Evaluation of uncomposted botanical-based soil amendments for organic management of downy mildew of Sorghum

Uncomposted dried, powdered biomass of 38 selected botanicals was evaluated as soil amendments in a pot experiment for their potential to suppress downy mildew of sorghum caused by soil-borne oosporic inoculum of Perenosclerospora sorghi. A negative control showed 11.1% disease incidence. Six botanicals proved effective in form of dry biomass powder at 0.5% (w/w) amendment rate to control infection by oospores (Allium cepa 0%, Lantana camara 1.6%, Polyalthia longofolia 0%, Hyptis suaveolens 1.5%, Eucalyptus globulus 0% and Nerium oleander 1.6% of disease incidence). Dry powders are not only effective in disease suppression but confer additional benefits over composts like reduced bulk, increased shelf-life, consistent composition and results.     

Impact of compost application on Fusarium wilt disease incidence and microelements contents of basil plants

Fusarium oxysporum was isolated from stem of basil plants showing symptoms of wilt, stem blight and collar root rot. Pathogenicity tests indicated that F. oxysporum f. sp. basilici is the causal agent of this disease. This is the first report of this pathogen in Egypt. The suppressive effects of six types of composts on Fusarium wilt disease incidence in basil were evaluated under greenhouse conditions. The effectiveness of these composts and their relation to the microelements content in treated plants was also assessed. Soil treatments with Khaya and Eucalyptus composts significantly reduced the infection percentage and disease severity of basil wilt. Otherwise, the applications of Araucaria, Datura, Ficus and Azadirachta composts showed no effect on both infection percentage and disease severity. Moreover, the Khaya and Eucalyptus compost treatments increased the levels of Iron (Fe), Zinc (Zn) and Manganese (Mn) in treated basil plants than application of Araucaria, Datura, Ficus and Azadirachta composts. In the case of Copper (Cu) content, it was significantly higher only in Eucalyptus-compost-treated plants than in other compost applications. These composts not only reduced the disease incidence but also increased both fresh and dry weight (FW and DW) and microelements contented in basil treated plants. In general, although soil amendment with either Khaya or Eucalyptus compost can reduce the disease incidence of Fusarium wilt on basil plants, microelements contented; FW and DW of these effects can be variable depending on their levels added in soil. According to the results of this study, it can be concluded that the use of compost in the soil as an organic fertiliser increased exchangeable form of microelements in the soil and also the availability of these elements by basil plants.     

Evaluation of different botanical for the management of cowpea bruchid (Callosobruchus maculatus) in north-eastern Ethiopia

The pesticide efficacy of locally available seven botanicals “Gime” (Chenopodium ambrosioides), “Ayderke” (Jatropha curcas), Neem (Azadirachta indica), Melia (Melia azadirach), “Chobe” (Cisus rotonifolia), “Kelewa” (Maesa lanceolata) and “Antharfa” at a rate of 4% weight by weight was evaluated for the control of cowpea bruchid using 200?g cowpea seeds in 500?cm³ volume jar in 2010 and 2011 under laboratory condition at Sirinka Agricultural Research Centre. The combined analysis showed that “Gime” (both leaf and seed) had high speed of pesticide effect as it showed significantly higher per cent of parent adult mortality (84 and 71%, respectively) as to the standard check Malathion 5% dust (100%) in the first day of adult mortality count. “Antharfa” and “Ayderke” also have shown significantly higher per cent of parent adult mortality as to Malathion in the third and fifth day of adult mortality count, respectively. In the seventh day, all botanicals showed significantly higher per cent of adult mortality as compared to untreated check. “Gime” leaf and seed powder, “Ayderke” seed, Neem seed and “Antharfa” leaf powders significantly reduced the number of progeny emergence per day as compared to all other treatments. Moreover, these botanicals were effective in reducing per cent seed damage (0.00, 0.00, 0.57, 5.86 and 10.86%, respectively) and storage loss (0.00, 0.00, 0.073, 1.02 and 2.27%, respectively). Gime (both leaf and seed powder), “Ayderke” seed and Neem seed are locally available, simple for preparation and environmentally friendly. Therefore, these three botanicals can be recommended to satisfy the demand for organic food and save the seed damage and yield loss of cowpea caused by Callosobruchus maculates and bean bruchid (Zabrotes subfasciatus) which has similar biology with Callosobruchus maculatus.     

Comparative effects of some botanicals for the control of the seed weevil Caryedon serratus Olivier (Col., Bruchidae)

Abstract:   Comparative efficacy of eco-friendly botanicals extracted from leaves and seed kernel of Azadirachta indica A. Juss (neem) and Eucalyptus camaldulensis Dehn was tested against the noxious weevil Caryedon serratus Olivier. Leaf powder, seed kernel powder and oil extracted from the seeds of A. indica and leaf powder and oil extracted from the leaves of E. camaldulensis and benzene hexachloride (BHC) were tested at 1, 3 and 5% (w/w or v/w) against C. serratus . Eucalyptus leaf oil (ELO) and neem oil (NO) at 3 and 5% were as efficient as BHC and significantly (P=0.0001) reduced egg laying by C. serratus, whereas Eucalyptus leaf powder (ELP) had no significant effect. Neem seed kernel powder (NSKP) at 5%, ELO (3 and 5%) and NO (3 and 5%) significantly (P=0.0001) reduced egg hatching more than BHC at all doses. NO (3 and 5%) and ELO (3 and 5%) significantly (P=0.0001) reduced larval development more than BHC, whereas ELP and Neam Leaf Powder had no significant effect. Adult emergence and mortality were also significantly (P=0.0001) affected by some botanicals tested, especially oils. Oils were more effective as compared with powder. The study indicated that the botanicals tested have a good potential in replacing conventional pesticides because of their high efficacy and environmental safety.     

Utilization of seaweed Ulva sp. in Paracas Bay (Peru): experimenting with compost

In Paracas Bay (Peru), large quantities of Ulva sp. interfere with various important activities of the zone. In this context, the present study was undertaken to evaluate the effect of adding Ulva sp. in compost piles and the quality of the resulting composts. Six compost piles were prepared using, straw, green material mixture, cow manure and Ulva in different quantities (9, 17 and 28% of volume) and forms. Several variables were monitored during the process and the chemical characteristics of the final composts were determined. Aerial biomass achieved by maize plants was also evaluated for each compost at different compost/sand proportions. Results show that the compost pile made with Ulva powder registered the highest temperature and the longest thermophilic phase. Piles prepared with 28% washed Ulvapresented anoxic conditions at the beginning and had higher electrical conductivity values. Carbon/Nitrogen ratio diminished appropriately in all piles and there was no negative effect observed on the pH of the piles. Compost prepared with Ulva had lower contents of Total Kjeldahl Nitrogen, and produced maize plants aerial biomass.     

The comparative efficacy of some botanicals for the control of the seed weevil Caryedon serratus Olivier (Col., Bruchidae) in seeds of Acacia seyal Del.

A comparative study on the efficacy of powder and oil extracts from leaves and seed kernels of Azadirachta indica Juss. and Eucalyptus camaldulensis Dehn. against the seed weevil Caryedon serratus Olivier infesting seeds of Acacia seyal Del. was carried out. EO 1, EO 5 and NSKO5% were comparable to BHC 3% in significantly reducing egg laying by C. serratus. With the exception of ELP and NLP, all botanicals significantly reduced egg hatching. Botanicals significantly reduced larval development with the exception of ELP and NLP. EO and NSKO at 3 and 5% were significantly more effective than BHC in reducing larval development by 95–97%. All botanicals had no significant effect on adult emergence which was only affected by BHC. Botanicals caused 4.3–43% mortality of C. serratus adults and the maximum mortality occurred in EO 3% as compared to BHC. It is apparent that oils extracted from E. camaldulensis had a fumigant and knock down effect on adult C. serratus. Extracted oils were more effective than leaf or seed powder. Oils extracted from leaves of E. camaldulensis were volatile and had a knock down effect on adult C. serratus indicating the possibility of using them as alternative fumigants in seed stores.     

The effects of spent mushroom compost and municipal solid waste compost on Phytophthora drechsleri in vivo and in vitro

Leached spent mushroom compost (SMC), municipal solid waste compost (MSWC) and their extracts, were tested to suppress Phytophthora drechsleri in cucumber plants. The composts were mixed with sand-loam soil in sterile and non-sterile types and were used to assess suppressiveness against P. drechselri in greenhouse experiments. The extracts of composts, in both sterile and non-sterile types, were applied to evaluate their effect in suppression of pathogen in vitro. The results of the experiments showed that all applications rate of non-sterile SMC were significantly effective in the control of the pathogen. However the sterile SMC amendments did not have a positive effect on the pathogen suppression in vitro or in vivo, as it was expected. In greenhouse experiments, both composts were effective in controlling pathogen at the rate of 15%, but the treatments amended with higher rate of MSWC did not show a positive effect. The treatments amended with MSWC (15%) and SMC (25%) showed the most suppressive effect in controlling the pathogen. The extract of leached-SMC could inhibit P. drechselri in petri dish.     

Use of composts to manage corky root disease in organic tomato production

Corky root disease of tomato caused by Pyrenochaeta lycopersici is an economically important disease in organic tomato production. This study aimed to evaluate the effects of various composts consisting of green manure, garden waste and horse manure against corky root disease through bioassay under greenhouse conditions, where soil naturally infested with P. lycopersici was used as a root substrate. The various composts were mixed at a rate of 20% (v/v) with the infested soil. Disease severity (measured as infected roots) in the unamended soil was compared with that in the soil–compost mixtures. One of the composts made from garden waste significantly reduced the disease, whereas horse manure compost significantly stimulated it. Lower concentrations of NH₄‐N and total carbon and a higher concentration of Ca in the substrate were correlated with lower level of corky root disease. Addition of green manure or garden waste compost to the infested soil increased total microbial activity or population density of copiotrophic bacteria and actinomycetes, respectively. However, increased microbial activity or microbial population in soil–compost mixtures was not associated with a reduction in corky root disease severity in the present study.     

Status of coastal dune communities invaded by Chrysanthemoides monilifera

It has often been assumed that the introduced species Chrysanthemoides monilifera is displacing native species in invaded coastal communities in Australia but no direct evidence has been presented that this displacement is occurring and, if so, to what extent. At an invaded site near Moruya, New South Wales, we found strong negative correlations between the presence (measured as cover, frequency or volume of shrub) of C. monilifera and Acacia longifolia, the hitherto dominant native species, and of C. monilifera and Lomandra longifolia. The negative correlations are partly accounted for by differences in the amounts of each species on different zones on the dune, but the negative correlations remain even within these zones. Also a comparison with uninvaded sites indicates that C. monilifera is displacing A. longifolia from the fore-dune and mid-dune but is having less effect in the swale. In addition, there is a trend towards reduced seed production of A. longifolia when growing in proximity to C. monilifera. There is no significant difference in the presence of L. longifolia in the uninvaded and invaded sites. In invaded sites, significantly fewer C. monilifera seedlings occur in the presence of L. longifolia. Thus it appears that the observed negative associations arise from different causes. Chrysanthemoides monilifera is displacing the structurally similar, and previously dominant A. longifolia, while the tussock-forming L. longifolia is locally hindering the invasion.     

Characterization of composted olive mill wastes to predict potential plant disease suppressiveness

Despite its proven agronomic value, the plant disease suppressive effect of composts from olive waste has not been adequately investigated. In the present study, the disease suppressive potential of two olive waste (OW) composts against soil-borne plant pathogens was investigated. Both OW composts showed sizeable, active microbial populations, which were able to grow actively on chitin and cellulose. In plate inhibition trials, OW compost water extracts (CWEs) exerted a significant inhibitory effect on the growth of the pathogens Fusarium oxysporum f.sp. lycopersici (Fol), Pythium ultimum, Phytophtora infestans, Sclerotina sclerotiorum and Verticillium dahliae; and in pot experiments, the OW composts significantly reduced P. ultimum damping-off and Fol wilt diseases on tomato seedlings. The disease suppressive effect of OW composts seems to be due to the combined effects of suppression phenomena caused by the presence of microorganisms competing for both nutrients and space as well as by the activity of specific antagonistic microorganisms.     

Modification of Fertility of Soil Materials for Restoration of Acid Grassland Habitat

Use of composts for habitat restoration offers advantages in terms of efficient use of resources. Chemical amendment of compost to reduce its pH and P availability was investigated in order to improve suitability for use in reclamation of blocky quarry waste to acidic grassy heathland. The effect of these amendments was observed on competition between two grass species: Agrostis capillaris and Festuca ovina. A factorial, pot‐scale greenhouse experiment was set up using two composts (one a mixture of green waste and catering waste, and the other a mixture of green waste and sewage sludge). In addition, two soils were collected from upland acidic grassland to provide a natural comparison. S⁰ was applied to reduce soil pH, and Fe(OH)₃ from a coal waste treatment plant was applied to counteract the expected increase in P availability due to acidification of the composts by S⁰. Addition of S⁰ significantly reduced soil solution pH and addition of Fe(OH)₃ significantly reduced soil solution P concentration. In one compost S⁰ reduced the biomass of F. ovina while increasing that of A. capillaris, whereas Fe(OH)₃ had no significant effect on the biomass of either species. Although S⁰ and Fe(OH)₃ did adjust the chemical properties of the soil solution, Fe(OH)₃ did not bind P strongly enough to make it unavailable to plants. Further work is required, however, the use of chemically amended composts provides a sustainable sink for organic wastes and we conclude from this study that they have great potential for large‐scale restoration of blocky waste tips.     

Single-cell protein of Rhodotorula sp. Y-38 from ethanol, acetic acid and acetaldehyde

Summary Continuous cultivation of Rhodotorula sp. Y-38 was carried out on ethanol, acetic acid or acetaldehyde. At a feed concentration of 1.0 % (w/v) ethanol, the cell yield of 64 g/100 g ethanol and crude protein of 52 g/100 g biomass were obtained at D=0.5 h^-1. The respective value of the content of amino acids and nucleic acids was 42.6 and 9.4 g/100 g biomass. At 2.0 % (w/v) acetic acid, cell yield was found to be 50 g/100 g acetic acid at D=0.4 h^-1. The optimum dilution rate ranged between 0.3 and 0.4 h^-1. At 0.05 % (w/v) acetaldehyde, the maximum cell yield was obtained at D=0.14 h^-1.     

Interactions between seedlings of Chrysanthemoides monilifera and Acacia longifolia

Displacement of Acacia longifolia on coastal dunes in New South Wales by the invasive species Chrysanthemoides monilifera may be linked to the greater competitiveness by the latter in the seedling stage, as demonstrated in pot experiments. This occurs despite a lower chlorophyll concentration in shoots of C. monilifera which leads to a lower assimilation rate per unit leaf area and lower carbohydrate concentrations. However, this assimilate is spread over a greater total leaf area. Such a strategy associated with‘quantity’may thus be more important than leaf‘quality’in terms of competitiveness. In A. longifolia, the production of higher quality‘leaves’but of lower total area may be well-suited in the often sparse native populations found in sand dunes, but appears disadvantageous when seedlings of C. monilifera also co-exist. The competitive advantage of C. monilifera over A. longifolia is reduced but not reversed under water stress. Under severe stress, mortality of C. monilifera is greater than that of A. longifolia in monocultures but mortality of both species is similar in mixtures. The reason appears to be that C. monilifera transpires more water per plant even though its rate of transpiration per unit leaf area is reduced under water stress because of early stomatal closure. In mixtures, faster root growth of C. monilifera ensures faster uptake of the available soil water, thus minimizing the inherent advantage in A. longifolia of its lower water use and greater efficiency.     

A gall-forming biological control agent suppresses vegetative growth of an invasive tree

Attack by the gall-forming biological control agent Lophodiplosis trifida Gagné (Diptera: Cecidomyiidae), reduced Melaleuca quinquenervia sapling height by 10.1%, leaf biomass by 42%, woody biomass by 42.7%, and root biomass by 30.3%. This provided the first quantitative evidence of the potential of L. trifida to suppress pre-reproductive M. quinquenervia.     

Lipid accumulation inRhodotorula glutinis on sugar cane molasses in single-stage continuous culture

Microbial lipids produced byRhodotorula glutinis grown in continuous culture with molasses under nitrogen-limiting conditions were evaluated and the effects of growth rate on fatty acid composition were studied. As the growth rate decreased, cell biomass, lipid content and lipid yield gradually increased. The maximum lipid content recorded was 39% (w/w) of dry cell biomass at a dilution rate of 0.04 h^–1. The growth rate also affected fatty acid composition: oleic acid decreased with decreasing growth rate while stearic acid increased.     

Suppression of Pythium ultimum by Biowaste Composts in Relation to Compost Microbial Biomass, Activity and Content of Phenolic Compounds

Seventeen composts from separately collected organic household waste plus one bark compost and one compost from grape marc were analysed for suppression of Pythium ultimum, phytotoxicity, microbial biomass and activity, substrate-induced respiration, extractible phenolic compounds and other physical and chemical parameters. Nine of the samples were mildly suppressive to P. ultimum, the others were conducive. The bark compost sample was strongly suppressive. Therefore of the examined composts, only the bark could be used to exert an economically relevant control of P. ultimum in horticultural media. A large part of the compost samples was slightly phytotoxic. Microbial biomass and SIR had only weak correlations with disease incidence. Microbial activity and content of extractible phenolics were positively correlated with disease incidence. None of the tested parameters were therefore suitable as a predictive test for suppression of P. ultimum with the compost samples used in this study.     

Effect of Trichoderma on plant growth: A balance between inhibition and growth promotion

The effect of lettuce (Latuca sativa L.) germination and growth in nonsterilized potting compost of 0.1% and 1.0% w/w incorporation of fermenter biomass inocula of six strains of Trichoderma was investigated. Except for strains WT and T35 at 0.1 % w/w, all inocula inhibited germination. Biomass of strains WT, T35, 20, and 47 at 1.0% promoted shoot fresh weight, whereas strains TH1 and 8MF2 were inhibitory. In contrast, when biomass of strains WT, TH1, and 8MF2 was autoclaved and incorporated at 1%, shoot fresh weight was promoted, but the biomass of T35 was inhibitory. None of the strains incorporated at 0.1 % w/w increased shoot fresh weight, and autoclaved biomass of TH1, T35, and 20 incorporated at 0.1% w/w resulted in lower shoot fresh weights in comparison with uninoculated controls. The shoot dry weight of lettuce seedlings could be enhanced by germinating seeds in uninoculated compost and after five days' growth transferring them into WT-inoculated compost. Inoculum of strain TH1 when applied using this method was very inhibitory. With WT the degree of increase in shoot fresh weight and germination rate declined as the fermentation time to produce inocula was increased. Offprint requests to: J.M. Lynch.     

Utilisation of Ulva rigida biomass in the Venice Lagoon (Italy): biotransformation in compost

In the Venice Lagoon (Italy), about 10⁶ t (wet weight) of Ulva rigida biomass are produced annually as one of the major results of eutrophication. Harvests have been initiated to reduce negative impacts of this biomass, however, due to the high costs of such effort, only 40 000 t yr^-1 are currently being collected. At the moment, biotransformation into compost seems to be the only feasible technology for utilising large quantities of Ulva biomass. We describe and discuss here a successful composting strategy together with the chemico-physical and microbiological characteristics of the resultant composts. Our composting experiments were conducted at a scale of 20 t. The composting technology utilises large proportions (70–90%) of Ulva biomass and results in a valuable, high-quality end product (compost and compost-based products). This process and the resulting products represents a relatively simple way of utilising the Ulva biomass produced annually in the Venice Lagoon.     

Efficacy of Organic Soil Amendments for Management of Heterodera glycines in Greenhouse Experiments

In a repeated greenhouse experiment, organic soil amendments were screened for effects on population density of soybean cyst nematode (SCN), Heterodera glycines, and soybean growth. Ten amendments at various rates were tested: fresh plant material of field pennycress, marigold, spring camelina, and Cuphea; condensed distiller’s solubles (CDS), ash of combusted CDS, ash of combusted turkey manure (TMA), marigold powder, canola meal, and pennycress seed powder. Soybeans were grown for 70 d in field soil with amendments and SCN eggs incorporated at planting. At 40 d after planting (DAP), many amendments reduced SCN egg population density, but some also reduced plant height. Cuphea plant at application rate of 2.9% (amendment:soil, w:w, same below), marigold plant at 2.9%, pennycress seed powder at 0.5%, canola meal at 1%, and CDS at 4.3% were effective against SCN with population reductions of 35.2%, 46.6%, 46.7%, 73.2%, and 73.3% compared with control, respectively. For Experiment 1 at 70 DAP, canola meal at 1% and pennycress seed powder at 0.5% reduced SCN population density 70% and 54%, respectively. CDS at 4.3%, ash of CDS at 0.2%, and TMA at 1% increased dry plant mass whereas CDS at 4.3% and pennycress seed powder at 0.1% reduced plant height. For Experiment 2 at 70 DAP, amendments did not affect SCN population nor plant growth. In summary, some amendments were effective for SCN management, but phytoxicity was a concern.     

Biological Control of Chickpea Collar Rot by Co-inoculation of Antagonistic Bacteria and Compatible Rhizobia

Two hundred and seven bacteria were isolated from composts and macrofauna and screened for plant growth promoting and antagonistic traits. Seven of the 207 isolates showed antagonistic activity against Sclerotium rolfsii in plate culture. Inhibition of S. rolfsii by the bacterial isolates ranged between 61 and 84%. Two of the seven isolates were Bacillus sp. and rest belonged to Pseudomonas sp. Two isolates, Pseudomonas sp. CDB 35 and Pseudomonas sp. BWB 21 was compatible with chickpea Rhizobium sp. IC 59 and IC 76 in plate culture conditions. Increase in plant biomass (dry weight) ranged between 18 and 30% on application of these bacteria by seed coating and seed priming methods. However, by seed-priming there was an increase in plant biomass by 5–7% compared to seed coating. Number of nodules and the nodule weight was similar by both seed coating and seed priming methods. Disease incidence was reduced up to 47% in treatments where captan (fungicide) or antagonistic Pseudomonas sp. CDB 35 was applied. Increase in shoot weight was 36% by seed coating with Rhizobium sp. IC 59 and Pseudomonas sp. CDB 35 when compared to captan application. Whereas by seed priming with IC 59 and CDB 35 increased shoot weight by 3 and 39% increase in nodulation was observed.