Combining Biocontrol Agents with Chemical Fungicides for Integrated Plant Fungal Disease Control

Abstract

Feeding a rising population of currently 7.8 billion people globally requires efficient agriculture, which is preferably sustainable. Today, farmers are largely dependent on synthetic fungicides to avoid food losses caused by fungal diseases. However, the extensive use of these has resulted in the emergence of fungicide-resistant pathogens and concerns have been raised over the residual effects on the environment and human health. In this regard, biocontrol agents (BCAs) have been proposed as an alternative to standard fungicides but their disease management capacity is usually incomplete and heavily relies on uncontrollable environmental conditions. An integrated approach combining BCAs with fungicides, which is the focus of this review, is put forward as a way to reduce the fungicide doses to manage plant diseases and thereby their residue on harvested crops. In addition, such a strategy of combining antifungal treatments with different modes of action reduces the selection pressure on pathogens and thereby the chances of resistance development. However, to allow its large-scale implementation, further knowledge is needed, comprising timing, number and interval of repeated BCA applications and their compatibility with fungicides. The compatibility of BCAs with fungicides might differ when applied in a mixture or when used in alternation.

Assessment of Commercial Fungicides against Onion (Allium cepa) Basal Rot Disease Caused by Fusarium oxysporum f. sp. cepae and Fusarium acutatum

“…One solution to cope with this problem is the use of a mixture of fungicides, each of which has a different action mechanism (see, for example [17,18]). Another approach is to decrease the fungicide dosages required by combining the chemical treatment with eco-friendly biological solutions [19]. Such an approach was already demonstrated as effective in reducing FBR damages [20,21] and is also very beneficial in coping with the long-term problems of intensive chemical pesticides' use.…”

“…In the long-term, chemical control of phytoparasitic fungi may cause environmental, animal, and human hazard risks. Reducing the use of chemical fungicides has become increasingly essential and is nowadays a worldwide effort [19].…”

Trichoderma longibrachiatum and Trichoderma asperellum Confer Growth Promotion and Protection against Late Wilt Disease in the Field

“…An integrated LWD control strategy can combine the Trichoderma species inspected here with other environmentally friendly solutions such as biopesticide that are gaining increasing importance [53]. In India, for instance, microbial biopesticides research is evolving rapidly, and such pesticides comprise ≈ 5% of the market [54].…”

Antofine inhibits postharvest green mold due to imazalil‐resistant Penicillium digitatum strain Pdw03 by triggering oxidative burst

“…digitatum is mainly through the use of synthetic fungicides, such as imazalil (IMZ), thiabendazole (TBZ), and fludioxonil (FLUD; D'Aquino et al., 2013; Liu et al., 2017). However, the persistent and extensive use of these chemical fungicides has resulted in the emergence of numerous fungicide‐resistant P. digitatum strains (Ons et al., 2020), for example, Duan (2015) isolated P. digitatum strains with high resistance to pyrimidine nucleoside antibiotic, 2, 4‐D and prochloraz (PPZ) in three citrus‐growing areas of China. Several other P. digitatum isolates presenting multiple resistance to IMZ, TBZ, guazatine (GZT), and PPZ were also reported by Erasmus et al., (2015).…”