ABSTRACT
Cowpea [Vigna unguiculata (L) Walp.] is an important staple legume in the diet of many households in sub-Saharan Africa. Its production, however, is negatively impacted by many insect pests including bean pod borer, Maruca vitrata F., which can cause 20-80% yield loss. Several genetically engineered cowpea events that contain a cry1Ab gene from Bacillus thuringiensis (Bt) for resistance against M. vitrata were evaluated in Nigeria, Burkina Faso, and Ghana (West Africa), where cowpea is commonly grown. As part of the regulatory safety package, these efficacy data were developed and evaluated by in-country scientists. The Bt-cowpea lines were planted in confined field trials under Insect-proof netting and artificially infested with up to 500 M. vitrata larvae per plant during bud formation and flowering periods. Bt-cowpea lines provided nearly complete pod and seed protection and in most cases resulted in significantly increased seed yield over non-Bt control lines. An integrated pest management strategy that includes use of Bt-cowpea augmented with minimal insecticide treatment for protection against other insects is recommended to control pod borer to enhance cowpea production. The insect resistance management plan is based on the high-dose refuge strategy where non-Bt-cowpea and natural refuges are expected to provide M. vitrata susceptible to Cry1Ab protein. In addition, there will be a limited release of this product until a two-toxin cowpea pyramid is released. Other than South African genetically engineered crops, Bt-cowpea is the first genetically engineered food crop developed by the public sector and approved for release in sub-Saharan Africa.
Subject(s)
Fabaceae , Lepidoptera , Moths/genetics , Vigna , Animals , Bacterial Proteins , Burkina Faso , Endotoxins , Larva , Nigeria , Pest Control, Biological , Plants, Genetically ModifiedABSTRACT
The PICS bags, originally developed for cowpea storage, were evaluated for sorghum (Sorghum bicolor) preservation. Batches of 25â¯kg of sorghum grain were stored in 50â¯kg PICS or polypropylene (PP) bags under ambient conditions for 12 months and assessed for the presence of insect pests and their damage, seed viability and, oxygen and carbon dioxide variations. The grain was incubated for 35 days to assess whether any insects would emerge. After six months of storage, oxygen levels decreased in the PICS bags compared to polypropylene bags. After 12 months of storage, only two pests, Rhyzopertha dominica and Sitophilus zeamais were found in the PICS bags. However, in PP bags there were additional pests including Tribolium castaneum and Oryzeaphilus mercator and Xylocoris flavipes. Grain weight loss and damage caused by these insects in the PP bags were significantly higher compared to those stored in PICS bags. Germination rates of sorghum grains stored in PP bags decreased significantly while no changes were observed in grains stored in PICS bags when compared to the initial germination. After the incubation post storage period, there was a resurgence of R. dominica in sorghum grains from PICS bags but the population levels were significantly lower compared to polypropylene bags. PICS bags preserved the quality and viability of stored sorghum grains and protected it from key insect pests. The PICS technology is effective for long-term sorghum storage but the potential resurgence of insects in low-oxygen environment calls for further research.
ABSTRACT
The egg parasitoid Gryon fulviventre is a potential biological control agent of Clavigralla tomentosicollis, a coreid pod-sucking pest of Vigna unguiculata. The host location behavior of naive parasitoid females was studied using a four-armed olfactometer. Two strains of G. fulviventre parasitoids from Burkina Faso and Benin were exposed to odors provided by healthy and infested pods as well as C. tomentosicollis females and males. The time spent in each odor zone was recorded to determine the preference of parasitoid females. Results show that odors from healthy pods, infested pods, and pest females did not attract the parasitoid. However, a significantly attractive response of both strains of G. fulviventre was recorded in the presence of volatiles from males of C. tomentosicollis. Moreover, experiments testing G. fulviventre females' behavior when simultaneously exposed to volatiles from cowpea pods (healthy and infested) and increasing numbers of C. tomentosicollis males revealed a significantly higher attraction of parasitoid females of both strains by volatiles from ten males of C. tomentosicollis. The results suggest that the males of the insect pest emit a pheromone used as kairomone by parasitoids to locate their host. The conditions determining this attractiveness at field level and its impact on host-searching efficiency are discussed.
ABSTRACT
The majority of the world's population lives in urban areas, and regions with the highest under-five mortality rates are urbanising rapidly. This 7-year interrupted time series study measured early access to care and under-five mortality over the course of a proactive community case management (ProCCM) intervention in periurban Mali. Using a cluster-based, population-weighted sampling methodology, we conducted independent cross-sectional household surveys at baseline and at 12, 24, 36, 48, 60, 72 and 84 months later in the intervention area. The ProCCM intervention had five key components: (1) active case detection by community health workers (CHWs), (2) CHW doorstep care, (3) monthly dedicated supervision for CHWs, (4) removal of user fees and (5) primary care infrastructure improvements and staff capacity building. Under-five mortality rate was calculated using a Cox proportional hazard survival regression. We measured the percentage of children initiating effective antimalarial treatment within 24 hours of symptom onset and the percentage of children reported to be febrile within the previous 2 weeks. During the intervention, the rate of early effective antimalarial treatment of children 0-59 months more than doubled, from 14.7% in 2008 to 35.3% in 2015 (OR 3.198, P<0.0001). The prevalence of febrile illness among children under 5 years declined after 7 years of the intervention from 39.7% at baseline to 22.6% in 2015 (OR 0.448, P<0.0001). Communities where ProCCM was implemented have achieved an under-five mortality rate at or below 28/1000 for the past 6 years. In 2015, under-five mortality was 7/1000 (HR 0.039, P<0.0001). Further research is needed to elucidate the mechanisms of action and generalizability of ProCCM.
ABSTRACT
BACKGROUND: The neonatal mortality rate in Mali is one of the highest in the world. Only one national reference neonatology unit is available in the country. AIM: To describe the time-course of morbidity, mortality, staff and accommodation facilities from 2008 to 2009 in Mali's unique national reference neonatology unit. METHODS: This descriptive and cross-sectional study was conducted in the neonatology unit of Gabriel Touré Teaching Hospital, Bamako. Data concerning staff number of admissions, sex ratio, diseases, patients outcome, capacity and length-of-stay were compiled for the period from 1st January 2008 to 31 December 2012. RESULTS: Medical staff increased from one to three in 2009 and the number of nurses and midwives decreased from 16 to 14 with an average number of beds of 44. The mean number of hospitalizations per year was 3,900 (range: 3667-4585) with 14% of in-born deliveries and a mean length-of-stay of 3.7 days. Prematurity birth asphyxia and infection represented 80.5% of reasons for admission and 79.5% of deaths. The mortality rate varied from 28.5% to 36.8% with an annual mean of 33.2%. The diseases associated with the highest mortality were tetanus (60.8%), prematurity (42.7%), birth asphyxia (29.4%) and infection (25.7%). CONCLUSION: Neonatal mortality remains very high in Mali. Health authorities should take measures to decentralize the care of sick newborns in order to reduce neonatal mortality in Mali.
