Temperature influencesKyllinga brevifoliaandK. squamulatagrowth

Abstract

Kyllingaspecies are becoming more common throughout the southeastern United States. Two species,Kyllinga brevifoliaandKyllinga squamulata, in particular are prevalent weeds in turfgrass. To better understand these weeds, growth chamber studies determined the growth ofK. brevifolia, K. squamulata, andCynodon dactylon×Cynodon transvaalensisas influenced by three temperature regimes (33/24, 25/17, 19/11 C day/night, respectively). Temperature influenced almost all aspects ofKyllingaspecies growth. Plant height of bothKyllingaspecies increased nearly twofold after 8 wk at high temperatures. Plants were mowed each week to 2.5 cm; both species produced more than twice as many clippings by 8 wk at high (33/24 C) temperatures than at low (19/11 C) temperatures. Destructive analysis at 8 wk revealed thatK. brevifoliashoot and root weight increased with decreasing temperature, whereasK. squamulatashoot and root weights were not affected by temperature. Shoot weight percentage for bothKyllingaspecies increased from 59% in medium temperatures to 69% in high temperatures.K. brevifoliashoot weight percentage decreased to 53% in low temperatures, whereasK. squamulatashoot weight percentage increased to 72%.K. brevifoliainflorescences formed at 2, 3, and 5 wk in high, medium, and low temperatures, respectively, whereasK. squamulataflowered immediately in all temperatures.C. dactylon×C. transvaalensisandKyllingaspecies growth were similar within each temperature regime throughout the 8-wk study.