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.

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.

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.

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.

Varietal reactions of Trifolium subterraneum L. to Phaseolus virus 2 Pierce.

1954 ◽  
Vol 5 (4) ◽  
pp. 598 ◽  
Author(s):  
EM Hutton ◽  
JW Peak
Keyword(s):  
Trypan Blue ◽  
Continuous Distribution ◽  
Systemic Infection ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Epidermal Cells ◽  
Severe Strain ◽  
Resistant Varieties ◽  
Lethal Reaction ◽  
The Mean

A number of varieties of subterranean clover (Trifolium subterraneum L.) were tested with a severe strain of Phaseolus virus 2 Pierce. Northam First Early, Dwalganup, and Pink Flowered gave lethal necrotic reactions while the rest developed mottles and chlorosis of different degrees of intensity. Reductions in the mean fresh weights of plants of five subterranean clover varieties ranged from 26.1 to 76.7 per cent. Epidermal cells of mottled leaves contained irregular aggregates of viroplasts stained by treatment with phloxine-trypan blue. Viroplasts in young tip leaves did not stain if the plants were held at temperatures below 44.6°F while those in mature basal leaves were not so affected. The lethal-reactors Northam First Early, Dwalganup, and Pink Flowered were resistant in the field to Phaseolus virus 2. With hand inoculation in the glass-house an average of 10 per cent. of plants of these varieties remained free from systemic infection, whereas all the plants of mottle-reacting varieties became systemically infected. The virus had a discontinous distribution in plants of lethal-reactors, compared with a continuous distribution in those of mottle-reactors such as Mount Barker. The lethal reaction is heritable in a dominant fashion in most crosses, so that the development of desirable new virus- resistant varieties is possible.

Phosphorus, sulphur, and molybdenum deficiencies in soils from eastern Australia in relation to nutrient supply and some characteristics of soil and climate.

1955 ◽  
Vol 6 (5) ◽  
pp. 673 ◽  
Author(s):  
KD McLachlan
Keyword(s):  
Phosphorus Deficiency ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Parent Material ◽  
The Other ◽  
Podzolic Soils ◽  
Sulphur Deficiency ◽  
Eastern Australia ◽  
Yield Responses ◽  
Western Victoria

Subterranean clover (Trifolium subterraneum L.) was grown on 32 virgin soils in pot cultures, and the yield responses to phosphorus, sulphur, and molybdenum were determined for each soil. The soils were collected from a wide area in eastern Australia, extending from south-western Victoria to southern Queensland. Sulphur deficiency occurred almost as frequently as phosphorus deficiency. In fact, 75 per cent. of the soils were deficient in both phosphorus and sulphur. Thirty-one per cent. were deficient in all three elements. The effect of the interaction between the elements on the occurrence and intensity of the deficiencies is shown. Molybdenum responses were obtained only after the other deficiencies had been corrected. A deficiency in one of the elements is no indication of deficiency or sufficiency of either of the other two. There was no correlation between the occurrence or intensity of the deficiencies and the geological origin of the soil parent material, the climate of the regions from which the soils were collected, or such soil characters as colour, organic matter, and texture. Responses to phosphorus were less on the black earths than on the red or yellow podzolic soils; those on the red earths were intermediate. The intensity of sulphur deficiency increased, and the intensity of molybdenum deficiency decreased, with increasing soil pH.

The growth of barley grass (Hordeum leporinum) in annual pasture. 3. Some factors affecting balance with subterranean clover (Trifolium subterraneum)

1968 ◽  
Vol 8 (35) ◽  
pp. 702 ◽  
Author(s):  
DF Smith
Keyword(s):  
Soil Nitrogen ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Moisture Stress ◽  
Nitrogen Addition ◽  
The Other ◽  
Early Start ◽  
Factors Affecting ◽  
Two Factors ◽  
Hordeum Leporinum

Mixed swards of barley grass (Hordeum leporinum) and subterranean clover (Trifolium subterraneum) of two densities were grown at two levels of nitrogen. Growth was started at two different times mid- April and mid-May-and at each time half the plots were subjected to moisture stress. The swards were harvested after nine weeks of growth. The survival of clover plants was reduced by an early start, moisture stress and nitrogen addition : much more so than barley grass. The root : shoot ratios of both species were calculated ; both showed some sensitivity to the time of break and moisture stress, and the grass was also affected by the other two factors. Total sward production and the ratios of clover to grass varied widely Grass daminance was favoured by moisture stress or a late break, and both of these factors tended to override the effect of higher soil nitrogen in determining clover-grass balance. Total sward production more dependent on density than any other factor, especially with the later start. Higher nitrogen was effective in boosting production only if the break was early and there was no moisture stress.

Seed production and persistence of Carnamah and other early strains of Trifolium subterraneum in the wheatbelt of Western Australia

1967 ◽  
Vol 7 (24) ◽  
pp. 25 ◽  
Author(s):  
GB Taylor ◽  
RC Rossiter
Keyword(s):  
Seed Production ◽  
Seed Yield ◽  
Western Australia ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Growing Season ◽  
Early Flowering ◽  
The Other ◽  
Factors Affecting ◽  
Seed Yields

Seed production and persistence of the Carnamah, Northam A, Dwalganup, and Geraldton strains of subterranean clover (Trifolium subterraneum L.) were examined in undefoliated swards in the wheatbelt of Western Australia. The early flowering characteristic of Carnamah was not always associated with higher seed yields. Only when there was a well-defined, early finish to the growing season, or when flowering was very much earlier in Carnamah (viz., following an early 'break' to the season), did this strain clearly outyield both Northam A and Geraldton. The seed yield of Dwalganup was generally inferior to that of the other strains. Factors affecting regeneration are discussed. Under low rainfall conditions, poorer germination-regulation of Carnamah, compared with Geraldton and Northam A, would be expected to result in poorer persistence unless offset by higher seed yields in the Carnamah strain.

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.

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