Round-leaved Mallow (Malva pusilla) Growth and Interference in Spring Wheat (Triticum aestivum) and Flax (Linum usitatissimum)

• Published in: Weed science Vol. 40; no. 3; pp. 448 - 454
• Main Authors: Friesen, Lyle F., Nickel, Kenneth P., Morrison, Ian N.
• Format: Journal Article
• Language: English
• Published: Cambridge, UK Cambridge University Press 01-07-1992; Weed Science Society of America
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; COMPETENCIA BIOLOGICA; COMPETITION BIOLOGIQUE; CRECIMIENTO; CROISSANCE; Crop density; DENSIDAD; DENSITE; Dry matter accumulation; Energy crops; Flowers; Food crops; Fruits; Fundamental and applied biological sciences. Psychology; Generalities, botany, ecology, damages, economic importance; LINUM USITATISSIMUM; MALEZAS; MALVACEAE; MANITOBA; MAUVAISE HERBE; MODELE; MODELE MATHEMATIQUE; MODELOS; MODELOS MATEMATICOS; Parasitic plants. Weeds; PERDIDAS; PERTE; Phytopathology. Animal pests. Plant and forest protection; Plant growth; Plants; RENDEMENT; RENDEMENT DES CULTURES; RENDIMIENTO; RENDIMIENTO DE CULTIVOS; TRITICUM AESTIVUM; Vegetation canopies; Weed Biology and Ecology; Weeds; Wheat; flax, Linum usitatissimum L. ‘Norlin’; Round-leaved mallow interference; spring wheat, Triticum aestivum L. ‘Katepwa’; mallow growth; MALPU; logistic function; Round-leaved mallow, Malva pusilla Sm. # MALPU; Competition; Monocotyledones; Photosynthetically active radiation; Weed; Growth habit; Cereal crop; Linum usitatissimum; Linaceae; Gramineae; Dicotyledones; Angiospermae; Spermatophyta; Interception; Yield; Population density; Triticum aestivum; Logistics
• ISSN: 0043-1745; 1550-2759
• DOI: 10.1017/S0043174500051894

Round-leaved mallow interference in spring wheat and flax was investigated under field conditions in southern Manitoba. Additionally, the growth of mallow alone and in a wheat crop was compared. In six of seven trials, wheat yield losses due to mallow interference were not significant. In a seventh trial, where mallow densities of up to 237 plants m−2 were recorded, wheat yields were reduced up to 15%. In contrast, significant flax yield losses occurred in each of three trials where maximum mallow densities ranged from 21 to 52 plants m−2. From the regression equations it was calculated that 20 mallow plants m−2 caused flax yield losses of 33, 9, and 10% in 1987, 1988, and 1989, respectively. Periodic sampling of mallow plants growing alone and in wheat, and regression analysis of these data using a logistic function as a biological model of plant growth indicated that mallow growth was severely suppressed by wheat By the eighth week after emergence, the lamina area and shoot dry matter of mallow plants growing in wheat was less than 3% of plants growing alone. Similarly, in wheat, mallow produced less than 1% of the seed produced by plants growing alone. This extreme suppression of mallow growth corresponded with an 80 to 90% decrease in photosynthetically active radiation penetrating the wheat canopy for approximately six continuous weeks, beginning 4 wk after crop emergence.