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Soybean (Glycine max [L.] Merrill) yield losses as a result of plant diseases were estimated by university and government plant pathologists in 29 soybean producing states in the United States and in Ontario, Canada, from 2015 through 2019. In general, the estimated losses that resulted from each of 28 plant diseases or pathogens varied by state or province as well as year. Soybean cyst nematode (SCN) (Heterodera glycines Ichinohe) caused more than twice as much loss as any other disease during the survey period. Seedling diseases (caused by various pathogens), Sclerotinia stem rot (white mold) (caused by Sclerotinia sclerotiorum [Lib.] de Bary), and sudden death syndrome (caused by Fusarium virguliforme O’Donnell & T. Aoki) caused the next greatest yield losses, in descending order. Following SCN, the most damaging diseases in the northern United States and Ontario differed from those in the southern United States. The estimated mean economic loss from all soybean diseases, averaged across the United States and Ontario, Canada was US$45 per acre (US$111 per hectare). The outcome from the current survey will provide pertinent information regarding the important soybean diseases and their overall severity in the soybean crop and help guide future research and Extension efforts on managing soybean diseases.

Producers managing Coastal Plain soils in Maryland have reported visual symptoms of P deficiency in corn (Zea mays L.) grown on soils with P concentrations above the agronomic optimum range (e.g., 40–84 mg kg–1 Mehlich 3‐extractable phosphorus [M3P]). Yet, corn yield response to starter P fertilizer on soils with M3P concentrations above this range has not been consistently demonstrated in the literature. The objective of this study was to evaluate corn yield response to application of starter P fertilizer to soils with varying M3P concentrations. This study was conducted at three locations in Maryland where, following 14 yr of phytoremediation by continuous cropping and no P applications, M3P concentrations ranged from 34 to 237 mg kg–1 in soil samples collected from plots prior to study commencement. Beginning in 2015, half of each main plot received inorganic P application prior to corn planting in 3 yr, with corn yield measured in each split plot in each year. We observed no interaction effect of starter P fertilizer and soil P category on corn yield at any location. When the data were analyzed by site‐year, we observed no interaction effect, an effect of soil P category in 5 of 9 site‐years, and a yield response to starter fertilizer in 2 of 9 site‐years, with a positive yield response in 1 site‐year and a negative yield response in the other. Based on these results, we do not recommend Mid‐Atlantic farmers invest in starter P fertilization for corn grown on Coastal Plain soils when not recommended by soil testing.

Experiments using soil-incorporated cover crops and amendments of poultry litter (PL) and PL compost to suppress root-knot (RKN) and root-lesion nematodes were conducted in response to increasing nematode populations in Maryland's potato production areas. Identical experiments were established in microplots infested with Meloidogyne incognita or Pratylenchus penetrans. Treatments consisted of 12 3-year rotational sequences comprising potato (year 1) and cucumber (year 2) followed by a moderately RKN-resistant or susceptible soybean cultivar, castor bean, grain sorghum, or sorghum sudangrass; PL or PL compost were amended to some of the RKN-susceptible soybean and sorghum sudangrass plots. In the third year of the rotation, potato followed by soybean was planted in all 12 treatments. The RKN-resistant soybean, castor bean, sorghum sudangrass, and fallow or tillage decreased the populations of M. incognita compared with microplots where RKN-susceptible soybean had been grown. However, RKN populations quickly recovered. Root-lesion nematode was reduced in the spring of 2001 following application of high rates of PL and PL compost in 2000. In the fall of 2001, sorghum sudangrass alone or in combination with PL or PL compost, grain sorghum, or fallow or tillage reduced root-lesion nematodes compared with either soybean cultivar. No treatment affected root-lesion nematode the following year. The use of cover crops and PL compost is an effective method to reduce nematode populations only if successively incorporated into rotational cropping sequences.

Agricultural nutrient management is an issue due to P loss from fields and water quality degradation. This is especially true in watersheds where a history of P application in excess of crop needs has resulted in elevated soil P (legacy P). As practices and policy are implemented in such watersheds to reduce P loss, information is needed on time required to draw down soil P and how much P loss can be reduced by drawdown. We used the Annual P Loss Estimator (APLE) model to simulate soil P drawdown in Maryland, and to estimate P loss at a statewide scale associated with different combinations of soil P and P transport. Simulated APLE soil P drawdown compared well with measured rates from three field sites, showing that APLE can reliably simulate P dynamics for Maryland soils. Statewide APLE simulations of average annual P loss from cropland (0.84 kg ha) also compared well with estimates from the Chesapeake Bay Model (0.87 kg ha). The APLE results suggest that it is realistic to expect that a concerted effort to reduce high P soils throughout the state can reduce P loss to the Chesapeake Bay by 40%. However, P loss reduction would be achieved gradually over several decades, since soil P drawdown is very slow. Combining soil P drawdown with aggressive conservation efforts to reduce P transport in erosion could achieve a 62% reduction in state-level P loss. This 62% reduction could be considered a maximum amount possible that is still compatible with modern agriculture.

Managing highly variable soil residual nitrate-nitrogen (NO 3 –N) following corn (Zea mays L.) is difficult because it can supply starter N for winter wheat (Triticum aestivum L.) and/or be leached into water resources during the fall–winter water-recharge season in the humid eastern United States. A series of 65 starter N response studies were conducted in the Coastal Plain and Piedmont regions of Maryland to estimate the soil NO 3 –N concentration that was both agronomically sufficient and cost effective for wheat. A subset of studies measured soil NO 3 –N loss (0–60 cm) during the fall–winter season, and additional studies evaluated bromide (Br) to index potential NO 3 –N leaching. A soil exchange frequency index [EFI = rainfall * (available soil water capacity) −1 ] was used to identify where NO 3 –N loss was high and wheat response to starter N was unlikely. A post-planting fall EFI ³ 2.5 was associated with NO 3 –N depletion of >65% (0–60 cm). A significant (P < 0.001) linear-plateau relationship was found between preplant soil NO 3 –N concentration (0–30 cm) and wheat grain-yield response to starter N for locations with EFI < 2.5. This agronomic linear-plateau relation was combined with a break-even economic scenario (fertilizer-N cost = grainresponse value) to estimate the fall NO 3 –N sufficiency for wheat, which was 7 mg NO 3 –N kg −1 soil (0–30 cm) and corresponded to 9 mg NO 3 –N kg −1 soil (0–15 cm). These findings show that a preplant soil NO 3 –N test for winter wheat can facilitate identification of sites where starter N will produce economic returns and reduce potential NO 3 –N losses to water resources. Abbreviations: AWHC, available water holding capacity between FC and PWP; Br, bromide; CV, coefficient of variation; EFI, exchange frequency index; FC, soil water content at field capacity; GS, growth stage; IC, ion-chromatography; LPNR, location previous N regimes; NDFF, the percent of plant N derived from fertilizer; NO 3 –N, nitrate-nitrogen; PWP, soil water content at permanent wilting point; UAN, urea-ammonium nitrate; URS, university research stations.

To determine the possible alternative use of tobacco, the seeds representing seven Maryland tobacco cultivars were investigated for their phytochemical, antioxidant, and antiproliferative properties. Tobacco seed oils were extracted by the Soxhlet method, and analyzed for their yield, density, refractive index, fatty acid profiles, and tocopherol profile. The defatted flours were extracted in 50% acetone and 80% ethanol. The tobacco seed oil and flour extracts were analyzed for total phenolic contents (TPC) and scavenging capacities against peroxyl, hydroxyl and 2,2-diphenyl-1-picryhydrazyl (DPPH) radicals. The fatty acid compositions of phospholipids and the protein content of the flours were also analyzed. In addition, oil and flour extracts of varieties MD609 and MD609LA were evaluated for their antiproliferative effects on HT-29 human colon cancer cells. All of the tested extracts significantly inhibited HT-29 cell proliferation except that from MD609 oil. The data from this study suggest the potential alternative use of tobacco seeds in developing natural antioxidants and antiproliferative agents for improving human health.

Agricultural nutrient runoff to the Chesapeake Bay has been under intense scrutiny for more than a decade in Maryland. One method for capturing these nutrients, especially N, is the use of winter cover crops. This study compared various broadcast cover crop treatments with and without soil incorporation to planting winter cover crop seed with a no-till drill. Seedling emergence and N uptake were the dependent variables measured for two planting dates and seven planting methods. The effects of planting date and planting method for winter wheat (Triticum aestivum L.) and cereal rye (Secale cereale L.) following corn (Zea mays L.) harvest were investigated at two locations. The study was conducted over two winter cover crop growing seasons: 2007―2008 and 2008―2009. Treatments that incorporated the seed into the soil consistently established better stands of cover crops and took up more N regardless of fluctuations in temperature, rainfall, and planting date. Early planted cover crops consistently took up more N than those planted on the later planting date. Performance of the broadcast treatments was highly dependent on rainfall and mild temperatures for success, but did take up notable amounts of N when planted early under good growing conditions. The few differences that were found in the N uptake between wheat and rye within the same planting treatment always indicated that the rye achieved better N uptake than wheat.

Many small unmanned aerial systems use true-color digital cameras for remote sensing. For some cameras, only the red channel is sensitive to near-infrared (NIR) light. Given a camera with this spec...

Establishment of an effective, high-throughput processing system to recover protein from tobacco with no nicotine contamination is essential and vital to the development of value-added, alternative applications for tobacco farmers. We have successfully developed a mechanism capable of processing up to 60 kg of tobacco leaves per hour with phosphate buffer (Na(2)HPO(4)-KH(2)PO(4)) simultaneously added to stabilize the protein as the plant was being disintegrated. The optimal processing parameters were identified, including the ratio of buffer to leaf (BLR) at 4.75 (w/w), buffer pH 7.85, and buffer concentration 0.085 mol/L, achieving a maximum yield of soluble protein at 12.85 mg/g fresh leaf. Acetone at -20 degrees C was the most effective among all methods investigated to remove nicotine from protein; however, it also drastically reduced the recovery rate of protein (63.3%). Ultrafiltration was only able to remove about 50% of the residual nicotine, although the protein recovery rate was high (94.7%). The residual nicotine content inherent in the recovered protein was completely removed by rinsing the protein with 85% phosphoric acid at pH 3.5 for three times with a protein recovery of 94.5%. The pilot-scale operation provides a solid foundation for further scale-up to industrial production of nicotine-free tobacco protein that could bring added value to tobacco for nonsmoking applications.

Eutrophication of freshwater bodies is frequently attributed to elevated phosphorus (P) concentrations in surface runoff from P-enriched agricultural soils. Forage and grain-cropping systems were compared for their effectiveness at remediating P-enriched soils. At each of four locations, one of three forage systems (Forage I = cereal rye silage and corn silage annually; Forage II = alfalfa; Forage III = annual ryegrass and corn silage annually) and the grain system (corn, small grain, and soybean rotation) were maintained for 3 yr on soils with five distinct initial soil P concentrations that were established by using four annual applications (1994-1997) of five different rates (0, 100, 200, 300, and 400 kg total P ha(-1) y(-1)) of poultry manure, dairy manure, or commercial fertilizer. Across all manure P treatments at all locations, the forage systems had greater removal of P than the grain system. Soil P concentration changes (2001-2004) did not reflect differences in crop P removal. Few significant reductions in soil P concentration were observed for either crop system. When reductions did occur, they were for the more highly enriched soil P treatments. No significant reductions in soil P concentration have occurred for the lowest manure P treatments. Considerable variability in crop P concentrations was observed among species at locations and among years produced. However, crop P concentrations did increase uniformly as soil P concentration increased, indicating that luxury consumption of P does occur in agronomic species produced on P-enriched soils.

Combinations of proline and glutamine significantly increased the functional properties of soft wheat that were unseen when added individually. To hard wheat, proline contributed more positively than glutamine on most dough and bread properties, which is different from the observations with soft wheat. Addition of glutamine to hard wheat increased the amount of gluten and glutenin after mixing, whereas proline hinders gluten formation despite the increase in glutenin. The ability of proline and glutamine to modify the functional properties of dough and bread appears to be interdependent. Addition of either proline or glutamine appears to have a protective effect on the retention of the other amino acid during breadmaking.

Although soft red winter wheat (SRWW) (Triticum aestivum L.) is the predominant class in the Mid-Atlantic, there is a recently established program for producers to grow hard red winter wheat (HRWW). This program offers a base price plus premiums for HRWW meeting quality (test weight and protein content) standards. This study's objectives were to evaluate the effect of N management strategies on HRWW yield and protein content and to determine the economic return using those strategies. Two HRWW cultivars used by producers in this HRWW program were produced at two locations in Maryland in a split plot arrangement of N treatments within a randomized complete block experimental design. Main plots (2002) were a factorial arrangement of those cultivars and four fall and Feekes growth stage (GS) 2/3 N treatments. Split plots (2002) were eight N timing and rate combinations at GS 5/6, GS 8, and/or GS 10.1. Main plots (2003) were a factorial arrangement of the cultivars and fall N supplied by either ammonium sulfate (AS) or urea-ammonium nitrate (UAN) and GS 2/3 N treatments. Split plots (2003) were GS 5/6, GS 8, and 10.1 N timing and rate combinations. Wheat yield was significantly improved with GS 8 and/or 10.1 N applications both years. Protein content responded to GS 8 and 10.1 N applications in 2002; however, the response in 2003 was dependent on location and N amount at GS 5/6. Within the price and premium structure, best return was observed for split applications of N; 50 or 68 kg ha -1 at GS 2/3 followed at GS 5/6 with 50 or 68 kg N ha -1 . No fall N benefit was observed.

Corn (Zea maize L.) produced in twin rows (two rows 7.5 inches apart on 30-inch centers) was compared to corn produced in rows spaced 30 inches apart over a range of plant populations at three Maryland locations and one Delaware location during 2003 and 2004. Grain yield averaged over the hybrids and populations differed between the two row spacing treatments at only one of the four locations and in that instance yield was greater in 30-inch rows. Corn produced in twin rows did not produce significantly better yields as plant population increased from 24,000 to 32,000 plants per acre. Only one of twenty-eight hybrid by row spacing combinations evaluated across the four locations had a significant linear response to population for yield. Yield response to population for both row spacing treatments varied across locations and hybrids. Greater levels of lodging occurred as population increased for twin-row corn. A greater incidence of stalk rot was also observed in twin-row corn. These results did nothing to indicate that planting corn in twin rows instead of the conventional 30-inch rows in the Delmarva region would be a beneficial management practice change.

Root-knot [Meloidogyne incognita (Kofoid & White) Chitwood] and lesion [Pralylenchus penetrans (Cobb) Chitwood & Oteifa] nematodes are important pathogens that cause yield and quality losses for most vegetable and field crops in Maryland when they exceed certain threshold levels and if control measures are not applied. Chemical nematicides are the primary control tactic, but their use is both costly and raises environmental concerns. This study was conducted to evaluate the efficacy of crop rotation and other cultural practices for management of southern root-knot nematodes (RKNs) and lesion nematodes. Three nonhost crops, a RKN-resistant soybean [Glycine max (L.) Merr.] cultivar, and poultry litter/tillage (Year 1) and fallow (Year 2) were used as summer rotation crops/management options following production of nematode-susceptible crops on two sites in Dorchester County, MD, on Downer and Hammonton sandy loam soils (coarse-loamy, siliceous, mesic Typic and Aquic Hapludults), respectively. Sorghum sudangrass [Sorghum bicolor (L.) x S. arundinaceum (Desv.) Stapf var. sudanense (Stapf) Hitchc.], grown annually as a green manure crop following a nematode-susceptible crop [potato (Solanum tuberosum L.) or cucumber (Cucumis sativus L.)], reduced the RKN population as effectively as the control treatment (soybean cultivar with no known RKN resistance and one nematicide application). Sorghum sudangrass and poultry litter/tillage/fallow were equally effective in managing the lesion nematode population. Annual inclusion of these practices was necessary to maintain the reduced population levels that were attained for these two nematode species. Finally, either summer or early-fall sampling dates were determined to be more effective than a midspring sampling date for identifying threshold levels of these two pests.

Glyphosate [N-(phosphonomethyl)-glycine]-resistant soybean [Glycine max (L.) Merr.] production in the Mid-Atlantic occurs under full-season and double-crop production systems. Row-spacing and seeding rate manipulation affects the yield of soybean. This study evaluated the effects upon yield caused by reductions in seeding rate from current standards for these two systems. During 2000-2002, row spacing (19 and 38 cm) and seeding rates (current standard, 20 and 40% less, and 20% greater than the standard) were tested using four glyphosate-resistant cultivars representative of the maturity groups for the region. Tests were conducted for both full-season and double-crop systems at two Maryland locations for each per year on coastal plain soils. During the 3 yr, only 1 out of 48 total cultivar × row spacing comparisons for the two production systems had better yield with 38-cm rows. At best, 38-cm row spacing produced equivalent to the 19-cm rows. A 20% seeding rate reduction (345 800 seeds ha -1 for full-season and 444 600 seeds ha -1 for double-crop production) was generally found to not yield significantly different than the standard seeding rates for both systems. A 40% reduction consistently had yield significantly less than the standards in both systems. These results indicate a 20% seeding rate reduction can be a cost-saving practice for glyphosate-resistant soybean production in the Mid-Atlantic. With no yield loss at a 20% reduced seeding rate, additional profit ranging from $14.30 to $27.72 ha -1 can be realized.

The European corn borer [Ostrinia nubilalis (Hubner)] is an important pest of field corn (Zea mays L.) in the northeastern USA. One option for reducing yield loss from European corn borer (ECB) is the use of transgenic corn hybrids containing a modified Bacillus thuringensis (Bt) gene. This study evaluated Bt hybrids, their near isolines, and leading non-Bt hybrids for grain yield, moisture, and test weight under natural infestations of ECB in 2000, 2001, and 2002 at four to six locations across Pennsylvania and Maryland each year. Averaged over all locations and years, Bt, isoline, and lead hybrids yielded 9.1, 8.6, and 8.5 Mg ha -1 , respectively. Grain moisture content at harvest was 224, 216, and 214 g kg -1 and test weight was 705, 713, and 713 kg m -3 for Bt, isoline, and lead hybrids, respectively. Overall, Bt hybrids produced higher yields, but also had higher grain moisture content at harvest and lower test weight than isoline and lead hybrids. Yield and moisture content differences were correlated with ECB infestations, but test weight was not. Isoline and lead hybrid yields were reduced by 2.37 and 2.60% respectively, for each ECB tunnel. Precipitation had no consistent effect on Bt and non-Bt hybrid differences for yield, moisture, or test weight. Delayed planting dates were associated with higher ECB infestations. This may be beneficial in predicting sites that could benefit from Bt hybrids. In some environments in Pennsylvania and Maryland, Bt hybrids can result in significant yield advantages.

Pre-harvest sprouting (PHS) of wheat occurs when the mature seed germinates on the plant prior to harvest. Sprouted grain has lower test weight and poor baking quality. It was of interest to evaluate the levels of PHS resistance in soft red winter wheat because moist conditions during harvest are common in the Mid-Atlantic region of the United States. Field studies to evaluate PHS resistance among eighty genotypes of soft red winter wheat were conducted over two years at two locations in Maryland (USA). PHS resistance was measured by conducting germination tests of seed harvested six weeks post-anthesis. Average sprouting was 15.8% in the first year and 69% in the second year. Genotypes that were highly resistant and highly susceptible to PHS were identified. This information will be useful for breeding of PHS resistance and for development of segregating populations for mapping of PHS resistance in soft red winter wheat.

AFLP (Amplified Fragment Length Polymorphism) markers were investigated for assessing diversity and fingerprinting of a selected sample of soft red winter wheat (SRWW) genotypes that differed for pre-harvest sprouting (PHS) resistance and for the presence of awns. Sixty AFLP primer pairs generated 2944 polymorphic bands out of a total of 6778 bands scored among 15 SRWW genotypes. The mean polymorphism information content was 0.37 and the average marker index was 15.1, indicating that AFLP generated more information in wheat than other molecular markers. Forty-two primer pairs that contained no missing data points were used to create a dendrogram to estimate the genetic distance among genotypes. A total of 4761 loci, of which 1915 were polymorphic, were included in the genetic similarity matrix. Primer pairs showed a high degree of correlation between four arbitrarily divided primer subsets (r=0.82). The SRWW genotypes investigated did not group together regarding resistance to PHS or the presence of awns. The mean genetic similarity values among the 15 genotypes ranged from 0.83 to 0.94. Although the genetic similarity among these soft red winter wheat genotypes was high, differences were found that could be used for assessing genetic diversity as well as for plant variety protection use.

In the Middle Atlantic Region, fall rain sometimes delays planting soft red winter wheat (Triticum aestivum L.). This study measured whether the yield loss due to a planting delay can be reduced by an increased seeding rate. Field experiments were carried out in the 1989-1990 and 1990-1991 crop years at Beltsville and Clarksville, MD. Cultivars 'Florida 302' and 'Twain' were planted on three dates, recommended seeding date (Date 1), 2 to 3 wk later (Date 2), and 4 to 6 wk later (Date 3) at seeding rates of 38.0 (Rate 1, currently recommended), 47.5 (Rate 2), 57.0 (Rate 3), and 66.5 seeds/sq ft (Rate 4). Delayed seeding had more detrimental effects on FL302 than on Twain. The effects of date, rate, and their interactions on yield were not significant at Beltsville [...]

Coenzyme Q10 (CoQ10), a potent antioxidative dietary supplement, was produced using a photosynthetic bacteria Rhodospirillum rubrum ATCC 25852 by submerged fermentation supplemented with tobacco biomass hydrolysate (TBH) in comparison with media supplemented with hydrolysates prepared with alfalfa (ABH) or spinach (SBH). Growth medium supplemented with 20% (v/v) TBH was found favorable with regard to cell density and CoQ10 concentration. The stimulation effects on cell growth (shortened lag phase, accelerated exponential growth, and elevated final cell concentration) and CoQ10 production (enhanced specific CoQ10 content per unit cell weight) could be attributed to the presence of solanesol, the precursor of CoQ10, in the tobacco biomass. The final yield of CoQ10 reached 20.16 mg/l in the fermentation medium supplemented with 20% TBH.

Field studies in Pennsylvania and Maryland were conducted during 2000, 2001, and 2002 to test the applicability of published yield loss relationships developed in central Pennsylvania for European corn borer, Ostrinia nubilalis (Hübner), management in warmer, longer season corn, Zea mays L., grain production regions of the northeastern United States. Both isoline hybrids and non-Bt lead hybrids were compared against Bacillus thuringiensis (Bt) hybrids to measure effects of the pest on yield. The European corn borer economic analysis model was used to make site-specific predictions of loss per European corn borer larva for comparison with measured yield loss per larva. Although the model did not predict loss per larva at a field level, it did predict loss at a regional level. The model predicted an overall percentage of yield loss per larva of 2.69+/-0.12% over the region, which was similar to the measured yield loss per larva of 2.66+/-0.59% for isoline hybrids and 3.08+/-0.51% for lead hybrids. The model, on average, provided a good prediction of percentage of yield loss per larva within the climatic zones of 1100-1700 degree-days (DD) (base threshold 12.5 degrees C). Our results suggest that the yield loss relationship developed in Central Pennsylvania, when matched to the timing of third instar second generation European corn borer stalk tunneling is adequate for major corn grain production zones of the northeast United States.