title: Feasible Management of Southern Corn Leaf Blight via Induction of Systemic Resistance byBacillus cereusC1L in Combination with Reduced Use of Dithiocarbamate Fungicides.
abstract: Dithiocarbamate fungicides such as maneb and mancozeb are widely used nonsystemic protectant fungicides to control various plant fungal diseases. Dithiocarbamate fungicides should be frequently applied to achieve optimal efficacy of disease control and avoid either decline in effectiveness or wash-off from leaf surface. Dithiocarbamates are of low resistance risk but have the potential to cause human neurological diseases. The objective of this study was to develop a strategy to effectively control plant disease with reduced use of dithiocarbamtes. Southern corn leaf blight was the model pathosystem for the investigation. When corn plants were drench-treated withBacillus cereusC1L, a rhizobacterium able to induce systemic resistance in corn plants against southern leaf blight, frequency of spraying dithiocarbamate fungicides could be decreased. The treatment ofB. cereusC1L was able to protect maize from southern leaf blight while residues of dithiocarbamates on leaf surface were too low to provide sufficient protection. On the other hand, frequent sprays of mancozeb slightly but significantly reduced growth of corn plants under natural conditions. In contrast, application ofB. cereusC1L can significantly promote growth of corn plants whether sprayed with mancozeb or not. Our results provide the information that plant disease can be well controlled by rhizobacteria-mediated induced systemic resistance in combination with reduced but appropriate application of dithiocarbamate fungicides just before a heavy infection period. An appropriate use of rhizobacteria can enhance plant growth and help plants overcome negative effects caused by dithiocarbamates.
authors.affiliation: Department of Plant Medicine, National Chiayi University, Chiayi 60004, Taiwan, Republic of China.
authors.forename: Yi-Ru
authors.initials: YR
authors.lastname: Lai
authors.affiliation: Department of Plant Medicine, National Chiayi University, Chiayi 60004, Taiwan, Republic of China.
authors.forename: Pei-Yu
authors.initials: PY
authors.lastname: Lin
authors.affiliation: Department of Plant Pathology and Microbiology, National Taiwan University, Taipei 10617, Taiwan, Republic of China.
authors.forename: Chao-Ying
authors.initials: CY
authors.lastname: Chen
authors.affiliation: Department of Plant Medicine, National Chiayi University, Chiayi 60004, Taiwan, Republic of China.
authors.forename: Chien-Jui
authors.initials: CJ
authors.lastname: Huang
keywords: Bacillus cereus; Cochliobolus heterostrophus; dithiocarbamate; induced systemic resistance