Secondary dispersal, spatial dynamics and effects of herbicides on reproductive capacity of a recently introduced population of Bromus sterilis in an arable field

An arable field was subdivided and subjected to either deep inversion ploughing or non‐inversion cultivation after viable seeds of Bromus sterilis had been sown into oilseed rape stubble. After sowing in isolated plots distributed within the field, sequences of cropping treatments for the establishment of two successive winter wheat crops were applied. Each subfield was split into an uphill and a downhill direction for soil cultivation. The field had a 10° slope. In the season following seed introduction, 2.6% of the introduced seeds had successfully germinated and established in the non‐inversion cultivation regime, when no effective graminicide was applied. Ploughing eradicated B. sterilis. Using differential global positioning system (DGPS) mapping of the whole field population, emerged plants were observed up to 8.7 m (uphill treatment) and 21.3 m (downhill treatment) of their initial source. The median distance seeds were transported was 2.3 m uphill and 4.8 m downhill. Post‐emergence application of the herbicide propoxycarbazone slightly reduced weed density and seed weight, and almost halved weed seed production. Application of fenoxaprop‐P‐ethyl was followed by higher density of plants, tillers and seeds of B. sterilis. Seed viability was unaffected by herbicide use. Thus, in the second wheat crop following seed rain, the weed population was dispersed more widely in the field, such that 20–30% of seeds were dispersed more than 5 m distance from the first year's foci of infestation. The relevance of soil cultivation to secondary dispersal of B. sterilis is discussed.     

Advanced lentil lines screened for resistance to <Emphasis Type="BoldItalic">Fusarium oxysporum</Emphasis> f. sp. <Emphasis Type="BoldItalic">lentis</Emphasis> under greenhouse and field conditions

Fusarium oxysporum f. sp. lentis is the most important pathogen of lentil plants, and most areas under lentil cultivation are reported to have a fusarium wilt disease background. The plants are infected in the seedling stage and later stages of their development. Fusarium wilt disease, which has appeared at high incidence rates during recent years, has caused sharp drops in the yield, especially in Moghan, in the northwest of Iran. Forty-five isolates of the pathogen were collected from different regions of the country with two isolates from ICARDA in the summer of 2008 and identified using Nelson’s key. The pathogenicity of the collected isolates was studied on a sensitive line (ILL 4605) under greenhouse conditions and significant differences in pathogenicity were found among them. The most pathogenic isolates from three provinces, East Azerbaijan (EA 30), Ardebil (Ar 3) and Khorasan (Kh 45), were selected and used in screening of 55 developed lines under greenhouse and field conditions. In the greenhouse, test plants were inoculated by immersing root tips in spore suspension and sowing seeds in pre-infested pot soil. Field tests were carried out in a naturally highly infested farm. At all stages, the plant response to the disease was based on the percentage of dead plants. Cluster analyses of the greenhouse and field data led to the selection of three lines (81S15, FLIP2007-42 L and FLIP2009-18 L) that were resistant under greenhouse and field conditions.     

Spread of seed-borne <Emphasis Type="Italic">Erwinia rhapontici</Emphasis> in bean,pea and wheat

Studies were conducted in the laboratory and greenhouse to determine the distribution of Erwinia rhapontici in plants arising from naturally infected seeds of pea or artificially inoculated seeds of bean and wheat, and whether the pathogen is transmitted to the subsequent generation of seeds. Infected seeds were planted in pots of Cornell mix in the greenhouse, and sampled at specified intervals throughout the plant growth cycle (seedling stage, elongation stage, flowering stage, seed formation stage, and maturity). Plating of surface sterilized lateral roots, tap roots, basal stems, mid-stems, apical stems, petioles, pods, and seeds of pea and bean, and of lateral roots, sub-crown internodes, basal stems, mid-stems, apical stems, peduncles, glumes, and seeds of wheat revealed that the bacterial pathogen spread from infected seeds to the lower parts of the plant tissues, but failed to spread further to the seeds produced on these plants. The study concludes that E. rhapontici did not establish systemic infection throughout the plants. Possible mechanisms of infection of seeds are discussed.     

Optimising cutting method and timing for the control of Abutilon theophrasti seed production

Abutilon theophrasti (velvetleaf) is a widespread and problematic annual weed. Greenhouse and field experiments were conducted to investigate the effects of different cutting methods on the viability of A. theophrasti seeds. Three cutting methods were assessed: (1) Entire plant cut and dried (EPD)—plants were cut at soil level and dried with capsules attached on the greenhouse bench or soil surface for 4 weeks; (2) capsules detached and dried (CD)—capsules were removed from plants and dried for 4 weeks; and (3) capsules detached and tested while fresh (CF)—a control treatment. Before drying, the developmental stage (stage one, dark green; stage two, light green; stage three, yellowish-green; or stage four, black with the slightly open capsule) and age (days after flowering, DAF) of each capsule was recorded. Seed viability was measured immediately in the CF treatment and after the 4-week drying period in the EPD and CD treatments. No seeds in the EPD and CD treatments were viable when harvested at the first developmental stage (1–8 DAF) in either experiment, but 100% of seeds in the CF treatment in the field were viable when harvested at 8 DAF. In both greenhouse and field experiments, seeds attained full viability at earlier harvest ages in CF than in EPD or CD treatments, suggesting that seeds might become viable relatively early in development but lose viability if allowed to dry. These findings could be applied to optimise late-season mechanical control of A. theophrasti.     

Investigation of wheat as a trap crop for control of Orobanche minor

Orobanche minor is a parasitic weed that attaches to the roots of red clover (Trifolium pratense) and a number of other broad‐leaved plant species in the Pacific Northwest USA. Orobanche minor seed must be stimulated by host plant exudates for germination and attachment to occur. However, plant species called false‐hosts can stimulate parasitic seed germination without attachment. These species could be utilized as trap crops to reduce the amount of parasitic seed in infested soil. Wheat (Triticum aestivum), was found to be a false‐host of O. minor; therefore, growth chamber, glasshouse and field soil experiments were conducted to evaluate the effect of six soft white winter wheats (T. aestivum), one durum wheat (Triticum turgidum), and one triticale (Triticale hexaploide) on O. minor germination. In growth chamber experiments, wheat and triticale induced 20–70% of O. minor seeds to germinate. In glasshouse studies, O. minor attachment was minimal on red clover plants grown in pots previously planted to wheat or triticale. In pots that did not receive a false‐host treatment, red clover plants averaged 4.2 O. minor attachments per plant. Red clover plants also had fewer O. minor attachments when grown in field soil taken from the plots where wheat or triticale were grown compared with plants grown in soil where no wheat or triticale were previously grown. Our results demonstrate that wheat may have the potential to be effectively integrated into an O. minor management system.     

Effectiveness of thiamethoxam and imidacloprid seed treatments against Bemisia tabaci (Hemiptera: Aleyrodidae) on cotton

BACKGROUND: Bemisia tabaci (Gennadius) biotype B is one of the most important pests on cotton around the world. Laboratory, greenhouse and field experiments were conducted to determine the efficacy of thiamethoxam and imidacloprid seed treatments against B. tabaci on cotton. RESULTS: Under laboratory conditions, the two treatments caused whitefly adult mortality, reduced oviposition and increased mortality of nymphs at 10, 20, 30 and 40 days after germination (DAG). The longer the adults fed on plants from treated seeds, the higher the mortality. The two treatments did not have any effect on eggs. The efficacy of the treated seeds against B. tabaci gradually decreased from 10 to 40 DAG, being the lowest at 40 DAG. In laboratory experiments, the efficacies between the two treatments were similar. In greenhouse experiments, the two treatments were equally effective with lower numbers of whiteflies than untreated controls. With both treatments the concentrations of the active ingredient were gradually reduced with aging of the plants and from the bottom to the top leaves of the plants. Numbers of live whiteflies were well correlated with the dosage of active ingredients. Under field conditions, the seeds treated with both insecticides exhibited similar efficacy against B. tabaci for up to ～2 months. CONCLUSION: Cotton seeds treated with imidacloprid and thiamethoxam were effective against B. tabaci for up to 45 days under laboratory and greenhouse conditions, and up to ～2 months under field conditions. Use of imidacloprid‐ and thiamethoxam‐treated seeds can be an important alternative for management of whiteflies on cotton. Copyright © 2010 Society of Chemical Industry     

Variation in reproductive characteristics of Eupatorium adenophorum populations in different habitats

The invasive plant, Eupatorium adenophorum, produces large numbers of small seeds with a high germination rate. However, this investigation showed that E. adenophorum populations in an evergreen broad‐leaved forest had a high proportion of seedlings when compared with clonal plants. Whereas an opposite pattern was found in a deciduous broad‐leaved forest and in a roadside site. A seed addition experiment where E. adenophorum seeds were added to each of the three habitats did not increase the number of E. adenophorum seedlings at any of the three field sites. Field and greenhouse experiments demonstrated that a soil litter layer significantly reduced the number of E. adenophorum seedlings during the early seedling emergence period. However, at later periods, the litter cover did not affect survival and growth of individuals. The emergence of E. adenophorum seedlings was significantly increased in field experiments when there was no litter, and parental plants were removed. Finally, the growth of seedlings was significantly reduced when planted with their parental plants in a root box experiment. In the low‐resource environment of the evergreen broad‐leaved forest, E. adenophorum reproduced primarily by its abundant seed production. In the more open deciduous broad‐leaved forest and roadside site, the populations reproduce primarily by vegetative clones that can grow quickly, are better competitors and could take advantage of the high‐resource environment.     

Effect of growth medium, Striga seed burial distance and depth on efficacy of Fusarium isolates to control Striga hermonthica in Burkina Faso

Striga hermonthica is a destructive parasite of cereal crops in the semi‐arid tropical zone. Two greenhouse experiments were conducted at Kamboinsé, Burkina Faso, to investigate the effect of inoculum substrate and location of Striga seeds on the ability of 14 indigenous Fusarium isolates to control the parasite. In Expt 1, Fusarium isolates reduced emerged Striga number, Striga vigour and dry biomass. As a result, sorghum dry biomass and grain yield were enhanced. Inoculum substrate did not influence the ability of Fusarium isolates to control Striga. In Expt 2, Fusarium isolates, substrate and their interaction significantly influenced germination of Striga seeds at both 35 and 50 days after sowing. Isolates grown on compost were more effective at reducing germination of Striga seeds than those grown on chopped sorghum straw. The per cent germination of seeds 50 days after sowing, buried at 5 cm depth, was significantly lower than that of seeds buried at 10 cm. At 10 cm depth, Fusarium isolates still reduced Striga seed germination with respect to the control; horizontal planting distance, 5 or 10 cm from sorghum hills, had no effect.     

A review of the effects of crop agronomy on the management of Alopecurus myosuroides

This study reviews 52 field experiments, mostly from the UK, studying the effects of cultivation techniques, sowing date, crop density and cultivar choice on Alopecurus myosuroides infestations in cereal crops. Where possible, a statistical meta‐analysis has been used to calculate average responses to the various cultural practices and to estimate their variability. In 25 experiments, mouldboard ploughing prior to sowing winter cereals reduced A. myosuroides populations by an average of 69%, compared with non‐inversion tillage. Delaying drilling from September to the end of October decreased weed plant densities by approximately 50%. Sowing wheat in spring achieved an 88% reduction in A. myosuroides plant densities compared with autumn sowing. Increasing winter wheat crop density above 100 plants m^?2 had no effect on weed plant numbers, but reduced the number of heads m^?2 by 15% for every additional increase in 100 crop plants, up to the highest density tested (350 wheat plants m^?2). Choosing more competitive cultivars could decrease A. myosuroides heads m^?2 by 22%. With all cultural practices, outcomes were highly variable and effects inconsistent. Farmers are more likely to adopt cultural measures and so reduce their reliance on herbicides, if there were better predictions of likely outcomes at the individual field level.     

Enhanced weed‐crop competition effects on growth and seed production of herbicide‐resistant and herbicide‐susceptible annual sowthistle (Sonchus oleraceus)

Enhanced crop competition could aid in the management of annual sowthistle (Sonchus oleraceus L.), a dominant weed of Australian cropping systems. A two‐year pot study was conducted to evaluate the effect of wheat (Triticum aestivum L.) planting densities (0, 82, and 164 wheat plants/m²) on growth and seed production of glyphosate‐resistant (GR) and glyphosate‐susceptible (GS) biotypes of annual sowthistle. Without competition, both biotypes produced a similar number of leaves and biomass, but the GS biotype produced 80% more seeds (46,050 per plant) than the GR biotype. In competition with 164 wheat plants/m², the number of leaves in the GR and GS biotypes was reduced by 62 and 61%, respectively, in comparison with the no‐competition treatment, and similarly, weed biomass was reduced by 78 and 77%, respectively. Compared to no‐competition treatment, the seed production of GR and GS biotypes was reduced by 33 and 69%, respectively, when grown with 82 wheat plants/m², but increasing wheat density from 82 to 164 plants/m² reduced the number of seeds only in the GS biotype (81%). Both biotypes produced greater than 6,000 seeds per plant when grown in competition with 164 plants/m², suggesting that increased crop density should be integrated with other weed management strategies for efficient control of annual sowthistle.     

Emmer wheat, a potential new host of Tilletia indica

Two representative Italian emmer wheat (Triticum dicoccum) landraces, two selected lines and three improved emmer wheat cultivars, derived from crosses with durum wheat (Molisano landrace × ‘Simeto’), were tested for their susceptibility to Tilletia indica, the cause of Karnal bunt of wheat. Plants of emmer wheat were inoculated by injecting allantoid sporidial suspensions into the boot cavity of plants, just prior to ear emergence. A highly susceptible Indian spring wheat cultivar (Triticum aestivum) was used as a comparative control. At maturity of the plants, the seeds were harvested and assessed for incidence and severity of disease. All emmer wheat genotypes tested were infected but showed differing levels of susceptibility. The percentage of infected seeds for individual genotypes ranged from 5.4 to 75.0% compared with 99.1% for WL-711. The severity of infection was less in the old landraces, but it was higher in all the improved emmer wheat cultivars. In conclusion, Italian cultivars of emmer wheat were found to be highly susceptible to T. indica, and are potentially able to support the establishment of the pathogen.Authors L. Riccioni and M. Valvassori contributed equally to this work and should both be considered as first author.     

Tracing seed to seedling transmission of the wheat blast pathogen Magnaporthe oryzae pathotype Triticum

Wheat blast caused by Magnaporthe oryzae pathotype Triticum (MoT), initially restricted to South America, is a global threat for wheat after spreading to Asia in 2016 by the introduction of contaminated seeds, raising the question about transmission of the pathogen from seeds to seedlings, a process so far not well understood. We therefore studied the relationship between seed infection and disease symptoms on seedlings and adult plants. To accomplish this objective, we inoculated spikes of wheat cv. Apogee with a transgenic isolate (MoT-DsRed, with the addition of being resistant to hygromycin). We identified MoT-DsRed in experiments using hygromycin resistance for selection or by observation of DsRed fluorescence. The seeds from infected plants looked either apparently healthy or shrivelled. To evaluate the transmission, two experimental designs were chosen (blotter test and greenhouse) and MoT-DsRed was recovered from both. This revealed that MoT is able to colonize wheat seedlings from infected seeds under the ground. The favourable conditions of temperature and humidity allowed a high recovery rate of MoT from wheat shoots when grown in artificial media. Around 42 days after germination of infected seeds, MoT-DsRed could not be reisolated, indicating that fungal progression, at this time point, did not proceed systemically/endophytically. We hypothesize that spike infection might occur via spore dispersal from infected leaves rather than within the plant. Because MoT-DsRed was not only successfully reisolated from seed coats and germinating seeds with symptoms, but also from apparently healthy seeds, urgent attention is needed to minimize the risks of inadvertent dispersal of inoculum.     

Dominant Colonisation of Wheat Roots by Pseudomonas fluorescens Pf29A and Selection of the Indigenous Microflora in the Presence of the Take-all Fungus

Increases in populations of fluorescent pseudomonads on wheat roots are usually associated with take-all decline, natural control of take-all, a disease caused by the fungus Gaeumannomyces graminis var. tritici (Ggt). Colonisation by Pseudomonas fluorescens strain Pf29A was assessed on the roots of healthy plants and of plants with take-all, and the effect of this bacterium on indigenous populations of fluorescent pseudomonads was studied. The efficacy of Pf29A as an agent for the biocontrol of take-all on five-week-old wheat seedlings was tested in non-sterile conducive soil in a growth chamber. RAPD (random amplification of polymorphic DNA) fingerprinting with a decamer primer was used to monitor strain Pf29A and culturable indigenous rhizoplane populations of fluorescent pseudomonad. Pf29A decreased disease severity and accounted for 44.6% of the culturable fluorescent pseudomonads on healthy plant rhizoplane and 75.8% on diseased plant rhizoplane. Fewer RAPD patterns were obtained when Pf29A was introduced into the soil with Ggt. In the presence of Ggt and necrotic roots, Pf29A became the dominant root coloniser and dramatically changed the diversity and the structure of indigenous fluorescent pseudomonad populations. The results show that Ggt and reduced lesion size on roots can trigger a specific increase in antagonist populations and that the introduction of a biocontrol agent in soil influences the structure of indigenous bacterial populations.     

Disease protection and growth promotion of potatoes (Solanum tuberosum L.) by Paenibacillus dendritiformis

One of the challenges in developing plant‐beneficial bacterial agents for agricultural application is ensuring that an effective selection and screening procedure is in place. The sporadic success of using bacterial agents in the field is usually due to the inability of added bacteria to compete with the local microorganisms. In the present study, the effectiveness of Paenibacillus dendritiformis, a unique pattern‐forming, Gram‐positive, soil bacterium, to reduce disease indices and increase yield in potato crops was examined. This bacterium was chosen as a potential agent based on genome analysis carried out in previous studies. In vitro laboratory experiments, as well as three greenhouse and one field experiment, were conducted. The results show that, in agreement with the hypothesis, P. dendritiformis significantly reduced the maceration area of tuber slices infected by Pectobacterium carotovorum subsp. carotovorum, significantly reduced disease indices in greenhouse experiments and significantly increased tuber yield of infected plants in the field. This work demonstrates the potential of preliminary screening based on genome analysis to identify effective biocontrol agents.     

覆膜对不同播期冬小麦根系生长和产量的影响

为探究覆膜对冬小麦根系生长和产量的影响,于2017—2018和2018—2019年度在冬小麦生育期设置2种栽培模式（CK: 裸地穴播,PM: 全膜穴播）和3个播种日期（0：传统播期,10：晚播10 d,20：晚播20 d）,分析了覆膜措施对不同播期冬小麦地上部和根系生长、产量及其构成,以及水分利用效率的影响。结果表明,覆膜处理有效增加了不同播期冬小麦返青期后的根长密度（RLD）、根表面积密度（RSD）、根系生物量、地上部生物量;各生育期PM0处理的RLD、RSD、根系生物量、地上部生物量均最大。覆膜对晚播冬小麦根系生长具有一定的加速作用,使得两季冬小麦PM10处理的RLD、RSD和根系生物量在返青期分别比CK0处理高2.90%、13.63%和23.04%。与CK0处理相比,两季冬小麦灌浆期 PM0、PM10、PM20处理的地上部生物量分别显著增加65.63%、75.57%和54.71%（P<0.05）。两季冬小麦覆膜处理的产量和水分利用效率均比同播期裸地处理高,其中,两季冬小麦PM0、PM10处理的产量分别比CK0处理提高28.92%、14.35%,水分利用效率分别比CK0处理提高17.87%、7.90%。此外,研究还发现,冬小麦返青期、开花期、灌浆期总RLD均与有效穗数、产量、水分利用效率呈极显著正相关关系（P<0.01）;冬小麦返青期总RSD、根系生物量均与有效穗数、产量及水分利用效率呈极显著正相关关系（P<0.01）。综上,覆膜措施通过改良土壤的水热环境,加速并促进了冬小麦根系的生长发育,进而改善了冬小麦根系对水分和养分的吸收,增加冬小麦植株的抗逆性。     

Effects of soil moisture and sowing depth on the development of bean plants grown in sterile soil infested by <Emphasis Type="Italic">Rhizoctonia solani</Emphasis> and <Emphasis Type="Italic">Trichoderma harzianum</Emphasis>

The effects of soil moisture (varying from 15% to 42% (v/v)) and sowing depth (1.5–6.0 cm) on the development of bean plants grown in sterile soil infested by the pathogen Rhizoctonia solani and its antagonist Trichoderma harzianum were studied under greenhouse conditions. The four possible combinations of soil infestation with both fungi were tested. Disease severity, percentage of plants emerged, plant height and dry weight were evaluated 3 weeks after sowing. Emergence rate and growth of plants inoculated only with R. solani were not affected by soil moisture, but in the presence of both fungi, plant emergence, plant height and dry weight significantly decreased when soil moisture diminished. Deep sowing significantly reduced the emergence rate and growth of those plants that were inoculated with R. solani only. However, when the soil was infested with both fungi, the effect of sowing depth was not significant. At a sowing depth of 6.0 cm, the percentage of plants emerged was 50% in the presence of T. harzianum, but only 6.7% when the pathogen was inoculated alone. The antagonist protected bean seedlings from pre-emergence damping-off, reduced disease severity and increased plant growth in the presence of R. solani, especially in moist soil.     

Growth and reproductive success of the seed‐derived plants of Sagittaria trifolia emerging at different times

In order to clarify the growth and reproductive success of seed‐derived Sagittaria trifolia individuals emerging at different times within a season, seeds were sown on May 16, June 16 and July 22 2010 and allowed to grow in pots under shaded and unshaded conditions. The timing of when the first inflorescence of each seedling appeared was recorded, as well as the number of seeds and tubers produced and the dry weight of each organ. In total, 220 seedlings were used, 23–59 in each treatment. As the sowing time was delayed, so too was the appearance of the first inflorescence. Additionally, the number of inflorescences, fruits and seeds produced by the unshaded plants significantly decreased with the sowing time. The total dry weight was significantly greater in the unshaded than in the shaded plants: the July‐sown, shaded plants grew very poorly. The relative resource allocation to the tubers was greater in the late‐emerging, shaded seedlings. Even in the shaded groups, except for the July‐sown plants, most of the plants set seed. Therefore, when addressing weed control in paddy fields, one should keep seedlings in mind, in addition to plants that have grown from tubers.     

Effect of vernalization on the development and growth of Alopecurus myosuroides

Alopecurus myosuroides is an annual winter grass weed present in many winter and spring crops. The vernalization responses of three populations of A. myosuroides were assessed using natural exposure during winter in two field experiments and using cold exposure of imbibed seeds in a refrigerator in two greenhouse experiments. It was observed that a period of chilling during the pregermination phase had a marked effect on subsequent phenology. In the greenhouse, the major effect of vernalization was the reduction in the vegetative period because of an early reproductive induction of the apex. Plant morphology was affected by vernalization via a decrease in biomass resulting from a reduced tiller number. In all experiments, the time to panicle emergence and the number of leaves on the main stem were reduced by the chilling treatment in field and greenhouse experiments. Alopecurus myosuroides appears to be a species with a partial (quantitative) requirement for cold vernalization, but polymorphism for vernalization requirement was observed within and between populations. Depending on the sowing date, 850–1200 day–degrees C were required for flowering. The possible existence of different annual life forms within A. myosuroides is discussed.     

Epiphytic growth of Xanthomonas arboricola and Xanthomonas citri on non‐host plants

The population dynamics of Xanthomonas arboricola pv. pruni (Xap) and X. citri subsp. citri (Xcc) was assessed on over three dozen plant species/genotypes under field and greenhouse conditions. Both Xap and Xcc multiplied on red nightshade, black nightshade, bindweed, Chenopodium, common bean and wheat up to 20 days post‐inoculation (dpi) under greenhouse conditions. A high bacterial growth rate was observed on all (alfalfa, bindweed, Chenopodium, field mustard, millet and prickly lettuce) but one (liquorice) plant species tested under field conditions. Xap successfully proliferated on both lemon and sweet lemon up to 140 dpi, attaining a population density even higher than that of Xcc. The latter showed an increased growth rate on GxN, GF677, Ghisella 6 and Mariana 2624 rootstocks up to 140 dpi. While Xap and Xcc did not grow on pomegranate and common fig, they had a steady population growth on apple and pear plants up to 140 dpi, although the final population sizes were smaller than those observed on lemon and sweet lemon plants. The results suggest that a large number of non‐host plant species could support epiphytic populations of Xap or Xcc, which may have implications for plant disease epidemiology.     

Efficacy of some rhizospheric and endophytic bacteria <Emphasis Type="Italic">in vitro</Emphasis> and as seed coating for the control of <Emphasis Type="Italic">Fusarium culmorum</Emphasis> infecting durum wheat in Tunisia

Sixty two rhizospheric and endophytic bacterial strains were evaluated for their biocontrol effect on two aggressive Fusarium culmorum isolates (Fc2 and Fc3). We observed that 35 % and 23 % of the tested strains inhibited the in vitro growth of Fc2 and Fc3 respectively. The observed antagonism was due to inhibition by contact (13–19 % of the strains) or at distance (10–16 % of the strains) for both fungal isolates. Some of the antagonistic bacteria showed the ability to produce diffuse and/or volatile compounds that inhibit the growth, the sporulation and macroconidia germination of F. culmorum. None of the tested antagonistic bacteria showed chitinase activity on synthetic medium. The sequencing of the 16S rDNA genes of some antagonistic bacteria showed that they belong to the genera Bacillus, Pseudomonas and Microbacterium. The double inoculation of durum wheat seeds by the antagonistic bacterial strains (B13, B18, BSE1, BSE3 and B16E) and the two F. culmorum isolates showed that germination and seedling vigor were generally improved in vitro. The percentage of infected seeds was also reduced. In greenhouse trials, the biocontrol effectiveness of F. culmorum was dependant from the virulence of the fungal strain and the specificity of the antagonistic interaction between bacterial and fungal strains. The bacterial strains B18 and B16E reduced F. culmorum infection on durum wheat plants probably due to their antagonistic and plant growth promoting activities and they may be used in a mixture as seed biopriming inoculum for plant growth bio-promoting and Fusarium wheat diseases biocontrol.