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									       Strobiluron Fungicide Greening Effects on Soybeans in Alabama, 2006 and
                       2007: Application Timing and Desiccants
                                      Limestone Valley


                                    Black Belt Prairie

                                     D.P. Delaney1, E. J. Sikora 2, M.A. Delaney 2, K.S. Lawrence 2 , R. Dawkins3, R. Durbin3, and B. Norris3
                                                   Coastal Plain

                                       1Dept. of Agronomy & Soils, 2Dept. of Entomology & Plant Pathology, 3AL Ag Experiment Station

                                                                           Auburn University, Alabama

                                                                               Methods                                                                                           Results
                                                                               Strobiluron Effects: Three trials investigated strobiluron timing at                              The 2006 and 2007 growing seasons were extremely dry in                                                     TVS
                                                                                  different growth stages, with and without desiccants applied                                   most of AL. Strobiluron greening effects were much reduced in                                                         SMS
                                                                                  to increase harvest efficiency. Trials were conducted in north                                 2006 and 2007, compared to 2005. In 2006, only 1 of 3
Introduction                                                                      and central AL at the Tennessee Valley RREC (TVS), Sand                                        locations recorded greening differences between strobiluron
Use of strobiluron fungicides is relatively new to Alabama                        Mountain RREC (SMS), and the EV Smith Field Crops Unit                                         application timings. At TVS, leaf greening was significantly
producers; however up to 50% of the soybean acreage was                           (EVS). Headline® (pyraclostrobin) @ 6 fl. oz/A was applied                                     increased by strobiluron applications at R1, R3, and R1+R3
treated in 2005, due to the presence of Asian Soybean Rust                        at R1, R3, and/or R5 in factorial combinations with or without                                 compared to untreated plots and applications at R5 and R3+R5.
(ASR). Many of these fields experienced retention of green                        desiccation. Only the EVS location was irrigated, however,                                     Harvested grain yield not affected by fungicide application at
leaves long after pod maturity in 2005, but was highly variable.                  its effects were limited due to water availability and hot and                                 any location, but was increased by desiccation at all locations
Differences were observed according to cultivars, use of                          dry weather. A tank mix of Gramoxone Inteon® 2L                                                with an average of increase of 2.6 bu/A. Total moisture content
different active ingredients and rates, timing and weather.                       (paraquat) @ 1 pt/A plus sodium chlorate @ 3 lb a.i. /A was                                    was reduced from 16.3 to 12.7 % at TVS, while it was                                                                   EVS
Many soybean producers delayed harvest until frost or                             applied to half the plots at pod maturity. All treatments were                                 unaffected by fungicide or desiccation at other locations. Trash
weathering removed these leaves, leading to seed deterioration                    applied with flat fan nozzles in a volume of 18 - 20 gpa.                                      and seed weight was little affected by treatments, although
and shattering losses. Others combined through fields which                       Desiccated treatments were harvested 10 to 15 days after                                       small differences were noted at EVS for fungicide application
had large amounts of green leaves and stems, but at greatly                       treatment (DAT), while non-desiccated plots were harvested                                     timing on 100-seed weights.
reduced speeds and with increased fuel and machinery costs                        after natural leaf drop (10 to 21 days later). Grain yield and                                 In 2007, no significant differences were recorded between
and foreign material dockage. Desiccant materials may dry up                      harvest moisture data was recorded. Seed samples were                                          fungicide timing treatments for greening, yield or 100-seed
these green leaves and stems for more timely and efficient                        also analyzed for foreign matter content and seed weight.                                      weights. In contrast to 2006, Desiccation treatments increased
harvest, but have been little used in Alabama soybean                                                                                                                            yield at only one location in 2007, by 5.2 bu/A at EVS.
production. A series of experiments was conducted across the                   Desiccation materials: Three trials investigated the use of                                       Leaf greening effects were also reduced in the Desiccation
state in 2006 and 2007 to investigate the effects of timing of                   different harvest aid materials and combinations to alleviate                                   Materials trials, with the GCS location abandoned due to nearly
strobiluron fungicide applications on retention of green leaves                  leaf greening effects. Trials were conducted at SMS, EVS,                                       complete leaf shed before treatments. All treatments increased
and stems, and of harvest aid treatments to alleviate effects.                   and the Gulf Coast RREC (GCS). Test areas had three                                             leaf desiccation 4 and 10 days at EVS and at 10 DAT at SMS.
                                                                                 applications of Headline @ 6 to 9 fl oz./A at R1, R3, and R5                                    At SMS at 4 DAT, all treatments except Aim + crop oil increased
                                                                                 to attempt to trigger greening effects. At pod maturity, ten                                    leaf desiccation. Several treatments reduced total harvest                      Locations of Strobiluron Greening and Desiccant Trials, 2006 and 2007
                                                                                 harvest aid materials were applied with flat fan nozzles in a                                   moisture at EVS and SMS compared to the check. Treatments
                                                                                 volume of 18 - 20 gpa. Trials were rated at 4 and 7 DAT,                                        which included paraquat (Gramoxone Inteon, Firestorm®) or
                                                                                 and harvested at 10 to 15 DAT. Grain yield and harvest                                          sodium chlorate as active ingredients were most effective in
                                                                                 moisture data was recorded. Seed samples were also                                              reducing harvest moisture. Harvested grain yield was
                                                                                 analyzed for foreign matter content and seed weight.                                            significantly increased by three treatments at EVS, but not at
                                                                               Data was analysed at p=0.10
                                                                                                                                                                                 SMS. There was no significant difference in trash content or                    Conclusions
                                                                                                                                                                                 seed weights between any treatments.
                                                                                                                                                                                                                                                                  . In contrast to the 2005 growing season, very little effect of
                                                                                                                                                                                 In 2007, the GCS location was again abandoned due to
                                                                                                                                                                                                                                                                 strobiluron fungicides on extended leaf greening was noted in
                                                              Green leaves                            Strobiluron Fungicide Effects on                                           complete leaf shed. No significant yield, grain moisture, or seed
                                                                                                                                                                                                                                                                 2006 or 2007 in Alabama. At one location in 2006, increased
                                                              and stems                             Soybeans, EVS, SMS and TVS, 2006                                             weight differences were recorded at EVS or SMS in 2007.
                                                                                                                                                                                                                                                                 strobiluron greening effects were noted with early applications of
                                                              retained after                                                                                                                                                                                     fungicide (R1 to R3). At this location only, grain moisture
                                                                                                                                                  LSD (0.10) = 3.0
                                                              pod maturity                     40                      LSD (0.10) = 2.4
                                                                                                                                                                                                          Desiccation Materials for Soybeans,                    content was also reduced by desiccation.
                                                                                                                                                                     No                                               EVS 2006
                                                                                                                                                                     Desiccant                       10
                                                                                                                                                                                                                                        Untreated Check             Several desiccant materials and combinations increased leaf
                                                                                               25                                                                                                     9
                                                                                                                                                                                                                                        Inteon +NIS, 1/8 lb

                                                                                                                                                                                                                                        Inteon +NIS, 1/4 lb =
                                                                                                                                                                                                                                                                 desiccation and decreased harvest moisture compared to check
                                                                                      b u /A

                                                                                                     LSD(0.10) = 2.1
                                                                                                                                                                                                                                        (1 pt)
                                                                                                                                                                                                                                        Inteon +NIS, 1/2 lb      treatments, and yield was also increased at one location.
                                                                                                                                                                                          10 = dry

                                                                                               15                                                                                                     5
                                                                                                                                                                                                                                        Inteon +NIS, 1/4 lb +

                                                                                                                                                                                                                                        Sod Chl 3 lb
                                                                                                                                                                                                                                        Sodium Chlorate 6 lb       In all trials, trash content and seed weights were little affected
                                                                                                                                                                     Desiccant                        3                                 Firestorm +NIS, 1/4 lb   by strobiluron fungicide applications or desiccant treatments.
                                                                                               5                                                                                                      2                                 Aim @ 1.4 fl oz + COC
                                                                                                                                                                                                      1                                 Aim @ 1.4 fl oz +
                                                                                               0                                                                                                      0                                 Inteon @1/8 lb + COC
                                                                                                          EVS                       SMS                TVS                                                    3 Days          10Days    Aim @ 1.4 fl oz +

                                                                                                                        Soybean Yield
                                                                                                                                                                                                                                        Roundup WM @22oz

                                                                                                                                                                                                                 Leaf Desiccation
                                                                                                      Strobiluron Fungicide Effects on
                                                                                                    Soybeans, EVS, SMS and TVS, 2007
                                                                                                                                                                                                          Desiccation Materials for Soybeans,
                                                                                                      LSD(0.10) = 2.0
                                                                                                                                                                                                                      SMS, 2006
                                                                                                                                                                     No                              10
                                                                                                                                                                                                                                        Untreated Check

                                                                                               50                                                                    Desiccant                        9                                 Inteon +NIS, 1/8 lb

                                                                                                                                                                                                      8                                 Inteon +NIS, 1/4 lb =
                                                                                                                                                                                                                                        (1 pt)
                                                                                               40                                                                                                     7
                                                                                      b u /A

                                                                                                                                LSD (0.10) = NS                                                                                         Inteon +NIS, 1/2 lb
                                                                                                                                                                                          10 = dry

                                                                                                                                                                                                                                        Inteon +NIS, 1/4 lb +
                                                                                               30                                                                                                     5                                 Sod Chl 3 lb
                                                                                                                                                   LSD (0.10) = NS                                                                      Sodium Chlorate 6 lb
                                                                                               20                                                                                                     3                                 Firestorm +NIS, 1/4 lb
                                                                                                                                                                                                                                                                 The support of the Alabama Soybean Producers through
                                                                                                                                                                     Desiccant                        2                                 Aim @ 1.4 fl oz + COC    checkoff funds, staff of the Alabama Agricultural
                                                                                                                                                                                                                                        Aim @ 1.4 fl oz +
                                                                                                                                                                                                                                        Inteon @1/8 lb + COC     Experiment Stations, and private industry sources of seed
                                                                                                0                                                                                                             3 Days          10Days    Aim @ 1.4 fl oz +

                                                                                                          EVS                       SMS                TVS
                                                                                                                                                                                                                                        Roundup WM @22oz
                                                                                                                                                                                                                                                                 and materials is gratefully acknowledged.
                                                                                                                         Soybean Yield                                                                          Leaf Desiccation

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