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The biomethane potential of insect frass and leachates from waste (larvae feedstock) stockpile was evaluated. Frass was derived from a black soldier fly larvae (BSFL) operation that uses a fruit and vegetable waste diet. The two waste streams were characterized and the results of their compositional, proximate, and ultimate analysis were used in estimating methane yields from these materials. The estimated biomethane potential (BMP) of the frass ranged 149–275 L/kgVS depending on the calculation method used. This result compares well with that of empirical studies for cow manure whose BMP ranges 110–275 L/kgVS. Cow manure is the most popular biogas feedstock globally. Leachates reported an estimated BMP of 150 L/kgCOD. We conclude that it may be technically feasible to produce biogas from BSFL frass and from fruit and vegetable waste leachates. However, standard BMP experiments and semicontinuous pilot studies are still necessary before commercialization of these findings. These extra tests are executed to validate these findings and ascertain the life cycle attribute and long‐term process stability and hence determine the economics of using these potential substrates for biogas production as a strategy to implementing circularity in the fruit and vegetable industry. [ABSTRACT FROM AUTHOR]

Waste management strategies specified in the hierarchy of waste management were evaluated by applying a Multi-Criteria Decision-Making (MCDM) technique called the Analytic Hierarchy Process (AHP) to choose a strategy for managing Johannesburg (JHB) city's food waste. Under the different weighting scenarios for the evaluation criteria considered in this AHP, the recovery strategy scored an average of 41% while other strategies each scored 33%, 29% and 22% for prevention and reduction, treatment and disposal, re-use and recycle, respectively. Optimisation of resource recovery strategies from food waste is recommended for further consideration and investigation by the JHB municipality in its attempt to promote a circular economy and surmount food waste hurdles. [ABSTRACT FROM AUTHOR]

Abstract Background New products aimed at augmenting or replacing chemical insecticides must have operational profiles that include both high efficacy in reducing vector numbers and/or blocking parasite transmission and be long lasting following application. Research aimed at developing fungal spores as a biopesticide for vector control have shown considerable potential yet have not been directly assessed for their viability after long-term storage or following application in the field. Methods Spores from a single production run of the entomopathogenic fungi Beauveria bassiana were dried and then stored under refrigeration at 7°C. After 585 days these spores were sub-sampled and placed at either 22°C, 26°C or 32°C still sealed in packaging (closed storage) or in open beakers and exposed to the 80% relative humidity of the incubator they were kept in. Samples were subsequently taken from these treatments over a further 165 days to assess viability. Spores from the same production run were also used to test their persistence following application to three different substrates, clay, cement and wood, using a hand held sprayer. The experiments were conducted at two different institutes with one using adult female Anopheles stephensi and the other adult female Anopheles gambiae. Mosquitoes were exposed to the treated substrates for one hour before being removed and their survival monitored for the next 14 days. Assays were performed at monthly intervals over a maximum seven months. Results Spore storage under refrigeration resulted in no loss of spore viability over more than two years. Spore viability of those samples kept under open and closed storage was highly dependent on the incubation temperature with higher temperatures decreasing viability more rapidly than cooler temperatures. Mosquito survival following exposure was dependent on substrate type. Spore persistence on the clay substrate was greatest achieving 80% population reduction for four months against An. stephensi and for at least five months against Anopheles gambiae. Cement and wood substrates had more variable mortality with the highest spore persistence being two to three months for the two substrates respectively. Conclusions Spore shelf-life under refrigeration surpassed the standard two year shelf-life expected of a mosquito control product. Removal to a variety of temperatures under either closed or open storage indicated that samples sent out from refrigeration should be deployed rapidly in control operations to avoid loss of viability. Spore persistence following application onto clay surfaces was comparable to a number of chemical insecticides in common use. Persistence on cement and wood was shorter but in one assay still comparable to some organophosphate and pyrethroid insecticides. Optimized formulations could be expected to improve spore persistence still further.

Abstract Background The use of insecticides to control malaria vectors is essential to reduce the prevalence of malaria and as a result, the development of insecticide resistance in vector populations is of major concern. Anopheles arabiensis is one of the main African malaria vectors and insecticide resistance in this species has been reported in a number of countries. The aim of this study was to investigate the detoxification enzymes that are involved in An. arabiensis resistance to DDT and pyrethroids. Methods The detoxification enzyme profiles were compared between two DDT selected, insecticide resistant strains of An. arabiensis, one from South Africa and one from Sudan, using the An. gambiae detoxification chip, a boutique microarray based on the major classes of enzymes associated with metabolism and detoxification of insecticides. Synergist assays were performed in order to clarify the roles of over-transcribed detoxification genes in the observed resistance phenotypes. In addition, the presence of kdr mutations in the colonies under investigation was determined. Results The microarray data identifies several genes over-transcribed in the insecticide selected South African strain, while in the Sudanese population, only one gene, CYP9L1, was found to be over-transcribed. The outcome of the synergist experiments indicate that the over-transcription of detoxification enzymes is linked to deltamethrin resistance, while DDT and permethrin resistance are mainly associated with the presence of the L1014F kdr mutation. Conclusions These data emphasise the complexity associated with resistance phenotypes and suggest that specific insecticide resistance mechanisms cannot be extrapolated to different vector populations of the same species.

South Africa is a frontline country for malaria elimination in the southern African region. It has three malaria‐endemic provinces, each with its own transmission pattern. The elimination of malaria depends, in part, on controlling and/or eliminating vectors responsible for transmission. Sustained entomological surveillance is an important factor to consider when shifting from a control to elimination framework. The Ehlanzeni district in Mpumalanga province is a key entomological sentinel surveillance area. It is one of the malaria‐endemic districts in South Africa with higher rates of malaria incidences. As such, entomological data about the Anopheles gambiae Giles (Diptera: Culicidae) complex have been collected in this province over a substantial period. These data are stored in a pre‐existing institutional database. An analysis of the trends that can be observed from this database has not been performed before. This retrospective (longitudinal) analysis provides a summary of the An. gambiae complex vector composition in this region from 2009 to 2021. Routine surveillance data were correlated with climatic data (obtained from the NASA LaRC POWER project database) for the same period to assess the role of climatic factors in vector dynamics. This review also identifies a number of limitations in the data collection process across the sampling period and provides recommendations on how to strengthen the database going forward. The most abundant member of the An. gambiae complex since 2009 in the province was An. merus Dönitz followed by An. arabiensis Patton. Collection methods used showed that human landing catches were successful for collecting An. arabiensis, while pit traps were the most effective in collecting An. merus and An. quadriannulatus Theobald. The latter two species were mainly collected in spring, whereas An. arabiensis abundance was larger during autumn collections. Vector abundance was not significantly correlated with annual climatic data. The information gained from this database provides insights into the vector dynamics of the Ehlanzeni district of the Mpumalanga province. [ABSTRACT FROM AUTHOR]

Successful implementation of an integrated vector control program will rely on availability of accurate vector information in the specific location. However, such information can be limited in some countries. The aim of this study was to obtain baseline vector information from Pointe Noire on the Congo coast (Republic of the Congo). Field sampling was conducted during April 2009 in the village of Boutoto and its surrounds, close to the city of Pointe Noire. Anopheles gambiae sensu lato mosquitoes were collected resting indoors. Samples were analyzed for insecticide susceptibility, species identification, and Plasmodium sporozoite infection. Molecular and biochemical assays were conducted to characterize insecticide resistance mechanisms. The malaria vector A. gambiae S-form was the only mosquito species identified, and it had a high Plasmodium falciparum infection rate (9.6%). Multiple insecticide resistance was detected in this population with full susceptibility to only one insecticide class, the organophosphates. Dieldrin and DDT resistance was mainly attributed to target-site resistance (the Rdl and L1014F/L1014S kdr mutations respectively), whereas pyrethroid resistance was mainly attributed to P450 metabolic enzyme-mediated detoxification in addition to kdr. The role of various insecticide resistance mechanisms revealed a complex association between metabolic detoxification and reduced target-site sensitivity.