Plasma‐assisted deposition of fungicide containing coatings for encapsulation and protection of maize seeds

Abstract

The aim of the research work here reported is to illustrate how to incorporate prothioconazole, a molecule with fungicide action, in plasma‐deposited polymeric coating, encapsulating maize seeds. With this approach, high fungicide effect with a small quantity of chemicals and less pollution of soil and water should be achieved. The fungicide composite coating is composed of three layers: a hydrophilic plasma deposited polymeric layer to increase the wettability of the seed surface; a layer of sprayed prothioconazole aqueous solution; and a hydrophobic plasma deposited barrier layer to limit leaching and mimic the natural seed wettability. The application of the composite coating is found not to interfere with the germination of the seeds, while the percentage of maize crowns infected by Fusarium graminearum was successfully reduced from 94% in the control to none in the coated seeds.

Plasma Technology Increases the Efficacy of Prothioconazole against Fusarium graminearum and Fusarium proliferatum Contamination of Maize (Zea mays) Seedlings

“…We reported a high capability of prothioconazole in inhibiting F. verticillioides, F. graminearum, and F. proliferatum in vitro and in field experiments, with respect to other fungicides [33]. Furthermore, prothioconazole encapsulated in the plasma-deposited bilayer has been reported to successfully reduce F. graminearum infection in maize seedlings [32]. The current technologies for seed coating provide several advantages, such as the containment of the chemical compounds in confined spaces, and the possibility to reduce the dose of fungicides to control fungal development, with a consequent decreased release of chemicals into the environment.…”

“…Part of the maize seeds were treated with the deposition of a plasma-based bilayer coating, as described by Lo Porto et al [32]. A home-made stainless steel parallel-plate capacitive-coupled RF (13.56 MHz)-driven low pressure plasma reactor was used to deposit a two-layer coating at the surface of maize seeds.…”

“…Among marketed fungicides, Masiello et al reported that the de-methylation inhibitor prothioconazole was the most active molecule in vitro against the most important mycotoxigenic fungi of maize and confirmed its effectiveness in reducing F. graminearum and F. proliferatum contamination of maize plants in the field [33]. Based on this knowledge, Lo Porto et al [32] developed a plasma-deposition approach to apply prothioconazole directly and only at the surface of the maize seeds, to enhance the effectiveness of the fungicide, to limit its used quantity, and to avoid its dispersion in the soil. Indeed, this approach is original so far in the literature, since plasma treatments of seeds, generally in the form of ablation and hydrophilization of their surfaces, are generally tested for direct decontamination or for inducing faster germination, but not plasma deposition.…”

“…We carried out a preliminary study applying a fungicide on maize seeds using plasma technology, by embedding it with a coating plasma-deposited directly on the seeds, for better investigation of the potentiality of this technology in controlling fungal infections and reducing the use of fungicides in agriculture [32]. Among marketed fungicides, Masiello et al reported that the de-methylation inhibitor prothioconazole was the most active molecule in vitro against the most important mycotoxigenic fungi of maize and confirmed its effectiveness in reducing F. graminearum and F. proliferatum contamination of maize plants in the field [33].…”

“…In the last decades, however, for several reasons, processes at atmospheric pressure have been developed too [34,35]. Two low pressure plasma-deposition processes were used by Lo Porto et al [32] to develop first a thin wettable layer around the seeds, where the prothioconazole could be sprayed and remain, and then a hydrophobic layer aimed to embed the fungicide, and repristinate the natural hydrophobicity of the seed surface. The effective total thickness of the two layers is in the order of hundreds of nanometers.…”