Submitted to: National Fusarium Head Blight Forum Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 10/27/1998
Publication Date: N/A
Technical Abstract: Gibberella zeae (Fusarium graminearum) is the primary causal agent of scab of wheat and causes extensive damage to wheat in humid and semihumid regions of the world. Damage includes reduced yields and poor grain quality. Disease control options are limited. Resistant varieties of wheat are not yet available. Fungicide residues and costs make chemical control options less attractive. To initiate the development of a biological control alternative to disease control, wheat anthers were collected throughout Illinois and Ohio and more than 700 microbial isolates obtained by plating anther washes on semi-selective and non-selective media. Putative antagonists from anthers were screened for their ability to utilize the anther compound, choline, using HPLC and liquid culture techniques. Approximately 40 of 700 strains utilized choline, and these anther colonists were selected for use in greenhouse tests, since choline-utilizing strains would have an increased chance of being effectiv competitors of F. graminearum. In greenhouse experiments, wheat heads were co-inoculated with conidia of F. graminearum and antagonist cells. Five antagonists reduced disease as indicated by increased 100 kernel weights of microbially treated wheat heads (P=0.05). Bacterial isolate AS 43.4 and yeast isolate OH 182.9 reduced disease severity by 93% and 57%, respectively. Effective antagonists were field tested in Illinois in the summer 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 controlling scab of wheat.