Fungicide Seed Treatment Effects on Seedling Damping-off of Pumpkin Caused by Phytophthora capsici

Abstract

Apron XL LS (mefenoxam) and Allegiance FL (metalaxyl) were highly inhibitory to growth of mycelium of Phytophthora capsici in vitro. Effective dose (ED50) of mefenoxam and metalaxyl for 50% inhibition of mycelial growth, for all five isolates of P. capsici tested, was 0.98 and 0.99 μg a.i./ml of culture medium, respectively. For mefenoxam at 200 μg a.i./ml, sporangium and zoospore germination were reduced by 92 and 96%, respectively, and 21 and 24%, respectively, for metalaxyl. In greenhouse studies, seed treatment with mefenoxam (0.42 ml of Apron XL LS/kg of seed) and metalaxyl (0.98 ml of Allegiance FL/kg of seed) significantly reduced pre- and post-emergence damping-off of seedlings caused by P. capsici in three pumpkin cultivars (Dickinson, Hybrid-401, and Hybrid-698) tested. Thirty-one days after seeding, at inoculum levels of 0, 90, 600, 1,400, and 4,000 CFU/g of soil, the average seedling stands for mefenoxam treatment were 98.4, 93.8, 88.3, 77.8, and 64.8%; for metalaxyl, 99.1, 85.3, 85.8, 73.5, and 59.3; and for the untreated control, 97.5, 55.2, 45.7, 37.0, and 22.9%, respectively. In field trials, the average seedling stands 35 days after seeding were 76.7, 74.7, and 44.9% for mefenoxam, metalaxyl, and untreated control, respectively. Seed treatment with mefenoxam or metalaxyl did not have any significant effect on either seed germination or seedling vigor.

Genetic diversity of Phytophthora capsici (Pythiaceae) isolates in Anhui Province of China based on ISSR-PCR markers

“…capsici belongs to the phytopathogenic oomycetes that produce both zoospores and oospores for colonizing plant tissues and overwintering, and can be dispersed by surface water, irrigation water and air currents. To date, management of P. capsici mainly relies on rotation, sanitation and the use of fungicides, but there is no effective method to provide enough protection against this disease during its epidemic period (Babadoost and Islam, 2001). As known, the genetic structure of pathogen populations reflects its evolutionary history and its potential to evolve.…”

Antagonistic Potential of Fluorescent Pseudomonads and Control of Crown and Root Rot of Cucumber Caused by Phythophtora drechsleri

“…Phytophthora capsici is usually reported as the principal cause of this disease (Babadoost and Islam, 2003), although P. drechsleri has been described as a major agent in Iran (Alavi and Strange, 1979). These pathogens cause damping-off, crown and root rot, stem lesions, foliar blight, and fruit rot on cucumber (Kreutzer et al, 1940;McGrath, 2001; Alavi and Strange, 1982).…”

Combining Trichoderma hamatum THSW13 and Pseudomonas aeruginosa BJ10–86: a synergistic chili pepper seed treatment for Phytophthora capsici infested soil

“…Mefenoxam is a registered seed treatment agent against several oomycetes, with recommended soil treatment only when necessary (Syngenta Crop protection, Jakarta). Several reports (Babadoost and Islam 2003;Hu et al 2008) have noted the high sensitivity of Phytophthora spp. to this fungicide.…”