Link to home

Evaluation of Agar and Grain Media for Mass Production of Conidia of Dactylaria higginsii

November 2001 , Volume 85 , Number  11
Pages  1,165 - 1,170

Gabriela S. Wyss , Postdoctoral Associate , Raghavan Charudattan , Professor , and James T. DeValerio , Senior Biologist, Plant Pathology Department, University of Florida, Gainesville 32611-0680

Go to article:
Accepted for publication 10 July 2001.

Growth and sporulation of Dactylaria higginsii were quantified on complex agar media containing biological materials (group 1) and chemically defined agar media (group 2), as well as on grains, and the inoculum produced on these various substrates was tested for virulence on Cyperus rotundus. The fungus grew well between 25 and 30°C on potato dextrose agar (PDA), with 27°C being the optimum temperature. Generally, conidial production was highly variable and lower on complex agar media than on chemically defined media. Addition of purple nutsedge leaves to PDA did not increase colony growth or conidial production when compared with una-mended PDA. Conidial production was lowest on brown rice compared with white rice or white rice with nutsedge leaves. Peak production on grain media occurred from day 12 in test 1 (2.4 × 106 spores/g of grain) and on day 16 in test 2 (2.5 × 106 spores/g of grain). Germination rate of conidia produced on white rice was 50% compared with the near 100% germination of conidia produced on PDA or on white rice amended with potato dextrose broth (PDB). Conidia produced on white rice or PDA, when tested fresh or after two washings, were less virulent on C. rotundus than conidia from white rice amended with PDB. After four washings, conidia from all three media produced the same level of disease severity. White rice supplemented with PDB and PDA in trays were suitable for mass production of conidia of D. higginsii.

Additional keywords: biocontrol, chemical stimulants, inhibitory substances

© 2001 The American Phytopathological Society