Derek M. Scroggs1, A. M. Stewart1, D. K. Miller2, B. R. Leonard2, James L. Griffin2, and David C. Blouin3. (1) LSU AgCenter, Dean Lee Research Station, 8105 Tom Bowman Dr., Alexandria, LA 71302, (2) LSU AgCenter, 8105 Tom Bowman Dr., Alexandria, LA 71302, (3) LSU AgCenter, Department of Experimental Statistics, Baton Rouge, Baton Rouge, LA 70803
This study was initiated at the Dean Lee Research Station, Alexandria, LA, in the fall of 2006 and continued through the spring of 2007. Three separate runs of the experiment were conducted. Cotton was sowed and grown in trade gallon nursery containers, three seed per pot, in a greenhouse. Soil type in each pot consisted of a fifty percent mixture of potting soil plus a fifty percent mixture of a sandy loam soil. Experimental design was Completely Randomized with 4 pots per treatment. Plants were grown under a solar light for twelve hours a day with daytime temperature at 80 degrees and nighttime temperature at 70 degrees. Plants were watered with an automatic misting system for 5 minutes once a day. Treatments consisted of a factorial arrangement of two pesticide applications (Factor A: 1= Roundup Weathermax alone or 2= Roundup Weathermax + Dimethoate) and six clean-out solutions (Factor B: 1= Water, 2= Ammonia @ 1% solution, 3= Bleach @ 1% solution, 4= Nitrogen @ 100% solution, 5= Wipe-out @ 1% solution, or 6= None). Two foot sections of sprayer hose (1 for each treatment) were allowed to soak for two weeks in a solution of 2, 4-D (ester formulation). After drying, sprayer hose was attached to a backpack sprayer and subjected to a clean-out procedure. When clean-out was complete, either Roundup Weathermax alone or Roundup Weathermax + Dimethoate were applied to cotton plants. Cotton plants were rated for 2, 4-D injury at 5, 11, and 14 days after treatment (DAT) and were assigned an indicator variable 0= no injury or 1= injury. Data were subjected to ANOVA using SAS PROC MIXED and means were separated using Tukey’s at the 0.05 level of significance.
