Submitted to: Weed Science Society of America Meeting Abstracts
Publication Type: Abstract only
Publication Acceptance Date: 2/4/2008
Publication Date: 2/10/2008
Citation: Williams, R.D., Bartholomew, P.W. 2008. Predation of italian ryegrass (Lolium multiflorum) seed [abstract]. Weed Science Society of America Meeting Abstracts, February 4-7, 2010, Chicago, IL. Abstract No. 72. Available on-line: http://wssa.net/meetings/wssaabstracts/abstractsearch.php Interpretive Summary: Abstract only.
Technical Abstract: Italian ryegrass (Lolium multiflorum Lam.) can be a productive and high-quality cool-season forage, but is considered a weed in some pastures. Italian ryegrass does not form a persistent seed bank and needs to produce sufficient seed annually for effective re-establishment. Before the re-seeding dynamics of Italian ryegrass can be modeled, an understanding of seed production, dispersal and predation are necessary. Here we examine insect predation of ryegrass seed over a 12-month period from May 2006 to June 2007. Seed cards (5 by 10 cm) were constructed from coarse sand paper, lightly sprayed with adhesive and 30 ryegrass seed set on their surface firmly enough to transport the seed cards to and from the field, but loose enough to allow insect removal of the seed. Forty cards were distributed randomly in a warm-season grass pasture that had been seeded to Italian ryegrass 3 yr earlier. The grass was maintained by frequent cutting to a height of approximately 10 cm. Cards were held in place on the soil surface with wire pegs and covered with wire mesh cages (to exclude rodents). Seed cards were collected weekly and replaced with fresh cards. Predators noticed in the field were mostly harvester ants, but other predators (eg. crickets) were also observed. Weekly mean seed predation ranged from 6 to 86 % over the 12-month period. Mean predation was greater in the winter months (53%) than in the summer (34%) or fall (26%). This information coupled with general seed survival data will provide a clearer understanding of the transient seed bank population.