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Developing novel biostimulant products based on Black Soldier Fly by-products for sustainable agriculture

Primary Supervisor: Dr Joe Roberts, Department of Agriculture and Environment

Secondary supervisor: Dr Simon Jeffery (HAU) and Dr Laura Vickers (HAU)

PhD project title: Developing novel biostimulant products based on Black Soldier Fly by-products for sustainable agriculture

University of Registration: Harper Adams University

Project outline:

Conventional agricultural production systems rely on intensive synthetic inputs to attain maximal yields, particularly with respect to protection against pests (i.e., pesticide use) and nutrient provision (i.e., fertiliser use).1 Modern production systems increasingly demand alternatives to synthetic inputs due to legislative changes, resistance to active ingredients and concern surrounding their impact on environmental and human health.2-4 Finding effective alternatives to synthetic inputs is, therefore, vital to meet sustainability demands while also ensuring food security and profitable harvests. Biostimulants are products derived from natural substances that offer an alternative to synthetic fertiliser inputs by provisioning supplementary nutrition to crops.

There is growing interest in the bioactive properties of Black Soldier Fly (BSF) (Hermetia illucens L.) (Diptera: Stratiomyidae) leachate as a by-product from BSF larvae production. Application of insect excreta (leachate and frass) to plants may confer protection against phytophagous insect pests and promote plant growth.5 It is hypothesised that microorganisms and bioactive molecules within BSF leachate activate systemic plant resistance and facilitate enhanced growth by upregulating biosynthesis of key plant hormones. Bioactivity of BSF leachate is likely to be determined by its composition, which is impacted by larval diet during rearing and may be enhanced through addition of certain vegetable wastes. Despite much interest in commercial BSF rearing and the by-products associated with this process, scientifically robust studies investigating plant health benefits from BSF leachate application are lacking.

This project will combine phenotyping experiments with molecular and chemical analyses to identify BSF leachate application effects on plant growth and insect resistance, as well as the molecular mechanisms underpinning these effects. Initial experiments will focus on quantifying changes in plant growth and vigour as well as insect performance after leachate application using glasshouse pot experiments. Subsequent experiments will use molecular techniques (e.g., real-time PCR) to measure gene expression changes in plants while hormone levels (jasmonic and salicylic acid) will be measured using gas chromatography coupled mass spectrometry. Full-scale field experiments will also be carried out to test the efficacy of BSF leachate under realistic conditions. These experiments will use a model crop system of strawberry (Fragaria × ananassa) and two economically important insect pests: vine weevil (Otiorhynchus sulcatus) and potato aphid (Macrosiphum euphorbiae).

Reference:

1Savary et al. (2019) Nature Ecology and Evolution 3:430-439; 2Sparks and Nauen (2015) Pesticide Biochemistry and Physiology 121:122-128; 3Fantke et al. (2012) Environment International 49:9-17; 4Ollerton et al. (2014) Science 346: 1360-1362; 5Poveda (2021) Agronomy for Sustainable Development 41:1-10.

BBSRC Strategic Research Priority: Sustainable Agriculture and Food:Plant and Crop Science

    Techniques that will be undertaken during the project:

    • Soil physicochemical analysis
    • Air entrainments to collect volatile organic compounds from organic material
    • Gas chromatography-mass spectrometry to identify volatile organic compounds
    • Insect assays to determine behavioural responses and mortality rates
    • Polymerase chain reaction (PCR) for gene expression studies

    Contact: Dr Joe Roberts, Harper Adams University