Fungi as Potential Biocontrol Agents Against Convolvulus arvensis and Portulaca oleracea Infesting the Agroecosystems of Egypt

Abstract

F UNGAL biocontrol of weed is a promising eco-friendly alternative solution to reduce risks of synthetic herbicides. A field survey conducted in Wadi El-Natroun and North Sinai, Egypt, resulted in the isolation of 36 fungal isolates. Culture filtrates of the obtained isolates were screened for their ability to inhibit the seed germination and seedling development of Portulaca oleracea and Convolvulus arvensis. Filtrates crude extracts of Albifimbria verrucaria MN094460.1 and Cladosporium cladosporioides MN094461.1 gave the highest herbicidal activity against both tested weeds. A. verrucaria caused high reductions in seed germination, shoot and root length, of both weeds. Also, its crude extract significantly reduced seedling fresh weight of P. oleracea (85%) and C. arvensis (59%). On the other hand, C. cladosporioides completely inhibited seed germination, shoot and root length of P. oleracea while its extract caused 78% reduction in seedling fresh weight. In greenhouse, foliar application of 5×10 7 conidia/ml of A. verrucaria with 0.2% silwet-L-77 significantly reducted P. oleracea chlorophyll a (74%) and fresh weight (82%) also, it reduced C. arvensis chlorophyll b (57%). Whereas, conidial sprays of C. cladosporioides (5×10 7 conidia/ml with 0.2% silwet-L-77) caused significant reductions in P. oleracea chlorophyll a (73%) and fresh weight (74%). LC-MS/MS analysis revealed the presence of 12 compounds in C. cladosporioides extract and 7 compounds in A. verrucaria extract. This study concluded that A. verrucaria MN094460.1 and C. cladosporioides MN094461.1 are potentially effective biocontrol agents against P. oleracea and C. arvensis. Besides, the herbicidal activity of C. cladosporioides against P. oleracea was reported for the first time.

Isolation, selection, and identification of phytopathogenic fungi with bioherbicide potential for the control of field bindweed (Convolvulus arvensis L.)

“…Although biological control of C. arvensis by phytopathogenic fungi has already been reported (El‐Sayed & Hurle, 2001; Ibrahim & Tawfik, 2019; Pfirter et al, 1997), there are no reports of M. phaseolina phytopathogenicity on C. arvensis . In this study, the phytotoxic effect of M. phaseolina on the host plant could be related to the production of cell wall hydrolytic enzymes (Marquez et al, 2021), which could support the entry of the biological agent or phytotoxins produced by it (Ghorbani et al, 2005; Harding & Raizada, 2015; Reichert Júnior et al, 2019).…”

“…FCFC were produced according to Ibrahim and Tawfik (2019) with some modifications. Erlenmeyer flasks (500 mL) containing 200 mL of potato dextrose broth (PDB) (BD Difco™, Cat.…”

“…Its root system can extend up to 6 m in diameter and 9 m deep (Pfirter et al, 1997), and it can produce 1 × 10 6 seeds per hectare, which survive up to 30 years in the soil (Timmons, 1949). These characteristics make it difficult to control by mechanical and chemical methods, and the inappropriate use of the latter can affect nontarget plants including crops of interest (Ibrahim & Tawfik, 2019). Chemical methods can also favor the appearance of resistant biotypes, as well as negatively affect the environment and human health (Harding & Raizada, 2015; Huang et al, 2019).…”

“…Due to the limitations of conventional methods, it may be necessary to develop alternative tools for weed control, such as biological products based on microorganisms (Reichert Júnior et al, 2019). Among biological agents, fungi are the most used, as they do not require a diffusion vector (Hershenhorn et al, 2016), and they are able to produce metabolites with bioherbicidal capacity (Ibrahim & Tawfik, 2019). Furthermore, they may have less of an environmental impact, which can minimize risks to human and animal health, and they have greater specificity than chemical methods (Harding & Raizada, 2015; Ibrahim & Tawfik, 2019).…”

“…Among biological agents, fungi are the most used, as they do not require a diffusion vector (Hershenhorn et al, 2016), and they are able to produce metabolites with bioherbicidal capacity (Ibrahim & Tawfik, 2019). Furthermore, they may have less of an environmental impact, which can minimize risks to human and animal health, and they have greater specificity than chemical methods (Harding & Raizada, 2015; Ibrahim & Tawfik, 2019). Therefore, the objective of this study was to isolate fungal strains from C. arvensis leaves, and to evaluate their bioherbicide potential on this weed.…”