Fungicidal Activity of Soybean Oil against Powdery Mildew on Wheat

Abstract

Products derived from soybean crops are not only global food staples, but are also used in pharmaceuticals, industry, and agriculture. Soybean oil (SBO) and other oils are often used as adjuvants in agricultural sprays to facilitate spread of the active ingredient (a.i.) across the plant surface. This chapter describes original research in which a natural fungicide (biofungicide) was formulated using SBO as the a.i. Antimicrobial activity of SBO against a powdery mildew (PM) pathogen, Blumeria graminis f. sp. tritici, was measured, as well as effects on plant health and yield of wheat plants. Results were compared with a conventional fungicide and another lipid biofungicide. The mode of action was investigated using scanning electron microscopy. Results showed that SBO provided PM control equal to the conventional fungicide when plants were adequately spaced and caused collapse of fungal structures and extrusion of cell contents. Commercialisation potential of SBO biofungicide is discussed.

Lipid-Based Natural Food Extracts for Effective Control of Botrytis Bunch Rot and Powdery Mildew on Field-Grown Winegrapes in New Zealand

“…Combining the two NPs together has been shown in other studies to have a complementary effect on disease control, making it possible to reduce the concentrations of the active ingredients (a.i.) of each [25], possibly because the NPs appear to have different physical modes of action, with NP1 causing withering and distortion/ridging of fungal structures, whilst NP2 application leads to the extrusion of cellular contents [23]. However, in this study, using alternating NP1 and NP2 at different times in the spray programme, instead of the use of just one NP product, seemed to exacerbate Botrytis latent infections (Figure 1a).…”

“…An LCD allows for greater air circulation around the bunches, thus lowering humidity, and creating a micro-environment that is less favourable to Botrytis [31]. However, the most likely reason for NP2 working better in an LCD is that it enables greater spray penetration to internal bunches (Figures 3 and 4), which is important to NP2 efficacy, because it has contact-only activity [23,32]. However, yield tended to be significantly lower in the LCD, possibly because insufficient leaf material remained to create adequate photosynthates for berry development.…”

“…Another advantage of the NPs is that pathogens do not tend to develop resistance to agricultural sprays containing lipids [19,20]. Given that NPs, like other lipids, appear to have contact-only action via a direct physical effect on the pathogen [23,32], control of latent infections is surprising and may suggest an, as yet undiscovered, mode of action, such as the direct induction of plant defences, or possibly indirect induction of defences via generation of fungal elicitors (compounds that activate plant defences) following the disruption of pathogen cells. This remains to be investigated.…”

“…Disease control offered by mineral oils, along with oils derived from plants and animals, is also very durable [19,20]. Research to date has shown that NP1 and NP2 were highly effective against various PM pathogens on different crops in laboratory and glasshouse experiments [21][22][23][24][25]. However, these environments were artificially controlled, and product efficacy in a highly variable field environment was unknown, hence the need for the current research.…”

Hot Water Treatment as Seed Disinfection Techniques for Organic and Eco-Friendly Environmental Agricultural Crop Cultivation

“…michiganensis, Alternaria dauci, and Botrytis aclada-thyme oil is already being used in Europe to treat seeds [45]. Refined soybean or mineral oil has been shown to reduce molds associated with storage diseases in corn and soybeans [46]. However, additional research is needed to investigate the potential of plant essential oils in inhibiting plant pathogens for the development of seed disinfection techniques.…”