Species feeding lower at the food web like cyprinids (carp) are often advocated for sustainable aquaculture. However, their gastrointestinal biology (lack of stomach) has limited their acid‐peptic digestion, acid lysis of plants and invertebrate tissues, and phosphorus uptake. This review presents data from 118 articles on the use of plant‐based feed additives (PFAs) in Cyprinus carpio (common carp). Our review shows that most PFA research in carp is focused on improving feed and nutrient utilization efficiency along various levels (in vivo digestibility, metabolizability to in situ nutrient loading), while other half is focused on ensuring animal welfare standards (biomass, immunity, welfare). Several reviewed plant‐based additives however tend to do both. The PFAs include essential oils (EOs), plant‐part extracts (PPEs), medicinal plants (herbs) and spices. The effective inclusion rate of EOs is lower (0.5%–0.75%). Whereas PPEs, herbs and spices work at a generic inclusion rate of 2%–5% in carp feeds. Even at an optimum inclusion rate, there are factors controlling PFAs efficacy such as methods of preparation (reviewed). PFAs like lemon beebrush, geranium, dill, Rosemary pepper and common mallow with/without certain pre‐conditions are better to avoid in cyprinid diets. Although certain PFAs may potentially alter organoleptic qualities of carp flesh or might assist in training carp immunity, information on these aspects is limited. The review also provides a quick guide to researchers and feed companies interested in exploring the potential of PFAs in C. carpio aquaculture. Potential PFAs that could be valuable for cyprinids, but not yet explored are also listed.

The use of hydroponics to cultivate economic crops is an emerging agricultural practice in Nigeria. There is, however, a paucity of information on the economic viability and valuation of the production systems. This study investigated hydroponics' profitability and economic viability under small- and medium-scale production systems. The economic viability of ten hydroponic farms were evaluated using the financial metrics: net present value (NPV), internal rate of return (IRR), benefit-cost ratio (BCR), and sensitivity analysis. Sensitivity analysis based on positive and negative changes in the running cost and gross annual revenue was adopted to measure the robustness of the production method. The positive NPVs of the small-scale farmer (€42,895) and medium-scale farmer (€331,465) at a 15% discount rate show that both production scales are economically viable. The ten-year IRR of both production scales was about 83%. Similarly, the BCR showed that both the small-scale farmers (5.07) and the medium-scale farmers (4.91) are significantly profitable. In the sensitivity analysis, the small-scale farmers were more sensitive to recurrent 5% changes in the running cost at the 13% threshold. On the other hand, medium-scale farmers were less sensitive with a threshold value of 58.4%. Similarly, small-scale farmers are more sensitive to a 15% reduction in the gross annual revenue, with a negative net return of -€956. It is imperative to state that, though starting an investment in hydroponics requires a high initial investment, medium-scale farmers would be less sensitive to changes in the running cost of production in the face of uncertainties.

BACKGROUND: Sweet potato whitefly (Bemisia tabaci) is one of the most destructive pests to an extensive range of crops and vegetables. Pesticide‐dependent management programs have led to severe health problems, including pesticide poisoning and cancer in human beings, as well as pesticide resistance in insect pests. Entomopathogenic fungi (EPF) are considered safe and highly effective against many pests. Therefore, identifying the pathogenicity and virulence of EPFs against Bemisia tabaci is a valuable addition to the management of their infestations. In this study, we investigated the efficacy of conidia suspensions of Aschersonia aleyrodis, Isaria fumosorosea, Beauveria bassiana, and Akanthomyces muscarius (= Lecanicillium muscarium) against nymphal stages of Bemisia tabaci in cucumber seedlings under both optimal and suboptimal conditions.RESULTS: All of the EPFs demonstrated significant ovicidal effects, with the highest cumulative mortalities observed in Aschersonia aleyrodis (96.46%) and I. fumosorosea‐treated (94.60%) seedlings against host eggs and crawlers. Similarly, in the L4‐instars experiment, Aschersonia aleyrodis and I. fumosorosea were the most efficient, resulting in cumulative mortalities of 94.82% and 94.75%, respectively. However, Bemisia tabaci cumulative mortalities on seedlings treated with Akanthomyces muscarius (78.36%) and Beauveria bassiana (85.90%) were also significantly different from untreated seedlings (7.10%). Under suboptimal relative humidity (RH) conditions (≤ 45% RH), Aschersonia aleyrodis exhibited greater tolerance to harsh conditions, causing a significantly higher infection rate in L1–L2 nymphs (~92%) compared to the approximately 32% infected young nymphs observed in I. fumosorosea‐treated seedlings.CONCLUSION: All the selected EPF were more effective against the young nymphal instars. Our results also highlight the efficacy of Aschersonia aleyrodis under suboptimal conditions. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.