Evaluation of the repellent and insecticidal activities of the leaf, stem and root powders of siam weed (Chromolaena odorata) against the Cowpea Beetle, Callosobruchus maculatus

This study investigated the repellency and toxicological activity of C. odorata root, stem and leaf powders against adults of the cowpea beetle, Callosobruchus maculatus (Fab.) (Coleoptera: Chrysomelidae). Adults of C. maculatus were exposed to grains treated separately with the root, stem and leaf powders of C. odorata at different exposure periods of 12, 24, 36, and 48 hours. All the three plant parts significantly repelled C. maculatus with the root powder showing the highest percentage repellency, although this was a function of exposure time. The order of repellency after 48 hours exposure was 88, 83 and 76% for the root, leaf and stem powders, respectively. Powders from the three plant parts exhibited insecticidal activity by causing varying levels of mortality to C. maculatus with mortality increasing with increase in exposure time. The root powder accounted for the highest adult mortality (74%) while the leaf powder accounted for the least mortality (51%) after 48 hours exposure time. The high repellent and insecticidal activities demonstrated by the root powder compared to the leaf and stem powders suggest that the root powder should be prioritized for the control and management of C. maculatus.Keywords: Chromolaena odorata, plant powder, toxicity, mortality, repellency, Callosobruchus maculatu

The Physicochemical Characteristics of Ibiekuma River Ekpoma, Nigeria

The Ibiekuma River is an important source of livelihood to its catchment. It contributes enormously to research success and living standard of students and staffs of the Ambrose Alli University Ekpoma, Nigeria. The aim of the study was to determine the impact of anthropogenic activities on the physicochemical properties of Ibiekuma River. Twenty seven water samples were collected at four stations during the study period and analyzed accordingly. The results obtained shows that the physicochemical parameters of the river were in conformity with the World Health Organization (WHO), National Agency for Food, Drug Administration and Control (NAFDAC) and Nigerian Industrial Standard (NIS) safe limits, except for pH values which ranged from 4.69 to 4.81. The heavy metal concentrations were found to be within the limit of the guidelines prescribed by WHO and NAFDAC. Also, there was no significant difference (P > 0.05) in the concentrations of the physicochemical parameters across the four stations sampled along the Ibiekuma River. Water obtained from Ibiekuma River will be fit for domestic use, only if purified

Nitrogen fertilisation improves growth of Chromolaena odorata (Asteraceae) and the performance of the biological control agent, Pareuchaetes insulata (Erebidae)

Recent studies have demonstrated, through their contrasting results, that relationships between nitrogen levels in host plants and phytophagous insect performance are not simple. This study examined the effect of varying fertilisation regimes on the invasive alien plant, Chromolaena odorata (L.) (Asteraceae) and the response of a specialist folivore (a biological control agent), Pareuchaetes insulata (Walker) (Lepidoptera: Erebidae). C. odorata plants were treated with 3 different levels of fertilisation and plant characteristics were measured within 2–3 months of fertiliser application. Leaves from each of the three treatments were fed to newly hatched larvae until pupation in order to determine the effect of nitrogen fertilisation on herbivore performance metrics such as survival, development time, fecundity and longevity. High and medium fertilisation significantly increased foliar nitrogen concentrations, basal stem diameter, leaf length, shoot height and above-ground biomass of C. odorata plants relative to low fertilisation. When individuals of P. insulata were fed on leaves from medium- or high-fertilisation treatments, they developed faster, grew to a larger size (by 8%) and achieved higher fecundity (19–22%) than leaves from the low-fertilisation treatment. The results suggest that in mass-rearing, increased production of this biological control agent will occur in high- or medium-fertilised plants

Flavonoids isolated from the South African weed Chromolaena odorata (Asteraceae) have pharmacological activity against uropathogens

BACKGROUND: Urinary tract infections (UTIs) caused by opportunistic pathogens are among the leading health challenges globally. Most available treatment options are failing as a result of antibiotic resistance and adverse effects. Natural sources such as plants may serve as promising alternatives. METHODS: Compounds were isolated from the South African weed Chromolaena odorata through column chromatography. Purified compounds were tested for antimicrobial activity using the p-iodonitrotetrazolium chloride (INT) colorimetric method, against uropathogenic Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Aspergillus fumigatus and Cryptococcus neoformans. Anti-biofilm, anti-adhesion and metabolic inhibition activities were investigated against selected strains. Safety of the compounds was determined against Vero monkey kidney, C3A human liver and colon (Caco2) cells. RESULTS: Four compounds identified as pectolinaringenin (1), (±)-4′,5,7-trimethoxy flavanone (2), 5-hydroxy-3,7,4′- trimethoxyflavone (3) and 3,5,7-trihydroxy-4′-methoxyflavone) (4) were isolated. Minimum inhibitory concentration (MIC) varied between 0.016 and 0.25 mg/mL. Compounds 2 and 3 showed promising antimicrobial activity against E. coli, S. aureus, K. pneumoniae, A. fumigatus and C. neoformans with MIC between 0.016 and 0.125 mg/mL, comparable to gentamicin, ciprofloxacin and amphotericin B used as positive controls. Compounds 2 and 3 showed good anti-biofilm and metabolic inhibition activities against E. coli and S. aureus but weak anti-adhesion activity against the organisms. Low toxicity with selectivity indexes between 1 and 12.625 were recorded with the compounds, indicating that the compounds were rather toxic to the microbial strains and not to the human and animal cells. CONCLUSION: Pharmacological activities displayed by compounds 2 and 3 isolated from C. odorata and low toxicity recorded credits it as a potential lead for the development of useful prophylactic treatments and anti-infective drugs against UTIs. Although known compounds, this is the first time these compounds have been isolated from the South African weed C. odorata and tested for antimicrobial, anti-biofilm, metabolic inhibition and anti-adhesion activities.The National Research Foundation, South Africahttps://bmccomplementmedtherapies.biomedcentral.compm2020Paraclinical Science

Exposure of the African mound building termite, Macrotermes bellicosus workers to commercially formulated 2,4-D and atrazine caused high mortality and impaired locomotor response.

Recent empirical evidence suggests that herbicides have damaging effects on non-target organisms in both natural and semi-natural ecosystems. The African mound building termite, Macrotermes bellicosus, is an important beneficial insect that functions as an ecosystem engineer due to its role in the breakdown of dead and decaying materials. Here, we examined the effects of 2,4-D amine salt (2,4-D) and atrazine based herbicides viz. Vestamine® and Ultrazine® on the survival and locomotion response of M. bellicosus. Worker termites were treated with a range of concentrations of Vestamine® (the recommended concentration: 6.25 ml per 500 ml of water, 0.25- and 0.5-fold below the recommended concentration and distilled water as control) and Ultrazine® (the recommended concentration: 3.75 ml per 500 ml of water, 0.25-, 0.5-, 2.0- and 4-fold of the recommended concentration and distilled water as control) for 24 hours for the mortality test, and allowed to run for 15 seconds for the locomotion trial. All concentrations of both Vestamine® and Ultrazine® were highly toxic to worker termites and mortality increased as the concentration and time after treatment increased. For both herbicides, concentrations far less than the recommended rates caused 100% mortality. The speed of termites was significantly influenced by both Vestamine® and Ultrazine® as termites exposed to all tested concentrations of the herbicides exhibited reduced running speed than the control. These findings suggest that beneficial insects, especially M. bellicosus may experience high mortality (up to 100%) and reduced mobility if they are sprayed upon or come in contact with plant materials that have been freshly sprayed with (less or more than) the recommended concentrations of Vestamine® and Ultrazine®. The findings of our study calls for the reassessment of the usage of 2,4-D and atrazine based herbicides in weed control in termite and other beneficial insect populated habitats

Laryngeal Trauma Complicating a Suicide Attempt by Hanging

A 40-year-old man was admitted to the emergency room after a suicide attempt. He was found hanged in his garden shelter by a neighbour. The patient complained only of a slight dysphagia and anterior cervical pain. The clinical examination revealed no cutaneous lesion or neurological deficit. Head and neck CT scan with and without injection of contrast agent was performed. CT has shown displaced fractures of the two horns of the thyroïd cartilage (Figs. A, B; white arrow). Fractures were associated with a small tumefaction of the left hypopharyngeal soft tissue (Fig. C; white star) and left side of the larynx. The airways were patent. The ENT specialist achieved a laryngoscopy and confirmed the small buldging of the larynx, with no significant effect on the airways. Larynx mobility was conserved. A control fibroscopy was done 12 hours later with no modification of the lesion

Statistical details (GLM ANOVA) for the analyses of the effects of season (autumn vs winter) and habitat condition (larval food source) on total development duration, pupal mass, growth rate, host suitability index, number of eggs and adult longevity.

<p>Statistical details (GLM ANOVA) for the analyses of the effects of season (autumn vs winter) and habitat condition (larval food source) on total development duration, pupal mass, growth rate, host suitability index, number of eggs and adult longevity.</p

Developmental and reproductive performance of a specialist herbivore depend on seasonality of, and light conditions experienced by, the host plant - Fig 4

<p><b>Seasonal (autumn vs winter) variation in total development duration (a), pupal mass (b) growth rate (c) and host suitability index (d) of <i>Pareuchaetes insulata</i> reared on <i>Chromolaena odorata</i> leaves from two different habitats.</b> Data represent means ± SE. Bars within each graph not sharing a common letter differ significantly (<i>P</i> < 0.05) after Tukey-Kramer test.</p

Seasonal (autumn vs winter) variation in leaf toughness [as indicated by specific leaf weight (SLW)] of <i>Chromolaena odorata</i> plants in two habitats (shade vs full sun).

<p>Data represent means ± SE. Bars within each graph not sharing a common letter differ significantly (<i>P</i> < 0.05) after Tukey’s Honest Significant Difference (HSD) test.</p