The production of food is an intensive source of environmental impact. In aquaculture, one source of impact is solid waste, which contains high concentrations of minerals, other nutrients, and metals. The larvae of Hermetia illucens are capable of consuming this material, but applying technology that is based on these larvae for managing waste streams, like those from aquaculture, requires careful examination of safety risks. A study is performed examining the growth performance of larvae that were fed on solid aquaculture waste. Subsequently, a thorough analysis of safety risks from inorganics, with detailed the results on microelements that have previously received little attention in the literature, is performed to serve as a guideline for how to assess the safety of waste streams such as these. Findings confirm existing results in the literature that Cd is bioaccumulative, but also that other elements, including Hg, Mn, and especially K, are bioaccumulative. To the authors’ knowledge, this is the first research where the accumulation of Ag is also tested. The results of these tests are explained within the context of regulations in various countries where Hermetia illucens is cultivated, serving as a reference for practitioners to rigorously screen out high risk feed streams that they may consider using as feed sources. It is intended that these references and the demonstrated accumulation of a range of elements motivate comprehensive industry safety practices when evaluating new feed sources.

Rhyzopertha dominica (F.) (lesser grain borer, Coleoptera: Bostrichidae) is a major pest of stored grain in the United States, Australia, and most other warm regions of the world. It has rarely been detected in Canadian grain, until recently. To determine the distribution of/R. dominica in western Canada, Lindgren multiple-funnel traps baited with R. dominica aggregation pheromones were placed near grain elevators, feed mills, and farms. Rhyzopertha dominica was found flying outside grain-handling facilities in all Prairie Provinces in 1990 and 1991, with thousands collected in Manitoba, hundreds in Alberta, and less than 100 in Saskatchewan. A few R. dominica were caught in Vancouver and Thunder Bay. None were caught in the traps placed beside two grain elevators in southern Ontario. In Alberta and Saskatchewan, the locations with R. dominica were mainly in the south. In Manitoba, the total number of R. dominica caught at each location was higher in the south than in the north. Rhyzopertha dominica were caught as early as 15 May and as late as 18 September, with the peak numbers for a given location occurring between July and September. No difference in the total number of R. dominica caught per year was found among farms, feed mills, or grain elevators in 1990 or 1991. Sampling of stored grain on three farms showed that two of the eight bins sampled had R. dominica. The possible origins of the R. dominica (importation of infested grain, wind-borne migration from the United States, or an established Canadian population) are discussed.

Background Novel malaria vector control approaches aim to combine tools to work in synergy for maximum protection. This study aimed to evaluate novel and re-evaluate existing, putative repellent ‘push’ and attractive ‘pull’ components for manipulating the odour-orientation of malaria vectors in the peri-domestic space. Methods Anopheles arabiensis outdoor human landing catches and trap comparisons were implemented in large semi-field systems to (1) test the efficacy of citriodiol or transfluthrin-treated fabric strips positioned in house eave gaps as push components for preventing bites; (2) understand the efficacy of an MB5-baited Suna-trap in attracting vectors in the presence of a human being; (3) assess 2-butanone as a CO2 replacement for trapping; and (4) determine the protection provided by a full push-pull set up. The air-concentrations of the chemical constituents of the push-pull mosquito control tool were quantified.Results Microencapsulated citriodiol eave strips did not provide any outdoor protection against host-seeking An. arabiensis. Transfluthrin-treated strips significantly reduced the odds of a mosquito landing on the human volunteer (OR 0.17; 95% CI 0.12-0.23). This impact was lower (OR 0.59; 95% CI 0.52-0.66) during the push-pull experiment which was associated with low night-time temperatures likely affecting the transfluthrin vaporisation. The MB5-baited Suna trap supplemented with CO2 attracted only a third of the released mosquitoes in the absence of a human being, however, with a human volunteer in the same system, the trap caught less than 1% of all released mosquitoes. The volunteer consistently attracted over two-thirds of all mosquitoes released. This was the case in the absence (‘pull’ only) and in the presence of a spatial repellent (‘push-pull’), indicating that in its current configuration the tested ‘pull’ does not provide a valuable addition to a spatial repellent. The chemical 2-butanone was ineffective in replacing CO2. Transfluthrin was detectable in the air space but with a strong linear reduction in concentrations over 5 metres from release. The MB5 constituent chemicals were only irregularly detected, potentially suggesting insufficient release and concentration in the air for attraction.Conclusion This step-by-step evaluation of the selected ‘push’ and ‘pull’ components led to a better understanding of their ability to affect host-seeking behaviours of the malaria vector Anopheles arabiensis in the peri-domestic space and helps to gauge the impact such tools would have when used in the field for monitoring or control.

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