Reproductive Capacities and Development of a Seed Bruchid Beetle, Acanthoscelides macrophthalmus, a Potential Host for the Mass Rearing of the Parasitoid, Dinarmus basalis

The reproductive capacities and development of the seed beetle Acanthoscelides macrophthalmus (Schaeffer) (Coleoptera: Bruchidae), found in Togo, were determined under natural conditions in a Guinean zone for its use as a substitute host for the mass rearing of the parasitoid Dinarmus basalts Rond (Hymenoptera: Pteromalidae), a biological agent for the control of beetles that are pests of cowpea, Vigna unguiculata (L.) Walpers (Fabales: Fabaceae). Population dynamics at the field level; and survival, fecundity and offspring production by A. macrophthalmus under laboratory conditions were measured when fed on its natural plant-host Leucaena leucocephala (Lamark) deWit (Fabales: Mimosaceae). The data resulting from the laboratory study were used to calculate the demographic parameters of A. macrophthalmus by establishing its fertility and life tables. Contrary to cultivated leguminous food plants, L. leucocephala is a perennial sub-spontaneous leguminous plant whose pods are available year round. Although A. macrophthalmus was present in nature throughout the year, its infestation rate of the pods fluctuated according to the phenology of the plant. The maximum infestation of L. leucocephala pods was observed between August and December. Four larval stages and one pupal stage of A. macrophthalmus were identified in the laboratory. The total mean development time varied on average 33.75 ± 2.87 days on the mature pods and 33.39 ± 2.02 days on seeds. The adult female lived from one to two weeks. During its life time, the female laid an average of 62.3 ± 19 and 43.1 ± 13 eggs on the mature pods and seeds respectively and produced an average of 36.7 ± 11.3 offspring on the mature pods and 21.8 ± 8.4 offspring on seeds. On seeds, the net reproduction rate was 5.88 females per female and the intrinsic rate of population increase 0.051 per day. The generation time was 34.59 days and the doubling time 13.59 days. The demographic parameters of A. macrophthalmus in this study are close to those of Callobruchus maculatus F. (Bruchidae), the natural host of D. basalts in a previous study. A. macrophthalmus could therefore be used as substitute host for the mass rearing of D. basalts and subsequently its release in farmers' storage containers. The data presented in this study provide some baseline information regarding the reproductive capacities of A. macrophthalmus that may be useful for its promotion as a substitute host for mass rearing of D. basalts

Efficacité d’extraits de feuilles de neem Azadirachta indica (Sapindale) sur Plutella xylostella (Lepidoptera : Plutellidae), Hellula undalis (Lepidoptera : Pyralidae) et Lipaphis erysimi (Hemiptera : Aphididae) du chou Brassica oleracea (Brassicaceae) da

Cette étude vise à évaluer l’efficacité d’extrait hydroéthanolique de feuilles de Azadirachta indica dans la lutte contre Plutella xylostella, Hellula undalis et Lipaphis erysimi, insectes ravageurs du chou dans une approche champ école paysan en milieu maraîcher au sud du Togo. L’efficacité de l’extrait hydroéthanolique a été comparée à celle d’un insecticide de synthèse (Cydim Super) et à celles d’un extrait aqueux de feuilles de A. indica et de deux pratiques paysannes. Les parcelles de chou ont été disposées en blocs complets randomisés et équilibrés. Les traitements à base d’extraits de feuilles de A. indica ont significativement réduit les populations de P. xylostella et de H. undalis par rapport à l’insecticide de synthèse et une pratique paysanne. Par contre, l’insecticide de synthèse a mieux contrôlé L. erysimi. Les rendements moyens en pommes de chou commercialisables sont compris entre 4,68 ± 1,63 t/ha pour le témoin, et 17,38 ± 0,98 t/ha pour les parcelles traitées avec l’extrait hydroéthanolique. Cet extrait a donné le double ou le triple du rendement des autres traitements. L’extrait hydroéthanolique peut être utilisé dans la gestion intégrée de P. xylostella, H. undalis et de L. erysimi sur le chou.Mots clés : Azadirachta indica, insectes ravageurs, chou, Togo

Comparaison de quelques caractéristiques biologiques entre Dinarmus basalis Rond. (Hymenoptera: Pteromalidae) élevé soit sur son hôte habituel Callosobruchus maculatus F. (Coleoptera: Bruchidae) soit sur Acanthoscelides macrophthalmus Schaef. ou Bruchidius lineatopygus Pic. identifiés comme hôtes de substitution

Comparison of some Biological Characteristics between Dinarmus basalis Rond. (Hymenoptera: Pteromalidae) Reared either on his Habitual Host Callosobruchus maculatus F. (Coleoptera: Bruchidae) or on Acanthoscelides macrophthalmus Schaef. and Bruchidius lineatopygus Pic. Identified as Substitution Hosts. In this study, we have measured some biological parameters of Dinarmus basalis Rond. (Hymenoptera: Pteromalidae) when this parasitoid grows on three hosts: Callosobruchus maculatus F. (usual host), Acanthoscelides macrophthalma Schaef. and Bruchidius lineatopygus Pic. (substitution hosts). The results of this comparative study in no choice situation show that, life duration and development duration of this parasitoid are identical in laboratory conditions. By contrast, the female fecundity, the sexual rate and the parasitism rate of D. basalis are different according to the hosts presented. Although such differences appear to be small between C. maculatus and A. macrophthalmus. In presence of these two species, the number of eggs laid by the female of D. basalis is respectively 61 ± 5.24 and 54 ± 5.60, the sexual rate 37.63 ± 2.13% and 41.73 ± 3.69% and the parasitism rate 85.46 ± 2.61% and 76.48 ± 5.90%. This indicates that these two Bruchids can be used as hosts to D. basalis for a mass production. In presence of B. lineatopygus, the fecundity and the parasitism rate of D. basalis female are very low and the sexual rate more favourable of the males. This situation is unfavourable for a parasitoid production. When D. basalis females are placed in choice situation with equal number of the hosts nowely C. maculatus and A. macrophthalmus, the parasitism rate obtained, is higher for C. maculatus that of A. macrophthalmus. This parasitism rate remains high for C. maculatus even when the other host A. macrophthalmus is twice the number of C. maculatus. Thus the parasitoid seems to have a preference for his natural host. However, A. macrophthalmus can still be used in production unit of D. basalis

Analyse de quelques aspects du système de production légumière et perception des producteurs de l’utilisation d’extraits botaniques dans la gestion des insectes ravageurs des cultures maraîchères au Sud du Togo

L’une des contraintes liée à la production maraîchère, est la pression exercée par les insectes ravageurs. Cette étude analyse quelques aspects du système de production légumière ainsi que la perception des   producteurs de l’utilisation d’extraits botaniques dans la gestion des  insectes ravageurs des cultures maraîchères. Elle a été réalisée à travers une enquête menée auprès de 217 maraîchers au Sud du Togo. L’analyse descriptive des données a révélé que plus d’hommes (72%) que de femmes (28%) pratiquent le maraîchage. Seul 33% a suivi une fois une formation en maraîchage. La contrainte majeure dans la production maraîchère est le problème de ravageurs et de maladies dont les principaux sont des insectes, des nématodes et des champignons. La lutte chimique constitue la principale méthode de lutte contre ces ravageurs. Néanmoins, les maraîchers connaissent des dangers induits par l’utilisation des pesticides de synthèse et sont au courant de l’utilisation des pesticides botaniques en maraîchage. Cependant, très peu les utilisent dans la gestion des ravageurs. Mais, ils sont disposés à utiliser les pesticides botaniques si ceux-ci sont disponibles, accessibles, efficaces et pas trop chers pour pallier les effets néfastes des pesticides de synthèse à la santé et à l’environnement.Mots clés : Maraîchage, perception des producteurs, extraits botaniques, Sud du Togo

Some biological parameters of Paracoccus marginatus Williams and Granara de Willink (Hemiptera: Pseudococcidae) and its natural enemy Acerophagus papayae Noyes et Schauff (Hymenoptera: Encyrtidae)

The papaya mealybug Paracoccus marginatus Williams and Granara De Willink (Hemiptera: Pseudococcidae) is an invasive insect species attacking diverse host plants causing enormous damage to crops including those of very high economic importance. Biological control of this mealybug is achieved through the field release of its natural enemy, Acerophagus papayae Noyes and Schauff (Hymenoptera: Encyrtidae). The study aims to determine the developmental time and mortality rate of the different stages of P. marginatus; daily fecundity and pre- oviposition, oviposition and post-oviposition times of a female P. marginatus and the total average number of emerging individuals of the hosts parasitized in 24 hours by a female and the total average development time of A. papayae. This study, which was conducted in the laboratory under conditions of 28 ± 2°C, 75 ± 5% RH, 12: 12 LD, determined the average daily fecundity of a female P. marginatus and the average number of offspring of a female A. papayae per day. The results obtained showed that a female P. marginatus has three periods of reproductive activity, namely the pre-oviposition, oviposition and post-oviposition periods, which are on average last 7.74 ± 1.26, 6.13 ± 3.02 and 7.45 ± 4.27 days respectively. During oviposition, a female P. marginatus lays an average of 25.262 ± 11.16 eggs per day, and an average total of 224.32 ± 29.99 eggs during her lifetime, which averages 18.44 ± 3.31 days. Also, during the development of the pre-imaginal stages of P. marginatus, significant mortality rates were noted in the first and second larval stages, which are 61.40 ± 0.05 and 52.8 ± 0.025 respectively, whereas in the third stage, this rate is 35.02 ± 0.03 for the female and zero for the male. The average total development time of the pest was 25.98 ± 4.47 days for the female and 29.70 ± 5.58 days for the male. In contrast, the progeny of its natural enemy A. papayae averaged 8.22 ± 4.676 males and 10.53 ± 4.43 females per day, giving an average total of 18.75 ± 9.087 offspring per day. During its lifetime (13.02 ± 0.08 days), a female A. papayae produced an average of 205.96 ± 9.87 offspring in an average development time of 13.82 ± 0.013 days. These results obtained on the progeny of a female and the development time of A. papayae species in relation to that of its host can be used to evaluate the effectiveness of the parasitoid in the management of the pest populations in Togo

Comparative performance of five hermetic bag brands during on-farm smallholder cowpea (Vigna unguiculata L.Walp) storage

Cowpea (Vigna unguiculata L. Walp) grain is an important source of protein for smallholder farmers in developing countries. However, cowpea grains are highly susceptible to bruchid attack, resulting in high quantitative and qualitative postharvest losses (PHLs). We evaluated the performance of five different hermetic bag brands for cowpea grain storage in two contrasting agro-ecological zones of Zimbabwe (Guruve and Mbire districts) for an 8-month storage period during the 2017/18 and 2018/19 storage seasons. The hermetic bag treatments evaluated included: GrainPro Super Grain bags (SGB) IVR™; PICS bags; AgroZ® Ordinary bags; AgroZ® Plus bags; ZeroFly® hermetic bags. These were compared to untreated grain in a polypropylene bag (negative control) and Actellic Gold Dust® (positive chemical control). All treatments were housed in farmers’ stores and were subjected to natural insect infestation. Hermetic bag treatments were significantly superior (p< 0.001) to non-hermetic storage in limiting grain damage, weight loss and insect population development during storage. However, rodent control is recommended, as rodent attack rendered some hermetic bags less effective. Actellic Gold Dust® was as effective as the hermetic bags. Callosobruchus rhodesianus (Pic.) populations increased within eight weeks of storage commencement, causing high damage and losses in both quality and quantity, with highest losses recorded in the untreated control. Cowpea grain stored in Mbire district sustained significantly higher insect population and damage than Guruve district which is ascribed to differences in environmental conditions. The parasitic wasp, Dinarmus basalis (Rondani) was suppressed by Actellic Gold Dust® and all hermetic treatments. All the hermetic bag brands tested are recommended for smallholder farmer use in reducing PHLs while enhancing environmental and worker safety, and food and nutrition security

Diversité des tiques de bovins et variation saisonnière des infestations dans la région maritime au Togo

Diversity of Cattle Ticks and Seasonal Variation of Infestations in the Maritime Region of Togo. Ticks are a major constraint for the development of livestock production in West Africa, particularly in Togo. With a view to reducing the level of tick infestation below economic thresholds of harm, the diversity and parasite load of these pests was assessed by collecting them from July 2013 to June 2014 in 9 localities in the Maritime Region in Togo. A total of 18,378 adult ticks were collected from cattle. These ticks belong to 5 genera and 17 species of which the most abundant and frequent are: Amblyomma variegatum (Fabricius, 1794) (38.30%), Rhipicephalus (Boophilus) microplus (31.84%), Rhipicephalus (Boophilus) decoloratus (17.43%). The different localities surveyed were similar in terms of specific diversity of ticks. The level of infestation of cattle by the 3 most abundant tick species was higher in Kamina with a mean of 22.02 ± 15.88 ticks/bovine/month (F = 5.836; df = 107; P<0.000). These results are core data for the identification of parasitic pests associated with bovine ticks and the assessment of the economic importance of bovine ticks in Togo

Diversité spécifique des termites (Isoptera) dans deux plantations de tecks (Tectona grandis L.) au sud du Togo

Les termites constituent en Afrique lfune des composantes la plus importante de la macrofaune terricole. Malgre lfimpact benefique sur lfagriculture, au plan de la fertilisation, de lfaeration et de la porositedes sols, certains de ces termites constituent pour la plupart des paysans en Afrique sub-saharienne, un probleme important a cause des degats occasionnes aux cultures et aux plantations dans les agro-systemes ainsique dans les stocks. La connaissance de leur diversite specifique et de leur repartition dans les ecosystemes est un prealable pour entreprendre une lutte adequate contre ces insectes. Cfest dans cet objectif qufun inventaire systematique des termites et une etude de leur repartition ont ete realises dans deux plantations de tecks a Noepe et a Eto, deux localites au sud du Togo. Des fouilles systematiques dans les deux plantations et dans les placeaux le long de transects, ainsi que sur les tecks nous ont permis dfinventorier onze especes de termites. Il sfagit de : Coptotermes intermedius Silvestri, Amitermes evuncifer Silvestri, Ancistrotermes guineensis Silvestri, Microcerotermes sp., Macrotermes bellicosus Smeathman, Microtermes sp., Odontotermes pauperans Silvestri, Pseudacanthotermes militaris Hagen, P. spiniger, Trinervitermes geminatus Wasmann et T. oeconomus. A part ces deux dernieres especes qui ne se retrouvent pas sur les pieds de tecks, toutes les autres especes se rencontrent a la fois dans le sol et sur les pieds de tecks et elles constituent des ravageurs potentiels pour ces essences vegetales, compte tenu de leur regime alimentaire lignivore ou champignonniste. Lfanalyse comparative des deux plantations par le calcul des indices &fnof;&iquest; et &fnof;&Agrave; a montre que les populations de termites de la plantation dfEto est plus diversifiee que celle de Noepe

Perception of farmers on seed production constraints of Jatropha curcas L. (Euphorbiaceae)

Asian Research Publishing Network (ARPN)Many countries have understood that an alternative is needed to the problems of depletion of fossil fuels. Emphasis is therefore put on biofuel-producing crops. One of the most important biofuel-producing plants in tropical is Jatropha curcas L. Several biotic and abiotic constraints limit J. curcas production. The present survey was performed in 13 villages in Benin to assess farmers' perceptions on the biotic constraints. These villages were located in J. curcas production supervised by the non-governmental organization ((Renewable Energy Group, Environment and Solidarity)), One hundred and three producers, representing 25% of the 411 producers of the 3 sites were surveyed. Most producers were illiterate. Only 20 to 40% went to school. About 90% of producers indicated that J. curcas is damaged by pests. During the study, the pictures of the main pests reported in the literature were shown to producers. The producers recognized pests in a proportion of 34, 32 and 43% in Cove, Djidja and Zagnanado, respectively. This shows that most of them could not easily identify pests in pictures. These pests are Meloidogyne incognita (Kofoid and White) Chitwood, Phenacoccus manihoti Matile-Ferrero (Homoptera: Pseudococcidae), Aulocophora africana Lucas (Coleoptera:Chrysomelidea), Stomphastis thraustica Meyrick (Lepidoptera: Graciillariidae), Scutellera nobilis Fabricius (Heteroptera:Scutelleridae) and Pempelia morosalis Saalm Uller (Lepidoptera:Pyralidae). No local name was given to these pests, pointing at the lack of knowledge on their status as pests. Their monitoring is therefore necessary as a first step in order to develop sustainable management methods