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Activités insecticides de Striga hermonthica (Del.) Benth (Scrophulariaceae) sur Callosobrichus maculatus (Fab.) (Coleoptera : Bruchidae)  [PDF]
Kiendrebeogo M.,Ouedraogo AP.,Nacoulma OG.
Biotechnologie, Agronomie, Société et Environnement , 2006,
Abstract: Insecticidal activities of Striga hermonthica (Del.) Benth (Scrophulariacecae) on Callobruchus maculatus (Fab.) (Coleptera Bruchidae). This paper deals with insecticidal potentialities of Striga hermonthica (Del.) (Scrophulariaceae) in protection of cowpea Vigna unguculata (L.) Walp against Callosobruchus maculatus (Fab.) (Coleoptera: Bruchidae) during storage. Crude acetone extract at 0,5% w/w (100 mg of extract for 20 g of grain) exhibits 48% of ovicidal effect and then reduces by half emergence rate of adult beetles at the first generation. This extract shows a weak insecticide activity against adults of C. maculatus. Petroleum ether fraction (0,4% w/w ) of the crude extract reveals ovicidal (51%) and larvicidal (72%) effects which reduce the emergence rate of adults to only 9%. LD50 and LD90 are monitored during crude extract fractionation to follow ovicidal and larvicidal compounds and to evaluate their efficacy during the isolation procedure. One fraction, mainly composed of two triterpenoid compounds has been identified as responsible of the ovicidal activity of S. hermonthica while the origin of the larvicidal activity hasn’t been identified.
Striga hermonthica (Del.) Benth: Phytochemistry and pharmacological properties outline  [cached]
Faisal H.M. KOUA
Journal of Applied Pharmaceutical Science , 2011,
Abstract: This mini-review aims to outlining the beneficial impacts of the witch-weed parasiticplant; Striga hermonthica (Del.) Benth. S. hermonthica plant beside its well-known devastatingimpacts on the most important food cereal crops in Africa and is deemed to be one of the mainfactors that threatens the food security in this continent; it does also have a beneficial side in thetradition medicine for the African people. S. hermonthica has a wide range of medicinal uses; thepharmacological abortificient effect, dermatosis, diabetes, leprosy ulcer, pneumonia and jaundiceremedy, trypanocidal effects, antibacterial and anti-plasmoidal activities have been approved.Here, we focus mainly in the phytochemical studies, its applications in the remediation of bothanimal and human physiological and infectious diseases and Striga tissue culture advantage asbiotechnological application for pharmaceutical production.
Effect of Klebsiella Spp. and Different Ethylene Inhibitors on Striga hermonthica Benth. (Del.) Seeds Germination  [cached]
M.M. Hassan,M.E. Abdelgani; A.E. Babiker; M.G. Osman
Asian Journal of Agricultural Sciences , 2010,
Abstract: The aim 0f this study was undertaken to evaluate the effect of the bacteria strain (Klebsiella spp.), silver nitrate, cobalt chloride and ACC in germination of Striga seeds. Striga seeds required after- ripening, pretreatment (conditioning) in moist warm environment for 2-14 days and subsequently exposure to an exogenous stimulant. In the present study, an inhibitor of ethylene biosynthesis, AgNO3 and CoCl2, was found to inhibit germination. Germination was found to be inhibited by higher concentrations of AgNO3 and CoCl2. Combination of ACC with AgNO3 and CoCl2 increased Striga seeds suppression as compared with control. Also this study investigates the effect of microorganism in Striga germination. Klebsiella spp. strains known to produce large amounts of ethylene w ere tested for efficacy in germinating seeds of Striga hermonthica (Del.) Benth. Incubation of conditioned S. hermonthica seeds over a medium inoculated with a Klebsiella sp. resulted in considerable germination (34-49%) this indicates an involvement of a volatile substance. Unconditioned S. hermonthica seeds were not stimulated.
Use of Local Plant Aqueous Extracts as Potential Bio-herbicides against Striga hermonthica (Del.) Benth. in Burkina Faso  [PDF]
D. Yonli,H. Traore,P. Sereme,P. Sankara
Asian Journal of Crop Science , 2010,
Abstract: This study was conducted to evaluate the allelopathic properties of endogenous plant species against Striga hermonthica (Del.) Benth., a root parasitic weed. In this respect, twenty five water extracts and eight freeze dried water extracts from sixteen plant species were screened in bio-assays to test their ability to induce or inhibit the germination of S. hermonthica seeds. Striga seeds were conditioned either in 10% water extracts or in 10% diluted lyophilisats to check their inhibition effect on Striga seed germination. Three doses, 1, 5 and 10% of water extracts were applied on conditioned Striga seeds to test their ability to induce Striga germination. Aqueous extracts from four plant species reduced Striga seed germination by 95.8 to 99.8% compared to the untreated control. Aqueous extracts from two others also significantly reduced Striga germination by 93.1 and 86.3%, respectively. Lyophilisats from four species inhibited Striga seeds germination, whereas that of two others reduced Striga seeds germination by 93.5 and 99.6%, respectively. Only 1% aqueous extracts of Ceiba pentandra and Eucalyptus camaldulensis significantly stimulated Striga seed germination by 39.2 and 38.9%. These results pointed out that the metabolites produced by some of the local plant species may have the potential to be used as bio-herbicides to control S. hermonthica and enhance cereals yield.
Magdoline Mustafa Ahmed,Mohammed Mahgoub Hassan,Ahmed ME Rugheim,Awad Galal Osman
Journal of Current Research in Science , 2013,
Abstract: Two laboratory experiments were conducted to assess the effects of fungal isolates on germination and haustorium initiation of Striga hermonthica. Forty three fungal isolates were isolated from infested and un-infested sorghum fields with Striga hermonthica. A preliminary screening was conducted to assess the effect of these isolates on germination of preconditioned Striga seeds. Sixteen fungal isolates in addition to a standard strain Trichoderma viride were selected according to their effects on Striga seeds germination and haustorium initiation. In the first experiment isolates and strain were assessed for their effect on germination of Striga seeds during conditioning in response to GR24. The second experiment was conducted to study the effects of fungal isolates and T. viride on Striga haustorium initiation. The results revealed that six fungal isolates had no effects; six isolates reduced germination (34-93%) significantly while other isolates significantly enhanced germination (15–59%) of Striga seeds. Moreover, isolate Ai 41 reduced germination over 90% as compared to the corresponding control. Similarly, few fungal isolates inhibited haustorium initiation while some had no effect. Isolate Ai 50 was the only isolate that completely (100%) inhibited haustorium in response to DMBQ. The study concluded that some fungi can be used as control agents against Striga and suggested that further studies had to be conducted in the green house and field to verify theses results and develop a strategy for the use of fungi as mycoherbicides against Striga.
Pathogenicity of Fusarium isolates to Striga hermonthica in Burkina Faso  [PDF]
D. Yonli,H. Traore,P. Sereme,D.E. Hess
Pakistan Journal of Biological Sciences , 2010,
Abstract: Striga hermonthica (Del.) Benth. is an important constraint to cereal crop production in Burkina Faso, of which sorghum (Sorghum bicolor L. Moench) is the most important component. Native Fusarium species to use as bio-control agents to S. hermonthica has been investigated. Fifty one Fusarium isolates obtained from diseased plants of S. hermonthica were evaluated for their pathogenicity against Striga under controlled environmental conditions. Of 51 Fusarium isolates, 14 were pathogenic to S. hermonthica but their virulence differed. These 14 isolates were evaluated for their effects on Striga seed germination in the laboratory and their ability to kill emerged Striga plants growing in greenhouse pots. Spores of Fusarium sp. isolates 150a-M, 125b-Za, 6-Fa, Fusarium equiseti isolates 5-Kou, 31-Kom, 32-Or, 13-Ba and Fusarium oxysporum isolate 34-Fo reduced Striga germination by 78 to 96% compared to the untreated control. The study showed that at the rate of 33 mg mL-1, metabolites of Fusarium sp. isolates 125b-Za, 6-Fa, F. equiseti 5-Kou and F. oxysporum 34-Fo prevented Striga seed germination. In addition to these four isolates, Fusarium sp. isolates 141b-O, 150a-M and F. equiseti isolate 32-Or were effective at 67 mg mL-1. Percentage of Striga mortality ranged from 17-37% between 14 and 28 days after inoculation with spores of F. oxysporum 34-Fo and F. equiseti 5-Kou. Striga dry biomass was reduced by 84 and 78% for the respective isolates compared to the untreated control with Striga. Sorghum yield was improved by 84 and 99% with Fusarium sp. 6-Fa and F. oxysporum 34-Fo, respectively, compared to the control without Striga. The use of Fusarium spores and metabolites against Striga offers different possibilities of bio-herbicides formulation that can be combined with other controls methods in the integrated Striga management. Further studies will be carried out under field conditions to assess the efficacy and safety of these Fusarium isolates to environment and humans and evaluate low cost strategies for transfer to subsistence farmers.
In vitro host-free seed culture, callus development and organogenesis of an obligatory root-parasite Striga hermonthica (Del.) Benth: the witch-weed and medicinal plant  [cached]
Faisal Hammad Mekky Koua,Fatima Misbah Abbas,Eisa Ibrahim Elgaali,Mutasim Mohammed Khalafallah
International Journal of Plant Biology , 2011, DOI: 10.4081/pb.2011.e9
Abstract: Striga hermonthica (Del.) Benth a well-known hemi-parasitic weed, it also has been used widely in African folk medicine to remedy broad spectra of diseases. The current contribution is an attempt to establish reproducible in vitro callusing system. In vitro seedling’s stem segments were used as an explant for callus induction, in 1.5% or 3.0% sucrose added into Murashig and Skoog medium (MS) and supplemented with different auxins, α-Naphthalene-3-acetic acid (NAA), 2,4-dichlorophenoxy acetic acid (2,4-D), Indole-3-acetic acid (IAA), or Indole-3-butryic acid (IBA) at different concentrations each alone or in combination with cytokinin 0.5 mgl-1 6-benzyl aminopurine. The most effective auxin was NAA with maximum 79% callus induction rate. All auxin treatments induced callus in all concentration when used alone or combined with BAP, except 2,4-D, which induced the callus only when combined with BAP. A high sucrose concentration was required for high callus induction rate by all auxin treatments. IAA and IBA auxins induced direct shoot regeneration and had low callus induction rates. NAA, IAA and IBA induced organogenic calli, whereas 2,4-D in combination with BAP induced non-organogenic callus. We further screened preliminarily the phytochemical contents of the callus and intact plant, which was revealed the presence of flavonoids, terpenes, saponins, cardiac glycosides, alkaloids, tannins and coumarins. Experimental data of both seed culture and callus induction could provide a route to further enhance the efficiency of callus initiation of S. hermonthica for medicinal purposes and understanding the infection mechanism of the witch-weed plant.
Development of sorghum populations for resistance to Striga hermonthica in the Nigerian Sudan Savanna
IE Ezeaku, SC Gupta
African Journal of Biotechnology , 2004,
Abstract: Six elite sorghum varieties, ICSV 111, ICSV 400, KSV 4, Gaya Early, CS 54, and CS 95 were used to improve Striga resistance through pedigree breeding. SRN 39 and IS 9830 varieties were confirmed resistant to Striga hermonthica (Del.) Benth in field trials. The two Striga resistance lines were crossed with the six elite varieties. Three hundred and sixty Striga-free plants from F2s of good agronomic traits were identified, and selfed to produce F3s. The number of selections varied from 12 (ICSV 400 x IS 9830) to 59 (ICSV 400 x SRN 39) per F2 population. About 50% more plants were selected from the crosses involving SRN 39 as donor parent for Striga resistance than the crosses involving IS 9830. In addition, 58 out of the 100 plants selected were from a cross, ICSV 111 and SRN 39. Crosses from which Striga free plants were obtained were CS 54 x SRN 39 (12 plants selected), CS 95 x SRN 39 (9), ICSV 400 x SRN 39 (6), Gaya Early x IS 9830 (6), Gaya early x SRN 39 (5), and KSV 4 x IS 9830 (4). Crop syndrome reaction score was higher in 1995 (2.3 - 4.0) than in 1996 (1.0 - 2.7). Our results suggest that SRN 39 is a better donor parent for Striga resistance than IS 9830. ICSV 00090 NG, a cross between ICSV 111 and SRN 39 gave the highest grain yield of 2.02 t/ha in a replicated trial compared to the two parents, ICSV 111 (1.11 t/ha) and SRN 39 (0.86 t/ha). This variety combines potential for high yield and resistance to Striga. Our data indicates that the elite varieties can be improved for Striga resistance using pedigree breeding. A large F2 population (500 to 1000 plants per cross) is recommended for the selection of transgressive segregants. Further efforts are required to back cross-promising segregants with established Striga resistant variety in order to develop durable Striga resistant varieties with acceptable agronomic traits.
Use of hand-weeding and herbicides to control Striga hermonthica in Burkina Faso
H. Traoré, D. E. Hess, G. Hoffmann, A. Son, G. Sallé
African Crop Science Journal , 2001,
Abstract: The parasitic weed Striga hermonthica (Del.) Benth. causes significant yield loss in sorghum [Sorghum bicolor (L.) Moench] in Burkina Faso. Two trials were conducted in the eastern part of the country to evaluate the efficiency of herbicides and mechanical weeding to control the parasite on sorghum. In 1994, 2,4-D, triclopyr, or 2,4-D + triclopyr were applied to striga parasitising the local sorghum landrace Itchoari. Single applications (2 l ha-1 at 85 days after sowing, DAS) of both 2,4-D and triclopyr reduced the number of emerged striga from 101 DAS until harvest (123 DAS). All herbicide applications significantly reduced striga flowering (average of 69 %)and seed formation (average of 93 %) at harvest as well as the dry biomass (average of 82 %) of non-parasitic weeds. In 1995, the residual effect of herbicide treatments in the previous year was examined. A residual effect was observed for triclopyr (1 l ha-1 at 70 and 85 DAS), with reduced emerged striga throughout the season. In 1996, the 1994 herbicide treatments were compared to manual weeding of striga on two sorghum entries. Both herbicides again reduced striga infestation, but 2,4-D was more effective on local Itchoari whereas triclopyr was more effective on Sariaso 9. Use of herbicides was more cost-effective than mechanical weeding and enhanced striga control contributed to improve sorghum 1000 grain weight. RéSUMé Le Striga hermonthica (Del.) Benth. provoque des baisses importantes de rendement du sorgho au Burkina Faso. Deux essais ont été conduits dans l'est du pays pour évaluer l'effet de trois herbicides et du sarclage mécanique sur le contr le du parasite du sorgho. En 1994, le 2,4-D, le Triclopyr et le 2,4-D + Triclopyr ont été comparés à un témoin sans herbicide sur une variété locale de sorgho. En 1995, le même sorgho a été semé sur la parcelle d'essai pour étudier l'arrière-effet des trois produits. En 1996, les trois herbicides ont été comparés à un sarclage manuel supplémentaire et à un témoin sans sarclage supplémentaire et sans herbicide, sur deux entrées de sorgho. En 1994, les herbicides ont réduit, significativement par rapport au témoin, le nombre de striga 101 et 116 jours après le semis, le nombre de striga fleuris et le nombre de striga portant des capsules. Par rapport au témoin, les herbicides ont réduit la biomasse sèche de striga et celle des autres adventices. L'arrière-effet des herbicides a réduit, de fa on significative par rapport au témoin, le nombre de striga 84 et 115 jours après le semis et la biomasse sèche de striga. En 1996, les herbicides ont entra né une baisse significative du nombre de S. hermonthica par rapport au témoin, 96 et 110 jours après le semis. Le sarclage supplémentaire a provoqué une plus forte émergence du striga par rapport au témoin. Les herbicides n'ont pas entra né, par rapport au témoin sans herbicide ou au sarclage supplémentaire, un gain significatif du rendement de sorgho. Toutefois, les herbicides et le sarclage suppléme
Effects of Prolonged Conditioning on Dormancy and Germination of Striga hermonthica  [PDF]
Israel K. Dzomeku,A.J. Murdoch
Journal of Agronomy , 2007,
Abstract: The impact of environment on the germination biology of Striga hermonthica was studied in the laboratory by conditioning seeds at various water potentials and urea concentrations at 17.5 to 37.5°C for up to 133 days. The experimental results presented in this research are related to the effects of temperature, water potential and urea nitrogen concentration during conditioning on subsequent germination percentage of S. hermonthica. Maximum germination in S. hermonthica seeds was observed at conditioning temperatures of 20 to 25°C within the range investigated of 17.5 to 37.5°C. Water stress and also urea during conditioning suppressed maximum germination. However, the conditioning temperature ranges at which maximum germination percentages occur vary with water stress and also urea concentration. In the presence of a high concentration of urea (3.16 mM), temperatures required for maximum germination narrowed to between 17.5 to 20°C. The optimum period of conditioning decreased with increase in water stress and also urea concentration similar to previous reports. The implications of these findings on Striga hermonthica field infestations have been investigated and being reported in another paper. Germination was greatly suppressed by conditioning environments including 3.16 mM urea and at 37.5°C. At the high concentration of 3.16 mM, temperatures required for maximum germination narrowed to between 17.5 and 20°C. Optimum conditioning period decreased with water stress and with increase in urea concentration.
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