scholarly journals Corn Rootworm Larval Control, 1994

1995 ◽  
Vol 20 (1) ◽  
pp. 174-174
Author(s):  
J. D. Oleson ◽  
J. J. McNutt ◽  
R. D. Pruisner ◽  
J. J. Tollefson
Keyword(s):  
Experimental Tests ◽  
Row Spacing ◽  
Larval Feeding ◽  
Silty Clay ◽  
Harvest Time ◽  
Trap Crop ◽  
Planting Time ◽  
Cultivation Time ◽  
Small Plot ◽  
Yield Trials

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).

scholarly journals Corn Rootworm Larval Control in Iowa, 1993

1994 ◽  
Vol 19 (1) ◽  
pp. 200-200
Author(s):  
J. D. Oleson ◽  
J. J. McNutt ◽  
A. R. Warshaw ◽  
J. J. Tollefson
Keyword(s):  
Row Spacing ◽  
Larval Feeding ◽  
Silty Clay ◽  
Harvest Time ◽  
Clay Loam ◽  
Silty Clay Loam ◽  
Trap Crop ◽  
Planting Time ◽  
Root Protection ◽  
Yield Trials

Abstract Rootworm planting-time, soil-insecticide test plots were established at 6 locations in 1993. Soil types were: Ames and Rhodes, silty clay loam; Nashua, loam; Newell and Waukee, clay loam; and Sutherland, silty clay. All plots were planted on areas that had been planted to trap crop (late-planted corn, heavy stand) the previous year. A RCB design, with 4 replications for the root-protection trials (registered and numbered products) and 8 replications for the yield trials (registered and EUP products) 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 10 gpa at 23 psi. Chemical phytotoxicity was checked in early Jun by taking stand counts from 1/1000 acre and measuring extended leaf heights on 10 consecutive plants. Rootworm larval feeding was evaluated in late Jul and Aug 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. To determine treatment differences, data were analyzed using ANOVA and means were separated with Ryan’s Q test (REGWQ).

scholarly journals Evaluation of Dimilin and Benlate for Soybean Insect Pest and Disease Control, 1991

1995 ◽  
Vol 20 (1) ◽  
pp. 250-250
Author(s):  
M. O. Way ◽  
N. G. Whitney ◽  
R. G. Wallace
Keyword(s):  
Agricultural Research ◽  
Insect Pest ◽  
Row Spacing ◽  
Silty Clay ◽  
Plot Size ◽  
Initial Application ◽  
Plastic Bag ◽  
Small Plot ◽  
Soybean Plants ◽  
Extension Center

Abstract The experiment was conducted at the Texas A&M University Agricultural Research and Extension Center, Beaumont. The experimental design was a randomized complete block with 6 treatments and 4 replications. Soil type was a Midland silty clay loam. Plot size was 40 ft × 6 rows (32-inch row spacing). Plots were planted 4 Jun at about 10 seeds/ft. Immediately after planting, plots were treated with 2 pt Dual + 1 qt Roundup + % pt Scepter per acre. Soybeans emerged 10 Jun. On 16 Aug (when plants were R2—3 and insect pest populations were beginning to increase) treatments were applied to 4 rows of a plot using a Solo backpack sprayer. Finished spray volume was 20 gal/acre. Immediately before application and 5, 12, 21, 28, 35, and 42 d after this initial application, plots were sampled for insects. Each sample consisted of shaking soybean plants along 9 ft of row over a vertical beat sheet. Insects were shaken and brushed from the vertical beat sheet into a plastic bag which was frozen for later inspection of the contents. One sample (9 ft of sampled row) was taken in each plot on each sample date. On 9 Sep (when soybeans were R5) a second application of Benlate was made to all treatments with Benlate (thus, after all treatments were applied, treated plots were exposed to a single application of Dimilin and/or a double application of Benlate). On the same dates plots were sampled for insects, 15 leaflets (5 each from top, middle, and bottom third of canopy) were randomly removed from each plot and taken to a laboratory where estimates of % defoliation were recorded by comparing leaflets with templates of leaflets of known defoliation. From time of initial application to the last sample date 5.26 inches of rain was recorded. On 21 and 29 Oct plots were visually rated for cercospora leaf blight and anthracnose disease severity, respectively. At maturity 120 ft of row in each plot were harvested with a small plot combine. Yields were adjusted to 13% moisture. Insect count data were transformed using Vx + 0.5 and all data analyzed by ANOVA and means separated by DMRT.

Adjustment for competition between varieties in plant breeding trials

1982 ◽  
Vol 98 (3) ◽  
pp. 599-611 ◽  
Author(s):  
R. A. Kempton
Keyword(s):  
Sugar Beet ◽  
General Term ◽  
Extended Model ◽  
Essential Difference ◽  
Single Row ◽  
Selection Programme ◽  
Competition Effects ◽  
Competition Coefficient ◽  
Small Plot ◽  
Yield Trials

SUMMARYA method is proposed for correcting for competition effects in yield trials by joint regression of plot yields on to the yields of neighbours. Estimation of the variety effects and competition coefficient along with tests of significance are described for a sugar-beet trial with single-row plots where competition effects are assumed to extend only to plants in immediately adjacent rows. For designs which are balanced for neighbouring varieties it is feasible to estimate separate varietal competition coefficients which may be partitioned into components for sensitivity and aggressiveness. An example is given of this extended model fitted to a competition diallel of seven species. While species differed in their sensitivity to competition there was no essential difference between inter- and intra-species behaviour. The model is used to assess comparative varietal performance in monocultures from performance in small plot trials.(Note that the general term ‘variety’ is used throughout this paper to refer to progenies at any stage in a selection programme.)

Helicoverpa zea (Lepidoptera: Noctuidae) Preference for Plant Structures, and Their Location, Within Bt Cotton Under Different Nitrogen and Irrigation Regimes

2019 ◽  
Vol 112 (4) ◽  
pp. 1741-1751
Author(s):  
Lewis R Braswell ◽  
Dominic D Reisig ◽  
Clyde E Sorenson ◽  
Guy D Collins
Keyword(s):  
Helicoverpa Zea ◽  
Resistance Management ◽  
Larval Feeding ◽  
Bt Cotton ◽  
Larval Distribution ◽  
Cotton Plants ◽  
Small Plot ◽  
Nitrogen Treatments ◽  
Behavioral Resistance ◽  
Lepidoptera Noctuidae

Abstract Helicoverpa zea Boddie is a common economic pest of cotton (Gossypium hirsutum L.), including transgenic cotton varieties that express Bacillus thuringiensis (Bt). Helicoverpa zea oviposition is similar in Bt and non-Bt cotton, but behavior of H. zea larvae can be different in the presence of Bt, with neonates moving away from terminals faster in single-toxin Bt than non-Bt cotton or avoiding Bt-treated diet in the lab. We quantified H. zea oviposition and larval distribution on structures within cotton plants in small plot experiments of Cry1Ac + Cry1F cotton for 2 yr under different irrigation and nitrogen treatments. More eggs were oviposited on plants receiving nitrogen application during 2016 and on leaves in the top section of irrigated plants during 2017, but other treatment effects on eggs or larvae were minimal. Helicoverpa zea eggs were most common on leaves in the top third of plants at position zero and middle section of cotton plants throughout the season, but some oviposition occurred on fruiting structures as well. First and second instars were more common on squares in the top section of plants during 2016 and bolls in the middle and lower sections during 2017 due to oviposition lower in the canopy during 2017. During both years, third through fifth instars were more common on bolls in the middle and lower section of plants closer to the main stem. These findings have resistance management implications as extended larval feeding on bolls could optimize nutrition, decrease Bt susceptibility, and potentially influence behavioral resistance.

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
Keyword(s):  
Growth Stage ◽  
Compressed Air ◽  
Row Spacing ◽  
Research Station ◽  
Velvetbean Caterpillar ◽  
Small Plot ◽  
Sweep Net

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.

scholarly journals Major Lessons From Large-Scale Trap Cropping Demonstrations for Pest Reduction in Vegetables

2019 ◽  
Vol 112 (4) ◽  
pp. 298-301 ◽  
Author(s):  
Ayanava Majumdar ◽  
Matthew Price
Keyword(s):  
Large Scale ◽  
Insect Pests ◽  
Research Approach ◽  
Vegetable Production ◽  
Trap Crop ◽  
Trap Crops ◽  
Trap Cropping ◽  
Small Plot ◽  
Participatory Research Approach

Abstract Vegetable production in the Southeast is always at high risk from insect pests. Alternative integrated pest management (IPM) systems have to be effective in small plot as well as at the farming scale. This article explores the recent studies on large-scale trap crops using single or multiple cultivars and innovative layouts for long-term pest reduction. Trap crops must be planned carefully under high pest pressure and drought conditions along with an insecticide use strategy that minimizes external inputs and conserves natural enemies. Through participatory research approach, trap crop systems continue to evolve into practical solutions for the vegetable producers.

scholarly journals NC 98-608: MANAGING THE POTENTIAL NEW SWEETPOTATO (Ipomea batatas) CLONE RELEASE

HortScience ◽  
2005 ◽  
Vol 40 (3) ◽  
pp. 869b-869
Author(s):  
Allan C. Thornton ◽  
Jonathan R. Schultheis
Keyword(s):  
Yield Potential ◽  
Row Spacing ◽  
Harvest Time ◽  
Planting Dates ◽  
Late Planting ◽  
Early Planting ◽  
Ipomea Batatas ◽  
Early Harvest ◽  
Over Time ◽  
Made In

The goal of this research was to determine the effects of in-row spacing and planting time on yield and root grade of NC 98-608 over time. Two plantings were made in two grower locations (four total). An early planting was made 19 and 25 May and a late planting 19 and 24 June. NC 98-608 was evaluated at the following in-row spacings; 23, 31, 38, and 46 cm. `Beauregard' spaced at 23 cm in-row and was used as the standard comparison. Roots were harvested and graded into canner, number one, jumbo and cull grades 90, 105, and 120 days after planting for each of the planting dates and locations. Each grade was weighed. An early planting in late May resulted in roots reaching the highest percentage grade of U.S. number one roots as early as 100 days after planting, while the late planting in June resulted in roots never reaching their full number one yield potential in some cases. For an early harvest after planting (90 days after planting) the 38 cm in-row spacing produced the most marketable number one yields compared with the 23, 31, and 46 cm in-row spacings. For a later harvest time after planting (105 days or later), it appeared as though the 31 cm in-row spacing was the most economical spacing to use. Roots from the early plantings (late May) and finer textured soils appeared to have shorter roots than roots harvested from later plantings (after 15 June) or coarser textured soil. Root shape and yield was more uniform with NC 98-608 than with the Beauregard clone. With yields comparable to Beauregard, the NC 98-608 clone provides an excellent opportunity to produce a quality sweetpotato with consistent shape.

scholarly journals Three mechanical weed control techniques in spring cereals

2000 ◽  
Vol 9 (4) ◽  
pp. 269-278 ◽  
Author(s):  
T. LÖTJÖNEN ◽  
H. J. MIKKOLA
Keyword(s):  
Weed Control ◽  
Field Experiments ◽  
Yield Loss ◽  
Row Spacing ◽  
Silty Clay ◽  
Control Techniques ◽  
Mechanical Methods ◽  
Spring Cereals ◽  
Silty Clay Soil ◽  
Mechanical Weed Control

An inter-row hoe suitable for cereals was developed for the study, and field experiments were conducted to compare inter-row hoeing with weed harrowing, rotary hoeing and chemical control. The treatments were performed once during the growing season. Inter-row hoeing was studied at row spacings of 180 mm and 250 mm. The weeding effect of the different methods was measured by weighing the weeds remaining just before harvesting. Inter-row hoeing was the most effective of the mechanical methods. Weed harrowing was as good as hoeing in silty clay soil but less effective in mull soil. Rotary hoeing was the least effective. Herbicide spraying was more effective than the mechanical methods in both soils. Increasing the spacing between rows from the standard 125 mm to 250 mm decreased the yield of barley by 12-13%. Inter-row hoeing affected the yield very slightly. The yield decreasing was lower at a row spacing of 180 mm than at 250 mm. Weed harrowing and rotary hoeing decreased the yield 5-10%. Although inter-row hoeing seems to be a fairly effective method for weed control, it may be difficult to compensate for the yield loss due to the increase in row spacing.;

scholarly journals Evaluation of Soil Insecticides on Continuous Corn in Ohio, 1995

1996 ◽  
Vol 21 (1) ◽  
pp. 233-233
Author(s):  
H. R. Willson ◽  
J. B. Eisley
Keyword(s):  
Reduced Tillage ◽  
Row Spacing ◽  
Field Station ◽  
Planting Time ◽  
Grain Yields ◽  
Leaf Stage ◽  
Continuous Corn ◽  
The Press ◽  
Untreated Check ◽  
Soil Insecticides

Abstract Soil insecticides were evaluated for stand protection and rootworm control at the OARDC Western Branch Field Station near South Charleston. The test included 19 treatments compared to an untreated check treatment on reduced tillage plots that were 18.2 m (60 ft) in length and 2 rows wide for granular treatments and 4 rows wide for liquid treatments. Row spacing was 76.2 cm (30 inches). A RCBD was applied with 4 replicates. Planting time granular applications were applied as a band prior to closure by the press wheel or in-furrow using a 2 row John Deere 7000 planter equipped with Noble granular applicators. Post-emergence applications of liquid formulations were applied as a banded or broadcasted treatment with a boom sprayer equipped with flat spray nozzles and calibrated to deliver desired dosages at 3 mph. Granular treatments were applied 22 May at planting, and post-emergence treatments were applied 5 Jun to coincide with rootworm hatch. Treatments were evaluated 14 Jun for stand loss with counts of the total and injured plants per 15.1 m (50 ft) of row when corn was predominantly at the 4th or 5th leaf stage. Root ratings were conducted 5 Jul on 5 plants per plot using the Iowa 1-6 scale. Grain yields were determined by machine harvest of total plots on 12 Oct.

scholarly journals Control of Lepidopterous Larvae on Spring Cabbage, 1995

1996 ◽  
Vol 21 (1) ◽  
pp. 95-95
Author(s):  
M. R. Peters ◽  
J. V. Edelson
Keyword(s):  
Agricultural Research ◽  
Evaluation Criteria ◽  
Row Spacing ◽  
Larval Feeding ◽  
Feeding Damage ◽  
Hollow Cone ◽  
Extension Center ◽  
Direct Counts

Abstract Cabbage plants were transplanted on 6 Apr at the Wes Watkins Agricultural Research and Extension Center, Lane, OK. Each plot consisted of two 15 ft-long rows bordered on each side by an unplanted row. Cabbage was transplanted with 18-inch plant and 36-inch row spacing. Treatments were replicated 4 times in a RCB design. Sprays were applied with a back-pack sprayer using 2 TXVS-26 hollow cone nozzles/row and delivering 36 gal/acre at 40 psi. Applications were made on 10, 16, and 23 May and on 2 and 9 Jun. Evaluation criteria consisted of direct counts of all lepidopterous larvae on 5 randomly selected plants until 22 May and then 3 randomly chosen plants/treatment for the rest of the experiment. On 13 Jun damage ratings were determined. A head was considered marketable if no visible evidence of larval feeding damage was observed on the head or wrapper leaves.

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