Velvetbean Caterpillar Control on Louisiana Soybean, 1993

1994 ◽  
Vol 19 (1) ◽  
pp. 271-272
Author(s):  
J. D. Thomas ◽  
A. T. Wier ◽  
M. L. Boyd ◽  
S. Lingren ◽  
D. J. Boethel

Abstract The efficacy of selected insecticides for control of VBC was evaluated in 3 small plot insecticide trials at the St. Gabriel Research Station near St. Gabriel, LA. Treatments in all 3 tests were applied to ‘Buckshot 723’ soybean in the R5 growth stage using a tractor and compressed air sprayer calibrated to deliver 93.5 1/ha at 2.66 kg/cm2 through 8002 flat fan nozzles. Plots in all tests were 5 rows wide (0.91 m row spacing) by 15.2 m, arranged in a RCBD with 4 replications. At 2 and 7 DAT in each test, one 25 sweep sample was taken from each plot with a standard 38.2 cm diam sweep net. Test 1 was applied 6 Sep, Test 2 was applied 8 Sep, and Tesi 3 was applied 14 Sep.

1995 ◽  
Vol 20 (1) ◽  
pp. 236-237
Author(s):  
P. S. Lingren ◽  
A. T. Wier ◽  
D. J. Boethel

Abstract Several insecticides were tested for efficacy of control against southern green stink bug in 3 small plot trials at the St. Gabriel Research Station in Iberville Parish, LA. Test 1 was conducted on 17 Aug on ‘Ring Around 452’ in the R6 growth stage. Tests 2 and 3 were conducted on 3 Sep on ‘Delta Pine 415’ in the R6 and R5 growth stages, respectively. Treatments in all tests were arranged in a RCBD with 4 replications. Plots were 50 ft by 5 rows (36 inch row spacing). Treatments were applied with a tractor using a compressed air sprayer calibrated to deliver 10 gpa at 44 psi with 8002 flat fan nozzles. At 2 and 7 DAT, one 25 sweep sample was taken from each plot using a 15 inch diameter sweep net. Nymph and adult SGSB were counted. No rainfall was recorded during any of the tests.


1995 ◽  
Vol 20 (1) ◽  
pp. 252-252
Author(s):  
Alan T. Wier ◽  
David J. Boethel ◽  
P. Scott Lingren ◽  
B. Roger Leonard

Abstract The efficacy of several experimental insecticides that consist of pyrrole or avermectin chemistry, or exhibit insect growth regulator activity were evaluated against the soybean looper (SBL) on soybean in a small plot insecticide screening trial at the Macon Ridge Branch of the Northeast Research Station near Winnsboro, Louisiana. Activity of these materials was compared to that of the standard recommended insecticide Larvin at 0.6 lb (AI)/acre. Plots measured 50 ft by 5 rows (40 inch spacing) and were arranged in a RCB with 4 replications. Insecticides were applied on 23 Aug (R5, beginning seed stage) with a tractor and compressed air sprayer calibrated to deliver 10 gpa at 38 psi through TX8 hollow cone nozzles. Treatments were evaluated using 25 sweeps (15 inch diameter sweep net) per plot at 2, 5, and 7 DAT. No precipitation occurred throughout the duration of this experiment.


1995 ◽  
Vol 20 (1) ◽  
pp. 238-238 ◽  
Author(s):  
Rosanne N. Mascarenhas ◽  
Alan T. Wier ◽  
David J. Boethel ◽  
P. Scott Lingren ◽  
B. Rogers Leonard

Abstract A field study was conducted at the Macon Ridge Branch, Northeast Research Station, located near Winnsboro (Franklin Parish), Louisiana, to evaluate the efficacy of several B. thuringiensis insecticides for soybean looper control. Test plots were 50 ft long by 5 rows with a 40 inch row spacing and were arranged in a randomized complete block design with four replications. Insecticides were applied with a tractor and compressed air sprayer calibrated to deliver 10 gpa at 38 psi through TX8 hollow cone nozzles (2 per row). Insecticide treatments were applied to soybeans in the R5 stage of growth (beginning seed) on 25 Aug. Posttreatment counts, consisting of 25 sweeps per plot, were taken with a 15 inch diameter muslin net at 2, 5, and 7 DAT. No rainfall occurred and the plots were not irrigated during the experimental period. Data were analyzed using analysis of variance followed by means separation according to DMRT.


1997 ◽  
Vol 22 (1) ◽  
pp. 312-313
Author(s):  
B. J. Fitzpatrick ◽  
C. G. Clemens ◽  
D. J. Boethel ◽  
S. Micinski

Abstract Efficacy of standard and experimental in secticides was evaluated in two small plot trials conducted at the Red River Research Station located near Bossier City, LA (Bossier Parish). Treatments were applied to ‘Hutcheson’ soybeans with a high clearance, CO2-pressurized sprayer calibrated to deliver 5.9 gpa at 40 psi through TXVS6 hollow cone nozzles (2/row). Plots were 50 ft X 4 rows (40 inch centers) and arranged in a RCBD with 4 replications. Treatments were applied on 20 and 22 Aug in Tests 1 and 2, respectively. One 25-sweep sample/plot was taken with a standard 15-inch diam sweep net at 2, 5, and 9 DAT in Test 1 and 3 and 7 DAT in Test 2. On 27, 28, and 29 Aug both tests received 0.17,0.92, and 0.27 inches of rainfall, respectively. Data were analyzed with ANOVA and means sep arated by DNMRT.


1995 ◽  
Vol 20 (1) ◽  
pp. 153-153
Author(s):  
John Wedberg ◽  
Bryan Jensen

Abstract Experimental plots measuring 40 × 50 ft were established in a field of ‘Olds 98’ alfalfa at the University of Wisconsin Agricultural Research Station, Arlington, WI. Treatments were replicated 4 times in a RCBD and applied on 21 Jul by using a tractor-mounted compressed air sprayer equipped with 8001 TeeJet flat fan nozzles delivering 17 gal/acre of finished spray at 40 psi when driven at 2.6 mph. Insect abundance was estimated by taking 20 consecutive pendulum sweeps in each plot with a 15 inch diam sweep net at 7, 11 and 15 DAT.


1995 ◽  
Vol 20 (1) ◽  
pp. 236-236
Author(s):  
B. R. Leonard ◽  
C. A. White ◽  
A. T. Wier ◽  
P. S. Lingren

Abstract Insecticide efficacy against soybean looper was evaluated at the Macon Ridge Branch of the Northeast Research Station. Plots consisted of 4 rows (40 inch centers) × 50 ft, planted 3 Jun. Treatments in both tests were arranged in a RCB with 4 replications. Insecticides were applied on 23 Aug with a tractor-mounted boom and compressed air system calibrated to deliver 10 gal total spray/acre through Teejet X-8 hollow cone nozzles (2/row) at 38 psi. Treatments were evaluated at 3 and 7 DAT using two 25-sweep samples/plot with a standard 15 inch diameter sweep net. Rows 2 and 3 were sampled 3 DAT and rows 4 and 5 were sampled 7 DAT. No rainfall occurred during the test.


2003 ◽  
Vol 83 (2) ◽  
pp. 319-326 ◽  
Author(s):  
B. L. Johnson

Growth compensation of dwarf sunflower (Helianthus annuus L.) hybrids to low initial stands, later stand losses, or plant defoliation has not been reported regarding replanting decisions and crop insurance yield loss assessment. Three experiments were conducted to study the affect of stand reduction, defoliation, and row spacing on dwarf sunflower yield and quality when grown in eastern North Dakota. Experiment 1 evaluated stand reduction (0, 25, 50 and 75%) applied at growth stages (V4, R1 and R6) in 15, 45 and 76 cm spaced rows. Row spacing interactions with stand reduction and growth stage were not significant for yield indicating growth stage and stand reduction effects on yield response were independent of row spacing. In exp. 2, significant growth stage (V4, V8, R1, R2, R3, R5 and R6) by stand reduction (0, 12, 25, 37, 50, 62 and 75%) interaction showed stand reduction at vegetative growth stages not influencing yield, but as maturity progressed yield reductions became greater with increased stand reduction. Achene weight increased with increasing stand reduction at vegetative and early reproductive stages. A reciprocal relationship was noted between achene weight and achene oil content where oil content decreased as achene weight increased. Interaction of growth stage (R1 and R6) and defoliation (0, 25, 50, 75 and 100%) in exp. 3 indicated greater reduction in yield, test weight, 1000-achene weight, and achene oil conte nt as defoliatin increased at growth stage R6. Yield compensating ability of dwarf sunflower is dependent on type and level of damage and growth stage of occurrence, with total yield reduction considering all effects. Key words: Sunflower, Helianthus annuus L., row spacing, stand reduction, defoliation


1995 ◽  
Vol 20 (1) ◽  
pp. 174-174
Author(s):  
J. D. Oleson ◽  
J. J. McNutt ◽  
R. D. Pruisner ◽  
J. J. Tollefson

Abstract Rootworm planting-time, soil-insecticide test plots were established at 3 IA locations in 1994. Soil types were: Ames (Chapin), silty clay loam; Nashua, loam; and Sutherland, silty clay. Plots were planted 9, 2 and 3 May, respectively, on areas that had been planted to trap crop (late-planted corn, high plant population) the previous year. A RCBD with 4 replications for the experimental and cultivation tests and 8 replications for the yield trials was used. All treatments were applied to single 50-ft length rows with 30-inch row spacing. Granular insecticide formulations were applied with modified Noble metering units mounted on a 4-row John Deere 7100 planter. Planting-time liquid formulations were applied with a compressed-air delivery system built directly into the planter; 8003E nozzles delivered 13 gpa at 23 psi. Liquid cultivation-time insecticides were applied with a small-plot bicycle sprayer. Two 8002E nozzles, 1 on each side of the corn row, were positioned to deliver either a 7 or 15-inch band width around the base of the plants; 13 gpa at 25 psi. Broadcast (30-inch band) applications of Furadan 4F were applied to single rows. A boom containing three 8002 nozzles (19-inch centers) delivered 13 gpa at 32 psi. One untreated buffer row was left on each side of a “broadcasted” row. Granular cultivation-time insecticide applications were made with electrically-driven Noble units mounted on the tool bar of a 2-row, rear-mounted cultivator. Plastic tubes, positioned directly in front of the cultivator sweeps, directed the insecticide granules to both sides of the corn row for basal treatments. Chemical phytotoxicity was checked in early Jun by taking stand counts from 1/1000 acre and measuring extended leaf heights on 10 consecutive plants (experimental tests only). Rootworm larval feeding was evaluated in Jul by digging 5 roots from each treatment row and rating them on the Iowa 1-6 scale (1 equal to no damage or only a few minor feeding scars, and a 6 rating equal to 3 or more nodes of roots completely destroyed). Lodging counts were taken at harvest time. A plant was considered lodged if the angle between the base of the plant and the ground was 45° or less. Stand counts were taken in the yield plots at harvest time. Yields were measured by hand harvesting 1/1000 acre from each treatment at Nashua and Chapin, and machine harvesting 25 row-ft at Sutherland. To determine treatment differences, data were analyzed using ANOVA and means were separated with Ryan’s Q test (REGWQ).


Plant Disease ◽  
2020 ◽  
Author(s):  
Kimberly Cochran ◽  
Adele Steger ◽  
Robert Holland ◽  
John C. Rupe

The effects of cultivar and foliar fungicide application on soybean seed germination, vigor, microflora, and yield after delayed harvest were determined at the University of Arkansas Vegetable Research Station in Kibler, AR, from 2008 to 2010. Seven cultivars with varying levels of resistance to Diaporthe spp. or Cercospora spp. were treated or not treated with a foliar application of azoxystrobin at the R5 growth stage. Plots were harvested three weeks after the plants had reached harvest maturity. Yields were recorded, samples of seed were collected, and standard germination (SG) and accelerated aging (AA) were assessed. Seeds were also assayed for infection by fungi on modified potato dextrose agar and by bacteria on nutrient agar. Seed vigor was significantly reduced by infection with Diaporthe spp., Fusarium spp., and Bacillus subtilis, but not with Cercospora spp. Cultivar had a significant impact on yield, seed vigor, and seed infection levels. The cultivar Osage consistently had high seed vigor and low overall seed infection incidence throughout the study. MO/PSD-0259, AG 4403 and UA 4805 also had relatively high seed vigor and low seed infection incidence. PI 80837 had low incidence of seed infection by Diaporthe spp. and Fusarium spp. in 2008 and 2010, but high levels in 2009 when environmental conditions were especially favorable for these pathogens. AP 350 and Suweon97 generally had relatively high seed infection incidences, particularly of Diaporthe spp. and Fusarium spp., and relatively low seed vigor. Application of the foliar fungicide azoxystrobin at the R5 growth stage significantly increased AA across years and cultivars and increased seed infection by Diaporthe spp. in 2009 across cultivars. There were significant negative correlations between yield and seed infection by Diaporthe spp. and Bacillus subtilis in one year and with Fusarium spp. in all three years. Overall, resistance to seed infection can persist even when harvest is delayed and in addition to Diaporthe spp., other seedborne pathogens may reduce seed vigor and yield.


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