VIEW ARTICLE

Cytology and Histology

Development of Galls Induced in Lolium rigidum by Anguina agrostis. Brian A. Stynes, Commonwealth Scientific and Industrial Research Organization, Institute of Biological Resources, Division of Horticultural Research, Adelaide, South Australia, 5001, Present address: Plant Pathology Branch, Department of Agriculture, South Perth, Western Australia, 6151; Alan F. Bird, Commonwealth Scientific and Industrial Research Organization, Institute of Biological Resources, Division of Horticultural Research, Adelaide, South Australia, 5001. Phytopathology 72:336-346. Accepted for publication 8 June 1981. Copyright 1982 The American Phytopathological Society. DOI: 10.1094/Phyto-72-336.

The growth and development of galls induced by Anguina agrostis were observed in the inflorescences of annual ryegrass (Lolium rigidum) plants harvested at weekly intervals from inoculated field plots. Infective dauer larvae of A. agrostis colonized plants during their vegetative growth phase, and gall induction had occurred by the time floret development was readily discernible within developing spikelets. Galls typically developed in place of ovules, less commonly in place of stamens, and rarely on glumes or rachis. The galls, which grew rapidly as nematodes developed, consisted of a wall several cell layers deep surrounding a central cavity. Cells adjacent to the cavity were modified, presumably to provide metabolites for development and reproduction of the nematodes, which completed a single generation before plant senescence occurred and the galls dried out. Cells at the surface were unchanged, thus maintaining the structure of the galls.