OALib Journal期刊

ISSN: 2333-9721




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匹配条件: “M. El Mahjoub” ,找到相关结果约409449条。
In vitro Determination of Fusarium spp. Infection on Watermelon Seeds and their Localization
N. Boughalleb,M. El Mahjoub
Plant Pathology Journal , 2006,
Abstract: In this study, we used direct incubation of watermelon dissected seeds on Komada`s selective medium for Fusarium spp. and incubation of entire seed on the same medium or on 2% agar medium. Identification of fungi was based on morphological criteria and also according to Koch`s postulate. Isolates from dissected seed were identified as F. oxysporum f. sp. niveum and F. solani f. sp. cucurbitae. These fungi were found to be externally and internally seed borne in watermelon. This is the first report of localization of Fusarium spp. transmitted by watermelon seeds in Tunisia.
Effet de la solarisation sur Phytophtora nicotianae Breda de Haan var. parasitica (Dastur) G.M. Waterhouse responsable d'un syndrome associant nécroses racinaires et flétrissement sur piment (Capsicum annuum L.) en Tunisie
Boughalleb, N.,El Mahjoub, M.
Tropicultura , 2005,
Abstract: The Effect of Soil Solarization on Phytophtora nicotianae Breda de Haan var. parasitica (Dastur) G.M. Waterhouse Responsable for Syndrome Associating Root Rots and Damping-off of Pepper (Capsicum annuum L.) in Tunisia. Mycological analysis of soil collected from solarized plot and non solarized plot showed that the inoculum of soil is composed mainly by Fusarium spp. The solarization permitted to reduce the density of this inoculum. Isolations done from peppers wilted plants have revealed the infestation by Phytophtora nicotianae Breda de Haan var. parasitica (Dastur) G.M. Waterhouse. This was on the basis of microscopic observation of different structures. It is assumed that the percentage of wilted plant showed a considerable reduction in solarized plot. In the same time, the impact of the solarization on the agronomic criteria showed an improvement of the vigour and also of the yield.
Présence en Tunisie d'isolats de Fusarium sambucinum résistants aux benzimidazoles : développement in vitro et agressivité sur tubercules de pomme de terre
Daami-Remadi M.,El Mahjoub M.
Biotechnologie, Agronomie, Société et Environnement , 2006,
Abstract: Presence in Tunisia of Fusarium sambucinum isolates resistant to benzimidazoles: in vitro growth and aggressiveness on potato tubers. The behaviour of 55 isolates of Fusarium spp. causing dry rot of the potato tubers, is studied against some enzimidazoles fungicides. Tunisian isolates of F. solani (12), F. oxysporum (23) and F. graminearum (10) are sensitive in vitro to carbendazime and benomyl at 5 mg.l-1. Their interaction with thiophanate-methyl is different; a complete inhibition of their mycelial growth is observed at doses higher than 500 mg.l-1. Tunisian isolates of F. sambucinum collected during 2002, 2003 and 2004 are resistant to these benzimidazoles showing existence of a cross-resistance. In fact, these isolates tolerated carbendazime (and benomyl) at 200 mg.l-1 and thiophanate-methyl at 1000 mg.l-1. This is the first study in Tunisia indicating emergence of this type of F. sambucinum resistance. Control isolates of F. sambucinum and those treated with carbendazime at 100 mg.l-1 showed a similar aggressiveness on potato tubers of the Spunta cultivar.
Variability in Pathogenicity among Tunisian Isolates of Phytophthora cactorum as Measured by Their Ability to Cause Crown Rot on Four Apple Cultivars and MM106 Roostock
N. Boughalleb,A. Moulahi,M. El Mahjoub
Journal of Agronomy , 2006,
Abstract: Studies on two isolates of Phytophthora cactorum recovered from apple plants identified the presence of diversity in pathogenicity. These isolates appeared pathogenic to tested apple trees. It revealed that Golden Delicious, Star Crimson and the rootstock MM106 were more susceptible than Richared and Red Delicious cultivars, but with variable levels of aggressiveness according to physiological stages of tested segments of apple plants. Necrosis caused by Phytophthora cactorum isolates was more important on shoot segments than on wood segments.
Effets de certains fongicides de synthèse et biologiques sur la croissance mycélienne et l'agressivité de Fusarium oxysporum f.sp. radicis-lycopersici
Hibar, K.,Daami-Remadi, M.,El Mahjoub, M.
Tropicultura , 2007,
Abstract: Effect of some Chemical and Biological Fungicides on Mycelial Growth and Disease Severity of Fusarium oxysporum f.sp. radicis-lycopersici. Fusarium is among the most aggressive telluric fungi causing wilt and root rots in several vegetable crops. A new disease caused by Fusarium oxysporum f. sp. radicis-lycopersici was recorded in southern Tunisia in the "Cinquième Saison" farm, situated in Hammet Gabès during 2000-2001 crop season. It caused death of up to 90% of tomato plants in some greenhouses. In the present research, the effect of 3 chemical and 4 biological fungicides was tested in vitro on mycelial growth and in vivo on disease severity of F. oxysporum f. sp. radicis-lycopersici. Hymexazol, benomyl and manebe were used as chemical fungicides whereas four biological products, i.e. two based on Trichoderma harzianum, one on Bacillus subtilis and another one on Bacillus thuringiensis were also tested. Among the chemical fungicides which were used, hymexazol and benomyl were the most effective in vitro and inhibited mycelial growth up to 80%. However, in vivo assays showed that only hymexazol was effective with a reduction in disease incidence of about 76%. In vitro, the product based on B. thuringiensis entailed a mycelial growth inhibition of less than 20%. This value is more than 75% higher than what was obtained through the other biological fungicides based on either T. harzianum or in B. subtilis. The efficacy of the latter 2 biological fungicides was more important in vivo assays using inoculated tomato plants. Indeed, by the use of the product based on B. subtilis, the reduction of disease incidence exceeded 95%. These results show that some biological fungicides can be used in controlling Fusarium crown and root rot of tomato.
>In vitro and in vivo Evaluation of 3 Insecticides and Bio-Insecticide Effects on Olive Pollen Germination and Tube Growth
H. Mehri,R. Mehri-Kamoun,M. El Mahjoub
Journal of Agronomy , 2007,
Abstract: In order to determine if insecticide treatment during bloom had an effect on olive productivity, three insecticides: Dimethoate (Dimate), Deltamethrine (Decis) and Oleoparathion (Oleokriss) and a bioinsecticide (Bactospeine) were studied over Coratina olive cultivar. These compounds, were applied, at variable concentrations of 100, 10 and 1% RFR, to pollen culture medium or sprayed to field-grown trees during green-cluster stage. Their effectiveness was evaluated on the germination capacity (% germination and tube growth). When added to pollen culture medium, increased germination percentage of Coratina pollen and in vitro enhanced tube elongation were obtained when Bactospeine at 100, 10 and 1% RFR. Germination and tube length were reduced when Dimethoate, Deltamethrine and Oleoparathion were applied to Coratina pollen germination media at 100% RFR. Oleoparathion at 100% and 10% RFR inhibited both pollen germination and tube growth. In contrast, at 1% RFR, Oleoparathion was less inhibitory. Deltamethrine at 100% RFR inhibited pollen germination and tube growth. An intermediate inhibitory effect on pollen germination and tube elongation were observed when Dimethoate was used at 100% RFR. When the insecticides were sprayed on the shoots of Coratina olive cultivar just before blooming, treatments showed similar trends with low pollen germination and tube growth in presence of Oleoparathion and increasing to high levels in presence of Bactopeine. Germination and tube length were reduced when Dimethoate, Deltamethrine and Oleoparathion at 100% RFR were applied to pollen insecticide-free media. In contrast, at 10 and 1% RFR, these insecticides were less inhibitory and showed no difference from the control. Applications of Oleoparathion most severely reduced pollen germination, retarded germination, ruptured pollen tubes and damaged stigmatic surfaces in vivo.
In vitro and in vivo Interaction of Four Fungicides with the Fusarium Species Complex Causing Tuber Dry Rot in Tunisia
M. Daami-Remadi,H. Jabnoun-Khiareddine,F. Ayed,M. El Mahjoub
Plant Pathology Journal , 2006,
Abstract: Several fungicides were tested against some isolates belonging to four Fusarium species causing potato tuber dry rot in Tunisia. Incorporated into the culture media PDA, the tested fungicides significantly inhibited the mycelial growth, observed after incubation at 25°C for 4 days, of all Fusarium isolates including those of F. sambucinum resistant to benzimidazoles. A significant interaction (p =< 0.05) was observed between both fixed factors where inhibition percentage varied depending on tested pathogens and fungicides. Applied on potato tubers (tuber immersion for 10 min) prior inoculation, certain tested fungicides such as azoxystrobin and fludioxonil significantly reduced by more than 50%, comparatively to the untreated controls, the development of dry rot occasioned by F. graminearum and F. sambucinum observed after 21 days of incubation at 25-27°C. A significant interaction (p =< 0.05) was noted between the treatments and the Fusarium species traduced by a variable inhibition percentage depending on tested pathogen and fungicides.
Effet inhibiteur in vitro et in vivo du Trichoderma harzianum sur Fusarium oxysporum f. sp. Radicis-lycopersici
Hibar K.,,Daami-Remadi M.,Khiareddine H.,El Mahjoub M.
Biotechnologie, Agronomie, Société et Environnement , 2005,
Abstract: In vitro and in vivo antagonistic effect of Trichoderma harzianum against Fusarium oxysporum f. sp. radicis-lycopersici. Tests of direct confrontation, on PDA medium or remote confrontation, between Fusarium oxysporum f. sp. radicislycopersici and Trichoderma harzianum, revealed that the latest has inhibited mycelial growth of the pathogen by more than 65% compared to the control and this after an incubation period of about four days at 25°C. Moreover, beyond this period and after six days, T. harzianum invades and also sporulates on F. oxysporum f. sp. radicis-lycopersici colonies revealing its high myco-parasitism. Some interesting results have also been obtained in vivo: indeed, transplantation of tomato seedlings in a mixture of perlite inoculated by F. oxysporum f. sp. radicis-lycopersici and T. harzianum reduced Fusarium crown and root rot incidence compared to seedlings planted in perlite only inoculated by the pathogen. Even better, seedlings planted in perlite containing the pathogen and the studied antagonist present a better vegetative growth and a vigorous root system compared to those of the healthy control (not inoculated and untreated).
Effect of Potato Cultivars on Incidence of Fusarium oxysporum f.sp. tuberosi and its Transmission to Progeny Tubers
F. Ayed,M. Daami-Remadi,H. Jabnoun-Khiareddine,M. El Mahjoub
Journal of Agronomy , 2006,
Abstract: Behaviour of some potato cultivars to Fusarium wilt caused by Fusarium oxysporum f.sp. tuberosi was studied. Plants were inoculated after two weeks by irrigation with a conidial suspension (107 spores mL-1). Variations of Fusarium wilt incidence were observed on potato 14 cultivars. Cv. Baraka was the most tolerant, Lyra and Platina were the most susceptible and Asterix, Alaska, Safrane and Timate were found to be intermediate with various degrees of response. Pathogen transmission to progeny tubers was assessed by planting daughter tubers coming from inoculated and non inoculated plants. Differences in incidence of cultivar susceptibility were significant. Disease incidence of Latona and Timate was the most and the least important, respectively.
Effect of Temperature on Aggressivity of Tunisian Fusarium species Causing Potato (Solanum tuberosum L.) Tuber Dry Rot
M. Daami-Remadi,H. Jabnoun-Khiareddine,F. Ayed,M. El Mahjoub
Journal of Agronomy , 2006,
Abstract: Mycelial growth on PDA of Fusarium graminearum, F. oxysporum f. sp. tuberosi, F. sambucinum and F. solani, causal agents of potato tuber dry rot, depends upon temperatures ranging from 5 to 40°C. An interaction between pathogens tested and temperatures used for culture incubation was observed (at p=<0.05). These Fusarium species showed in vivo both thermal pics of aggressivity: a first one at low temperatures (10-15°C) and a second at higher temperatures (30-35°C). Nevertheless, at temperatures less than 25°C, F. sambucinum and F. graminearum were the most aggressive, while F. solani was the most aggressive at temperatures superior to 30°C.

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