Le profenofos, un alternatif à l’endosulfan en culture cotonnière au Bénin

Dans l’objectif de trouver un alternatif à l’endosulfan, l’efficacité du profenofos et de l’endosulfan a été étudié dans un dispositif de bloc aléatoire complet en station et en milieu réel. Sur station, le profenofos assure un contrôle, équivalent et parfois significativement supérieur (p < 0,001) à l’endosulfan, des populations des ravageurs comme Helicoverpa armigera, Earias spp, Pectinophora gossypiella, Cryptophlebia leucotreta. Le Fanga 500 EC (profenofos 750 g/ha) a été significativement supérieur (p < 0,05) à Callisulfan 350 EC (endosulfan 700 g/ha) pour le contrôle des populations de Aphis gossypii, Pectinophora gossypiella et Earias spp. Il en résulte une production de capsules vertes saines qui montre que le Calfos 500 EC (profenofos 750 g/ha) est équivalent aux différentes formulations d’endosulfan testées et parfois significativement meilleur (p < 0,01) au Thiofanex 350 EC (endosulfan 700 g/ha). A la récolte du coton graine, le profenofos procure un rendement significativement supérieur (p < 0,05) à l’endosulfan. En milieu paysan, aucune différence significative (p > 0,05) n’a été observée entre le Calfos 500 EC (profenofos 750 g/ha) et le Callisulfan 350 EC (endosulfan 700 g/ha) à la récolte du coton graine. Le profenofos peut être appliqué comme un alternatif à l’endosulfan en culture cotonnière au Bénin.© 2016 International Formulae Group. All rights reserved.Mots clés: Profenofos, alternatif à l’endosulfan, culture cotonnière, BéninEnglish Title: The profenofos, an alternative to endosulfan in cotton crop in BeninEnglish AbstractIn the objective to find an alternative to endosulfan, the efficacy of profenofos and endosulfan has been studied in a complete randomized block design in experimentation station and in real environment. In station, the profenofos provides, in comparison with endosulfan, an equivalent control, and sometimes, a significantly higher (p < 0.001) control, of cotton pest populations including Helicoverpa armigera, Earias spp, Pectinophora gossypiella, Cryptophlebia leucotreta. The effect of Fanga 500 EC (profenofos 750 g/ha) has been significantly higher (p < 0.05) than the effect of Callisulfan 350 EC (endosulfan 700 g/ha) for the control of the populations of Aphis gossypii, Pectinophora gossypiella and Earias spp. It results, of this fact, a production of the best quality of cotton which shows that the Calfos 500 EC (profenofos 750 g/ha) is equivalent to various formulations of endosulfan tested and sometimes significantly better (p < 0.01) than Thiofanex 350 EC (endosulfan 700 g/ha). At harvest time, the profenofos provides a yield of seed cotton significantly higher (p < 0.05) than those obtained with endosulfan. In real environment, at harvest time of seed cotton, no  significant difference (p > 0.05) has been observed between the Calfos 500 EC (profenofos 750 g/ha) and the Callisulfan 350 EC (endosulfan 700 g/ha). The profenofos can be used as an alternative to endosulfan in cotton crop in Benin.© 2016 International Formulae Group. All rights reserved.Keywords: Profenofos, alternative to endosulfan, cotton crop, Beni

In vitro growth characterization and biocontrol potential of naturally occurring nematophagous fungi recovered from rootknot nematode infested vegetable fields in Benin

Naturally occurring fungal antagonists of root-knot nematodes (Meloidogyne spp., RKNs) were collected from 88 root and corresponding rhizosphere soil samples from 50 intensively cultivated fields used for peri-urban vegetable production in Benin, West Africa. Five species of Trichoderma viz.: T. asperellum, T. harzianum, T. brevicompactum, T. hamatum and T. erinaceum and four isolates of Pochonia chlamydosporia were isolated from RKN egg masses on root systems of crops and/or infested soil. During temperature-tolerance assessment studies, most isolates had maximum growth rates in Petri dishes at 28 C. Chlamydospore production by P. chlamydosporia was high in 2:1 v/v sand-milled corn medium. In pots, P. chlamydosporia isolates showed high ability to colonize and persist in tomato rhizosphere over 10 weeks. Pre-planting application with some P. chlamydosporia isolates led to up to 50% infected eggs and 25% reduction of RKN multiplication and root galling damage. This study provides valuable information for the mass rearing of the respective fungal inoculum and the first information on the potential of West African P. chlamydosporia isolates for use against RKN in vegetable production systems.Naturally occurring fungal antagonists of root-knot nematodes (Meloidogyne spp., RKNs) were collected from 88 root and corresponding rhizosphere soil samples from 50 intensively cultivated fields used for peri-urban vegetable production in Benin, West Africa. Five species of Trichoderma viz.: T. asperellum, T. harzianum, T. brevicompactum, T. hamatum and T. erinaceum and four isolates of Pochonia chlamydosporia were isolated from RKN egg masses on root systems of crops and/or infested soil. During temperature-tolerance assessment studies, most isolates had maximum growth rates in Petri dishes at 28 C. Chlamydospore production by P. chlamydosporia was high in 2:1 v/v sand-milled corn medium. In pots, P. chlamydosporia isolates showed high ability to colonize and persist in tomato rhizosphere over 10 weeks. Pre-planting application with some P. chlamydosporia isolates led to up to 50% infected eggs and 25% reduction of RKN multiplication and root galling damage. This study provides valuable information for the mass rearing of the respective fungal inoculum and the first information on the potential of West African P. chlamydosporia isolates for use against RKN in vegetable production systems.Naturally occurring fungal antagonists of root-knot nematodes (Meloidogyne spp., RKNs) were collected from 88 root and corresponding rhizosphere soil samples from 50 intensively cultivated fields used for peri-urban vegetable production in Benin, West Africa. Five species of Trichoderma viz.: T. asperellum, T. harzianum, T. brevicompactum, T. hamatum and T. erinaceum and four isolates of Pochonia chlamydosporia were isolated from RKN egg masses on root systems of crops and/or infested soil. During temperature-tolerance assessment studies, most isolates had maximum growth rates in Petri dishes at 28 C. Chlamydospore production by P. chlamydosporia was high in 2:1 v/v sand-milled corn medium. In pots, P. chlamydosporia isolates showed high ability to colonize and persist in tomato rhizosphere over 10 weeks. Pre-planting application with some P. chlamydosporia isolates led to up to 50% infected eggs and 25% reduction of RKN multiplication and root galling damage. This study provides valuable information for the mass rearing of the respective fungal inoculum and the first information on the potential of West African P. chlamydosporia isolates for use against RKN in vegetable production systems

First report of Aspergillus allahabadii Mehrotra and Agnihotri in vegetable fields in Northern Benin (West-Africa)

Aspergillus allahabadii, previously reported only from soils in India and El Salvador, was isolated from root-knot nematode egg masses (Meloidogyne spp.) in vegetable fields in Benin. Three populations were recovered from separate fields in the Guinea savannah region from tomato and/or cabbage. The populations were morphologically identified to genus level under the microscope and to species level from molecular sequences based on ITS 1 and ITS 2 regions using purified fungi. All populations were able to produce spores on potato dextrose agar following incubation at 25 °C as well as room temperature (24 ± 2 °C), producing as many as 7.9 x 108 and 3.0 x 108 spores per plate after 10 days, respectively. Pre-planting inoculation of the populations onto tomato (cv. Tounvi) seedlings in 1-L pots increased tomato shoot and root fresh weights by up to 13 and 24 %, respectively, compared to untreated controls after five weeks. The three populations all successfully established and remained in the rhizosphere of tomato plants until termination of the experiment at seven weeks after inoculation. Given that the populations were all isolated from nematode egg masses, the current study can be considered as the starting point for further research on their possible use for biological control

Prevalence De La Maladie Du Deperissement De L’ananas (Wilt) Et Perception Des Producteurs Au Benin

Pineapple [Ananas comosus (L.) Merril], cultivated in Benin for it economical importance is affected by Pineapple mealybug wilt, a viral disease. The objectives of this study were to evaluate the determining factors of its prevalence and farmers knowledge on the disease. To achieve these, a total number of 180 farmers, distributed in five communes of southern Benin have been interviewed in 2014 and 2015. In order to identify factors that influence the disease distribution, generalized linear models with the binomial and multinomial distribution family were used to explain the effect of the variables (field and plant levels) and disease severity, respectively. Only factors ‘commune’ 'and' year ' had a significant effect on the incidence at field level (69% in 2014 and 78% in 2015) while three predictors (township, year and variety) explained the severity of the disease and the interaction year -township was significant. Farmers perceive the disease and attribute five causes responsible for its expression. They use height methods to manage the disease. These findings constitute a qualitative as well as quantitative information to build on in designing methods of controlling the disease in order to boost the productivity of pineapple in Benin

Root endophytic status of west African biocontrol agents and implications for root-knot nematode management

The potential of four fungal biocontrol isolates (Trichoderma asperellum T-12, Pochonia chlamydosporia Pc-1, Kuklospora kentinensis BEN302, Aspergillus allahabadii BEN03) from West Africa to endophytically colonize tomato plants and provide in planta protection against root-knot nematodes (Meloidogyne spp.), was assessed in pots in the greenhouse. Colonization assessment at 11 wk after inoculation indicated that all the fungal isolates were able to internally develop and colonize tomato roots. The root dip treatments with the fungi led to significant inhibition of root-knot nematode reproduction, juvenile hatching, and root galling damage. Pre-planting treatment with T. asperellum T-12 showed the greatest nematode control, reducing root galling severity and nematode reproduction by 47% and 67%, respectively, and significantly inhibiting egg hatch by up to 85%, compared to the control. Endophytic protection by the individually inoculated fungal isolates also led to significantly improved tomato growth of shoots and roots. Such in planta host plant nematode suppression lends itself to novel, cost-effective, and environmentally suitable pest management options that can be efficiently integrated into seedling production systems. This study provides strong evidence and justification for exploring other mechanisms such as systemic effects of the fungi and, in particular, the effect of fungi on reducing egg hatching

Biocontrol potential of native Trichoderma isolates against rootknot nematodes in West African vegetable production systems

Seventeen isolates of the free-living soil fungus Trichoderma spp., collected from Meloidogyne spp. infested vegetable fields and infected roots in Benin, were screened for their rhizosphere competence and antagonistic potential against root-knot nematodes, Meloidogyne incognita, in greenhouse pot experiments on tomato. The five isolates expressing greatest reproductive ability and nematode suppression in pots were further assessed in a typical double-cropping system of tomato and carrot in the field in Benin. All seventeen isolates were re-isolated from both soil and roots at eight weeks after application, with no apparent crop growth penalty. In pots, a number of isolates provided significant nematode control compared with untreated controls. Field assessment demonstrated significant inhibition of nematode reproduction, suppression of root galling and an increase of tomato yield compared with the non-fungal control treatments. Trichoderma asperellum T-16 suppressed second stage juvenile (J2) densities in roots by up to 80%; Trichoderma brevicompactum T-3 suppressed egg production by as much as 86%. Tomato yields were improved by over 30% following the application of these biocontrol agents, especially T. asperellum T-16. Although no significant effects were observed on carrot galling and yield, soil J2 densities were suppressed in treated plots, by as much as 94% (T. asperellum T-12), compared with the non-fungal controls. This study provides the first information on the potential of West-African Trichoderma spp. isolates for use against root-knot nematodes in vegetable production systems. The results are highly encouraging, demonstrating their strong potential as an alternative and complementary crop protection component

Effectiveness of native West African arbuscular mycorrhizal fungi in protecting vegetable crops against root-knot nematodes

Twenty strains of arbuscular mycorrhizal fungi (AMF), native to West Africa, and three commercial AMF, were evaluated for their protective effect against root-knot nematodes, Meloidogyne spp., in pots and field experiments in Benin. In pots, these strains were assessed in sterilized soil following inoculation of nematodes and in nonsterilized soil naturally infested with nematodes using tomato. The four strains showing greatest potential in suppressing nematode development were further assessed in the field with a relatively high natural infestation level of nematodes (155 per 100 cm3 soil) over a tomato–carrot double cropping. In the pot experiments, most native strains provided significant suppression of nematode multiplication and root galling, but in most cases the level of nematode control depends on either sterilized or non-sterilized soils. In the field experiments, application of AMF mostly resulted in significant suppression of nematode multiplication and root galling damage on both crops indicating that the AMF persists and remains protective against root-knot nematodes over two crop cycles. Field application of AMF increased tomato yields by 26% and carrot yields by over 300% compared with the non-AMF control treatments. This study demonstrates for the first time, the protective effect of indigenous West African AMF against root-knot nematodes on vegetables. The potential benefits of developing nonpesticide AMF-based pest management options for the intensive urban vegetable systems are evident

Better vegetable production systems in West Africa: prospects for the use of native antagonistic fungi for nematode management

Four isolates of the free-living antagonistic fungi Trichoderma asperellum T-12 (1012 spores/m2), Trichoderma brevicompactum T-3 (1012 spores/m2), Pochonia chlamydosporia Pc-1 (5×107 chamydospores/m2) and Paecilomyces sp. Pl-3 (1012 spores/m2), and two arbuscular mycorrhizal fungi, Kuklospora kentinensis M-233 (1000 spores/m2), Acaulospora scrobiculata M-353 (1000 spores/m2), all native to West Africa, were assessed for their root-knot nematode control potential on urban vegetable fields in the coastal area of Benin. The fungi were applied individually or in combination using a coconut husk carrier substrate, and were compared with the synthetic nematicide Furadan® (5 g/m2) under a double-cropping system of either tomato-carrot or carrot-lettuce, under farming conditions. Results were variable across sites; however, application of some native microorganisms alone or in combination resulted in significant suppression of nematode multiplication and root galling damage, improving crop yields and quality. Root galling severity on tomato and carrot was reduced by up to 70 and 30% in tomato-carrot cropping, and 16 and 40% on carrot and lettuce in carrot-lettuce cropping, respectively, compared to the Furadan treatment. Yields of tomato, carrot and lettuce were significantly improved by up to 70, 57 and 37%, respectively, following the application of various biocontrol agents. This study provides evidence that some beneficial microorganisms native to West Africa provide better protection for vegetables against root-knot nematode damage than the synthetic nematicides. This was observed especially in the poor sandy soils typical of urban and peri-urban sites of coastal cities in Benin, which reflect the situation in most West African countries. The results are highly encouraging, demonstrating the strong potential of the fungal isolates as an alternative to pesticides and a complementary crop protection component for the intensive (peri) urban vegetable systems

Molecular diversity of Scutellonema bradys populations from Benin, based on ITS1 rDNA and COI mtDNA

Published online: 10 May 2018In Benin, yam production continues to face numerous production constraints, including yield and quality reduction by Scutellonema bradys. Implementation of efficient management techniques against this pest requires an improved understanding, including at the molecular level, of the pest. The current study aimed at identifying the Scutellonema spp. associated with yam in Benin and investigating the phylogenetic relationships between populations. Nematodes of the genus Scutellonema were obtained from tubers exhibiting external dry rot symptoms. DNA was extracted from nematodes belonging to 138 populations collected from 49 fields from 29 villages. For 51 of these populations, both the ITS1 and COI regions could be amplified via PCR, sequenced, compared with available sequences in the NCBI database and were identified as S. bradys. Maximum likelihood was used to construct 60% consensus phylogenetic trees based on 51 sequences. This phylogenetic analysis did not reveal any genetic separation between populations by cultivar, village, cropping system nor by agroecological zone. Neither could any subgroups within S. bradys be separated, indicating that no subspecies were present. An earlier published species-specific primer set was verified with the DNA of the 51 sequences and was considered a reliable and rapid method for S. bradys identification