scholarly journals Effects of invertebrate pests on white and annual clovers in dryland soil

2010 ◽  
Vol 63 ◽  
pp. 235-240
Author(s):  
T.M. Eden ◽  
P.J. Gerard ◽  
D.J. Wilson ◽  
N.L. Bell

Two experiments were carried out at Ruakura in soil taken from Whatawhata hill country pasture The relative susceptibility of several annual clovers (Trifolium spp) and perennial white clover (T repens) to slugs (Deroceras reticulatum) clover root weevil (Sitona lepidus) adults native crickets (Nemobius sp) or wheat bugs (Nysius huttoni) was tested by sowing seed of the clovers into separate rows in turf Susceptibility of clovers to clover cyst nematode (Heterodera trifolii) was tested by sowing each clover variety into Whatawhata soil inoculated with the nematode Plant growth was assessed in both experiments 4 weeks after sowing White clover was more susceptible to pests than the annual clovers with slugs and clover root weevil significantly reducing seedling survival and clover cyst nematode significantly reducing plant growth Subterranean clover (T subterraneum) cv Denmark was the least affected by pests showing no significant reduction in survival in the presence of slugs the most damaging pest and no significant decrease in plant root and shoot dry weight when exposed to nematodes

Author(s):  
J.R. Crush ◽  
P.J. Gerard ◽  
L. Ouyang ◽  
D.J. Wilson

The effect on plant growth of clover root weevil (CRW) larval feeding on nodules and roots was examined for the annual clovers, subterranean cv. Leura, balansa cv. Bolta, arrowleaf cv. Arrowtas and Persian cv. Mihi, and white clover cv. Tribute. Mini-swards of each clover species were used in a glasshouse experiment, with half of these exposed to CRW larval feeding. Keywords: Sitona lepidus, root herbivory, annual clovers, drought


1987 ◽  
Vol 38 (2) ◽  
pp. 317 ◽  
Author(s):  
MJ Barbetti ◽  
K Sivasithamparam

Subterranean clover was exposed to two levels of inoculum of millet seed colonized by Fusarium avenaceum, Fusarium oxysporum, Phoma medicaginis, Phytophthora clandestina, Pythium irregulare, or Rhizoctonia solani within pasteurized and unpasteurized field soil from sites with (root rot site) and without (virgin site) a history of subterranean clover root rot at Augusta, W.A., with the aim of establishing their pathogenicity in the presence of other soil organisms including resident pathogens. Introduction of F. avenaceum (2.5% w/w), P. clandestina (0.5 and 2.5%), P. irregulare (0.5 and 2.5%), or R. solani (0.2 and 1.0%) increased damage to tap and lateral roots of subterranean clover in pasteurized and unpasteurized root rot and virgin soils. All fungi tested, with the exception of P. medicaginis (2.0 and 10.0%) or P. medicaginis (2.0 and 10.0%) and F. oxysporum (0.5 and 2.50%), caused reduction of seedling survival in pasteurized root rot and virgin soils respectively. When the soil was unpasteurized, all fungi except F. oxysporum (2.5%) and P. medicaginis (2.0 and 10*0%) in virgin soil, but only P. irregulare (2.5%) or R. solani (0.2 and 1.0%) in root rot soil, reduced seedling survival. In unpasteurized soils plant dry weight was reduced by P. clandestina (2.5%), P. irregulare (0.5 and 2.5%), or R. solani (0.2 and 1.0%) in root rot and virgin soils, but F. oxysporum (0.5%) reduced plant size only in the root rot soil. Within pasteurized soil all fungi, with the exception of P. medicaginis (2.0 and 10.0%) in virgin soil and F. avenaceum (2.5%), P. irregulare (0.5 and 2.5%), or R. solani (0.2%) in root rot soil, caused reduction in plant size. P. clandestina, P. irregulare or R. solani, in particular, and to a lesser extent, P. avenaceum, are capable of causing serious damage to subterranean clover in natural soil.


Author(s):  
J.R. Crush ◽  
L. Ouyang ◽  
P.J. Gerard ◽  
S. Rasmussen

The effect of clover root weevil (Sitona lepidus) (CRW) larval feeding on subterranean, suckling, striated and clustered clovers was compared with white clover in a glasshouse experiment. Growth of suckling, striated, and clustered clover was significantly reduced by CRW, approaching the levels of damage recorded in white clover. N fixation in suckling and clustered clovers was also reduced. Growth and nitrogen fixation of two subterranean clovers (cv. Denmark, cv. Leura) were changed relatively little by CRW larval feeding. The relatively high level of the isoflavonoid biochaninA that was present in subterranean clover roots may explain the species' tolerance of CRW. These results suggest that CRW may not pose a major threat to dryland farming systems based on subterranean clover. Keywords: annual clover, clover root weevil, roots, Trifolium dubium, Trifolium glomeratum, Trifolium striatum, Trifolium subterraneum


Author(s):  
Mahmoud Ahmed Touny El-Dabaa ◽  
Hassan Abd-El-Khair

Abstract Background Orobanche crenata is an obligate root parasite belonging to Orbanchaceae. Broomrape causes great damage to the faba bean. Several attempts were applied for controlling parasitic weeds. So, the aim of this work is to study the application of Trichoderma spp. as well as three rhizobacteria species in comparison to herbicidal effect of Glyphosate (Glialka 48% WSC) for controlling broomrape infesting faba bean (Vicia faba). Materials and methods Three pot experiments were carried out in the greenhouse of the National Research Centre, Dokki, Giza, Egypt during two successive winter seasons. Trichoderma inocula were adjusted to 3.6 × 108 propagules/ml and the bacterium inocula were adjusted at 107–109 colony-forming unit (CFU)/ml. All treatments were applied, before 1 week of sowing, at rate of 50 ml per pot in experiments I and II, while 100 ml per pot in experiment III. Results Trichoderma spp. (T. harzianum, T. viride and T. vierns) as well as three rhizobacteria species (Pseudomonas fluorescens, Bacillus subtilis and Bacillus pumilus) enhanced the growth parameters in faba bean plants, i.e. shoot length, shoot fresh weight, shoot dry weight and leaf number in the first experiment when applied without O. crenata infection. In the second experiment, all bio-control could protect plants against O. crenata infection, where it had better juvenile number reduction, than glyphosate after 2 months of application. Both B. subtilis and B. pumilus had the highest reduction to juvenile fresh weight, while their effect was equal to herbicide for juvenile dry weight, respectively. The bio-control agents had high effects until the 4th month, but it was less than that of the herbicide. In experiment III, the bio-control agents could highly reduce the juvenile parameters after 2 months, as well as juvenile fresh weight and juvenile dry weight after 4 months, than the herbicide, respectively. The bio-control agents were effective until 6 months, but less than the herbicide effect. All bio-control treatments highly increased the plant growth parameters, than the herbicide. Conclusion The application of Trichoderma spp. as well as rhizobacteria species could play an important role in controlling broomrape in faba bean as a natural bioherbicide.


2021 ◽  
Author(s):  
Leila Tabande ◽  
Mozhgan Sepehri ◽  
Jafar Yasrebi ◽  
Mehdi Zarei ◽  
Reza Ghasemi-Fasaei ◽  
...  

Abstract Zinc oxide nanoparticles (ZnO-NPs) are among the most commonly used nano-fertilizers (NF). However, elevated levels of ZnO-NPs in soil may affect plant growth and development due to its potential toxicity when accumulated in large amounts in plant tissues. This research was conducted using an in situ rhizobox system with the aims of evaluating Zinc uptake from nano-zinc oxide amended rhizosphere soil by alfalfa plant and the effect of plant growth promoting microorganisms on alleviating the phytotoxicity of ZnO-NPs. Treatments included microbial inoculations (Sinorhizobium meliloti, Serendipita indica) and different ZnO-NPs concentrations (0, 400 and 800 mg Kg− 1) with three replications. The results indicated that S. indica minimized the phytotoxicity of ZnO-NPs to alfalfa by enhancing growth rate and decreasing Zinc (Zn) translocation from root to shoot. Compared with plants inoculated with S. meliloti, co-inoculation with S. indica increased the shoot dry weight by 18.33% and 8.05% at 400 and 800 mg Kg− 1ZnO-NPs. However, at the highest level of ZnO-NPs (800 mg kg− 1), root inoculation of S. indica and S. indica + S. meliloti decreased Zn transfer factor by 60.2% and 44.3% compared to S. meliloti, respectively. Furthermore, a distinct relation between tolerance of S. indica-colonized plant to ZnO-NPs and the ability of S. indica in inhibiting or retarding degradation of polyunsaturated lipids through prevention of excess reactive oxygen species formation was observed. Malondialdehyde content of inoculated plants with S. indica either alone or in combination with S. meliloti was significantly lower than non-inoculated plants (p < 0.01). Zn-induced oxidative stress was mitigated by S. indica through enhanced activities of catalase and peroxidase enzymes. The findings of the present study indicate the potential use of endophytes fungus S. indica for ensuring food safety and security, and human health in heavy metal–polluted soil by reducing the phytoavailability of heavy metals in the aerial parts of the host plants.


mSphere ◽  
2020 ◽  
Vol 5 (4) ◽  
Author(s):  
Dario X. Ramirez-Villacis ◽  
Omri M. Finkel ◽  
Isai Salas-González ◽  
Connor R. Fitzpatrick ◽  
Jeffery L. Dangl ◽  
...  

ABSTRACT Glyphosate is a commonly used herbicide with a broad action spectrum. However, at sublethal doses, glyphosate can induce plant growth, a phenomenon known as hormesis. Most glyphosate hormesis studies have been performed under microbe-free or reduced-microbial-diversity conditions; only a few were performed in open systems or agricultural fields, which include a higher diversity of soil microorganisms. Here, we investigated how microbes affect the hormesis induced by low doses of glyphosate. To this end, we used Arabidopsis thaliana and a well-characterized synthetic bacterial community of 185 strains (SynCom) that mimics the root-associated microbiome of Arabidopsis. We found that a dose of 3.6 × 10−6 g acid equivalent/liter (low dose of glyphosate, or LDG) produced an ∼14% increase in the shoot dry weight (i.e., hormesis) of uninoculated plants. Unexpectedly, in plants inoculated with the SynCom, LDG reduced shoot dry weight by ∼17%. We found that LDG enriched two Firmicutes and two Burkholderia strains in the roots. These specific strains are known to act as root growth inhibitors (RGI) in monoassociation assays. We tested the link between RGI and shoot dry weight reduction in LDG by assembling a new synthetic community lacking RGI strains. Dropping RGI strains out of the community restored growth induction by LDG. Finally, we showed that individual RGI strains from a few specific phyla were sufficient to switch the response to LDG from growth promotion to growth inhibition. Our results indicate that glyphosate hormesis was completely dependent on the root microbiome composition, specifically on the presence of root growth inhibitor strains. IMPORTANCE Since the introduction of glyphosate-resistant crops, glyphosate has become the most common and widely used herbicide around the world. Due to its intensive use and ability to bind to soil particles, it can be found at low concentrations in the environment. The effect of these remnants of glyphosate in plants has not been broadly studied; however, glyphosate 1,000 to 100,000 times less concentrated than the recommended field dose promoted growth in several species in laboratory and greenhouse experiments. However, this effect is rarely observed in agricultural fields, where complex communities of microbes have a central role in the way plants respond to external cues. Our study reveals how root-associated bacteria modulate the responses of Arabidopsis to low doses of glyphosate, shifting between growth promotion and growth inhibition.


Biocelebes ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 1-9
Author(s):  
Wahyu Harso ◽  
Isna Isna ◽  
Yusran Yusran

Arbsucular mycorrhizal fungi promote plant growth by enhancing mineral uptake. Contribution degree of arbuscular mycorrhizal fungi to promote plant growth depend on species of plant-fungus association. The aim of this study was to compare the ability of three species of Glomus to promote maize plant growth. Maize plants were inoculated with 20 g inoculum of either Glomus deserticola, Glomus etunicatum, or Glomus clorum.  Inoculum was soil containing spore, hyphae and infected root. Maize plants without addition inoculum were also used as a control. Water availability in the soil as growing medium was maintained on 40% field capacity. The results showed that addition of inoculum from three species of Glomus increased average of maize plant shoot dry weight  although there was no statisticaly significant differences.  Maize plant inoculated with G. clorum had higher shoot dry weight than maize plant inoculated either with G. etunicatum or G. deserticola while root colonization by G. clorum was lowest.


2019 ◽  
Vol 67 (4) ◽  
Author(s):  
Felipe Romero-Perdomo ◽  
Jhonnatan Ocampo-Gallego ◽  
Mauricio Camelo-Rusinque ◽  
Ruth Bonila

In this study, we aimed at examining the potential to stimulate growth in Pennisetum clandestinum using four isolated bacterial strains from soils obtained from a Colombian tropical silvopastoral system. We previously identified genetically the strains and characterized two plant growth promotion activities. We found that the four bacterial strains were phylogenetically associated with Klebsiella sp. (strains 28P and 35P), Beijerinka sp. (37L) and Achromobacter xylosoxidans (E37), based on partial 16S rRNA gene sequencing. Moreover, the in vitro biochemical assays demonstrated that the strains exhibited some plant growth promotion mechanisms such as 1-aminocyclopropane-1-carboxylic acid deaminase activity and indole compound synthesis. Notably, bacterial inoculation under greenhouse conditions showed a positive influence on P. clandestinum growth. We found a significant (p < 0.05) effect on root and shoot length, and shoot dry weight. Shoot length increased by 52% and 30% with 37L and 35P, respectively, compared to those without inoculation treatment. Similarly, the use of 37L and 28P raised shoot dry weight values by 170% and 131%, respectively. In root development, inoculation with strains 37L and E37 increased root length by 134% and 100%, respectively. Beijerinckia sp. 37L was the most effective of the four strains at increasing P. clandestinum biomass and length.


Author(s):  
C.F. Mercer ◽  
R.N. Watson ◽  
D.R. Woodfield

Breeding for improved resistance and tolerance to the clover root-knot nematode, Meloidogyne trifoliophila, and the clover cyst nematode, Heterodera trifolii , has been successful in white c lover, Trifolium repens. White clover lines developed from three independent breeding programmes were established in field trials at Lincoln, Palmerston North, Cambridge and Kerikeri. Plants were established in areas either untreated or treated with nematicide, so as to have contrasting pest loads on the plant material and evaluated for up to 4 years. Plant vigour was scored before each grazing at each site. Clover cyst nematode cysts were counted twice in Palmerston North and all nematodes were counted in stained roots on four occasions in Cambridge. Resistant lines from the clover cyst nematode programme performed better than susceptible lines and as well as most cultivars reflecting the high level of resistance developed in this glasshouse-based programme. This resistance was also reflected in the generally lower number of cysts counted under resistant lines from Palmerston North. The root-knot nematode resistant material performed better than the susceptible and as well as most cultivars. The tolerance selections, developed under field conditions, performed as well as, or better than the cultivars. The selections from the breeding programmes have exhibited strong agronomic potential across locations and years and the best material has been crossed, with progeny being assessed in current field trials. Keywords: Heterodera trifolii, Meloidogyne trifoliophila, nematode, pasture, resistance, tolerance, white clover


2014 ◽  
Vol 76 ◽  
pp. 197-202
Author(s):  
S.N. Nichols ◽  
J.R. Crush

Abstract Strategies to reduce the economic and environmental costs of phosphate (P) fertiliser use in mixed pastures through plant breeding are focussed on inefficiencies in the legume component. One approach is breeding within white clover for root systems with improved P acquisition properties. Selection for root length per unit root weight (specific root length, SRL) showed that higher SRL plants could retain more biomass in the above ground fraction with decreasing soil P, whereas plants with lower SRL diverted more biomass to roots. Back cross 1 (BC1) generation interspecific hybrids between white clover and a wild relative, Trifolium uniflorum L., may possess additional root traits influencing P acquisition. In glasshouse experiments, some T. repens × T. uniflorum hybrids, back-crossed to white clover, also exhibited higher shoot dry weight than their white clover cultivar parents at low nutrient supply levels and low to intermediate soil Olsen P. This, combined with low internal P concentrations, suggests some BC1 hybrids may be more tolerant of low soil P than white clover. Differences in both P acquisition ability and internal P use efficiency may contribute to the observed yield differences. There are good prospects for delivery of new-generation clover cultivars with improved phosphate use efficiency to New Zealand farmers. Keywords: phosphorus, white clover, Trifolium uniflorum, interspecific


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