Fungicide Treatments to Control Seed-borne Fungi of Sunflower Seeds

Abstract

Seed-borne fungi in 69 sunflower cultivars were evaluated which comprised 52 confectionery and 17 oilseed types. Seed coats were placed on both NP-10 (Nonylphenol Ethoxylate based surfacant −10) and potato dextrose agar (PDA) media to culture fungi. The rate of contamination among the different varieties was calculated by counting seed coats with fungal colonies. The rate of contamination in the confectionary group (88%) was significantly (p ≤ 0.05) higher than in the oilseed group (71%). Of the 52 confectionery varieties, the dominant fungi recovered were Verticillium dahliae along with Alternaria spp., Fusarium spp., and Rhizopus spp., whereas the oilseed type varieties were contaminated with only V. dahliae. Molecular identification of fungal species via BLAST (Basic Alignment Search Tool) was performed on fungal sequences obtained from PCR (Polymerase Chain Reaction) analysis. The results included five Alternaria spp. that included Alternaria tenuissima, Alternaria alternata, Alternaria helianthiinficiens, Alternaria longipes, and Alternaria tamaricis, three Fusarium spp. such as Fusarium oxysporum, Fusarium incarnatum, and Fusarium proliferatum, and V. dahliae and Cladosporium cladosporioides. These were identified from pure fungal cultures recovered from seed coats. To efficiently control seed-borne fungi, four broad spectrum fungicides (carbendazim, triadimefon, caprio F-500, and flusilazole) were screened against V. dahliae isolate Gn3, which was isolated from a diseased LD 5009 sunflower plant. Flusilazole was selected based on its low half-maximal effective concentration value (EC50), 78.7 µg/mL. Seeds of diseased LD 5009 plants obtained from two different locations treated with formulated flusilazole fungicide at optimum parameters showed a significant (p ≤ 0.05) increase in seed germination and a decrease in contamination rate from 98% to less than 10%. The results affirmed that confectionery cultivars are much more susceptible to fungal contamination than oilseeds, and also that seed pretreatment is a suitable way to prevent the spread of soil- and seed-borne fungi in sunflower production.

Application of Raw Secondary Metabolites From Four Entomopathogenic Fungi Against Chilli Disease Caused by Viruses

“…The soaking time the seeds into the raw secondary metabolites was only 30 min. According to Addrah et al (2020), soaking the seeds in formulated flusilazole fungicide for 12 h was significantly reduced fungal contamination on the seeds. A method of soaking seeds in a 0-2% aqueous suspension of thiram for 24 h at 30 °C was able to eradicate infection by several fungi (Maude et al, 1969).…”

Identification and comparison of biological characteristics and pathogenicity of different mating types of V. dahliae isolated from potato and sunflower

“…A quarter of the world’s Potato ( Solanum tuberosum L.) is produced from China, making it the largest producer of such an important crop globally 1 . Recently, potato has been listed as the fourth largest staple crop in China, after rice, wheat, and maize.…”

Screening of Marine Bioactive Antimicrobial Compounds for Plant Pathogens

“…Traditionally, agricultural synthetic chemicals, including fungicides and bactericides, have been widely used in the control of plant pathogens. Although most of the chemical agents have the characteristics of high efficiency and persistence [ 2 , 3 ], many of them are toxic and harmful to the environment, sometimes leading to high resistance of pathogens (due to the evolution of pathogenic bacteria, pathogenic mutation, etc.) [ 4 , 5 , 6 , 7 ].…”