Significance: Growing food in cities for human consumption could be one means of increasing global food supply in the face of rising population growth and global food security concerns. While previous studies have shown that urban agricultural systems are productive, few studies provide yield figures that incorporate data on the inputs used to achieve the outputs. Across 13 urban community gardens, we show that yields were nearly twice the yield of typical Australian commercial vegetable farms. However, economic and emergy (embodied energy) analyses indicated they were relatively inefficient in their use of material and labor resources. Balancing the sustainability of urban food production with the cost of inputs is important to determine the trade-offs required to achieve high yields.

Pollination is an important ecosystem service to agriculture, however, the factors influencing pollination in urban food gardens are poorly understood. We investigated how features within urban environments, including floral resources and canopy cover, impacted (a) flower visitation and seed production of a model plant (Brassica rapa) and (b) total yields of produce from urban gardens in Sydney, Australia. Floral visitation to model plants was dominated by a few common species, with honeybees responsible for 53.4% of visitation and native stingless bees and two hoverfly species accounting for another 37.1% of visitors; 28 other species were collectively responsible for less than 10% of visitation. While insect pollinators were abundant, the relationship between floral visitation and model plant reproductive output was weak and not always positive. The pollination success of model plants was only marginally impacted by environmental features, while pollinator visitation had a small negative impact. However, total crop yields across urban gardens were strongly influenced by local canopy cover and garden scale plant species richness. Synthesis and applications. The factors influencing pollination service delivery to urban gardens are complex; pollinator visitation, richness and/or floral resource availability may not always reflect positive, plant reproductive outcomes. Yields of garden crops, whether pollinator dependent or not, were more strongly influenced by surrounding environmental variables, including broad scale measures of canopy cover and local plant diversity, than pollination‐related metrics. This implies policies to support pollinator richness will likely differ to those supporting crop yields in urban gardens and will require assessment and management of external environmental factors.

Understanding cues for diapause termination in insects can be valuable in predicting phenological events in their lifecycles. Once identified, such cues can be utilized as a biofix, the point at which the majority of individuals within a population begin to accumulate degree days. We investigated the impact of photoperiod on completion of reproductive diapause in the invasive eastern North American population of the brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), by exposing diapausing females to varying light regimes in otherwise identical environments. The critical photoperiod estimated to initiate reproductive development in at least 50% of the potential reproductive population was 13.0–13.5 h, with increasing photoperiods coinciding with increased probability of females reproducing, earlier time to first oviposition, and higher rates of fecundity. These data on the species’ response to photoperiod are in agreement with previous modeling that predicted the twin constraints of photoperiod and temperature on H. halys reproduction prevents populations that undergo diapause from producing more than two generations annually anywhere within the continental U.S. However, the facultative nature of diapause in H. halys leaves open the possibility that sub-populations may not enter diapause in some conditions, potentially allowing for additional annual generations.

Aphids are a major pest of cropping systems throughout the world. In most cases, crop aphids are controlled with broad‐spectrum insecticides; although generally very effective at preventing yield loss, this approach risks non‐target damage to beneficial organisms. In the last 20 years, a number of selective insecticides have become available to control aphids while minimising harm to other arthropods. Previous studies have found that two such insecticides, flonicamid and afidopyropen, cause only low‐level acute mortality impacts on aphid parasitoids in Australian grain crops. However, little research has examined the sub‐lethal effects of these chemicals, which could induce various physiological changes that impact pest control. We hypothesised that both flonicamid and afidopyropen have negative effects that extend beyond the immediate acute mortality previously published. To test this hypothesis, we undertook a series of experiments to determine the effects of flonicamid and afidopyropen, along with the synthetic pyrethroid gamma‐cyhalothrin, on aphid parasitism (mummification) rate, emergence rate of the next generation and the next generation sex ratio in three important aphid parasitoids,Aphidius colemani(Viereck),Diaeretiella rapae(M'Intosh) andAphelinus abdominalis(Dalman). Analogous with previous research, our acute toxicity bioassays showed that all three insecticides had low (<30%) mortality impacts. Although sub‐lethal impacts could not be assessed forD. rapaedue to the low level of aphid parasitism by that species, our findings showed negative impacts on fecundity in survivingA. abdominalisandA. colemani. Of particular note is the increase in International Organisation for Biological Control ratings to moderate (30%–80% mortality and/or reproductive reduction) when mortality and reduced fecundity effects were combined to determine overall fitness impacts. Gamma‐cyhalothrin typically resulted in higher negative impacts onA.abdominalisandA.colemani(compared with flonicamid and afidopyropen); however, quite surprisingly, these impacts were not rated as highly toxic. Taken together, our results suggest that, even when sub‐lethal impacts are considered, flonicamid and afidopyropen are useful tools for farmers targeting aphid populations while minimising the non‐target impacts on parasitoids. We recommend semi‐field and/or field trials to further assess the impacts of these insecticides on aphid parasitoid populations.

Predatory mites biologically control a range of arthropod crop pests and are often central to agricultural IPM strategies globally. Conflict between chemical and biological pest control has prompted increasing interest in selective pesticides with fewer off-target impacts on beneficial invertebrates, including predatory mites. However, the range of predatory mite species included in standardized pesticide toxicity assessments does not match the diversity of naturally occurring species contributing to biocontrol, with most testing carried out on species from the family Phytoseiidae (Mesostigmata). Here, we aim to bridge this knowledge gap by investigating the impacts of 22 agricultural pesticides on the predatory snout mite, Odontoscirus lapidaria (Kramer) (Trombidiformes: Bdellidae). Using internationally standardized testing methodologies, we identified several active ingredients with minimal impact on O. lapidaria mortality, including Bacillus thuringiensis, nuclear polyhedrosis virus, flonicamid, afidopyropen, chlorantraniliprole, and cyantraniliprole, which may therefore be good candidates for IPM strategies utilizing both chemical and biological control. Comparison of our findings with previous studies on Phytoseiid mites reveals important differences in responses to a number of chemicals between predatory mite families, including the miticides diafenthiuron and abamectin, highlighting the risk of making family-level generalizations from acute toxicity assessments. We also tested the impacts of several pesticides on a second Bdellidae species (Trombidiformes: Bdellidae) and found differences in the response to chlorpyrifos compared with O. lapidaria, further highlighting the taxon-specific nature of nontarget toxicity effects.