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  • Author or Editor: R.K. Nishimoto x
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Abstract

Diclofop (2-(4-(2,4-dichlorophenoxy)phenoxy)propanoic acid) caused little to no injury to common bermudagrass [Cynodon dactylon (L.) Pers.] mowed twice weekly at 1.6-2.0 cm at rates of 0.56,1.12, 2.24, and 4.48 kg/ha or to ‘Tifdwarf’ bermadagrass Cyndon dactylon × C. transvaalensis Burtt-Davey, mowed daily at 0.5 cm at rates of 0.56, 1.12, and 2.24 kg/ha. Diclofop at 0.56, 1.12, and 2.24 kg/ha gave good control of mature goosegrass [Eleusine indica (L.) Gaertn.] in ‘TifdwarP turf mowed daily at 0.5 cm, but resulted in inadequate control at 4.48 kg/ha in common bermudagrass turf mowed twice weekly at 1.6 or 2.0 cm.

Open Access

Abstract

Water was applied to watercress (Nasturtium officinale R. Br.) by overhead sprinkling for various day periods during the warm-season (summer) and cool-season (winter) to determine its effect on leaf temperature and yield. Intermittent overhead sprinkling throughout the day increased watercress yield and quality during the warm-season, but not the cool-season. Sprinkling reduced leaf temperature by as much as 4.8°C during the warm-season and by only 1.1°C during the cool-season. The increased yield and quality was attributed to substantially reduced leaf temperature during the warm season.

Open Access

Abstract

Root exudates of guava (Psidium Guajava L. cv. Beaumont) grown in sand culture were collected on columns of XAD-4 resin attached to the nutrient solution circulation system of sand-cultured plants. The compounds were eluted from the resin columns with methanol and the eluates were concentrated. The root exudates were inhibitory to the radicle growth of both lettuce (Lactuca sativa L. cv. Anuenue) and bristly foxtail (Setaria verticillata L. Beauvois) and lettuce seed germination was inhibited. Fractionating the root exudates resulted in the neutral and acidic fractions being inhibitory, the basic fraction having no effect. Methanolic extracts of oven-dried guava roots were also inhibitory.

Open Access
Authors: , , and

Cyperus kyllingia and Cyperus brevifolius are problematic turfgrass weeds in Hawaii. Both are closely related weed species with similar morphology and growth characteristics. C. kyllingia appears to be a more successful weed with regards to interference than C. brevifolius. Greenhouse experiments were conducted to compare the levels of interference exerted by C. kyllingia and C. brevifolius upon Cynodon dactylon turfgrass. C. kyllingia reduced the growth of C. dactylon by about 50 %, while C. brevifolius did not significantly reduce C. dactylon growth. These results correspond with the chemical profiles of C. kyllingia and C. brevifolius. Analysis has shown that C. kyllingia contains two sesquiterpenes which have been identified as potentially allelopathic components of Cyperus rotundus. C. brevifolius contains waxes and the two sesquiterpenes found in C. kyllingia are absent. This suggests that allelopathy may be the mechanism responsible for the different levels of interference exhibited by C. kyllingia and C. brevifolius, and these species may provide an important model for the study of allelopathy.

Free access