In vitro analysis of antimicrobial and phytochemical properties of crude extracts of selected plants against the tomato wilt disease

The wilt disease by fungal and bacterial pathogens is one of the most devastating diseases of tomato ( Solanum lycopersicum L.) worldwide. Chemical-based control of the wilt-causing pathogens often leads to environmental pollution and pest resistance; hence the need for alternative sustainable approaches. We evaluated the in vitro antimicrobial and phytochemical properties of aqueous crude extracts of roots, leaves, flowers, and barks of Solanum incanum L., Laurnea cornuta , Tagetes minuta L., Ageratum conyzoides , Opuntia monacantha , and Euphorbia tirucalli L. from Kano-Kisumu against Erwinia chrysanthema , Ralstonia solanacearum and Fusarium oxysporum isolated from diseased tomato tissues and rhizospheres. Sterile distilled water and the amoxicillin antibiotic were used as negative and positive control treatments, respectively. The experiment was carried out in diameters of zones of inhibition and levels of phytochemicals determined. Ageratum conyzoides and O. monacantha extracts were least effective against the pathogens, with means of inhibition of only up to 8.7 and 12.3 mm, respectively. Euphorbia tirucalli and L. cornuta were the most effective against the pathogens, with means of inhibition of up to 30 mm. Except for anthocyanins and anthraquinones, no significant (P<0.05) differences were observed for levels of other phytochemicals in different plant extracts. We concluded that plant extracts showing remarkable antimicrobial activities against the pathogens can be used to make viable formulations to combat the devastating tomato wilt disease.La maladie fl\ue9trissures caus\ue9e par des agents pathog\ue8nes fongiques et bact\ue9riens est l\u2019une des maladies les plus d\ue9vastatrices de la tomate ( Solanum lycopersicum L.) dans le monde. La lutte chimique contre les agents pathog\ue8nes responsables du fl\ue9trissures entra\ueene souvent une pollution de l\u2019environnement et une r\ue9sistance aux ravageurs; d\u2019o\uf9 la n\ue9cessit\ue9 d\u2019approches alternatives durables. Nous avons \ue9valu\ue9 in vitro les propri\ue9t\ue9s antimicrobiennes et phytochimiques d\u2019extraits bruts aqueux de racines, feuilles, fleurs et \ue9corces de Solanum incanum L., Laurnea cornuta , Tagetes minuta L., Ageratum conyzoides , Opuntia monacantha et Euphorbia tirucalli L. de Kano- Kisumu contre Erwinia chrysanthema , Ralstonia solanacearum et Fusarium oxysporum isol\ue9s de tissus et de rhizosph\ue8res de tomate malades. L\u2019eau distill\ue9e st\ue9rile et l\u2019antibiotique amoxicilline ont \ue9t\ue9 utilis\ue9s comme traitements t\ue9moins n\ue9gatifs et positifs, respectivement. L\u2019exp\ue9rience a \ue9t\ue9 r\ue9alis\ue9e dans des diam\ue8tres de zones d\u2019inhibition et des taux de compos\ue9s phytochimiques d\ue9termin\ue9s. Les extraits d\u2019Ageratum conyzoides et d\u2019O monacantha \ue9taient les moins efficaces contre les agents pathog\ue8nes, avec des moyens d\u2019inhibition de seulement 8,7 et 12,3 mm, respectivement. Euphorbia tirucalli et L. cornuta se sont r\ue9v\ue9l\ue9s les plus efficaces contre les agents pathog\ue8nes, avec une inhibition pouvant atteindre 30 mm. \uc0 l\u2019exception des anthocyanes et des anthraquinones, aucune diff\ue9rence significative (P <0,05) n\u2019a \ue9t\ue9 observ\ue9e pour les concentrations d\u2019autres compos\ue9s phytochimiques dans diff\ue9rents extraits de plantes. Nous avons conclu que des extraits de plantes pr\ue9sentant des activit\ue9s antimicrobiennes remarquables contre les agents pathog\ue8nes peuvent \ueatre utilis\ue9s pour \ue9laborer des formulations viables permettant de lutter contre la maladie d\ue9vastatrice de la tomate

Factors Influencing the Economic Performance of Women Fish Processors: The Case of Small Scale Omena Fish Processors in Lake Victoria-Homabay County, Kenya

In Homabay County, women are predominant in fish marketing and processing. However there are bottlenecks towards women economic progress. Socio-economic and demographic characteristics are indicators of performance in the society. A study was undertaken to understand the constraints to economic performance among women fish processors. Structured questionnaires were administered randomly to 120 women fish processors. Descriptive statistics was used for data analysis. Results indicate that poor environmental condition and poor personal hygiene contribute to poor quality of fish. The study recommends that there is the need for awareness creation on food safety regulations and implementation of environmental management systems. Keywords: Women, Fish Processing, Economic performance, Sanitation, Environmental System

Occurrence of cystacanths of Polyacanthorhynchus kenyensis larvae (Acanthocephala) in four teleostean fishes from a tropical lake, Lake Naivasha, Kenya

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Growth and mortality of black bass, Micropterus salmoides (Pisces, Centrachidae; Lacapède, 1802) in a reservoir in southern Brazil

The black bass, Micropterus salmoides, was introduced to Brazil from North America in 1922. Since then the species has been reared in aquaculture facilities intended to stock reservoirs as additions to native stocks available for angling. At present no scientific information on the biology of black bass in Brazilian waters is available. Since black bass dispersion may cause severe impacts on native Brazilian fish fauna, information on the basic biological parameters of this species is necessary. The objective of the present study is to provide information on the growth, age structure, and mortality of the species in a small reservoir in southern Brazil, where the species reproduces regularly. Based on scale readings, the von Bertalanffy growth curve was calculated and compared to the length-frequency distribution of the population. Both methods showed similar results. Maximum length was about 44 cm. The mean length at the end of the first year was 23.1 cm (s.d. = 13.88); at that of the second, 37.3 cm (s.d. = 12.52); and 41.4 cm (s.d. = 9.92) at the third. Oldest fish were three years old. The growth performance index ø' was 3.28 cm year-1. Mortality increased from 0.16 year-1 between the first and the second cohort, to 0.8 year-1 between the second and third. The results show that black bass in Brazil grows faster than in its area of origin, but longevity is shorter and body shape, stouter. The cause of high mortality at a relatively early age may be connected with the loss of genetic diversity due to inbreeding of the Brazilian stocks, which originated from few introduced individuals a long time ago. The fact that black bass reproduces in reservoirs and grows rapidly may be considered a threat to conserving fish diversity in Brazilian ecosystems