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• 1. [Article] The herbicide HOE 23408; soil persistence, spring wheat cultivar tolerance, and interaction with broadleaf herbicides

  HOE 23408 [ 4-(2' , 4'-dichlorophenoxy)-phenoxy-u-propionic methylester.1 is a promising new compound for control of wild oats and other grass weeds in small grains. Several factors influencing its use ...

  Citation × Citation Citation Abstract Copy Title: The herbicide HOE 23408; soil persistence, spring wheat cultivar tolerance, and interaction with broadleaf herbicides Author: Ivackovich, Branislav D. HOE 23408 [ 4-(2' , 4'-dichlorophenoxy)-phenoxy-u-propionic methylester.1 is a promising new compound for control of wild oats and other grass weeds in small grains. Several factors influencing its use for this purpose were investigated. Greenhouse bioassay studies were conducted in 1975 to determine relative persistence of HOE 23408 in four western Oregon soils following application in the fall and winter. -Wild oats (Avena fatua L.) were used as a test plant. Soil from each of three application timings at all four locations contained measurable amounts of herbicide. Generally, residue levels in soil treated at the same herbicide rate approximately 1, 2, and 4 months before sampling were similar. Possibly less herbicide reached the soil from postemergence treatments, compensating for the longer degradation time of the preemergence treatments. Variation in residue levels among locations occurred. This may be explained by differences in smoothness of seedbeds and amounts of plant residue at the various locations. A study was conducted to determine persistence of HOE 23408 applied to bare soil on April 29, 1975. Wild oats and corn (Zea mays L.) were used as bioassay plants. Evaluation of plants seeded into the plots at intervals showed a gradual reduction in levels of herbicide through the season. At 1 lb/A, neither species planted 9 weeks after application was injured, indicating that no significant carry-over can be expected from this rate applied in spring wheat. Two and 4 lb/A persisted longer, causing injury to test plants seeded 9 weeks after treatment. A field experiment was established to evaluate the effect of combining each of four commercially used broadleaf herbicides with 1 and 2 lb/A of HOE 23408 on control of wild oats and barnyardgrass (Echinochloa crus-galli (L.) Beauv. ) and on yield of Fielder spring wheat. The addition of bromoxynil improved the effect of HOE 23408 on wild oats but reduced its effectiveness on barnyardgrass. Addition of 2,4-D LV ester, MCPA LV ester, or dicamba amine reduced its activity on both wild oats and barnyardgrass. Delaying the application of 2,4-D for 3 or 7 days eliminated the antagonistic effect but a delay of only 1 day was not sufficient. No detrimental effect on yield was observed from any treatment. A tolerance study was conducted in three commercially used spring wheat cultivars (Waldron, Twin, and WS-1). Excellent tolerance to HOE 23408 was observed in all cultivars, even when the rate was increased from 1 lb/A (proposed use rate) to 4 lb/A. Title: The herbicide HOE 23408; soil persistence, spring wheat cultivar tolerance, and interaction with broadleaf herbicides Author: Ivackovich, Branislav D. HOE 23408 [ 4-(2' , 4'-dichlorophenoxy)-phenoxy-u-propionic methylester.1 is a promising new compound for control of wild oats and other grass weeds in small grains. Several factors influencing its use for this purpose were investigated. Greenhouse bioassay studies were conducted in 1975 to determine relative persistence of HOE 23408 in four western Oregon soils following application in the fall and winter. -Wild oats (Avena fatua L.) were used as a test plant. Soil from each of three application timings at all four locations contained measurable amounts of herbicide. Generally, residue levels in soil treated at the same herbicide rate approximately 1, 2, and 4 months before sampling were similar. Possibly less herbicide reached the soil from postemergence treatments, compensating for the longer degradation time of the preemergence treatments. Variation in residue levels among locations occurred. This may be explained by differences in smoothness of seedbeds and amounts of plant residue at the various locations. A study was conducted to determine persistence of HOE 23408 applied to bare soil on April 29, 1975. Wild oats and corn (Zea mays L.) were used as bioassay plants. Evaluation of plants seeded into the plots at intervals showed a gradual reduction in levels of herbicide through the season. At 1 lb/A, neither species planted 9 weeks after application was injured, indicating that no significant carry-over can be expected from this rate applied in spring wheat. Two and 4 lb/A persisted longer, causing injury to test plants seeded 9 weeks after treatment. A field experiment was established to evaluate the effect of combining each of four commercially used broadleaf herbicides with 1 and 2 lb/A of HOE 23408 on control of wild oats and barnyardgrass (Echinochloa crus-galli (L.) Beauv. ) and on yield of Fielder spring wheat. The addition of bromoxynil improved the effect of HOE 23408 on wild oats but reduced its effectiveness on barnyardgrass. Addition of 2,4-D LV ester, MCPA LV ester, or dicamba amine reduced its activity on both wild oats and barnyardgrass. Delaying the application of 2,4-D for 3 or 7 days eliminated the antagonistic effect but a delay of only 1 day was not sufficient. No detrimental effect on yield was observed from any treatment. A tolerance study was conducted in three commercially used spring wheat cultivars (Waldron, Twin, and WS-1). Excellent tolerance to HOE 23408 was observed in all cultivars, even when the rate was increased from 1 lb/A (proposed use rate) to 4 lb/A. Close