Alleviating the Antagonistic Effect of Moisture Stress on Smooth Crabgrass (Digitaria ischaemum) Control with Fenoxaprop

• Published in: Weed science 1994-07, Vol.42 (3), p.418-423
• Main Authors: Rossi, Frank S., Neal, Joseph C., Senesac, Andrew F.
• Format: Article
• Language: English
• Subjects: Acid soils; Agronomy. Soil science and plant productions; ALCOHOLES; ALCOHOLS; ALCOOL; APPLICATION RATES; Biological and medical sciences; Chemical control; CONTENIDO DE MATERIA SECA; DESHERBAGE; DIGITARIA; DOSE D'APPLICATION; DOSIS DE APLICACION; DROUGHT; DROUGHT STRESS; DRY MATTER CONTENT; DURACION; DURATION; DUREE; EFFICACY; ESCARDA; ESTRES DE SEQUIA; Fatty acids; FENOXAPROP; Fundamental and applied biological sciences. Psychology; HERBICIDAS; HERBICIDE; HERBICIDE MIXTURES; HERBICIDES; INTERACTIONS; IRRIGATION; Lysimeters; MATRIC POTENTIAL; Parasitic plants. Weeds; PENDIMETALINA; PENDIMETHALIN; PENDIMETHALINE; Phytopathology. Animal pests. Plant and forest protection; Plants; POLIETILENO; POLYETHYLENE; POLYETHYLENE GLYCOL; POTENCIAL HIDRICO DEL SUELO; POTENTIEL HYDRIQUE DU SOL; RIEGO; Sandy loam soils; SECHERESSE; SEQUIA; SINERGISMO; Soil water; SOIL WATER POTENTIAL; STRESS DU A LA SECHERESSE; SYNERGISM; SYNERGISME; TENEUR EN MATIERE SECHE; Turf grasses; WATER STRESS; WEED CONTROL; Weed Control and Herbicide Technology; Weeds
• ISSN: 0043-1745; 1550-2759
• DOI: 10.1017/S0043174500076712

The influence of moisture stress intensity and duration, as well as tank mixtures with pendimethalin, which mitigated the antagonistic effects of drought, on fenoxaprop efficacy were evaluated. In growth chamber tests, specific soil matric potential (Ψm) levels of −0.01 to −1 MPa were imposed and maintained using a polyethylene glycol semipermeable membrane system. Moisture stress was alleviated by irrigation 48 or 96 h after herbicide treatment. Fenoxaprop efficacy was influenced by moisture stress intensity, posttreatment stress duration, and application rate. Under conditions of mild stress (Ψ ≥ −0.2 MPa), both increased application rate and irrigation 48 h after treatment alleviated the effects of drought on fenoxaprop efficacy. Under moderate stress (Ψm = −4.4 MPa), the antagonistic effects of drought were alleviated by a combination of increased rate and irrigation 48 h after treatment However, under more severe stress (Ψm ≤ −0.8 MPa), irrigation coupled with increased rate did not increase crabgrass control above 50%. Where irrigation within 48 h of treatment is not feasible, tank mixes of fenoxaprop with pendimethalin were shown to enhance smooth crabgrass control. Field lysimeter tests indicated that under moisture stress, Ψm of −0.7 MPa, smooth crabgrass shoot dry weight was reduced 65 to 94% with tank-mix combinations of ≥ 0.27 kg ai ha−1 fenoxaprop plus ≥ 2.2 kg ai ha−1 pendimethalin. These rate combinations were shown to be synergistic and able to alleviate the antagonistic effect of moisture stress on fenoxaprop efficacy.