US EPA

6980512 

Journal Article 

Long-term population development of Viola arvensis Murr. in a crop rotation. I. Field experiments 

Gerowitt, B; Bodendorfer, H; , 

1998 

1 

Zeitschrift fuer Pflanzenkrankheiten und Pflanzenschutz
ISSN: 0340-8159 

EUGEN ULMER GMBH CO 

STUTTGART 70 

105 

6 

641-654 

WOS:000078442000010 

Observations of the population of Viola arvensis Murr. (Field pansy) were carried out from 1981-96 in a long-term experiment (rotation beets- winter wheat - winter barley) with different weed control frequencies in the cereal crops. Data from two experiments in winter wheat on seed production influenced by nitrogen fertilization and on losses of produced fresh seeds were added.In barley, the development of seed-producing plants was more important for the population than in wheat. Under fertilized conditions, the seed bank and the actual infestations only rose if weed control was consequently omitted in barley. Herbicide treatments according to economic thresholds for all parts of the weed infestation never focused V. arvensis, bur the population development was efficiently restricted by secondary effects of the applied herbicides.Development and reproduction of individual plants of V. arvensis were supported by N-fertilization. However, reduced fertilization supported the entire population, since in the than less competitive barley, V. arvensis can achieve a higher effective reproduction. 

Viola arvensis; long-term development; seed bank; seed production; economic threshold