排序方式: 共有2条查询结果,搜索用时 0 毫秒
1
1.
Eunice Golda Danièle Ndo Faustin Bella-Manga Sali Atanga Ndindeng Michel Ndoumbe-Nkeng Ajong Dominic Fontem Christian Cilas 《European journal of plant pathology / European Foundation for Plant Pathology》2010,128(3):385-397
In Cameroon and most countries of tropical Africa where Phaeoramularia leaf and fruit spot disease of citrus is reported, a total yield loss of 50–100% is common. For effective control of this
disease, it is imperative to understand how it originates, and which factors contribute to its development. To this end, the
environmental and biological characteristics of each tree from 39 sites located in 13 citrus production basins in the humid
zones of Cameroon were collected by means of a survey. Information was collected by interviewing heads of households, and
by visual inspection of trees and their environment. The independent variable was severity of the disease while the dependent
variables were environmental and biological characteristics. Climatic characteristics varied from one basin to another. The
13 citrus production basins were regrouped in five categories based on disease severity. Altitude, tree species and soil type
were the main factors influencing the disease severity. Thus the higher is the altitude, the more important is the disease
severity. Also, disease severity increased with increasing number of grape fruit, orange and pummelo trees. However, disease
severity was lower on trees growing on volcanic soils as compared with the other soil types. Further analysis of these factors
could lead to the development of a risk assessment model for Phaeoramularia leaf and fruit spot of citrus. 相似文献
2.
Jean Kuate Jacob Foko Sali Atanga Ndindeng Pierre Michel Jazet-Dongmo Eric Fouré François Damesse Bella-Manga Daniel Ducelier 《European journal of plant pathology / European Foundation for Plant Pathology》2006,114(2):151-161
Citrus leaf and fruit spot disease caused by Phaeoramularia angolensis is a serious production constraint in tropical Africa. In previous studies, essential oils extracted from fruit peels of
two tolerant varieties exhibited a strong antifungal activity in vitro against P. angolensis as compared to oils from susceptible ones. In order to investigate if the susceptibility of citrus varieties is associated
with the antifungal activity of their essential oils, some 22 varieties of different susceptibility levels (tolerant, susceptible
and highly susceptible) and belonging to different botanical groups were studied. Oils extracted from fruit peels were evaluated
for their activity against radial growth and sporulation using the poisoned food technique. The optimal doses for growth inhibition
and conidial reduction were 2500 and 1000 ppm, respectively. At these doses, radial growth and sporulation exceeded the untreated
control respectively for four and nine varieties suggesting that oils from these varieties promote fungal development. In
general, oils from the tolerant group were most effective in reducing radial growth irrespective of dose. The highly susceptible
group ranked first in reducing sporulation at dose 1000 ppm (45.93%) while at higher doses of about 2000–2500 ppm, oils from
the tolerant varieties could reduce sporulation up to 100%. The marked dose effect in reducing sporulation suggests that there
may be different compounds acting with changing dose. Botanically, oils from pummelo (Citrus maxima, tolerant group), were best in reducing radial growth (>87% inhibition) while those from grapefruits (C. paradisi, highly susceptible group) were most effective in reducing sporulation (>64% reduction). 相似文献
1