Soybeans In Alabama Research Articles

The First Record of Ooencyrtus nezarae (Hymenoptera: Encyrtidae) on Kudzu Bug (Hemiptera: Plataspidae) in North America

The kudzu bug, Megacopta cribraria (F.) (Heteroptera: Plataspidae), is an invasive insect pest introduced from Asia in 2009 that poses a threat to soybeans (Glycine max [L.] Merr. [Fabales: Fabaceae]) and other legume crops in the United States. Initially discovered in Georgia, M. cribraria rapidly expanded across the southeast until 2014 when a significant decline in its population was observed across many locations. This notable decline in M. cribraria populations is attributed to the emergence of new parasitoids and pathogens in its new invasive range. So far, only a single egg parasitoid, Paratelenomus saccharalis (Dodd) (Hymenoptera: Platygastridae), is known to parasitize the eggs of M. cribraria in the United States. Here, we report a new egg parasitoid of M. cribraria identified as Ooencyrtus nezarae Ishii, 1928 (Hymenoptera: Encyrtidae), recovered from egg masses of M. cribraria collected from soybean in Alabama. O. nezarae is reported to parasitize eggs from a variety of heteropteran families and has been observed parasitizing M. cribraria in China. To the best of our knowledge, this is the first report of O. nezarae in North America. The potentials of O. nezarae for biological control of M. cribraria in the United States and the direction of future studies are discussed.

Monitoring Bean pod mottle virus and Soybean mosaic virus Incidence at Different Soybean Growth Stages in Alabama

This study focuses on Bean pod mottle virus (BPMV) and Soybean mosaic virus (SMV) incidence over time relative to stages of plant growth in selected fields in Alabama. Five commercial soybean fields in west-central Alabama were surveyed for BPMV and SMV in 2010-2012 and 2014. Incidence of BPMV was typically highest at crop maturity. Incidence of 10% or higher was recorded at full bloom in at least one field in each year of the study, but incidence did not exceed 23% at bloom in any field with one exception. SMV was not detected at high levels during this study and incidence above 10% at full bloom was recorded for only one field. Results from this study, combined with observations from a previous statewide survey, indicate that BPMV is the most common virus disease of soybeans in Alabama. BPMV has the potential to cause yield loss in years when bean leaf beetles, its most important vector, are present at high levels early in the season when infection of soybean prior to flowering is possible. Results also suggest that SMV incidence in soybean in Alabama is low in most years and the disease might not pose a significant threat to soybean production at this time, especially in the absence of high populations of soybean aphids in the state.

First Report of Soybean vein necrosis-associated virus Affecting Soybeans in Alabama

Soybean vein necrosis-associated virus (SVNaV) is a relatively new disease of soybeans in the United States. This is the first report of SVNaV in Alabama. The disease was confirmed to be SVNaV by ELISA and sequencing virus specific PCR products. Confirmation of the disease in Alabama is an important step in developing management recommendations for growers. Accepted for publication 10 May 2013. Published 29 July 2013.

Survey of Fungal, Nematode and Virus Diseases of Soybean in Alabama

Observations on incidence of foliar diseases, plant viruses, and plant-parasitic nematodes were collected from soybean fields in Alabama from 2008-2010. Cercospora leaf blight (Cercospora kikuchii), downy mildew (Peronospora manshurica), and target spot (Corynespora cassiicola) were the most common foliar diseases observed in the study. Cercospora leaf blight was found in 45% (2008), 77% (2009), and 70% (2010) of the fields surveyed. Downy mildew was observed in 72% (2008), 38% (2009), and 29% (2010) and target spot was detected in 45% (2008 and 2009) and 29% (2010) of the fields in the study. Soybean rust (Phakopsora pachyrhizi) was found in 43% of the fields surveyed in 2009 but was only found in one field in 2008 and was not detected in 2010. Bean pod mottle virus was detected at relatively high levels in all three years, whereas Soybean mosaic virus occurrence was less consistent and of lower incidence. Tomato spotted wilt virus was detected for the first time on soybean in Alabama. Reniform (Rotylenchulus reniformis), soybean cyst (Heterodera glycines), root-knot (Meloidogyne spp.), and lesion nematodes (Pratylenchus spp.) were the most common plant-parasitic nematodes collected with reniform nematodes found in over 30% of the fields surveyed. Soybean cyst nematode races 2, 4, 5, 6, and 14 were identified among the field population collected. The survey has increased disease awareness among growers and has aided in directing research efforts in the state. Accepted for publication 18 November 2011. Published 27 December 2011.

First Report of Asian Soybean Rust Caused by Phakopsora pachyrhizi on Soybean in Alabama.

On November 4, 2004, soybean leaves (Glycine max (L.) Merr) were submitted to the Auburn University Plant Diagnostic Lab by a State Department of Agriculture and Industries Inspector. Samples were collected from an 80-ha field of soybean plants in a late-reproductive-growth stage in Mobile County, Alabama. Under microscopic examination, leaves showed rust pustules in advanced stages of development with urediniospores and sori characteristic of Phakopsora spp. Uredinia were ostiolate in small, brown, angular leaf spots (2 to 3 mm) on lower leaf surfaces. Urediniospores were pale yellow-to-white, globose or ovate, 20 to 40 × 15 to 25 μm. In a subsequent visit to the field, symptoms and signs of the rust disease were observed on plants bordering the edge of the field since the majority of plants were senescent. Tan lesions on lower leaf surfaces contained small pustules surrounded by a small zone of slightly discolored necrotic tissue. Masses of tan spores covered the lower leaf surface pustules. Leaves were mailed overnight to the USDA National Identification Services (Mycology) Laboratory in Beltsville, MD. The fungal structures were confirmed to be a Phakopsora sp., and the sample was forwarded to the USDA National Plant Germplasm and Biotechnology Laboratory in Beltsville, MD. DNA was extracted from leaf pieces containing sori using the Qiagen DNeasy Plant Mini kit (Qiagen, Valencia, CA). Phakopsora pachyrhizi was detected using a real-time polymerase chain reaction (PCR) protocol (1) performed in a Cepheid SmartCycler (Sunnyvale, CA). The PCR master mix was modified to include OmniMix beads (Cepheid). The field and microscopic suspect diagnosis of P. pachyrhizi was confirmed officially by APHIS on November 18, 2004. This was the fourth USDA official confirmation of Asian soybean rust in the continental United States during 2004, and to our knowledge, this is the first report of the disease in Alabama. This report helps confirm that early occurrences of Asian soybean rust in the United States were present in other areas in addition to the first reported finding in Louisiana (2).

First Report of Bean pod mottle virus in Soybean in Alabama.

During October 2003, soybean (Glycine max (L.) Merr.) plants showing symptoms of delayed maturity of stems, or green stem, were observed in a soybean cultivar trial on Dee River Ranch in Pickens County, Alabama. Symptoms were characteristic of those caused by Bean pod mottle virus (BPMV). BPMV infections have been identified in other southern states, including Arkansas, Louisiana, and neighboring Mississippi, but had not yet been identified in Alabama (1,2,3). In this study, a cultivar trial was established as a nonreplicated strip test to evaluate the performance of nongenetically modified soybean cultivars in high-pH soils. The trial consisted of 12 maturity group V cultivars planted side by side in 24-row plots approximately 1 km long. The cultivars consisted of Anand, Asgrow 5547, Asgrow 5944, Delta King 5995, Deltapine 4748, Deltapine 5110, Deltapine 5989, Essex, Hutcheson, Pioneer 9594, Pioneer 9597, and USG5601T. During the season, a known vector of BPMV, the bean leaf beetle (Cerotoma trifurcate Forster), was identified in the plots (4). On 10 October, the majority of plants in the trial had senesced; however, it was observed that plants of 6 of the 12 cultivars were showing symptoms of green stem typical of BPMV infection. A visual assessment was taken to determine incidence of green stem for Asgrow 5547, Delta King 5995, Deltapine 5110, Deltapine 5989, Pioneer 9594, and USG5601T. Incidence between 1 and 5% was observed for Delta King 5995, Deltapine 5989, and Pioneer 9594. Incidence of less than 1% was observed for Asgrow 5547, Deltapine 5110, and USG5601T. Twenty soybean plants showing symptoms of green stem and retaining green leaves were sampled from each of the six cultivars by collecting one trifoliate leaf near the top of the plant. All samples were tested for BPMV using double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) according to the manufacturer's instructions (Agdia, Inc., Elkart, IN). BPMV was detected in 30% of Deltapine 5989, 10% of Delta King 5995, and 45% of Pioneer 9594 plants. BPMV was not detected in Asgrow 5547, Deltapine 5110, and USG5601T. Ten of the samples shown to be infected with BPMV using DAS-ELISA were mechanically transferred to soybean seedlings in the greenhouse. These plants developed systemic mottle symptoms typical of those caused by BPMV and tested positive for the virus BPMV using DAS-ELISA. To our knowledge, this is the first report of BPMV in Alabama.

Control of Threecornered Alfalfa Hoppers and Green Cloverworms on Soybeans in Alabama, 1986

Abstract This field test was conducted in conventionally planted and tilled soybeans grown in a Vaiden soil at the Marion Junction Substation of Auburn University. Eight treatments and a control were replicated 3 times in a randomized complete block design. Each 0.014-acre plot was 4 rows wide (36-inch row spacing) and 50 ft long. Treatments were applied on 12 Aug with a backpack sprayer equipped with 3 TX3 nozzles per row operating at 40 psi and delivering 4.6 gal/acre, Insect populations were sampled by placing a standard 3 ft beat sheet between the rows and beating the plants on both sides. Two samples from each plot were taken prior to treatment application (20 Aug) and 3 samples from each plot were taken at 2 and 9 days postspray (22 and 29 Aug).

Control of Soybean Loopers on Soybeans in Alabama, 1985

Abstract The test was conducted on soybeans planted at the Plant Breeding Unit of Auburn University, Tallassee, AL. Eleven treatments and an untreated were replicated 4 times in a randomized complete block design. Each plot was 4 rows wide (40-inch row spacing) and 40 ft long. Plots were separated by a 2-row mowed alley, and replicates were separated by a 10-ft mowed alley. Treatments were applied on 4 Sep, at soybean growth stage R5, with a tractor-mounted boom sprayer equipped with 3 TX-3 hollow cone nozzles per row. The sprayer was operated at 40 psi, delivering 8.9 gal/acre. Insect populations were sampled by placing a standard 3-ft beat sheet between the rows and beating the plants of both rows. Soybean looper larvae were counted and recorded as small (<0.2 inch) medium (0.2 to 0.5 inch), and large (>.5 inch). Three samples from the middle 2 rows of each plot were taken at 1 day pretreatment and 2, 5, and 12 days posttreatment.

Control of Small, Medium, and Large Soybean Loopers on Soybeans in Alabama, 1984

Abstract This test was planted in Cahaba sandy loam soil at the Plant Breeding Unit of Auburn University, Tallassee, AL. Thirteen treatments and an untreated were replicated 4 limes in a randomized complete block design. Each 0.012 acre plot was 4 rows wide (40-inch row spacing) and 40 ft long. Treatments were applied on 10 Sep with a high clearance boom sprayer equipped with three TX6 hollow-cone nozzles/per row, operating at 40 psi and delivering 8 gal/ acre. Insect populations were sampled by placing a standard 3-ft beat sheet between the rows and beating the plants on both sides. Larvae were identified and classified as small (instar 1-2), medium (instar 3-4), or lage (instar 5 +); they were then counted and recorded. Three samples from each plot were taken 1, 4, and 10 days postspray (10, 14, and 20 Sep).

Dinitrogen Fixation by Soybeans in Alabama1

AbstractThe contribution of symbiotic N2 fixation to total N and yield of soybeans [Glycine max (L.) Merr.] ranges widely among soils and cultural conditions. Utilization of nonnodulating soybean isolines and 15N‐dilution techniques has provided estimates of fixation in indeterminate cultivars on soils of relatively high N supply. Few estimates are available, however, for determinate soybeans on low N soils of the southeastern United States. This work compared the N assimilation of ‘Lee’ soybean with that of its nonnodulating isoline (N‐N Lee) at 10 locations in Alabama over an 8‐year period. Nitrogen accumulations by higher yielding cultivars were also determined. Dinitrogen fixation was estimated as the difference in the amount of N contained in N‐N Lee and Lee or other fixing cultivar. One approach considered N in harvested beans only while another approach involved total N in aboveground plant material at physiological maturity. Results showed that Lee soybeans grown in Alabama without irrigation but with rainfall sufficient for yields exceeding 1640 kg ha−1 fixed an average 172 kg ha−1 of N, while maximum yielding cultivars fixed 217 kg ha−1 of N in aboveground plant material. The estimate for midwestern soybeans of 40% of plant total N derived from the atmosphere is too low for Alabama soybeans, where 70% or more is obtained by fixation.

Control of Small, Medium, and Large Soybean Loopers on Soybeans in Alabama, 1983

Abstract This field test was conducted on soybeans planted in Cahaba sandy loam soil at the Plant Breeding Unit of Auburn Univ., Tallassee, Ala. Five treatments and an untreated check were replicated four times in a randomized complete block design. Each 0.012 acre plot was four rows wide (40-in. row spacing) and 40 ft long. Treatments were applied on 8 Sep. with a high clearance boom sprayer equipped with three TX6 hollow-cone nozzles per row operating at 50 lb/in2 and delivering 9 gal/acre. Insect populations were sampled by placing a standard 3-ft beat sheet between the rows and beating the plants on both sides. Larvae were identified and assigned a classification of small (instars 1 to 2), medium (instars 3 to 4), or large (instars 5 +); they were then counted and recorded. Three samples from each plot were taken 1, 4, and 7 days postspray 9, 12, and 15 Sep. At 1 day postspray, both Lorsban (1.0 lb (AI)/acre) and a tank mixture of Lorsban (0.5 lb) and Ambush (0.05 lb) effectively reduced numbers of small and medium soybean loopers. On the second sampling date (4 days postspray), the Lorsban-Ambush mixture plots and the plots treated with Orthene (0.75 lb) had fewer large soybean loopers than the untreated check. By 7 days postspray, the only treatment effective in reducing numbers of small soybean loopers was the Lorsban-Ambush mixture. The Lorsban-Ambush mixture. Scout (0.015 lb), and Lorsban (1.0 lb) all effectively reduced numbers of medium loopers, but no significant differences were detected among treatments on large loopers. Overall, the Lorsban (0.5 lb) and Ambush (0.05 lb) mixture was the most effective treatment against soybean loopers.

Control of Soybean Loopers and Threecornered Alfalfa Hoppers on Soybeans in Alabama, 1983

Abstract This field test was conducted on soybeans planted in Cahaba sandy loam soil at the Plant Breeding Unit of Auburn Univ., Tallassee, Ala. Six treatments and an untreated check were replicated four times in a randomized complete block design. Each 0.012 acre plot was four rows wide (40-in. row spacing) and 40 ft long. Treatments were applied on 8 Sep. with a High-Boy boom sprayer equipped with three TX6 hollow cone nozzles per row operating at 50 lb/in2 and delivering 9 gal/acre. Insect populations were sampled by placing a standard 3-ft beat sheet between the rows and beating the plants on both sides. Soybean looper larvae and threecornered alfalfa hoppers (adults and nymphs combined) were counted and recorded. Three samples from each plot were taken 1, 4, and 7 days postspray (9, 12, and 15 Sep.)

Control of Small, Medium, and Large Velvetbean Caterpillars, Total Soybean Loopers, and Total Green Cloverworms on Soybeans in Alabama, 1983

Abstract This field test was conducted on soybeans planted at the Auburn University Wiregrass Agric. Exp. Substn. at Headland, Ala. Nine treatments and an untreated check were replicated four times in a randomized complete block design. Each 0.012 acre plot was four rows wide (40-in. row spacing) and 40 ft long. Treatments were applied on 16 Sept. with a tractor-mounted boom sprayer equipped with one control droplet applicator nozzle per row adjusted to produce approximately 150 micron droplets. Spray pressure was 20 lb/in2 and the sprayer was delivering 1.6 gal/acre. Each of three insecticides (Ambush, Cymbush, and DPX 5249, a more oil-soluble formulation of Lannate) were applied alone, with soybean oil, and with Agridex. Agitation was achieved with recirculation of the insecticide solution. Insect populations were sampled by placing a standard 3-ft beat sheet between the rows and beating the plants on both sides. Larvae were identified and recorded; velvetbean caterpillar larvae were separated into small (instars 1 to 2), medium (instars 3 to 4), and large (instars 5 +) larvae. F6ur samples from each plot were taken 3, 7, and 11 days postspray (19, 23, and 27 Sept.)

Control of Threecornered Alfalfa Hoppers on Soybeans in Alabama, 1982

Abstract This field test was conducted on sandy loam soil at the Auburn University Plant Breeding Unit, Tallassee, AL. Five chemical treatments and an untreated check were replicated 4 times in a randomized complete block design. Each of the .01-acre plots was 4 rows wide (36-in row spacing) and 37 ft long. Plots were treated at planting on May 31. Treatments were in-furrow and banded applications of soil insecticides. Insect populations were sampled by placing a standard 3-ft beat sheet between the rows and beating the plants on both sides. Numbers of immature threecornered alfalfa hopper (TCAH) were counted and recorded. Two samples were taken from each plot on Jun 16, when the first trifoliate leaves appeared. Weekly sampling continued until Sep 16.

Control of Small, Medium and Large Corn Earworms and Soybean Loopers on Soybeans in Alabama, 1982

Abstract This field test was conducted on soybeans planted in sandy loam soil at the Plant Breeding Unit of Auburn Univ., Tallassee, AL. Fourteen treatments and an untreated check were replicated 4 times in a randomized complete block design. Each of the .012-acre plots was 4 rows wide (40-in row spacing) and 38 ft long. Treatments were applied on Aug 16 with a CO2-pressurized sprayer equipped with 3 D-2 nozzles per row operating at 25 psi and delivering 18 gal/acre. Insect populations were sampled by placing a standard 3 ft beat sheet between the rows and beating the plants on both sides. Larvae were identified and assigned a classification of small, medium or large. They were then counted and recorded. Two samples from each plot were taken prespray (Aug 16) and 24 h and 72 h post spray (Aug 17 and 19). Only 2 of 4 blocks were sampled at the 24 h count due to rain. Lannate treated plots were not sampled at all on this date.

Soybean Looper Control on Soybeans in Alabama, 1982

Abstract This field test was conducted at the Auburn Univ. Plant Breeding Unit, Tallassee, AL. Eight treatments and an untreated check were replicated 4 times in a randomized complete block design. Soybeans were planted Jun 2 in a cahaba sandy loam soil - pH = 5.9, 1.5% organic matter. Each 0.012 acre plot was 4 rows wide (40 in row spacing) and 37 ft long. Treatments were applied Aug 24 with a CO2-pressurized garden sprayer equipped with D-2 nozzles (3/row) operating at 25 psi and delivering 18 gal/acre. Insect populations were sampled by placing a standard 3 ft beat sheet between the rows and beating the foliage on both sides of the sheet. Larvae were identified, sized, counted, and recorded. Three samples from each plot were taken prespray (Aug 24), and 1, 3, 6, 9 and 15 days post spray.

Bean Leaf Beetle and Threecornered Alfalfa Hopper Control on Soybeans in Alabama, 1982

Abstract This field test was conducted in soybeans planted on Vaiden soil at the Auburn Univ., Blackbelt Substation, Marion Jet., AL. Ten treatments and an untreated check were replicated 4 times in a randomized complete block design. Each of the .01-acre plots was 4 rows wide (36-in row spacing) and 37 ft long. Treatments were applied on Aug 31 with a CO2-pressurized sprayer equipped with 3 D-2 nozzles per row, operating at 30 psi, and delivering 22 gal/acre. Insect populations were sampled by placing a standard 3-ft beatsheet between the rows and beating the plants on both sides. Insects were identified, counted and recorded. Immature threecornered alfalfa hoppers (3CAH) were rated as small, medium, and large. Two samples from each plot were taken prespray (Aug 31) and 24 h, 72 h and 1 wk post spray (Sep 1, 3 and 7).

Neocosmospora Stem Rot of Soybeans in Alabama

Neocosmospora Stem Rot of Soybeans in Alabama

Survey of Heliothis spp.1 Infestations in Soybeans in Alabama

Survey of Heliothis spp.1 Infestations in Soybeans in Alabama

Influence of Defoliation on Yield and Quality of Soybeans

Soybeans in Alabama are attacked every year by several species of defoliating insects. Control measures are essential particularly in the southern part of the State. Entomologists have not agreed when control measures should be applied to prevent yield losses.