Effect of endophytic Fusarium oxysporum on paralysis and mortality of Pratylenchus goodeyi

Three bioassays were conducted to investigate the antagonistic effect of secondary metabolites produced by 5 endophytic Fusarium oxysporum isolates from banana (Musa spp.) plants in Kenya, against Pratylenchus goodeyi. Percentage paralyses were recorded 3, 6 and 24 h after exposure to culture filtrates. Percentage mortality was evaluated after 48 h. All isolates caused significantly higher percentage paralysis (17.5 - 25.9%) and percentage mortality (62.3 - 72.8%) of P. goodeyi motile stagescompared to the control (8.4 - 10.9% and 17.3 - 34.6%, respectively). Percentage paralysis of motile stages of P. goodeyi decreased as the length of time exposure to culture filtrates increased, while mortality increased as length of nematodes exposure to culture filtrates increased. Kenyan isolates performed equally as good as the Ugandan isolate (V5W2) in causing paralysis and mortality. Results from this study demonstrated that endophytic F. oxysporum antagonizes P. goodeyi through production of secondary metabolites

Effect of endophytic Fusarium oxysporum on paralysis and mortality of Pratylenchus goodeyi

Open Access JournalThree bioassays were conducted to investigate the antagonistic effect of secondary metabolites produced by 5 endophytic Fusarium oxysporum isolates from banana (Musa spp.) plants in Kenya, against Pratylenchus goodeyi. Percentage paralyses were recorded 3, 6 and 24 h after exposure to culture filtrates. Percentage mortality was evaluated after 48 h. All isolates caused significantly higher percentage paralysis (17.5 - 25.9%) and percentage mortality (62.3 - 72.8%) of P. goodeyi motile stages compared to the control (8.4 - 10.9% and 17.3 - 34.6%, respectively). Percentage paralysis of motile stages of P. goodeyi decreased as the length of time exposure to culture filtrates increased, while mortality increased as length of nematodes exposure to culture filtrates increased. Kenyan isolates performed equally as good as the Ugandan isolate (V5W2) in causing paralysis and mortality. Results from this study demonstrated that endophytic F. oxysporum antagonizes P. goodeyi through production of secondary metabolites

Endophyte enhanced banana tissue culture: technology transfer through publicprivate partnerships in Kenya and Uganda

The lack of clean planting material is a major constraint for banana production in East and Central Africa. When establishing new fields, tissue culture plantlets will reduce damage by banana pests and diseases. Pest infestation or reinfestation, however, remains a vital concern. Fungal endophytes, when inoculated into banana tissue culture plants, extend the benefits of clean planting material. Endophyte-enhanced tissue culture technology is being developed at the International Institute of Tropical Agriculture (IITA). Tissue culture production facilities in Uganda are in their infancy, while in Kenya the situation is more developed. Public-private partnerships between IITA and Agro-Genetic Technologies Ltd (Uganda), and Jomo Kenyatta University of Agriculture and Technology (Kenya) have recently enabled IITA’s project to make great progress towards bridging upstream research and downstream technology transfer. Additionally, unexpected synergisms have emerged through mutual exchange of information and experience. Based on IITA’s highly positive experience, such public-private partnerships should be introduced as early as possible in the developmental stages of activities to maximize the benefits to research for development

Potential biological control of lesion nematodes on banana using Kenyan strains of endophytic Fusarium oxysporum

Published online: 22 August 2012.The root-lesion nematode Pratylenchus goodeyi is a common pest of banana in Kenya, which results in significant yield losses. An emerging option for the management of banana nematodes includes the use of endophytic fungi, which cause no damage to their hosts but often extend benefits, such as enhanced protection against various biotic and abiotic constraints. In the current study, non-pathogenic Fusarium oxysporum strains originating from banana (Musa spp.) in Kenya (4MOC321 and 11SR23) and Uganda (V5w2) were evaluated for their efficacy against P. goodeyi in tissue culture-derived plantlets (cv. Giant Cavendish and cv. Grand Nain) in pots. Pratylenchus goodeyi densities were 47-60% lower in endophyte-inoculated relative to non-inoculated plants and root necrosis damage was reduced by >30%. Endophyte treatment had no effect on plant growth parameters compared with untreated control plants. The performance of the two Kenyan strains was equally effective as the positive control (V5w2), thus demonstrating their potential as nematode bio-control agents under Kenyan growing conditions

Nonpathogenic Fusarium oxysporum endophytes provide field control of nematodes, improving yield of banana (Musa sp.)

Endophytic colonization by the fungus Fusarium oxysporum can result in increased host resistance topests and diseases, and greater biomass production. However, few studies have assessed the field performanceof this fungus for biological control of pests and diseases in banana. Further to greenhouse assessment,studies were carried out to evaluate the performance of F. oxysporum strains against plant-parasiticnematodes on banana (Musa sp., cv. Giant Cavendish and cv. Grand Nain) in the field using tissue-culturedplants. Plants were inoculated separately with one of three strains (V5W2, Eny 7.11o and Emb 2.4o)before being inoculated with Pratylenchus goodeyi and Helicotylenchus multicinctus in an on-station trialand in an on-farm trial planted in a field naturally infested with the same nematodes. All three endophyticstrains significantly suppressed P. goodeyi and H. multicinctus densities and damage in the field.On-station, nematode population densities were reduced by >45% in endophyte-inoculated plants comparedto non-inoculated plants, while percentage root necrosis was reduced by >20%. Similarly, on-farm,nematode damage to roots and densities were also significantly lower in endophyte-inoculated plantscompared with control plants. Significantly improved yields were observed for plants inoculated withendophytes when compared to the control plants, with inoculation with strains Emb 2.4o and V5W2resulting in up to 35% and 36% increased banana yields, respectively, for the on-station trial. For theon-farm trial, up to 20% increase in yields were observed for strain Eny 7.11o compared to control plants.This study provides the first report from the field in Africa on the reduction of nematode populations anddamage, and the increase in banana production by fungal endophytes. The study shows that endophyteshave potential to enhance yields of tissue-cultured banana plants and protect them against pests

Financing, handling, hardening and marketing of tissue culturederived planting material through nurseries: the case of banana and plantain in Kenya, Uganda and Burundi

The distribution of contaminated planting material (suckers) remains a major cause of spread of pests and diseases in banana. A traditional subsistence staple in East Africa, banana is becoming increasingly a commercialized commodity in the region. Essential for effective commercialization of this crop, however, is the supply and use of uniform and healthy planting material. Tissue culture (TC) technology can help provide this. However, TC plantlets are delicate and require substantially greater care and handling than conventional sucker planting material. To distribute TC seedlings to farmers and improve their robustness for successful use on farms, numerous hardening nurseries have been established by TC producers in Kenya, Uganda and Burundi. These nurseries are pivotal in the dissemination of plantlets. In 2008, financing, handling, hardening and marketing of TC-derived planting material through nurseries was assessed using semi-quantitative interviews of nursery operators. The nurseries in Kenya and Uganda are mostly farmer-led and obtain their material from the producer. In Burundi, the nurseries are owned and centrally managed by the producer, while daily activities are handled by technicians. In each country, water supply was identified as a key limiting factor, as the young plantlets desiccate easily. In farmer-led nurseries, plantlet transport and phytosanitary measures, such as soil sterilization and plant protection, are often limited, which can lead to significant plant losses. Governmental and non-governmental institutions purchase large fractions of the TC planting material. Public extension services for TC nurseries were evaluated as poor, leaving the TC producers as the single source of information for nursery operators. Additionally, plantlets tend to be viewed as relatively expensive, while supply is currently sub-optimal, compared to traditional planting material, resulting in a relatively limited and exclusive market. TC planting material in the region is therefore yet to be become sufficiently available for most banana farmers

Factors influencing in vitro shoot regeneration of Macadamia integrifolia

study was carried out to investigate the effect of culture medium factors that influence the shoot regenerative potential of Macadamia nodal segments in vitro. Explants were obtained from shoots ofcurrent growth flush of Macadamia integrifolia and inoculated onto different test media. Woody plant medium (WPM) gave results comparable to MS medium whose macronutrients had been reduced to half rate. Explants cultured on media gelled with Biotec agar No. 1 and Purified agar had significantly higher bud breaking frequency and shoot number per explant than Phytagel and Gelrite. Optimum cultureperformance was obtained on MS medium enriched with 30 g/L sucrose. Highest bud breaking frequency (98%), shoot number per explant (8.1) and shoot length (3.3 cm) were obtained when WPM was supplemented with 2 mg/L BAP, 1 mg/L IBA and 1 mg/L GA3. When elongated shoots were cultured on to medium supplemented with cytokinins for rooting, only excessive callusing was obtained but no roots were formed within the culture period. The results of this study indicate that M. integrifolia is amenable to tissue culture but further studies are required to obtain rooting of in vitro shoots to come up with an optimized commercially feasible protocol for Macadamia tissue culture

ARPN Journal of Agricultural and Biological Science VIRULENCE OF THREE STRAINS OF Beauveria bassiana AGAINST THE BANANA WEEVIL

ABSTRACT The banana weevil, Cosmopolites sordidus Germar, is the most important insect pest of banana and plantain. Beauveria bassiana is the most researched and commercialized fungal biopesticide effective against a variety of insects. Laboratory studies have revealed a great potential of this entomopathogen for use against the banana weevil, Cosmopolites sordidus in banana. Use of traps for collecting adults or infecting them with biopesticides will most likely capture only those weevils in the immediate vicinity of the traps. The indiscriminate use of chemicals has resulted in the development of resistance in insect pests, adverse ecological events, affecting beneficial fauna, and accumulation of residues in the environment. There is considerable need therefore to develop safe and cheaper biocontrol alternatives that can be used to complement existing control methods. The potential of utilizing the entomopathogen B. bassiana for control of banana weevil was evaluated by testing the virulence of three isolates of Beauveria bassiana (ICIPE 273, M353 and M207) at three concentration (10 8 , 3x10 8 and 10 9 ). From previous pathogenicity tests these three isolates were the most pathogenic. At higher fungal concentrations of 3x10 8 and 10 9 adult mortality for all the three isolates was between 35%-70%. The highest mortality was achieved using an elevated concentration of 10 9 , causing mortalities varying from 50-70% 40 days after exposure depending on the isolate. ICIPE 273 was the most virulent, killing 70% of adults followed by M353 (65% mortality) and M207 (51% mortality). This was far much greater than when a standard concentration of 10 8 was used (mortalities ranged between 28%-50%). Differences in virulence among the tested isolates were due to their geographical origins