Articles
Effective seed treatment for managing seedling damping-off of pumpkin, caused by Phytophthora capsici
Article number
1453_9
Pages
67 – 74
Language
English
Abstract
Illinois is the leading state in pumpkin production in the United States. Phytophthora capsici causes pre- and post-emergence seeding damping-off, vine blight, and fruit rot.
Seedling death in some pumpkin fields was so severe that growers had to replant the fields for a second and even a third time.
This study was conducted to develop effective seed-treatments to protect pumpkin plants against P. capsici during stand establishment.
Mefenoxam (Apron XL LS) and metalaxyl (Allegiance F) were highly inhibitory to growth of mycelium of P. capsici in vitro.
Effective dose for 50% inhibition of mycelial growth (ED50) of mefenoxam and metalaxyl, for all five isolates of P. capsici tested, was 0.98 and 0.99 μg a.i. mL‑1 on culture medium, respectively.
Effectiveness of the seed-treatments were evaluated on pumpkins ‘Dickinson’, ‘Hybrid-401’, and ‘Hybrid-698’ in a greenhouse and a field with infested soil with P. capsici oospores.
In the greenhouse evaluations, 31 days after seeding, at inoculum levels of 0, 90, and 600 CFU g‑1 of soil, the average seedling stands for mefenoxam treatment were 98.3, 93.8, and 88.3%; for metalaxyl, 99.1, 85.3, and 85.8%; and for the untreated control, 97.5, 55.2, and 45.7%, respectively.
In the field evaluations, the average seedling stands 35 days after seeding were 76.7, 74.7, and 44.9% for mefenoxam, metalaxyl, and untreated check, respectively.
Seed treatment with mefenoxam or metalaxyl did not have any significant effect on either seed germination or seedling vigor.
Seedling death in some pumpkin fields was so severe that growers had to replant the fields for a second and even a third time.
This study was conducted to develop effective seed-treatments to protect pumpkin plants against P. capsici during stand establishment.
Mefenoxam (Apron XL LS) and metalaxyl (Allegiance F) were highly inhibitory to growth of mycelium of P. capsici in vitro.
Effective dose for 50% inhibition of mycelial growth (ED50) of mefenoxam and metalaxyl, for all five isolates of P. capsici tested, was 0.98 and 0.99 μg a.i. mL‑1 on culture medium, respectively.
Effectiveness of the seed-treatments were evaluated on pumpkins ‘Dickinson’, ‘Hybrid-401’, and ‘Hybrid-698’ in a greenhouse and a field with infested soil with P. capsici oospores.
In the greenhouse evaluations, 31 days after seeding, at inoculum levels of 0, 90, and 600 CFU g‑1 of soil, the average seedling stands for mefenoxam treatment were 98.3, 93.8, and 88.3%; for metalaxyl, 99.1, 85.3, and 85.8%; and for the untreated control, 97.5, 55.2, and 45.7%, respectively.
In the field evaluations, the average seedling stands 35 days after seeding were 76.7, 74.7, and 44.9% for mefenoxam, metalaxyl, and untreated check, respectively.
Seed treatment with mefenoxam or metalaxyl did not have any significant effect on either seed germination or seedling vigor.
Authors
M. Babadoost
Keywords
Phytophthora capsici, seedling death, seed-treatment, mefenoxam, metalaxyl
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