Louisiana State University Department of Agronomy and Environmental Management. Rescue Treatments in Roundup Ready Soybeans

Transcription

1 Louisiana State University Department of Agronomy and Environmental Management Experiment number...: 03SB05JG Location...: Ben Hur Research Farm Baton Rouge, LA Experimental design...: Randomized complete block Number of reps...: 4 Plot size...: 10 x 25 Row width/# per plot...: 15 /7 Soil type...: clay loam %OM...: 1.9 ph...: 6.3 Planting date...: Harvest date...: N/A Crop/Variety...: Soybean/Asgrow AG5902 Uniform std. treatment...: N/A Application type...: POST1 POST2 Date applied (mm/dd/yy)...: Time (hh:mm-hh:mm)...: 01:30-02:30p 02:30-03:00p Incorporation equipment...: N/A N/A Incorporation depth...: N/A N/A Air/Soil temperature (F)...: 89/93 92/90 Wind (mph, direction)...: 5-7/WSW 2-4/WSW Cloud cover (%)...: Relative humidity (%)...: Soil/Leaf surface moist...: moist/dry dry/dry Crop stage/height...: V2-3/7-10 V4-6 /18-20 Sprayer type/mph...: trctrca/3.75 trctrca/3.75 Nozzle type/size...: FF/11003VS FF/11003VS Boom ht/#noz/spacing(in)...: 18 /4/20 18 /4/20 GPA/psi...: 15/26 15/26 Applied by...: Etheredge Jones Weed species (population/ft 2 ).: (height/# leaves) ECHCG (20)...: 7-12 / IPOLA (0.5)...: 5-10 runners 6-12 runners IPOHE (0.5)...: 5-10 runners 6-12 runners SEBEX (1)...: 2-8 / Rainfall (in.) 0-24 hr/1-3 days / / days/2nd week...: 0.61/ /0.03 3rd week/4th week...: 0.03/ /3.45 1

2 Project Code: 03SB05JG This research was conducted to evaluate weed control in situations when herbicide application is delayed and weeds are large and more difficult to control. In this study the initial herbicide application was made when barnyardgrass was 7 to 12 inches tall and when morningglory had runners 5 to 10 inches long and hemp sesbania was as tall as 8 inches. In a situation like this it would be necessary in a Roundup Ready program to plan for two applications of Roundup with a broadleaf herbicide added at the second application. In conventional soybeans (non Roundup Ready) the grower could choose to apply a graminicide as the first application to control grasses followed by a broadleaf herbicide as the second application. In this study sequential applications of 0.73, 1.09, 1.45, 1.82, and 2.18 pts/a of Roundup WeatherMAX were made as well as Roundup WeatherMAX at 1.09 pts/a followed by Cobra, Reflex, Classic, or Ultra Blazer. For comparison Select was applied initially followed by Cobra, Reflex, Classic, or Ultra Blazer. Eight days following the initial herbicide application maximum barnyardgrass control was obtained with the two highest rates of Roundup WeatherMAX (around 78%). Morningglory and hemp sesbania control was no more than 53% for any of the herbicide treatments 8 days after treatment. Eleven days after the second application (19 days after the initial application) barnyardgrass control was 75 to 86% for treatments that included Roundup WeatherMAX, but was 61 to 69% for the Select treatments. Morningglory control ranged from 59 to 79% and hemp sesbania from 55 to 75% control. In this study where barnyardgrass was the predominant weed problem the Roundup program was superior to that of the Select program. It should be noted, however, that weed control in this rescue situation was not acceptable regardless of the herbicide program used and that the lack of weed control would be expected to result in significant yield losses. 2

3 ECHCG IPOSS control control Trt Treatment Form Form Rate Other Other Growth Appl No. Name Conc Type Rate Unit Rate Rate Unit Stage Code 8 DA-A 8 DA-A 1 Roundup WeatherMAX 5.5 L 0.5 lb ai/a 0.73 pt/a POST1 A 61 cd 45 bcd Roundup WeatherMAX 5.5 L 0.5 lb ai/a 0.73 pt/a POST2 B 2 Roundup WeatherMAX 5.5 L 0.75 lb ai/a 1.09 pt/a POST1 A 71 ab 48 abc Roundup WeatherMAX 5.5 L 0.75 lb ai/a 1.09 pt/a POST2 B 3 Roundup WeatherMAX 5.5 L 1.0 lb ai/a 1.45 pt/a POST1 A 74 a 48 abc Roundup WeatherMAX 5.5 L 1.0 lb ai/a 1.45 pt/a POST2 B 4 Roundup WeatherMAX 5.5 L 1.25 lb ai/a 1.82 pt/a POST1 A 78 a 53 a Roundup WeatherMAX 5.5 L 1.25 lb ai/a 1.82 pt/a POST2 B 5 Roundup WeatherMAX 5.5 L 1.50 lb ai/a 2.18 pt/a POST1 A 79 a 50 ab Roundup WeatherMAX 5.5 L 1.50 lb ai/a 2.18 pt/a POST2 B 6 Select 2.0 EC lb ai/a 6.0 oz/a POST1 A 53 de 0 e 7 Select 2.0 EC lb ai/a 6.0 oz/a POST1 A 54 de 0 e 8 Select 2.0 EC lb ai/a 6.0 oz/a POST1 A 50 e 0 e 9 Select 2.0 EC lb ai/a 6.0 oz/a POST1 A 53 de 0 e 10 Roundup WeatherMAX 5.5 L 0.75 lb ai/a 1.09 pt/a POST1 A 64 bc 40 d 3

4 ECHCG IPOSS control control Trt Treatment Form Form Rate Other Other Growth Appl No. Name Conc Type Rate Unit Rate Rate Unit Stage Code 8 DA-A 8 DA-A 11 Roundup WeatherMAX 5.5 L 0.75 lb ai/a 1.09 pt/a POST1 A 71 ab 44 cd 12 Roundup WeatherMAX 5.5 L 0.75 lb ai/a 1.09 pt/a POST1 A 71 ab 40 d 13 Roundup WeatherMAX 5.5 L 0.75 lb ai/a 1.09 pt/a POST1 A 73 ab 46 bc 14 Nontreated 0 f 0 e LSD (P=.05) Standard Deviation CV Replicate F Replicate Prob(F) Treatment F Treatment Prob(F)

5 SEBEX Soybean control injury Trt Treatment Form Form Rate Other Other Growth Appl No. Name Conc Type Rate Unit Rate Rate Unit Stage Code 8 DA-A 8 DA-A 1 Roundup WeatherMAX 5.5 L 0.5 lb ai/a 0.73 pt/a POST1 A 40 b 0 a Roundup WeatherMAX 5.5 L 0.5 lb ai/a 0.73 pt/a POST2 B 2 Roundup WeatherMAX 5.5 L 0.75 lb ai/a 1.09 pt/a POST1 A 41 b 0 a Roundup WeatherMAX 5.5 L 0.75 lb ai/a 1.09 pt/a POST2 B 3 Roundup WeatherMAX 5.5 L 1.0 lb ai/a 1.45 pt/a POST1 A 45 ab 0 a Roundup WeatherMAX 5.5 L 1.0 lb ai/a 1.45 pt/a POST2 B 4 Roundup WeatherMAX 5.5 L 1.25 lb ai/a 1.82 pt/a POST1 A 49 a 0 a Roundup WeatherMAX 5.5 L 1.25 lb ai/a 1.82 pt/a POST2 B 5 Roundup WeatherMAX 5.5 L 1.50 lb ai/a 2.18 pt/a POST1 A 49 a 0 a Roundup WeatherMAX 5.5 L 1.50 lb ai/a 2.18 pt/a POST2 B 6 Select 2.0 EC lb ai/a 6.0 oz/a POST1 A 0 c 0 a 7 Select 2.0 EC lb ai/a 6.0 oz/a POST1 A 0 c 0 a 8 Select 2.0 EC lb ai/a 6.0 oz/a POST1 A 0 c 0 a 9 Select 2.0 EC lb ai/a 6.0 oz/a POST1 A 0 c 0 a 10 Roundup WeatherMAX 5.5 L 0.75 lb ai/a 1.09 pt/a POST1 A 40 b 0 a 5

6 SEBEX Soybean control injury Trt Treatment Form Form Rate Other Other Growth Appl No. Name Conc Type Rate Unit Rate Rate Unit Stage Code 8 DA-A 8 DA-A 11 Roundup WeatherMAX 5.5 L 0.75 lb ai/a 1.09 pt/a POST1 A 44 ab 0 a 12 Roundup WeatherMAX 5.5 L 0.75 lb ai/a 1.09 pt/a POST1 A 43 b 0 a 13 Roundup WeatherMAX 5.5 L 0.75 lb ai/a 1.09 pt/a POST1 A 44 ab 0 a 14 Nontreated 0 c 0 a LSD (P=.05) Standard Deviation CV Replicate F Replicate Prob(F) Treatment F Treatment Prob(F)

7 ECHCG IPOSS control control Trt Treatment Form Form Rate Other Other Growth Appl No. Name Conc Type Rate Unit Rate Rate Unit Stage Code 11 DA-B 11 DA-B 1 Roundup WeatherMAX 5.5 L 0.5 lb ai/a 0.73 pt/a POST1 A 75 cd 65 de Roundup WeatherMAX 5.5 L 0.5 lb ai/a 0.73 pt/a POST2 B 2 Roundup WeatherMAX 5.5 L 0.75 lb ai/a 1.09 pt/a POST1 A 78 bc 68 cde Roundup WeatherMAX 5.5 L 0.75 lb ai/a 1.09 pt/a POST2 B 3 Roundup WeatherMAX 5.5 L 1.0 lb ai/a 1.45 pt/a POST1 A 86 a 78 ab Roundup WeatherMAX 5.5 L 1.0 lb ai/a 1.45 pt/a POST2 B 4 Roundup WeatherMAX 5.5 L 1.25 lb ai/a 1.82 pt/a POST1 A 85 ab 79 a Roundup WeatherMAX 5.5 L 1.25 lb ai/a 1.82 pt/a POST2 B 5 Roundup WeatherMAX 5.5 L 1.50 lb ai/a 2.18 pt/a POST1 A 83 abc 76 abc Roundup WeatherMAX 5.5 L 1.50 lb ai/a 2.18 pt/a POST2 B 6 Select 2.0 EC lb ai/a 6.0 oz/a POST1 A 69 de 69 bcd 7 Select 2.0 EC lb ai/a 6.0 oz/a POST1 A 65 e 59 e 8 Select 2.0 EC lb ai/a 6.0 oz/a POST1 A 61 e 66 de 9 Select 2.0 EC lb ai/a 6.0 oz/a POST1 A 65 e 73 a-d 10 Roundup WeatherMAX 5.5 L 0.75 lb ai/a 1.09 pt/a POST1 A 78 bc 74 a-d 7

8 ECHCG IPOSS control control Trt Treatment Form Form Rate Other Other Growth Appl No. Name Conc Type Rate Unit Rate Rate Unit Stage Code 11 DA-B 11 DA-B 11 Roundup WeatherMAX 5.5 L 0.75 lb ai/a 1.09 pt/a POST1 A 80 abc 73 a-d 12 Roundup WeatherMAX 5.5 L 0.75 lb ai/a 1.09 pt/a POST1 A 80 abc 69 bcd 13 Roundup WeatherMAX 5.5 L 0.75 lb ai/a 1.09 pt/a POST1 A 79 abc 78 ab 14 Nontreated 0 f 0 f LSD (P=.05) Standard Deviation CV Replicate F Replicate Prob(F) Treatment F Treatment Prob(F)

9 SEBEX Soybean control injury Trt Treatment Form Form Rate Other Other Growth Appl No. Name Conc Type Rate Unit Rate Rate Unit Stage Code 11 DA-B 11 DA-B 1 Roundup WeatherMAX 5.5 L 0.5 lb ai/a 0.73 pt/a POST1 A 61 bc 0 c Roundup WeatherMAX 5.5 L 0.5 lb ai/a 0.73 pt/a POST2 B 2 Roundup WeatherMAX 5.5 L 0.75 lb ai/a 1.09 pt/a POST1 A 69 ab 0 c Roundup WeatherMAX 5.5 L 0.75 lb ai/a 1.09 pt/a POST2 B 3 Roundup WeatherMAX 5.5 L 1.0 lb ai/a 1.45 pt/a POST1 A 75 a 0 c Roundup WeatherMAX 5.5 L 1.0 lb ai/a 1.45 pt/a POST2 B 4 Roundup WeatherMAX 5.5 L 1.25 lb ai/a 1.82 pt/a POST1 A 73 a 0 c Roundup WeatherMAX 5.5 L 1.25 lb ai/a 1.82 pt/a POST2 B 5 Roundup WeatherMAX 5.5 L 1.50 lb ai/a 2.18 pt/a POST1 A 73 a 0 c Roundup WeatherMAX 5.5 L 1.50 lb ai/a 2.18 pt/a POST2 B 6 Select 2.0 EC lb ai/a 6.0 oz/a POST1 A 60 bc 6 b 7 Select 2.0 EC lb ai/a 6.0 oz/a POST1 A 55 c 0 c 8 Select 2.0 EC lb ai/a 6.0 oz/a POST1 A 58 c 0 c 9 Select 2.0 EC lb ai/a 6.0 oz/a POST1 A 61 bc 4 b 10 Roundup WeatherMAX 5.5 L 0.75 lb ai/a 1.09 pt/a POST1 A 71 a 13 a 9

10 SEBEX Soybean control injury Trt Treatment Form Form Rate Other Other Growth Appl No. Name Conc Type Rate Unit Rate Rate Unit Stage Code 11 DA-B 11 DA-B 11 Roundup WeatherMAX 5.5 L 0.75 lb ai/a 1.09 pt/a POST1 A 68 ab 0 c 12 Roundup WeatherMAX 5.5 L 0.75 lb ai/a 1.09 pt/a POST1 A 69 ab 0 c 13 Roundup WeatherMAX 5.5 L 0.75 lb ai/a 1.09 pt/a POST1 A 73 a 5 b 14 Nontreated 0 d 0 c LSD (P=.05) Standard Deviation CV Replicate F Replicate Prob(F) Treatment F Treatment Prob(F)