Determination of critical period for weed control in intensive and non-intensive sugarcane (Saccharum officinarum L., Poaceae) production systems in center Côte d’Ivoire

Field experiments were conducted in Zuenoula and Yamoussoukro for determining Critical Period for Weed Control (CPWC) in sugarcane. The treatments consisted in two sets of weed interference. In the first set, the crop was kept weed-free until 31, 61, 92, 123 days after planting (DAP) in Zuenoula and until 32, 69, 98 and 162 DAP in Yamoussoukro. In the second set, weeds were permitted to grow within the crop until the above-mentioned DAP. The CPWC was determined for 5, 10, 15 and 20% acceptable yield loss levels by fitting Logistic and Gompertz nonlinear equations to relative yield data. In both locations, increasing the duration of weed interference decreased sugarcane yield significantly. In Zuenoula, the CPWC was from 28 to 117, 30 to 93, 32 to 75 and 34 to 59 DAP to prevent yield losses of 5, 10, 15 and 20%, respectively. In Yamoussoukro, the CPWC ranged from 38 to 163, 39 to 112, 40 to 99 and from 40 to 91 DAP to prevent yield losses of 5, 10, 15 and 20%, respectively. Results suggest weed control between 28 and 117 DAP in Zuenoula and between 38 and 163 DAP in Yamoussoukro to provide maximum yield.Keywords: Weed interference, Gompertz, Logistic, weed control, yield

Adventices des vergers de l'anacardier en Cote d'Ivoire

RESUMELe présent travail vise à contribuer à la connaissance de la composition et la diversité floristiques des adventices des vergers de l’anacardier dans la zone de savane de Côte d’Ivoire. Dans chacun des 261 vergers de l’anacardier visités dans les 10 antennes de production d’anacarde, une ou deux placette(s) de 100 m2 ont été installées et prospectées pour l’inventaire des adventices selon que le verger de l’anacardier est à couronnes homogènes ou hétérogènes. Dans les 261 vergers ainsi prospectés, 438 espèces d’adventices appartenant à 73 familles et 276 genres ont été recensées. Les familles des Leguminosae (18,49 %), des Poaceae (9,13 %), des Rubiaceae et des Compositae (6,39 % chacune), des Malvaceae (4 %), des Lamiaceae (3,88 %), des Combretaceae (3,42 %), des Cyperaceae et des Apocynaceae (3,19 % chacune), des Euphorbiaceae et des Phyllanthaceae (2,73 % chacune) sont les plus représentées de cette flore. L’indice de diversité générique, estimé à 1,58, indique que les vergers sont diversifiés floristiquement. Le total pluviométrique annuel, la température moyenne journalière, les coordonnées géographiques, le type de sol et l’état de couverture des houppiers d’anacardiers n’influencent pas la richesse des adventices. Toutefois, l’état de couverturedes houppiers influence la nature et le recouvrement des adventices. ABSTRACTWEEDS OF CASHEW ORCHARDS IN COTE D’IVOIREThe present work aims to contribute to the knowledge of the floristic composition and diversity of weeds of cashew orchards in the savannah area of Côte d’Ivoire. In each of 261 cashew orchards visited, in the 10 cashew production branches, a single or couple of 100 sqm plots were established and assessed for weeds according to heterogeneous (closed and juxtaposed or separated) or homogeneous crowns (closed or juxtaposed or separated). In these 261 assessed orchards, 438 weed species belonging to 73 families and 276 genera were found. The families Leguminosae or Fabaceae (18.49 %), Poaceae (9.13%), Rubiaceae and Compositae (6.39% each), Malvaceae (4%), Lamiaceae (3.88%),Combretaceae (3.42%), Cyperaceae and Apocynaceae (3.19%) and Euphorbiaceae and Phyllanthaceae (2.73% each) are the most represented. A 1.58 generic diversity index value indicates that orchards are floristically diverse. Total annual rainfall, average daily temperature, geographic coordinates, soil type and coverage of cashew crowns do not influence the richness of weeds. However, the crown cover status influences the nature and cover of weeds

Widespread occurrence of copy number variants and fixation of pyrethroid target site resistance in Anopheles gambiae (s.l.) from southern Cote d’Ivoire

Resistance to pyrethroid and organophosphate insecticides in the malaria vector Anopheles gambiae (s.l.) is conferred by a variety of genetic mutations, including single nucleotide polymorphisms (SNPs) and copy number variants (CNVs). Knowledge of the distribution of these mutations in mosquito populations is a prerequisite for establishing better strategies for their management. In this study, a total of 755 Anopheles gambiae (s.l.) from southern Côte d’Ivoire were exposed to deltamethrin or pirimiphos-methyl insecticides and were screened to assess the distribution of SNPs and CNVs known or believed to confer resistance to one or other of the insecticide classes. Most individuals from the An. gambiae (s.l.) complex were identified by molecular tests as Anopheles coluzzii. Survival to deltamethrin (from 94% to 97%) was higher than to pirimiphos-methyl (from 10% to 49%). In An. gambiae (s.s.), the SNP in the Voltage Gated Sodium Channel (Vgsc) at the 995F locus (Vgsc-995F) was fixed, while other target site mutations were rare or absent (Vgsc-402L: 0%; Vgsc-1570Y: 0%, Acetylcholinesterase Acel-280S: 14%). In An. coluzzii, Vgsc-995F was the target site SNP found at highest frequency (65%) followed by other target site mutations (Vgsc-402L: 36%; Vgsc-1570Y: 0.33%; Acel-280S: 45%). The Vgsc-995S SNP was not present. The presence of the Ace1-280S SNP was found to be significantly linked to the presence of the Ace1-CNV, Ace1_AgDup. Significant association was found between the presence of the Ace1_AgDup and pirimiphos-methyl resistance in An. gambiae (s.s.) but not in An. coluzzii. The deletion Ace1_Del97 was found in one specimen of An. gambiae (s.s.). Four CNVs in the Cyp6aa/Cyp6p gene cluster, which contains genes of known importance for resistance, were detected in An. coluzzii, the most frequent being Dup 7 (42%) and Dup 14 (26%). While none of these individual CNV alleles were significantly associated with resistance, copy number in the Cyp6aa gene region in general was associated with increased resistance to deltamethrin. Elevated expression of Cyp6p3 was nearly associated with deltamethrin resistance, although there was no association of resistance with copy number. Use of alternative insecticides and control methods to arrest resistance spread in An. coluzzii populations is merited

Caracterisation moleculaire et selection de varietes de manioc resistantes contre Xanthomonas axonopodis PV. Manihotis en Cote d’Ivoire

La bactériose du manioc causée par Xanthomonas axonopodis pv. manihotis cause de dommages aux cultures de manioc en Côte d’Ivoire. En vue d’avoir une meilleure connaissance de l’agent pathogène, 800 isolats ont été collectés des fragments de feuilles et de tiges de manioc malades dans six des sept zones agroécologiques (ZAE). Les colonies bactériennes de chaque isolat montrant les caractéristiques morphologiques typiques Xanthomonas axonopodis pv. manihotis ont été soumises à une analyse moléculaire. En se basant sur le dénombrement des feuilles attaquées par la maladie, la sensibilité de huit variétés de manioc a été évaluée dans les conditions d’infestation naturelle à Ferkessédougou. Les résultats ont montré après 48 heures d’incubation, des colonies de caractéristiques morphologiques, blanc-ivoire, lisses, brillantes, convexes, avec des contours réguliers, non puantes et d’aspect visqueux. L’amplification par PCR de l’ADN, a montré un profil à une seule bande d’une taille d’environ 900 pb caractéristique de Xanthomonas axonopodis pv. manihotis. Des huit variétés testées, seules les variétés améliorées « Bocou 2 » et « Yavo » ont été les moins attaquées. Xanthomonas axonopodis pv. manihotis est bien sûr l’agent causal des taches, brûlures et dieback observées sur les variétés de manioc en Côte d’Ivoire. Donc, les variétés « Bocou 2 » et « Yavo » peuvent être recommandées aux producteurs des zones où la bactériose vasculaire du manioc sévit plus.Mots clés : Manioc, Xanthomonas axonopodis pv. manihotis, caractérisation moléculaire, résistance variétal

Early Diagnosis of HIV Infection in Infants - One Caribbean and Six Sub-Saharan African Countries, 2011-2015.

Pediatric human immunodeficiency virus (HIV) infection remains an important public health issue in resource-limited settings. In 2015, 1.4 million children aged 50% decline. The most common challenges for access to testing for early infant diagnosis included difficulties in specimen transport, long turnaround time between specimen collection and receipt of results, and limitations in supply chain management. Further reductions in HIV mortality in children can be achieved through continued expansion and improvement of services for early infant diagnosis in PEPFAR-supported countries, including initiatives targeted to reach HIV-exposed infants, ensure access to programs for early infant diagnosis of HIV, and facilitate prompt linkage to treatment for children diagnosed with HIV infection

PLANTAIN TREE GROWTH (MUSA SP., AAB CULTIVAR HORN 1) MODELING USING THE ARTIFICIAL NEURAL NETWORKS METHOD

The plantain tree growth is made up of a number of growth parameters such as leaves number (Ln), leaf length (Ll), leaf width (Lw), pseudo-stem height (Hp), width at 10 cm above the ground (W10), pseudo-stem width at middle (Wm) and its width at top (Wt). A study of these growth parameters was carried out in the area of Azaguié (Côte d'Ivoire). The results show that plantain tree growth depends on growth parameters evolution. For this purpose, mathematical models were developed to predict the growth using an artificial neural network. Satisfactory results were obtained since all the determination coefficients were higher than 0.97. These coefficients are approximately 1, and it points out the ability of the artificial neural network to map suitably the experimental data

Artificial wounds implication for the development of mango (Mangifera Indica L. Anacardiaceae) fruit disease caused by Colletotrichum gloeosporioïdes (Penz.) Sacc. (Glomerellaceae)

Anthracnose is the most important post-harvest disease of mango caused by Colletotrichum gloeosporioïdes in Côte d’Ivoire. This study was conducted to evaluate the pathogenicity of 5 isolates (CA1, CA2, CB2, CB3 and CK2) of C. gloeosporioïdes. The isolates were obtained from naturally infected fruits of varieties including Brooks (CB2 and CB3), Kent (CK2) and Amelia (CA1 and CA2). The mycelium plugs of each purified isolate were used for a wound or no wound inoculation of Brooks and Keitt mango fruits. The dates of the first lesions appearance with their sizes were assessed. The inoculation without wounds didn’t produce any lesion on both varieties. On the other hand, with the wounded method, all the isolates caused lesions on the varieties studied. The first lesions were induced on the 6th day after inoculation (DAI) on both varieties by isolate CA2. It also produced the largest lesion size on Keitt (3.19 ± 0.39 cm) and Brooks (2.61 ± 0.34 cm). On the opposite, isolate CA1 induced lesions lately with an average at 10.75 and 8.50 DAI, as well asa lower average size of 0.12 ± 0.07 cm and 0.62 ± 0.21 cm, respectively on Brooks and Keitt varieties. Isolates CA2 was the most virulent on the two varieties

Bayesian Estimation of MSM Population Size in Côte d’Ivoire

Côte d’Ivoire has among the most generalized HIV epidemics in West Africa with an estimated half million people living with HIV. Across West Africa, key populations, including gay men and other men who have sex with men (MSM), are often disproportionately burdened with HIV due to specific acquisition and transmission risks. Quantifying population sizes of MSM at the subnational level is critical to ensuring evidence-based decisions regarding the scale and content of HIV prevention interventions. While survey-based direct estimates of MSM numbers are available in a few urban centers across Côte d’Ivoire, no data on MSM population size exists in other areas without any community group infrastructure to facilitate sufficient access to communities of MSM. The data are used in a Bayesian regression setup to produce estimates of the numbers of MSM in areas of Côte d’Ivoire prioritized in the HIV response. Our hierarchical model imputes missing covariates using geo-spatial information and allows for proper uncertainty quantification leading to confidence bounds for predicted MSM population size estimates. This process provided population size estimates where there are no empirical data, to guide the prioritization of further collection of empirical data on MSM and inform evidence-based scaling of HIV prevention and treatment programs for MSM across Côte d’Ivoire

HIV prevalence and behavioral and psychosocial factors among transgender women and cisgender men who have sex with men in 8 African countries: A cross-sectional analysis

<div><p>Introduction</p><p>Sub-Saharan Africa bears more than two-thirds of the worldwide burden of HIV; however, data among transgender women from the region are sparse. Transgender women across the world face significant vulnerability to HIV. This analysis aimed to assess HIV prevalence as well as psychosocial and behavioral drivers of HIV infection among transgender women compared with cisgender (non-transgender) men who have sex with men (cis-MSM) in 8 sub-Saharan African countries.</p><p>Methods and findings</p><p>Respondent-driven sampling targeted cis-MSM for enrollment. Data collection took place at 14 sites across 8 countries: Burkina Faso (January–August 2013), Côte d’Ivoire (March 2015–February 2016), The Gambia (July–December 2011), Lesotho (February–September 2014), Malawi (July 2011–March 2012), Senegal (February–November 2015), Swaziland (August–December 2011), and Togo (January–June 2013). Surveys gathered information on sexual orientation, gender identity, stigma, mental health, sexual behavior, and HIV testing. Rapid tests for HIV were conducted. Data were merged, and mixed effects logistic regression models were used to estimate relationships between gender identity and HIV infection. Among 4,586 participants assigned male sex at birth, 937 (20%) identified as transgender or female, and 3,649 were cis-MSM. The mean age of study participants was approximately 24 years, with no difference between transgender participants and cis-MSM. Compared to cis-MSM participants, transgender women were more likely to experience family exclusion (odds ratio [OR] 1.75, 95% CI 1.42–2.16, <i>p <</i> 0.001), rape (OR 1.95, 95% CI 1.63–2.36, <i>p <</i> 0.001), and depressive symptoms (OR 1.30, 95% CI 1.12–1.52, <i>p <</i> 0.001). Transgender women were more likely to report condomless receptive anal sex in the prior 12 months (OR 2.44, 95% CI 2.05–2.90, <i>p <</i> 0.001) and to be currently living with HIV (OR 1.81, 95% CI 1.49–2.19, <i>p <</i> 0.001). Overall HIV prevalence was 25% (235/926) in transgender women and 14% (505/3,594) in cis-MSM. When adjusted for age, condomless receptive anal sex, depression, interpersonal stigma, law enforcement stigma, and violence, and the interaction of gender with condomless receptive anal sex, the odds of HIV infection for transgender women were 2.2 times greater than the odds for cis-MSM (95% CI 1.65–2.87, <i>p <</i> 0.001). Limitations of the study included sampling strategies tailored for cis-MSM and merging of datasets with non-identical survey instruments.</p><p>Conclusions</p><p>In this study in sub-Saharan Africa, we found that HIV burden and stigma differed between transgender women and cis-MSM, indicating a need to address gender diversity within HIV research and programs.</p></div

Multivariable logistic regression of odds of HIV infection.

<p>Multivariable logistic regression of odds of HIV infection.</p