Six biotypes of Dactylopius tomentosus (Lamarck) (Hemiptera: Dactylopiidae) have been imported into Australia as biological control agents to combat the eight naturalised invasive Cylindropuntia species. Each D. tomentosus biotype tested exhibited significant differences in host specificity, host preference and performance across the Cylindropuntia species. Biocontrol success is dependent on th...

Evaluation of Genetic Variation and Simultaneous Selection for Seed Forage Yield in Selected Genotypes Dactylis glomerata Bromus inermis

Generalist plant pathogens may have wide host ranges, but many exhibit varying degrees of host specialization, with multiple pathogen races that have narrower host ranges. These races are often genetically distinct, with each race causing highest disease incidence on its host of origin. We examined host specialization in the seed pathogen Pyrenophora semeniperda by reciprocally inoculating path...

Bradley N. Johnson Tami L. Stubbs Land Management and Water Conservation Research Unit, USDA Agricultural Research Service, 215 Johnson Hall, Washington State University, Pullman, WA, 99164-6421 Pseudomonas fluorescens strain D7 (P. f. D7; NRRL B-18293) is a root-colonizing bacterium that inhibits downy brome (Bromus tectorum L. BROTE) growth. Before commercialization as a biological control ag...