Detection of high concentrations of organic acids in fish emulsion and their role in pathogen or disease suppression.

Fish emulsion (FE) added to a sandy-loam soil at 1 and 2% rates reduced the viability of Verticillium dahliae microsclerotia by 39 and 74% in 1 day, 87 and 98% in 3 days, and 95 and 99% in 6 days, respectively. The immediate kill of microsclerotia indicated that FE contains toxic substances. We found in FE high concentrations (400 mmol/liter) of organic acids, including some known toxicants.

Systemic Induction of Peroxidases, 1,3-beta-Glucanases, Chitinases, and Resistance in Bean Plants by Binucleate Rhizoctonia Species.

ABSTRACT Inoculation of bean hypocotyls with a nonpathogenic binucleate Rhizoctonia (BNR) species induced systemic resistance and protection of the roots and cotyledons to later challenge with the root rot pathogen Rhizoctonia solani or the anthracnose pathogen Colletotrichum lindemuthianum. Bean seedlings that were treated with BNR 48 h prior to their challenge with R. solani or C.

Metallothionein and bZIP Transcription Factor Genes from Velvetleaf and Their Differential Expression Following Colletotrichum coccodes Infection.

ABSTRACT Colletotrichum coccodes is a biocontrol agent of velvetleaf (Abutilon theophrasti), a noxious weed of corn and soybean. Metallothioneins (MTs) and basic region/leucine zipper motif (bZIP) are heavy-metal-binding proteins and transcription factors, respectively, that have been related to several plant processes, including the responses of plants to pathogen attack. Previous investigation of the determinants involved in the velvet-leaf-C.

Nonpathogenic Binucleate Rhizoctonia spp. and Benzothiadiazole Protect Cotton Seedlings Against Rhizoctonia Damping-Off and Alternaria Leaf Spot in Cotton.

ABSTRACT Recent reports have shown induction of resistance to Rhizoctonia root rot using nonpathogenic strains of binucleate Rhizoctonia spp. (np-BNR). This study evaluates the biocontrol ability of several np-BNR isolates against root and foliar diseases of cotton in greenhouse trials, provides evidence for induced systemic resistance (ISR) as a mechanism in this biocontrol, and compares the disease control provided by np-BNR with that provided by the chemical inducer benzothiadiazole (BTH).

Quantification of Fusarium solani f. sp. phaseoli in Mycorrhizal Bean Plants and Surrounding Mycorrhizosphere Soil Using Real-Time Polymerase Chain Reaction and Direct Isolations on Selective Media.

ABSTRACT The capacity of the arbuscular mycorrhizal fungus Glomus intraradices in reducing the presence of Fusarium solani f. sp. phaseoli in bean plants and the surrounding mycorrhizosphere soil was evaluated in a compartmentalized experimental system.