scholarly journals Studies on the fungal dieback disease on some fruit trees in Zalingei Locality, Darfur, Sudan

2021 ◽  
pp. 71-77

The study was carried out at Zalingei locality, Central Darfur State, in the year 2017, to determine the fungal pathogens that causing dieback disease to the fruit trees, and to study the effect of aqueous Neem extract (Azadirachta indica) on growth of the identified fungal pathogens under laboratory conditions. Experimental approach and descriptive analytical method were used. Primary data were collected using the questionnaires, laboratory experiment, field survey and personal interviews. Results revealed that there are two types of fungi (Fusarium oxysporum and Rhizoctonia sp.) which causing dieback disease in the study area. The highest dieback disease incidence recorded was found to be: 5.0% (In Mango), 4.3% (In Guava) and 2.5% (In Citrus), in Zalingei, Orukum and Qere area, respectively. Results showed that the water extract of neem seeds had an inhibitory effect on growth of both Fusarium oxysporum and Rhizoctonia sp. There was no significant difference between the effect of different concentrations 12.5%, 25%, and 50% of aqueous neem extracts on dieback fungal causal agents growth but in case of Fusarium oxysporum growth of the colony was reduced by 21.0%, 38.57%, and 54.47% respectively, while in case of Rhizoctonia sp., it reduced by 25%, 51.10%, and 51.34% respectively. The study suggested to raise the awareness of the farmers about the dieback disease through workshops, trainings and control campaigns, Additional studies for others substitutes and additional studies on other Dieback disease causes.

1987 ◽  
Vol 33 (5) ◽  
pp. 349-353 ◽  
Author(s):  
T. C. Paulitz ◽  
C. S. Park ◽  
R. Baker

Nonpathogenic isolates of Fusarium oxysporum were obtained from surface-disinfested, symptomless cucumber roots grown in two raw (nonautoclaved) soils. These isolates were screened for pathogenicity and biological control activity against Fusarium wilt of cucumber in raw soil infested with Fusarium oxysporum f. sp. cucumerinum (F.o.c.). The influence of three isolates effective in inducing suppressiveness and three ineffective isolates on disease incidence over time was tested. The effective isolates reduced the infection rate (R), based on linear regressions of data transformed to loge (1/1 – y). Effective isolate C5 was added to raw soil infested with various inoculum densities of F.o.c. In treatments without C5, the increase in inoculum densities of F.o.c. decreased the incubation period of wilt disease, but there was no significant difference in infection rate among the inoculum density treatments. Isolate C5 reduced the infection rate at all inoculum densities of F.o.c. Various inoculum densities of C5 were added to raw soils infested with 1000 cfu/g of F.o.c. In the first trial, infection rates were reduced only in the treatment with 10 000 cfu/g of C5; in the second trial, infection rates were reduced in treatments with 10 000 and 30 000 cfu/g of C5.


2021 ◽  
Vol 38 (1) ◽  
pp. 20-37
Author(s):  
Yohana Patricia Anama ◽  
Ricardo Díaz ◽  
David Esteban Duarte-Alvarado ◽  
Tulio Cesar Lagos-Burbano

Fusarium oxysporum is one of the most limiting fungal pathogens of lulo crop. To determine its pathogenicity, this work morphologically and pathogenically characterized F. oxysporum isolates from different lulo-growing municipalities of the Department of Nariño. Twenty isolates were evaluated through a completely randomized design with two factors and three replicates per treatment, including a control. The first factor corresponded to 20 isolates of F. oxysporum and the second to 10 lulo genotypes. The morphological characterization involved determining growth rate (GR), color (CO), mycelial type (MT), medium coloration (Mc), shape (Sh), size (S), number (N) of macroconidial (Ma) and microconidial (Mi) septa, presence of chlamydospores (PC), and chlamydospore shape (CS). Moreover, the pathogenic characterization was based on the incubation period (IP), absolute growth rate (AGR), disease severity (DS), disease incidence (I), and vascular discoloration (VD). The morphological characterization demonstrated that all isolates corresponded to F. oxysporum. For IP, genotype G1 showed the lowest average at 18 days. For AGR, genotype G2 had the lowest height increase at 0.05 cm.day-1. For DS, genotype G1 reached the highest severity level (level 9) and a disease incidence of 100%. This study provides the first report of the special form of F. oxysporum f. sp. quitoense in Nariño. Solanum hirtum, Solanum sessiliflorum, and Solanum estramonifolium were resistant to the isolates evaluated, demonstrating that wild species should be considered as sources of resistance for breeding programs aiming to obtain resistant commercial genotypes.


HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 472F-473 ◽  
Author(s):  
D.W. Lotter ◽  
J. Granett ◽  
A.D. Omer

Secondary infection of roots by fungal pathogens is a primary cause of vine damage in phylloxera-infested grapevines. In summer and fall surveys in 1997 and 1998, grapevine root samples were taken from organically managed vineyards (OMVs) and from conventionally managed vineyards (CMVs), all of which were phylloxera-infested. In both years, root samples from OMVs showed significantly less fungal pathogen-caused root necrosis than samples from CMVs, averaging 9% in OMVs and 31% in CMVs. There was no significant difference in phylloxera populations per 100 g of root between OMVs and CMVs, although there was a trend toward higher populations in CMVs. Soil characteristics, percent organic matter, total nitrogen, nitrate, and percent sand/silt/clay were not significantly different between the two regimes. Cultures of necrotic root tissue showed significantly higher levels of the benefical fungus Trichoderma in OMVs in 1997 but not in 1998, and there were significantly higher levels of the pathogens Fusarium oxysporum and Cylindrocarpon spp. in CMVs in 1998 but not in 1997. Implications for further research and viticulture are discussed.


2017 ◽  
Vol 53 (No. 2) ◽  
pp. 85-95 ◽  
Author(s):  
Thongkamngam Titi ◽  
Jaenaksorn Tanimnun

Efficacy of non-pathogenic Fusarium oxysporum (F221-B) was assessed as a possible biocontrol agent against fungal pathogens, namely Curvularia lunata (C11, C12), F. semitectum (F113), F. oxysporum f.sp. lactucae (F221-R, F442-G), Rhizoctonia solani (R11, R12), Rhizoctonia sp. (R111, R112, R113) in vitro, while F221-B showed a moderate ability to inhibit the mycelial growth of tested fungi about 36–56%. Then, F221-B was further evaluated for its ability of controlling lettuce root rot and wilt caused by F442-G in hydroponics. It was revealed that F221-B reduced disease incidence and severity about 60–80% compared to the inoculated control and significantly promoted the growth of 3 lettuce varieties. Interestingly, using only F221-B gave the significantly highest fresh weight (twice over the healthy control). Conclusively, this study provides an important suggestion for further development of F221-B since it showed the ability of biocontrol agent and plant growth promoting fungus.


2018 ◽  
Vol 24 (3-4) ◽  
Author(s):  
B. Molnár ◽  
M. Varga ◽  
A. Vámos ◽  
I. J. Holb

In a two-year study, we aimed to determine the susceptibility of four plum cultivars to two fungal pathogens of plum (Stigmina carpophila and Polystigma rubrum) in two training systems with tree spacings of 4 x 1.5m and 6 x 3m. Results showed that shothole symptoms were not detected on cvs ’Bluefre’ and ’Stanley’ in August, 2016. Disease incidence was above 50% in the case of ’Čačanska lepotica’ in both training systems in 2016. There were no significant difference between the two training systems. Shot hole incidence was lower in the 6 x 3m spacings compared to the 4 x 1.5m spacings on cv ’President’ in 2016. Cultivar ’Čačanska lepotica’ showed the highest incidence of Stigmina carpophila in the 4 x 1.5m spacing in 2017. Disease incidence of Stigmina carpophila was significantly lower in the 6 x 3m spacing compared to the 4 x 1.5m spacing. Shothole incidences on cv ’President’ were similar to the values in 2016 ranging from 40% to 60%. Leaf disease incidence was higher in the 4 x 1.5m spacing compared to the 6 x 3m plot. Low disease incidence (below 10%) was observed on cv ’Stanley’ in 2017 and only in the 4 x 1.5m spacing. There were no visible symptoms of blackhorn dotty in 2016 due to inadequate weather conditions for the Polystigma rubrum fungus. However, all the four cultivars were infected by Polystigma rubrum in 2017. The most susceptible cultivar was cv ’Čačanska lepotica’ with the highest disease incidence in the 4 x 1.5m spacing. Disease incidence of this cultivar was lower in the 6 x 3m spacing which was significantly less than in the 4 x 1.5m spacing. The least susceptible cultivar was ’Bluefre’ and symptoms were observed only in the spacing of 4 x 1.5m. The disease incidence of cv ’President’ was similarly low to cv ’Stanley’ in both spacings.


2018 ◽  
Vol 15 (4) ◽  
pp. 392-400
Author(s):  
Baghdad Science Journal

This paper involved the registration of 1,936 cases of infection of the Leishmania tropica parasite observed at hospitals and health centers in Ramadi, Fallujah, Baghdadi, and Hit during 2017. The results revealed that the highest rates of infection were found in Ramadi and Fallujah. The 1-10 years age group recorded the highest rate at 35.5%. There was no significant difference (p ≥ 0.05) between the sexes. December and January saw the highest rate of infection, where the rate in rural townships was found to be 65.5%, higher than in urban regions which saw a rate of 34.4%. Facial lesions were the most prominent area of infection, recorded at a rate of 41.3%. The study also included an examination of 180 rodents (94 mice and 86 black rats) - the investigation demonstrated the presence of the amastigote stage at a rate of 43.6% among mice and 53.4% among rats. The study also involved an analysis of the impact of the use of a water extract from the Rhanterium epapposum plant, also locally known as the Arfaj plant, on Leishmania tropica parasite growth. As part of this study, a concentration of between 0.05-5 mg/ml was used. The application of these concentrations led to an inhibitory effect on parasite growth - an application of relatively higher concentrations caused greater effects in times of growth between 1-5 days.


2020 ◽  
Vol 8 (2) ◽  
pp. 785
Author(s):  
R. A. Adebayo ◽  
O. A. Isah

There have been paradigm shift to the use of biopesticides as alternative to synthetic pesticides in recent years due to its environment friendliness and non-toxic to the non-target organisms. Therefore, three synthetic insecticides and water extract from neem back powder were evaluated on cowpea in the field and their residual toxicity tested against C. maculatus in the laboratory. The insecticides were applied at the rate of 2ml in 2L of water and 2L of extract from neem back powder on the field. The harvested seeds were infested with C. maculatus to evaluate the residual toxicity of the insecticides. Data on growth and yield parameters were taken on the field while data on adult mortality, oviposition, adult emergence and weight loss were recorded for the laboratory experiment. The results showed positive response of cowpea to the applied chemicals as they had higher values for the number of leaves, branches and reduced number of holes. Number of holes was significant (p< 0.05) at the 8th week with the control having highest number of holes. Cowpea treated with cypermethrin had highest number of pods at both 7th and 8th week and showed significant difference at 7th week. Highest weight of seeds per pod was obtained from the cowpea treated with water extract from neem back powder and was significantly different (p< 0.05) from other treatments. Seeds treated with the three insecticides had the same number of mortality while neem extract had highest but was not significantly different (p> 0.05). There was a reduction in number of eggs laid, adult emergence, seeds with holes and weight loss in the seeds treated with the four insecticide compounds. It was concluded that application of the insecticidal compounds positively enhanced the performance of cowpea on the field and could protect the seeds against C. maculatus in the laboratory. This study revealed that water extract from back powder of neem could be used as a botanical in the protection of cowpea against seed beetles.


2021 ◽  
Vol 12 ◽  
Author(s):  
Jun Chen ◽  
Liuting Zhou ◽  
Israr Ud Din ◽  
Yasir Arafat ◽  
Qian Li ◽  
...  

Under consecutive monoculture, the abundance of pathogenic fungi, such as Fusarium oxysporum in the rhizosphere of Radix pseudostellariae, negatively affects the yield and quality of the plant. Therefore, it is pertinent to explore the role of antagonistic fungi for the management of fungal pathogens such as F. oxysporum. Our PCR-denatured gradient gel electrophoresis (DGGE) results revealed that the diversity of Trichoderma spp. was significantly declined due to extended monoculture. Similarly, quantitative PCR analysis showed a decline in Trichoderma spp., whereas a significant increase was observed in F. oxysporum. Furthermore, seven Trichoderma isolates from the R. pseudostellariae rhizosphere were identified and evaluated in vitro for their potentiality to antagonize F. oxysporum. The highest and lowest percentage of inhibition (PI) observed among these isolates were 47.91 and 16.67%, respectively. In in vivo assays, the R. pseudostellariae treated with four Trichoderma isolates, having PI &gt; 30%, was used to evaluate the biocontrol efficiency against F. oxysporum in which T. harzianum ZC51 enhanced the growth of the plant without displaying any disease symptoms. Furthermore, the expression of eight defense-related genes of R. pseudostellariae in response to a combination of F. oxysporum and T. harzianum ZC51 treatment was checked, and most of these defense genes were found to be upregulated. In conclusion, this study reveals that the extended monoculture of R. pseudostellariae could alter the Trichoderma communities in the plant rhizosphere leading to relatively low level of antagonistic microorganisms. However, T. harzianum ZC51 could inhibit the pathogenic F. oxysporum and induce the expression of R. pseudostellariae defense genes. Hence, T. harzianum ZC51 improves the plant resistance and reduces the growth inhibitory effect of consecutive monoculture problem.


2020 ◽  
Vol 7 (15) ◽  
pp. 19-27
Author(s):  
U. N. Emiri ◽  
E. B. Enaregha

Biochemical changes in Mucuna sloanei Fawc. & Rendle (Fabaceae) seeds induced by six pathogenic fungi and comparative analysis of the pathogenic fungi were investigated. The fungal pathogens isolated from partially rotted seeds of M. sloanei seeds include Rhizopus stolonifer, Aspergilus flavus, Aspergillus niger, Penicillium italicum, Alternaria altermata and Fusarium oxysporum. These fungi were used as test fungi to inoculate healthy M. sloanei seeds aseptically. The results of proximate analysis in (%w/w)/100 g of seeds inoculated with the test fungi and uninoculated (control) seeds carried out revealed that there was a significant increase (P < 0.05) in moisture, ash, lipid and carbohydrate content of seeds inoculated with the test fungi, relative to uninoculated (control) seeds. While fiber and protein content decreased in fungi inoculated seeds relative to uninoculated seeds. There was a significant difference (P < 0.05) in mineral content evaluated. Calcium, phosphorus and sodium increased in seeds inoculated with the test fungi relative to the uninoculated, while iron, potassium and magnesium decreased in seeds inoculated with the test fungi. Phytochemical (anti-nutrient) contents (tannin, saponins, total oxalate and cynogenic glucoside) increased in the fungi inoculated seeds, relative to uninoculated seeds. Significant differences also occurred among the test fungi. Fusarium oxysporum, Alternaria altermata and Penicillium italicum appeared to induce more changes in proximate and mineral composition. Penicillium italicum also recorded the highest increase in phytochemical content (tannin, saponin and total oxalate) in seeds inoculated with test fungi relative to the uninoculated (control) seeds.


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