructor (Acarina: Penthaleidae), in an annual subterranean clover pasture

1996 ◽  
Vol 86 (3) ◽  
pp. 247-252 ◽  
Author(s):  
K.R. Gaull ◽  
T.J. Ridsdill-Smith
Keyword(s):  
Foraging Behaviour ◽  
Subterranean Clover ◽  
Ground Cover ◽  
Soil Surface ◽  
Trifolium Subterraneum ◽  
Reproductive Behaviour ◽  
Host Plant Selection ◽  
Halotydeus Destructor ◽  
Adult Sex Ratio ◽  
Redlegged Earth Mite

AbstractThe foraging behaviour of the redlegged earth mite, Halotydeus destructor (Tucker), in annual pasture was documented and the relative numbers of individuals foraging on subterranean clover, Trifolium subterraneum (Leguminosae), capeweed, Arctotheca calendula (Compositae) and grasses (mainly Lolium rigidum (Gramineae)), estimated in winter and spring in south-western Australia. The main feature of H. destructor foraging behaviour was the presence of aggregations ranging in size from 3–36 individuals on the adaxial surfaces of the upper canopy of the pasture. Most aggregating individuals were feeding, while most solitary and paired individuals were searching. There was no evidence that individuals aggregated for reproductive behaviour; the adult sex ratio was similar to that of the population even though immatures were under-represented in aggregations. During winter the distribution of numbers of H. destructor on subclover, capeweed and grasses in the upper canopy of pasture was similar to the estimated ground cover of these plant species. However, individuals showed host-plant selection for subclover when feeding. During spring, when the pasture plants were flowering, there were more H. destructor in capeweed flowers than in aggregations on subclover foliage. The capeweed flowers were shown to enhance the rate of H. destructor reproduction in a laboratory experiment. Most H. destructor were on or near the soil surface, with 10% at any one time on the upper canopy of the pasture. H. destructor is polyphagous, and behaved in pasture as a selective opportunist feeder.

Examination of the involvement of mechanical strength in antixenotic resistance of subterranean clover cotyledons to the redlegged earth mite (Halotydeus destructor) (Acarina: Penthaleidae)

1996 ◽  
Vol 86 (3) ◽  
pp. 263-270 ◽  
Author(s):  
Y. Jiang ◽  
T.J. Ridsdill-Smith
Keyword(s):  
Mechanical Strength ◽  
Cell Walls ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Petri Dish ◽  
Resistant Variety ◽  
Electron Microscopic ◽  
Halotydeus Destructor ◽  
Choice Tests ◽  
Redlegged Earth Mite

AbstractResistance involving penetrability of cotyledons of subterranean clover Trifolium subterraneum (Leguminosae) by the redlegged earth mite, Halotydeus destructor Tucker, was examined in this study using several approaches. Values of penetrability, presented as mechanical strength measured with a penetrometer with a tubulated probe, of cotyledons tested 11–13 days after seeding, from nine varieties of two subspecies of subterranean clover (T. subterraneum subsp. yanninicum and subsp. brachycalicinum) were negatively correlated with feeding damage caused by H. destructor in both 3 h pairwise choice tests in a Petri dish with detached cotyledons, and in 2 week multiple choice tests in containers with seedlings. Simulation tests with different artificial membranes (Parafilm and Gladwrap) making up sachets, containing 5% glucose as a feeding stimulant, indicated that within 3 h H. destructor preferred membranes with lower strength. Field-collected young adults had significantly higher physical fitness to feed and/or gather on the artificial membrane sachet containing 5% glucose, than those from the laboratory culture, when the sachet was compared with cotyledons of either resistant (DGI007) or susceptible (Dalkeith) varieties in the choice tests. Electron microscopic observations of mite infested cotyledons of the resistant variety (DGI007) reveal that upper epidermal cell walls around penetration holes are bent inwards. Anticlinal cell walls of palisade cells appear buckled following attack by H. destructor. The results from these studies were taken as further evidence for the involvement of mechanical factors in antixenotic resistance of subterranean clover cotyledons to H. destructor.

Effect of aphids and mites on herbage and seed production of subterranean clover (cv. Daliak) in response to superphosphate and potash

1992 ◽  
Vol 32 (1) ◽  
pp. 39 ◽  
Author(s):  
RF Brennan ◽  
M Grimm
Keyword(s):  
Potassium Chloride ◽  
Seed Yield ◽  
Quadratic Function ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Response Curves ◽  
Halotydeus Destructor ◽  
Redlegged Earth Mite ◽  
Yield Responses ◽  
The Relationship

The dry matter production (DM) and seed yield of subterranean clover (Trifolium subterraneum L. cv. Daliak) were reduced by infestations of redlegged earth mite (Halotydeus destructor Tucker) and blue-green aphid (Acyrthosiphon kondoi Shinji) during spring growth, flowering and burr burial. The dominance of these pests varied with season. The effects of spraying with insecticides on the DM and seed yield responses to superphosphate and potassium chloride fertilisers were measured. Responses to superphosphate were described by Mitscherlich functions for each of 3 levels of potassium chloride, except for seed yields with pest sprays. At optimum levels of superphosphate and potassium chloride, controlling pests increased DM by up to 150% (from 4.37 to 6.52 t/ha). For all levels of superphosphate, spraying to control pests where no potassium chloride was applied significantly increased DM over that on unsprayed plots that were fertilised with potassium chloride. The maximum DM response to superphosphate application was achieved at 15-20 kg P/ha. With optimum superphosphate, the value for DM depended on the combination of spraying for pests and amount of potassium chloride applied, generating a series of Mitscherlich response curves for superphosphate application with differing maximum yields. With optimum superphosphate applied, the least DM recorded within a season was 3.47 t/ha (pests not sprayed, nil potassium chloride), and the most was 6.52 t/ha (pests sprayed, 120 kg potassium chloride/ha), an increase of about 180%. At optimum levels of superphosphate and potassium chloride, controlling pests increased seed yield by up to 380% (from 290 to 1100 kg/ha). With optimum superphosphate, seed yield within a season ranged from 210 (pests not sprayed, nil potassium chloride) to 1100 kg/ha (pests sprayed, 120 kg potassium chloride/ha), an increase of 524%. With pests sprayed, seed yield declined with superphosphate applications >20 kg P/ha; the relationship was best described by a quadratic function. With pests not sprayed, seed yield did not decline with increasing amounts of superphosphate, and the relationship fitted a Mitscherlich function.

Comparison of single superphosphate and superphosphate coated with bauxite residue for subterranean clover production on phosphorus-leaching soils

Soil Research ◽  
2000 ◽  
Vol 38 (3) ◽  
pp. 735 ◽  
Author(s):  
Robert Summers ◽  
Martin Clarke ◽  
Tim Pope ◽  
Tim O'Dea
Keyword(s):  
Field Experiment ◽  
Soil Phosphorus ◽  
Bauxite Residue ◽  
Phosphorus Uptake ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Single Superphosphate ◽  
Glasshouse Experiment ◽  
The Impact ◽  
Coated Granules

Bauxite residue from alumina refining was used to coat granules of single superphosphate to reduce the leaching of phosphorus in coarse, sandy soils for pastures in high rainfall areas of south-western Australia (>800 mm annual average). The impact of coating the superphosphate on the leaching of phosphorus was measured in a glasshouse experiment and the effectiveness of the fertiliser using dry herbage yield of subterranean clover (Trifolium subterraneum) was measured in a field experiment. The glasshouse experiment measured the effect of coating the superphosphate with bauxite residue at 0, 5, 10, 15, 20, 25, 30, 35, and 40% by weight. A coating of 25% (by weight) was chosen for the field experiment. In the glasshouse experiment, the coated granules were applied to columns of soil, where subterranean clover was grown under leaching conditions. A coating of 30%, by weight, reduced leaching of single superphosphate by about half. Increasing the coating of bauxite residue also increased the phosphorus uptake and increased the plant growth. In the field trial, the effectiveness of single superphosphate with a bauxite residue coating of 25% by weight was increased on average by 100% in Year 1, 303% in Year 2, and 158% in Year 3, relative to freshly applied single superphosphate. The bauxite residue coating also increased the phosphorus content of the herbage in a similar manner to the increases in yield. Limited soil phosphorus tests showed only minor increases in the residues of phosphorus where the superphosphate had been coated with bauxite residue.

Monitoring ley pastures and their response to winter cleaning

2006 ◽  
Vol 46 (8) ◽  
pp. 1023 ◽  
Author(s):  
E. C. Wolfe ◽  
J. A. Paul ◽  
P. D. Cregan
Keyword(s):  
Rapid Development ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Total Biomass ◽  
Seedling Density ◽  
Bare Ground ◽  
Herbicide Application ◽  
Seeding Rate ◽  
The Impact ◽  
Legume Growth

The purposes of this study were to evaluate subterranean clover-based leys on farms and in experiments using several pasture parameters, and to assess the impact of winter cleaning on the productivity and botanical composition of clover swards. Annual pastures were monitored on a group of 5 farms in the Wagga district and compared with an experimental subterranean clover (Trifolium subterraneum L.) pasture. The major problem in the farm paddocks was a lack of legume biomass due to poor legume densities, a consequence of the use of the soft-seeded cultivar Woogenellup and a high content of grassy weeds. The farmers in the group were unaware of the tools, parameters and benchmarks for making quantitative pasture comparisons. In 2 experiments, a range of subterranean clover swards were generated through the use of cultivars, seeding rate and winter cleaning treatments, grazed at 15 sheep/ha and monitored for 3 years. Appropriate benchmark values for the seed pool of subterranean clover were 300–350 kg/ha in winter and 600–700 kg/ha in summer. On the basis of both winter production, a function of May seedling density (target >1000 seedlings/m2) and spring production, which depended on the cultivar maturity, Junee was superior at Wagga to either Dalkeith (earlier maturing) or Woogenellup (softer seeded). Winter cleaning, using selective herbicides (fluazifop, simazine) to remove grasses and weeds, was advantageous in achieving a high content (>90%) and productivity of subterranean clover, provided that the legume content of the pasture was at least 28%, or >20% of total ground area before herbicide application in winter. In winter-cleaned swards, legume growth increased by up to 80%, legume biomass was improved by up to 46% and legume content increased from <50 to >95%. The main disadvantages of winter cleaning were increased areas of bare ground and reduced total biomass for several weeks after herbicide application, and the rapid development of ryegrass that was resistant to at least 1 of the herbicides used. The strategic use of observations to monitor the performance of pastures and their response to management is discussed.

Pathogenesis-Related Proteins in Trifolium subterraneum: A General Survey and Subsequent Characterisation of a Protein Inducible by Ethephon and Redlegged Earth Mite Attack

1997 ◽  
Vol 24 (6) ◽  
pp. 819 ◽  
Author(s):  
Kevin Broderick ◽  
Christopher Pittock ◽  
Tony Arioli ◽  
Ernest H. Creaser ◽  
Jeremy J. Weinman ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Chitinase Activity ◽  
Pr Proteins ◽  
Gene Encoding ◽  
Pathogenesis Related ◽  
Redlegged Earth Mite ◽  
Ethephon Treatment

One of the chief predators of subterranean clover (Trifolium subterraneum) pastures is redlegged earth mite (Halotydeus destructor; RLEM). Subterranean clover pathogenesis-related (PR) proteins induced by RLEM attack and ethephon treatment were surveyed, and PR proteins with peroxidase, β-1,3-glucanase and chitinase activities were detected. A protein co-migrating with a chitinase activity, induced by RLEM predation and treatment with ethephon, was isolated. It was purified and the N-terminal amino acid sequence determined. Using a degenerate oligonucleotide primer designed from this sequence, a corresponding cDNA fragment was amplified by reverse transcriptase-PCR, then cloned, and used as a probe to screen a subterranean clover cv. Karridale genomic library. The cDNA and a 97% homologous genomic clone were sequenced and the deduced amino acid sequence revealed an open reading frame of 157 amino acids capable of encoding a peptide of 16 478 Da. Significant homology (80%) was found between this protein and an abscisic acid (ABA)-responsive protein from Pisum sativum of unknown function which is an intracellular pathogenesis-related (IPR) protein. The gene encoding this protein also has homology to pea ‘disease response resistance genes’ and to proteins from other plant species in the PR-10 family. The induced protein was designated TsPR-10a due to its homology to other PR-10 proteins. Genomic Southern analysis indicates that the gene encoding this protein, designated Ypr10a, is a member of a multigene family with at least three members. Northern blot analysis indicates that the subterranean clover Ypr10a mRNA, or homologous transcript, level is strongly induced by ethephon treatment in both root and aerial tissues of 3 week old plants. The rapid induction kinetics of Ypr10a mRNA under ethephon treatment, its correlation with a putative chitinase activity, and homology to other PR-protein genes, suggests a pathogenesis-related role for TsPR-10a protein in subterranean clover.

Controlling redlegged earth mite, Halotydeus destructor (Acari: Penthaleidae), with a spring spray in legume pastures

2015 ◽  
Vol 66 (9) ◽  
pp. 938 ◽  
Author(s):  
T. J. Ridsdill-Smith ◽  
C. C. Pavri
Keyword(s):  
Seed Yield ◽  
South Australia ◽  
Subterranean Clover ◽  
Early Summer ◽  
Eastern Region ◽  
The West ◽  
Halotydeus Destructor ◽  
South Wales ◽  
Redlegged Earth Mite ◽  
Clover Seed

The use of a TIMERITE® spring spray to control redlegged earth mite (RLEM), Halotydeus destructor (Tucker) (Acari: Penthaleidae), in annual pastures was evaluated on farms across Australia. RLEM populations in autumn in the treatments sprayed in spring 1998 and 1999 were 97% lower in 1999 and 97% in 2000 in the western region (Western Australia), and 93% lower in 1999 and 93% in 2000 in the eastern region (Victoria, New South Wales and South Australia). At sites in the west, control of RLEM resulted in significant increases in subterranean clover seed yield in 1999 and in clover seedling numbers in autumn 1999 and 2000. Penthaleus major (blue oat mite) populations in autumn were 60% lower in sprayed treatments, but Sminthurus viridis (lucerne flea) populations were not affected. Differences in weather between the west (where there is a hot, dry summer) and the east (where temperature and rainfall regimes are more variable in spring and early summer) seem to cause greater RLEM control and greater benefits in subterranean clover seed yield and seedling numbers with a spring spray in the west.

Genetic improvement of subterranean clover (Trifolium subterraneum L.). 2. Breeding for disease and pest resistance

2014 ◽  
Vol 65 (11) ◽  
pp. 1207 ◽  
Author(s):  
P. G. H. Nichols ◽  
R. A. C. Jones ◽  
T. J. Ridsdill-Smith ◽  
M. J. Barbetti
Keyword(s):  
Plant Breeding ◽  
Mosaic Virus ◽  
Pest Resistance ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Yellow Mosaic Virus ◽  
Genotypic Differences ◽  
Pythium Irregulare ◽  
Halotydeus Destructor ◽  
Subterranean Clover Stunt Virus

Subterranean clover (Trifolium subterraneum L.) is the most widely sown pasture legume in southern Australia and resistance to important diseases and pests has been a major plant-breeding objective. Kabatiella caulivora, the cause of clover scorch, is the most important foliar fungal pathogen, and several cultivars have been developed with resistance to both known races. Screening of advanced breeding lines has been conducted to prevent release of cultivars with high susceptibility to other important fungal foliar disease pathogens, including rust (Uromyces trifolii-repentis), powdery mildew (Oidium sp.), cercospora (Cercospora zebrina) and common leaf spot (Pseudopeziza trifolii). Several oomycete and fungal species cause root rots of subterranean clover, including Phytophthora clandestina, Pythium irregulare, Aphanomyces trifolii, Fusarium avenaceum and Rhizoctonia solani. Most breeding efforts have been devoted to resistance to P. clandestina, but the existence of different races has confounded selection. The most economically important virus diseases in subterranean clover pastures are Subterranean clover mottle virus and Bean yellow mosaic virus, while Subterranean clover stunt virus, Subterranean clover red leaf virus (local synonym for Soybean dwarf virus), Cucumber mosaic virus, Alfalfa mosaic virus, Clover yellow vein virus, Beet western yellows virus and Bean leaf roll virus also cause losses. Genotypic differences for resistance have been found to several of these fungal, oomycete and viral pathogens, highlighting the potential to develop cultivars with improved resistance. The most important pests of subterranean clover are redlegged earth mite (RLEM) (Halotydeus destructor), blue oat mite (Penthaleus major), blue-green aphid (Acyrthosiphon kondoi) and lucerne flea (Sminthurus viridis). New cultivars have been bred with increased RLEM cotyledon resistance, but limited selection has been conducted for resistance to other pests. Screening for disease and pest resistance has largely ceased, but recent molecular biology advances in subterranean clover provide a new platform for development of future cultivars with multiple resistances to important diseases and pests. However, this can only be realised if skills in pasture plant pathology, entomology, pre-breeding and plant breeding are maintained and adequately resourced. In particular, supporting phenotypic disease and pest resistance studies and understanding their significance is critical to enable molecular technology investments achieve practical outcomes and deliver subterranean clover cultivars with sufficient pathogen and pest resistance to ensure productive pastures across southern Australia.

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