Insect pests’ incidence and variations due to forest landscape degradation in the humid forest zone of Southern Cameroon: farmers’ perception and need for adopting an integrated pest management strategy

Group surveys were conducted in five villages in each of the three resource-use zones of the humid forest zone of Southern Cameroon, to assess insect pests’ incidence and the variation due to forest landscape degradation in the agricultural production systems. 389 farmers were interviewed. The results show that: (1) In annual crop systems, insect pests in general rank together with vertebrate pests and diseases amongst the most important agronomic constraints. No differences were found between the intensification zones, except for weeds, which appeared to be a greater constraint in the slightly degraded area. Within the insect pest, the greatest damage to crops according to farmers originated from borers and scales, followed by variegated grasshopper. Only the termites showed a difference between zones - the problem being greatest in the high-degraded areas. (2) In the young perennial crop systems, all the categories of agronomic constraints were equally important. Within the insect pest, mirids were identified as the greatest constraint, followed by borers and caterpillars. There were more variations in the responses according to zones compared to annual crops. Termites and scales were relatively more important in the high-degraded area. In term of control strategy, we recommended an integrated pest management.Keywords: Farmers, pest, insect, annual crop, perennial crop, integrated pest managemen

Morphologie et abondance des stades de développement d’Ilyocoris cimicoïdes Linné 1758 (Heteroptera : Naucoridae) dans un lac anthropisé en zone tropicale (Cameroun)

Objectifs : Une étude conduite au laboratoire de Zoologie et de Biologie Générale de l’Université de Yaoundé I a porté sur l’écologie de la punaise aquatique Ilyocoris cimicoïdes Linné 1758 (Heteroptera : Naucoridae) prélevée dans le lac d’Obili (Yaoundé, Cameroun). Méthodologie et résultats : L’analyse physico-chimique montre que ce lac est dans un état eutrophe à hypereutrophe et ses eaux sont fortement chargées en matière organique. Les observations morphologiques et l’illustration des stades de développement ainsi que l’étude de leurs fluctuations numériques montrent que I. cimicoïdes à six stades post-embryonnaires parmi lesquels cinq sont larvaires. La taille des individus augmente de la larve de 1er stade jusqu’au stade adulte. Les stades larvaires d’I. cimicoïdes se distinguent les uns des autres par la présence ou l’absence du ptérothèque, la forme de la marge postérieure du mésotergum et la taille relative du ptérothèque par rapport à la base du mésotergum. Conclusions : L’abondance des stades de développement d’I.cimicoïdes est influencée par la saisonnalité et l’évolution de certaines variables physico-chimiques. Les larves pullulent pendant la saison sèche et les oeufs et adultes pendant la saison des pluies.Mots clés : Pollution aquatique, morphologie, développement, Ilyocoris cimicoïdes.  Objectives : A study conducted at the Laboratory of Zoology and General Biology, University of Yaoundé I focused on the ecology of aquatic bug Ilyocoris cimicoides Linnaeus 1758 (Heteroptera : Naucoridae) taken from Lake Obili (Yaoundé, Cameroon). Methodology and Results: The physico-chemical analysis showed that this lake is in a eutrophic state and its waters are heavily loaded with organic matter. Morphological observations and illustration stages of development and the study of their digital fluctuations show that I. cimicoides, has six post-embryonic stages of which five are breeding. The sizes of individuals increase the first stage larva to adult. Larval stages of I.cimicoides are distinguished from each other by the presence or absence of pterotheque, the shape of the posterior margin and mesotergum pterotheque relative size with respect to the base of mesotergum. Conclusions : Abundance stages of development I. cimicoides is influenced by seasonality and the evolution of certain physico-chemical variables. Larvae swim in the dry season and eggs and adults during the rainy season.Keywords : Water Pollution, morphology, development, Ilyocoris cimicoides

Farmers' perception on the importance of variegated grasshopper (Zonocerus variegatus (L.)) in the agricultural production systems of the humid forest zone of Southern Cameroon

BACKGROUND: Zonocerus variegatus (Linnaeus, 1758) (Orthoptera: Pyrgomorphidae) is known as an agricultural pest in West and Central Africa. However, its importance in the agricultural production system in Cameroon has not been investigated. The study assesses farmers' perception on the importance of Z. variegatus in the agricultural production systems of the humid forest zone of Southern Cameroon. METHODS: Research was carried out in 5 villages of each of three Agro-Ecological, Cultural and Demographic Blocks (AECD-Blocks) of the Forest Margin Benchmark Area (FMBA). In each village, a semi-structured survey was used; male and female groups of farmers were interviewed separately. RESULTS: Z. variegatus is present throughout the humid forest zone of Southern Cameroon, where it is ranked as the third most economically important insect pest of agriculture. In the farmers' opinion, Z. variegatus is a polyphagous insect with little impact on young perennial crops. The length of the pre-farming fallow does not affect Z. variegatus pest pressure in the following crops. The increased impact of the grasshopper observed today in the fields, compared to what existed 10 years ago is as a result of deforestation and increase in surface of herbaceous fallow. The damage caused by Z. variegatus is higher in fields adjacent to C. odorata and herbaceous fallows than in those adjacent to forests and shrubby fallows. The fight against this grasshopper is often done through physical methods carried out by hand, for human consumption. The farmers highlight low usage of the chemical methods and a total absence of biological and ecological methods. CONCLUSION: Farmers' perception have contributed to understanding the status of Z. variegatus in the humid forest zone of Southern Cameroon. The results are in general similar to those obtained in other countries

Phytiatrie et fonction du phytiatre en phytoprotection

La phytiatrie est une branche de la phytoprotection dont la définition est peu claire, variable et très confuse dans la littérature. Dans cet article dont les données sont issues de sources secondaires, nous essayons de : (1) clarifier la définition des mots phytiatrie et phytiatre ; (2) préciser le contenu d’une formation de base en phytiatrie ; (3) proposer une organisation de la fonction de phytiatre. Le phytiatre (médecin de la plante), s’occupe de la gestion des maladies, des agresseurs et des traumatismes des plantes. La phytiatrie se distingue clairement de la phytopathologie, science qui étudie les maladies des plantes causées par les microorganismes et les facteurs environnementaux. Le phytiatre a des connaissances en phytopharmacie, mais n’est pas un phytopharmacien. Le diplômé en phytiatrie doit être capable d’analyser et de comprendre les exigences de la phytoprotection afin de développer et de proposer des solutions adéquates, dans un contexte de protection de l’environnement. Le grade de phytiatre devrait être réservé aux ingénieurs en phytiatrie, aux titulaires d’un Master ou d'un Doctorat / Ph.D en phytiatrie. Une meilleure structuration des formations en phytiatrie et de la fonction de phytiatre, peut contribuer à une meilleure prise en charge des affections des plantes dans les systèmes de production en Afrique. English title: Phytiatrics and function of the phytiatrist in plant protection Abstract Phytiatrics is a branch of Phytoprotection whose definition is unclear, variable and very confused in the literature. In this article, whose data come from secondary sources, we try to: (1) clarify the definition of phytiatrics and phytiatrist; (2) specify the content of basic training in phytiatrics; (3) propose an organization of the function of phytiatrist. The phytiatrist (plant medical doctor) deals with the management of plant diseases, pests and trauma. Phytiatrics is clearly distinguished from phytopathology which is the science that studies plant diseases caused by microorganisms and environmental factors. The phytiatrist has knowledge in phytopharmacy, but is not a phytopharmacist. The graduate in phytiatrics must be able to analyze and understand the requirements of phytoprotection in order to develop and propose adequate solutions, in a context of environmental protection. The rank of phytiatrist should be reserved for engineers in phytiatrics, holders of a Master’s degree or a doctorate in phytiatrics. A better structuring of training in phytiatrics and the function of phytiatrist can contribute to better management of plant ailments in plant production systems in Africa. Keywords: plant, disease, aggressors, training, phytiatrist

Redescription and diagnosis of the African genus Gemeneta Karsch, 1892 (Orthoptera: Acrididae: Catantopinae)

The subfamily Catantopinae is a poorly defined subfamily of the Acrididae, having many genera that require taxonomic clarification. The genus Gemeneta from this subfamily is found in African forests and has only two described species, Gemeneta terrea and Gemeneta opilionoides. However, the original descriptions of the genus relied heavily on external female morphology, and a description of male G. opilionoides was completely lacking. The present work provides the first description of the male of G. opilionoides, a morphological description of both species, including internal genitalia, and clarifies the generic diagnosis. This study is a contribution to a better understanding of the taxonomy of Catantopinae in the tropical forests of Africa

Prévalence et abondance de Charletonia cameroonensis Haitlinger & Kekeunou 2014 (Acari : Erythraeidae) parasite de Zonocerus variegatus (Linnaeus 1758) (Orthoptera : Pyrgomorphidae) dans la zone côtière du Cameroun

Objectifs: La recherche d’une stratégie de protection des cultures vivrières contre le criquet ravageur Zonocerus variegatus (Linnaeus 1758) (Orthoptera : Pyrgomorphidae) a consisté à étudier chez cet hôte, la prévalence et l’abondance de Charletonia cameroonensis Haitlinger & Kekeunou 2014 (Acari : Erythraeidae) dans la zone côtière du Cameroun.Méthodologie et résultats: Les captures et observations ont été menées hebdomadairement d’avril 2013 à avril 2014 à Logbessou, un quartier de la banlieue Nord-est de la ville de Douala. Pendant une heure (8h30-9h30), les individus de Z. variegatus ont été capturés et C. cameroonensis a été énuméré sur tout le corps de chacun. Il apparait que C. cameroonensis est un ectoparasite permanent de Z. variegatus, puisqu’il a été rencontré durant toute la période d’étude et sur la quasi-totalité des stades postembryonnaires. Sa prévalence a atteint 21,40 %. Le pourcentage d’infestation a significativement augmenté du stade larvaire 1 (4,14%) au stade adulte (67,58%). Ce pourcentage d’infestation a été plus élevé en saison pluvieuse (31,02%) qu’en saison sèche (7,69%). L’abondance de C. cameroonensis a varié de 0 à 23 individus parasites par individu de Z. variegatus. Cette abondance s’est accrue du stade larvaire1 au stade adulte. C. cameroonensis a été présent sur les trois tagmes de Z. variegatus, avec une charge significativement plus élevée sur le thorax et principalement au niveau des ailes. Une corrélation significativement positive a été obtenue entre l’abondance du parasite et la taille des populations du ravageur.Conclusions et application des résultats: Ces résultats préliminaires apportent des connaissances qui pourraient être approfondies dans le cadre d’études ultérieures pour une exploitation de C. cameroonensis dans une optique de lutte biologique contre Z. variegatus.Mots clés: Abondance, prévalence, C. cameroonensis, Z. variegatus, Zone côtièreEnglish AbstractObjectives: The search for a strategy to protect food crops against Zonocerus variegatus (Linnaeus 1758) (Orthoptera : Pyrgomorphidae) was to investigate the prevalence and abundance of Charletonia cameroonensis Haitlinger & Kekeunou 2014 (Acari : Erythraeidae) in the coastal area of Cameroon.Methodology and results: Catches and observations were conducted weekly from April 2013 to April 2014 in Logbessou, a sub-urban North-East of Douala. For one hour (8:30 to 9:30), individuals of Z. variegatus (all stages combined) were captured and the distribution of C. cameroonensis on each insect was recorded. It appears that C. cameroonensis was a permanent parasite of Z. variegatus. Parasite prevalence reached 21.40 %; this prevalence increased significantly from the stage 1 larva population (4.14%) to adult stage (67.58%). Parasite prevalence was higher during the rainy season (31.02%) than during the dry season (7.69%). C. cameroonensis abundance varied from 0-23 (averagely 0.54±1.65 parasites per host). This abundance also increased significantly from stage 1 larva (0.05±0.24 parasites per host) to adult (2.36±3.4 parasites per individual host). C. cameroonensis was present on the three body regions of the host, with a significantly greater parasite load on the thorax and more precisely on the wings. A significantly and positive correlation has been established between the parasite abundance and the size of Z. variegatus population.Conclusion and application of results: These preliminaries results provides important information that could be explored in future studies in the context of biological control of Z. variegatus by C. cameroonensis.Keywords: Abundance, prevalence, C. cameroonensis, Z. variegatus, Coastal zon

Black-bellied pangolin Phataginus tetradactyla documented in Deng Deng National Park, Cameroon, using camera traps

Information on pangolin life history and ecology is becoming increasingly available in African countries through community based surveys and camera-trapping. However, there is a paucity of information on the largely arboreal black-bellied pangolin Phataginus tetradactyla, which is categorized as Vulnerable on the IUCN Red List. By targeting fallen trees or logs with camera traps we recorded the black-bellied pangolin opportunistically in Deng Deng National Park (East Region, Cameroon), a locality within the presumed distribution of the species within Cameroon. We obtained a low trapping rate of 0.063 events per 100 trap days and the capture probability was one event recorded over 1571 trap-days (0.0006 captures per day). Deploying camera traps that focus on fallen trees or logs could be explored as a method for detecting black-bellied pangolins

Larval habitats and susceptibility of malaria vectors to insecticides in semi-urban and rural localities of the Coast-Cameroon region: preliminary data

Le choix d’une stratégie appropriée de lutte anti-paludique dans un faciès éco-climatique donné requiert une bonne connaissance de l’écologie des vecteurs, notamment la distribution spatiale et la productivité des gîtes larvaires, et de leur niveau de sensibilité aux insecticides. La présente étude cartographie, caractérise les gîtes de ponte des moustiques et évalue la susceptibilité aux insecticides des vecteurs de paludisme à Banya II et Bodiman, deux localités l’une sub-urbaine et l’autre rurale, de la région du littoral camerounais. Les enquêtes sur le terrain ont été menées en mai 2015. Les gîtes de moustiques ont été géo-réferencés. Pour chaque gîte, les larves ont été prélevées puis élevées et les paramètres physico-chimiques mesurés in situ. La sensibilité des vecteurs au Dichlorodiphényltrichloroéthane (DDT), à la Deltaméthrine et à la Perméthrine a été évaluée sur les anophèles issus de l’élevage des larves. Une diversité de gîtes a été identifiée dans les sites d’étude (mares, cours d’eau, caniveaux, pneus, emballages-plastiques, récipients de réserve d’eau, récipients abandonnés, trous de papayer, trous de bambou). Cependant, Anopheles gambiae s.l., l’espèce la plus abondante à Banya II a été plus fréquente dans les mares, alors que Culex poicilipes, l’espèce la plus abondante à Bodiman a été majoritairement collectée dans des récipients abandonnés. Les deux catégories de gîtes avaient respectivement une conductivité électrique de 167,5 [16,9-305] et 170,43 [11,6-461] µs/cm ; une salinité de 90,5 [23,5-157] et 94,6[15-240] g/l ; un total de solides dissous (TDS) de 119,6 [20,6-215] et 123,3 [7,8-354] ppm. Les trois insecticides testés ont induit des taux de mortalité inférieurs à 85 % pour la souche Banya II d’A. gambiae s.l. et supérieurs à 98 % pour la souche Bodiman d’A. nili. Les présentes informations devraient être prises en compte pour une meilleure orientation des stratégies de lutte si l’on veut contrôler efficacement les vecteurs dans les localités d’étude.Choosing an appropriate strategy for mosquito control in an eco-climatic facies requires knowledge of vector ecology, including the spatial distribution and productivity of larval habitats and their level of susceptibility to insecticides. This study maps, characterizes the mosquito breeding sites and evaluates the susceptibility to insecticides of malaria vectors to Banya II and Bodiman, two semi-urban and rural areas of the coastal region of Cameroon. The field surveys were conducted in May 2015. The mosquito breeding sites were geo-referenced. For each breeding site, larvae were collected then reared and physico-chemical parameters measured in situ. The susceptibility of vectors to dichlorodiphenyltrichloroethane (DDT), deltamethrin and permethrin was evaluated on the anopheline obtained from larva rearing. A variety of breeding sites has been identified in the study sites (ponds, rivers, ditches, tires, plastic wrap, water storage containers, abandoned containers, papaya holes, bamboo holes). However, Anopheles gambiae s.l, the most abundant species in Banya II was more common in the pools, while Culex poicilipes, the most abundant species in Bodiman was mainly collected in abandoned containers. The two categories of breeding sites had respectively electrical conductivity of 167.5 [16.9-305] and 170.43 [11.6-461] µs/cm, salinity of 90.5 [23.5-157] and 94.63[15-240] g/l and total dissolved solids of 119.6 [20.6-215] and 123.3 [7.8-354] ppm. Insecticides tests revealed mortality rates below 85 % for the Banya II Strain of A. gambiae s.l. and over 98 % for the Bodiman strain of A. nili. These informations should be taken into account for a better orientation of control strategies in order to control effectively the vectors in the study localities

Using local ecological knowledge to improve the effectiveness of detecting white-bellied pangolins (Phataginus tricuspis) using camera traps: A case study from Deng-Deng National Park, Cameroon

First paragraph: Pangolins (Order: Pholidota) remain one of the most challenging groups of mammals to detect and study. Yet, locating and documenting pangolin presence is essential to provide data on their distribution and population, which help to build effective conservation strategies. Pangolins are considered to be elusive and many of their ecological traits, such as low population density, largely nocturnal and solitary lifestyle, and use of burrows and cavities make it difficult to gather relevant information from commonly used monitoring approaches that are effective for other mammals (Ingram, Willcox, & Challender, 2019; Nash, Wong, & Turvey, 2016; Willcox et al., 2019). The white-bellied pangolin, Phataginus tricuspis, is a semi-arboreal species that feeds exclusively on ants and termites (Akpona, Djagoun, & Sinsin, 2008; Kingdon et al., 2013). They typically inhabit dense forest though also occur in forest–savannah–crop mosaics at times(Pietersen et al., 2019). The ecology of this species is poorly known due in part, to the challenges of studying pangolins and a lack of standardised research methods. (Willcox et al., 2019). Here, we evaluate the utility of local ecological knowledge (LEK) in tailoring camera-trap surveys, a detection method increasingly used for pangolins, to improve detection efficiency for occurrence and ecological studies for the white-bellied pangolin