|Slininger, Patricia - Pat|
Submitted to: American Society for Microbiology
Publication Type: Abstract Only
Publication Acceptance Date: 6/3/1999
Publication Date: N/A
Technical Abstract: Damage associated with Fusarium head blight of wheat includes reduced yields and poor grain quality due to the pathogen producing the estrogenic toxin zearalenone and the trichothecene deoxynivalenol (vomitoxin). To evaluate the feasibility of biologically controlling Gibberella zeae, wheat anthers were collected throughout Illinois and Ohio, and more than 700 microbial isolates were obtained by plating anther washes on semi-selectiv and non-selective media. Isolates from anthers were screened for their ability to utilize the anther compound, choline, using HPLC and liquid culture techniques. Choline stimulates early germ-tube growth of G. zeae, and microbial isolates that utilized the compound were considered likely to be effective competitors of G. zeae. Choline-utilizers and an additional 170 randomly selected strains were used in replicated greenhouse tests where wheat heads were co-inoculated with conidia of G. zeae and antagonist tcells. Five antagonists, including three choline-utilizing strains, reduced disease as indicated by increased 100 kernel weights of microbially treated wheat heads (P=0.05). Bacterial strain AS 43.4 and yeast strain OH 182.9 reduced disease severity by 93% and 57%, respectively. In separately conducted greenhouse experiments, 4 strains reduced disease severity 10 and 16 days after inoculation and disease incidence was reduced by 5 and 3 strains, respectively (P=0.05). Strain AS 43.4 reduced disease severity by 85% and 25% after 10 and 16 days, respectively, compared to the G. zeae control. Effective antagonists were field tested in Illinois in the spring of 1998 and three isolates, including OH 182.9, reduced wheat scab disease severity by an average of 35%. Biological control shows great promise as part of an IPM program for managing FHB.