scholarly journals Evaluation of Fungicide against Taro Leaf Blight Disease Caused by Phytophthora colocasiae in Three Agro-Ecological Zones of Cameroon

Author(s):  
Manju Evelyn Bi ◽  
Ache Neh Teke ◽  
Suh Christopher ◽  
Mbong Grace Annih ◽  
Fokunang Charles

Globally the taro leaf blight (Phytophthora colocasiae) disease causes between 50 to 70% yield loss. Four taro landraces were planted in three agroecological zones of Cameroon; the Western Highlands (Bambui), Mono-Modal Humid Forest (Ekona), and the Bimodal Humid Forest (Nkolbisson) and evaluated for taro blight severity in four successive growing seasons in March and July, 2018 and 2019. Different concentrations of copper oxide (600 g)–Metalaxyl (120 g) fungicide were applied to control taro blight before and during plant growth. Results showed that, in all the field sites, the disease severity of Phytophthora colocasiae greatly decreased below 1.5 with varying concentrations of copper oxide (600 g)–Metalaxyl (120 g) fungicide applied at two-week intervals. The control field at Ekona recorded the highest taro blight severity of 7.8. There was no significant difference in taro blight severity (P≤0.05) between landraces treated with the different concentrations of copper oxide (600 g)–Metalaxyl (120 g) fungicide. Therefore, lower concentrations (0.33% and 0.27%) of copper oxide (600 g)–Metalaxyl (120 g) can be effectively used in the pre and post control of taro blight in the field. All the landraces in the screen house experiments were susceptible to P. colocasiae.   In all the zones, Landrace L2 (red petiole small leaves) was highly resistant to P. colocasiae and should be recommended to farmers for optimum taro production in the three agro-ecological zones and zones with similar characteristics.

Author(s):  
Bersissa Kumsa ◽  
Kebede Beyecha ◽  
Mesula Geloye

A cross-sectional study was conducted to determine the prevalence and risk factors for ectoparasites infestation in sheep in three agro-ecological zones in central Oromia, Ethiopia, from October 2009 to April 2010. The study revealed that 637 (48.1%) of the 1325 sheep examined were infested with one or more ectoparasites. The ectoparasites identified were Bovicola ovis (27.2%), Melophagus ovinus (16.4%), Ctenocephalides sp. (2.3%), Linognathus africanus (1.2%), Linognathus ovillus (0.3%), Sarcoptes sp. (1.2%), Amblyomma variegatum (4.4%), Rhipicephalus evertsi evertsi (1.9%), Rhipicephalus pravus (1.9%), Rhipicephalus (Boophilus) decoloratus (1.1%), Rhipicephalus sanguineus (0.9%), Rhipicephalus praetextatus (1.1%) and Hyalomma truncatum (1.6%). Statistically significant difference was observed in prevalence of B. ovis amongst study agroecological zones: highland 36.6%, midland 20.9% and lowland 14.0%. Significantly higher prevalence was recorded in highland agroecological zone. A significantly (OR = 0.041, p < 0.001) higher prevalence of M. ovinus in the highland (31.7%) than in both the lowland (0%) and midland (1.9%) was observed. The risk of tick infestation in the lowland and midland was 9.883 times and 13.988 times higher than the risk in the highland, respectively. A significantly higher prevalence of Ctenocephalides species was encountered in both the lowland (OR = 4.738, p = 0.011) and midland (OR = 8.078, p = 0.000) than in the highland agro-ecological zone. However, a significant difference (p = 0.191) amongst agro-ecological zones was not found for the prevalence of Linognathus and Sarcoptes species. Statistically significant variation (p > 0.05) was never recorded in the prevalence of all the identified species of ectoparasites between male and female sheep hosts. However, a significantly (p = 0.006) higher prevalence of B. ovis was recorded between young and adult sheep. The risk of B. ovis infestation was 1.45 times higher in young than the adult sheep. Furthermore, a significantly (p < 0.001) higher prevalence of M. ovinus, B. ovis and Sarcoptes sp. was found between sheep with poor and a good body condition. The ever increasing threat of ectoparasites on overall sheep productivity and tanning industry in Ethiopia warrants urgent control intervention. Further studies on the role of ectoparasites in transmission of diseases to sheep, zoonotic importance, comparative prevalence and load, and the importance of sheep as alternative hosts in different agroecological zones, breeds and management systems in Ethiopia are recommended so as to design applicable control programme in the country.


2020 ◽  
Vol 46 (2) ◽  
pp. 8226-8239
Author(s):  
S. Pindé ◽  
A.S.R. Tapsoba ◽  
F. Traoré ◽  
R. Ouédraogo ◽  
S. Ba ◽  
...  

La présente étude est une contribution à l’établissement des caractéristiques et de la typologie des systèmes d’élevage de la poule locale dans les 3 zones agro écologique du Burkina Faso. Des informations ont été collectées sur 251 éleveurs de poules locales à travers une enquête de type transversale dans les 3 zones agro-écologiques, du Burkina Faso. Les résultats indiquent que l’élevage des poules locales est pratiqué principalement par des autochtones (84,91%) et des hommes (70,26%) dans un système extensif (63,83%). Les enquêtés sont pour la plupart des adultes (66,38%), sont mariés (92,41%), n’ont reçu aucune formation technique (45,69%) et pratiquent l’agriculture comme activité principale (67,93%). Les petits éleveurs de poules locales (effectif inférieur ou égal à 25 têtes) sont les plus nombreux (40,56%). Les enquêtés disposent majoritairement de poulaillers/abris (76,37%), utilisent des mangeoires (58,65%), des abreuvoirs (73%) et distribuent principalement des céréales à leurs poules. Les maladies aviaires sont la première cause de mortalités dans les effectifs visités (89,22%), malgré que presque la quasi-totalité des éleveurs (98,77%) administrent des traitements sanitaires à leurs poules. L’âge de la maturité sexuelle chez les poules mâles est en moyenne de 5,46±0,12 mois et de 5,49±0,10 mois chez les femelles, avec une différence statistiquement significative pour ce paramètre, au seuil de p<0,05, entre les femelles des 3 zones agroécologiques. Le nombre d’œufs pondus par cycle et par poule dans la zone d’étude est en moyenne de 11,52±0,17 œufs, avec la zone sahélienne qui a le nombre moyen d’œufs pondus le plus élevés (12,6±0,32 œufs). La majorité des enquêtés (75,58%) affirme que la période de ponte favorable dans leur exploitation s’étale du début saison des pluies à la fin de la saison sèche froide. L’âge de la réforme des poules dans la zone d’étude est, en moyenne, de 36,82±1,63 mois pour les femelles et de 24,55±1,16 mois chez les mâles avec une forte variabilité existant au niveau surtout des femelles des différentes zones agro-écologiques. L’âge moyen à la réforme des femelles (36,82±1,63 mois) révèle une différence statistiquement significative, à p<0,05, entre les oiseaux de la zone sahélienne et ceux des zones soudanienne et soudano-sahélienne. Pinde et al., 2020 Journal of Animal & Plant Sciences (J.Anim.Plant Sci. ISSN 2071-7024) Vol.46 (2): 8212-8225 https://doi.org/10.35759/JAnmPlSci.v46-2.6 ABSTRACT This study is a contribution to the establishment of the characteristics and the typology of the farming systems of the local hen in the 3 agro-ecological zones of Burkina Faso. Information was collected on 251 local chicken farmers through a cross-sectional survey in the 3 agroecological zones of Burkina Faso. The results indicate that the rearing of local chicken is practiced mainly by natives (84.91%) and men (70.26%) in an extensive system (63.83%). Respondents are mostly adults (66.38%), are married (92.41%), have received no technical training (45.69%) and practice agriculture as their main activity (67.93%). The smallest local chicken breeders (number less than or equal to 25 heads) are the most numerous (40.56%). Respondents have chicken coops / shelters (76.37%), use feeders (58.65%), drinkers (73%) and mainly distribute cereals to their hens. Avian diseases are the leading cause of mortality in the numbers visited (89.22%), although almost almost all breeders (98.77%) administer sanitary treatments to their hens. The age of sexual maturity in male hens is on average 5.46 ± 0.12 months and 5.49 ± 0.10 months in females, with a statistically different significant for this parameter, at the threshold of p <0.05, between the females of the 3 agro-ecological zones. The number of eggs laid per cycle and per hen in the study area averages 11.52 ± 0.17 eggs, with the Sahelian zone having the highest average number of eggs laid (12.6 ± 0.32 eggs). The majority of respondents (75.58%) say that the favorable spawning period in their exploitation extends from the beginning of the rainy season to the end of the cold dry season. The age of hen reform in the study area is, on average, 36.82 ± 1.63 months for females and 24.55 ± 1.16 months in males with high variability. level especially of females from different agroecological zones. The culling age of females (36.82±1.63 months) reveals a statistically significant difference, at p <0.05, between birds in the Sahelian zone and those in the Sudanian and Sudano-Sahelian zones.


Author(s):  
Zhang Hong ◽  
Kalhoro Muhammad Talib ◽  
Kalhoro Ghulam Mujtaba ◽  
Hou Dabin ◽  
Faqir Yahya ◽  
...  

Abstract Background Taro leaf blight, caused by a severely destructive oomycete fungus Phytophthora colocasiae, is responsible for threatening yield loss worldwide. The pathogen has the ability to germinate and spread rapidly to other plants during favorable conditions resulting in acute decline and even death, causing 100% crop loss. Farmers usually rely on highly toxic systemic fungicides to control the disease, which is effective, but residual effects and resistance of these agrochemicals is still a concern. Recently as returning to nature people tend to use chemical-free products, especially edible stuff produced in organic agriculture. Therefore, the use of bio-pesticides and phytochemicals is gaining special attention by scientists as they are ecofriendly non-hazardous, sustainable, and potent alternatives to control many virulent plant pathogens The present research was conducted to assess the antifungal potential of cinnamon essential oils against P. colocasiae. Materials and methods The essential oils from cinnamon bark were extracted using microwave-assisted hydrodistillation equipment, and then their chemical constituents were evaluated using ATR FTIR spectroscopy. The antifungal potential of essential oil was assessed against mycelium, sporangia, zoospore, leaf necrosis, and corms lesions under laboratory conditions at, 0.156, 0.312, 0.625, 1.25, 2.5, 5.0 mg/mL concentrations. Hymexazol was used as positive control and no essential oil as negative control, while each treatment have three replications and experiment repeated twice. Results The main component of oil was identified as cinnamaldehyde. The pathogen isolated from infected taro leaves was identified as P.colocasiae and then was used as a test fungus in the current study. Repeated experiments show maximum inhibition percentage of mycelial growth, zoospore germination, and sporulation of the fungus were observed at 0.625 mg/mL, whereas leaf necrosis was 100% inhibited at 1.25 mg/mL concentration. Conclusion This research can be a reference for easy, cost-effective and environment-friendly management and control of taro leaf blight with phytochemicals and plant essential oil derivatives. Graphic abstract


2014 ◽  
Vol 140 (2) ◽  
pp. 243-250 ◽  
Author(s):  
Modeste Lambert Sameza ◽  
Marie Ampere Bedine Boat ◽  
Séverin Tchameni Nguemezi ◽  
Lile Christere Nguemnang Mabou ◽  
Pierre Michel Jazet Dongmo ◽  
...  

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