Submitted to: Weed Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 25, 2003
Publication Date: January 1, 2004
Citation: Bailey, B.A., Lumsden, R.D., O'Neill, N.R., Lewis, J.A. 2004. Production of Pleospora papaveracea biomass in liquid culture and its infectivity on opium poppy (Papaver somniferum). Weed Science. 51:91-97.
Interpretive Summary: Opium poppies, the source of heroin, are illegally grown in many countries. Bio control strategy using the fungi, Pleospora papaveracea or Dendryphion penicillatum is being developed to augment current control measures. P. papaveracea and D. penicillatum produce spores, the fungal component most often used in bio herbicides, on solid media but this method is cumbersome and expensive. We developed liquid fermentation methods for producing biomass of both fungi. Liquid fermentation is commonly used for growing fungi used in bio control. The fungal biomass contains resting structures and mycelia that are capable of infecting opium poppies. Production of P. papaveracea and D. penicillatum by liquid fermentation is the first step toward large-scale production of biomass. Large-scale production of biomass should improve their potential for use as bio control agents for control of opium poppy offering drug enforcement agencies around the world a new strategy for controlling heroin production at its source in the field.
Dendryphion penicillatum and Pleospora papaveracea, potential opium poppies (Papaver somniferum) bio control agents, were grown on agar media containing wheat germ, corn cobs, soy fiber, cottonseed meal, rice flour, cornstarch, pectin, dextrin, or molasses, and brewers' yeast (BY). The fungi preferred molasses, soy fiber, and a wheat germ based on radial growth. D. penicillatum microsclerotia (Microscl) was produced on all media but molasses/BY and rice flour/BY. P. papaveracea chlamydospores (Chla) were produced on dextrin/BY and corn starch/BY only. Fungal growth in liquid media with 1% w v-1 dextrin, cornstarch, soy fiber, or wheat germ resulted in production of log10(CFU/mL+1) greater than 6.0 within 3-5 days. After five days, log10((Microscl/mL)+1) greater than 5.0 were formed by D. penicillatum in liquid media. P. papaveracea produced log10((Chla/mL)+1) less than 5.0 in wheat bran/BY and soy fiber/BY media after 10 days compared to log10((Chla/mL)+1) greater than 5.0 in dextrin/BY or corn starch/BY after five days. Less CFU was produced by D. penicillatum with 0.25% and 0.5% dextrin or soy fiber than with 1 percent substrate. Similarly, 0.25% dextrin or 0.25 and 0.50% soy fiber reduced CFU production by P. papaveracea compared to 1 percent substrate. Microsclerotia/ chlamydospores of D. penicillatum and P. papaveracea were produced in dextrin/BY in a commercial bench-top fermentor. After drying six days, the biomass of both fungi was infective on an opium poppy with mycelia and microsclerotia/ chlamydospores germinating to form appressoria. Dilutions of dried biomass caused necrosis within 48 h when applied to opium poppy leaves.