Field and greenhouse experiments were conducted to determine barnyardgrass control as affected by glufosinate and graminicide tank-mixtures, application timing of tank-mixtures of graminicides plus glufosinate and application time of day of tank-mixtures of glufosinate and clethodim. When increased rates of graminicide were tank-mixed with glufosinate, barnyardgrass control was unaffected by quizalofop-P plus glufosinate; however, clethodim plus glufosinate control in the field indicated the potential for reduced barnyardgrass control. When evaluating increasing glufosinate rates tank-mixed with graminicides, barnyardgrass control was not negatively affected by the combination of glufosinate and graminicides. The difference in soybean yield among the graminicides may indicate that the cyclohexanedione herbicides had a slight yield advantage over the aryloxyphenoxypropionate herbicides due to potential increased levels of barnyardgrass control. Applications of glufosinate alone provide variable control throughout the growing season in both field and greenhouse experiments. Although barnyardgrass control in the field was not affected by glufosinate application timing, data from the greenhouse indicates potential exists for reduced control if glufosinate is applied 1 or 3 d before graminicides. Clethodim was unaffected by application time of day; however, glufosinate applications at midnight reduced barnyardgrass control compared to applications made at noon and 6 P.M. Applications at 6 A.M. also reduced barnyardgrass efficacy compared to applications at 6 P.M. Environmental factors such as temperature and light at the time of application are likely responsible for the time of day effects observed in these studies. For maximum benefit from incorporating graminicides into a glufosinate weed control system, fluazifop-P, quizalofop-P, clethodim and sethoxydim should be applied with glufosinate at 594 or 890 g ai ha-1. Sequential treatments of glufosinate should be applied 7 d prior to a graminicide application or 1, 3 or 7 d after a graminicide application. To optimize barnyardgrass efficacy with tank mixtures of glufosinate and clethodim, applications should be made at noon or early evening to avoid potential time of day effects.

Field and greenhouse experiments were conducted to determine the effect of auxin injury on soybean and cotton due to spray hose material, formulation and cleanout procedures on auxin equipment cleanout. Visual estimations of injury (VEOI) in wheat, height reduction, and yield reduction due to rimsulfuron and glyphosate titration was higher when compared to rimsulfuron only treatments with respect to 1/2X through the 1/256X treatments. Sequestration of 2,4-D within agricultural hose types did differ due to hose type and is confirmed by analytical testing, but field observation of wheat did not show differences among treatments due to VEOI, height reduction or yield reduction. Using soybean as a bio-indicator, differences did occur with respect to dicamba sequestration in agricultural hose types with respect to VEOI, height reduction, node reduction, yield reduction and ppm analyte retained. Results indicate chemical makeup of hose type in determination of ppm analyte dicamba retained. Cleaning procedures of water or ammonia do not prove to be different with respect to VEOI, height reduction, yield reduction or ppm analyte retained. Sequestration of 2,4-D within valved manifold systems and using water or ammonia as cleanout procedures in conjunction with rinse procedures did not show differences with respect to VEOI, height reduction, nodes above cracked boll (NACB), yield reduction or ppm analyte retained. It was not until standard 2,4-D applications were applied in field experiments when differences were observed. Deactivation of dicamba and 2,4-D using the Fenton procedure within various rates, showed an interaction with respect to VEOI, height reduction, node reduction, yield reduction and ppm analyte. Using soybean as a bio-indicator showed differences with the Fenton procedure deactivating the dicamba analyte in the 1/16X, 1/64X and 1/256X rate with respect to VEOI, height reduction, node reduction, yield reduction and ppm analyte retained. Using cotton as a bio-indicator showed differences with the Fenton procedure deactivating the 2,4-D analyte in every rate with respect to VEOI, height reduction, yield reduction and ppm analyte.