The importance of fungicide seed treatments on cotton was examined using a series of standardized fungicide trials from 1993 to 2004. Fungicide seed treatments increased stands over those from seed not treated with fungicides in 119 of 211 trials. Metalaxyl increased stands compared to nontreated seed in 40 of 119 trials having significant fungicide responses, demonstrating the importance of Pythium spp. on stand establishment. Similarly, PCNB seed treatment increased stands compared to nontreated seed for 44 of 119 trials with a significant response, indicating the importance of Rhizoctonia solani in stand losses. Benefits from the use of newer seed treatment chemistries, azoxystrobin and triazoles, were demonstrated by comparison with a historic standard seed treatment, carboxin + PCNB + metalaxyl. Little to no stand improvement was found when minimal soil temperatures averaged 25°C the first 3 days after planting. Stand losses due to seedling pathogens increased dramatically as minimal soil temperatures decreased to 12°C and rainfall increased. The importance of Pythium increased dramatically as minimal soil temperature decreased and rainfall increased, while the importance of R. solani was not affected greatly by planting environment. These multi-year data support the widespread use of seed treatment fungicides for the control of the seedling disease complex on cotton.

Soybean [Glycine max (L.) Merr.] germplasm SS93‐6012 (Reg. No. GP‐362, PI 652442) and SS93‐6181 (Reg. No. GP‐363, PI 652443) were developed and released by the University of Missouri–Columbia in January 2006 as resistant to Phomopsis seed decay (PSD), caused by Phomopsis spp. Both lines were developed from a cross between MO/PSD‐0259 (PI562694) (PSD‐resistant MGIV germplasm) and ‘Asgrow 3834’ (PSD‐susceptible MGIII cultivar) made in 1990 at the Bradford Research and Extension Center of the University of Missouri, Columbia, MO. The lines were composited in the F5 generation and evaluated for yield and Phomopsis seed decay infection. These lines are highly resistant to Phomopsis spp. SS93‐6012 has a relative maturity of 4.2, purple flowers, gray pubescence, an indeterminate growth habit, tan pods at maturity, yellow color seeds, buff hila, and seed weight of ∼14 g per 100 seeds. SS93‐6181 has a relative maturity of 4.0, purple flowers, tawny pubescence, an indeterminate growth habit, tan pods at maturity, yellow color seeds, imperfect black hila, and seed weight of ∼16 g per 100 seeds. So far, PSD‐resistant commercial soybean cultivars are not available, and these two lines may be used for development of PSD‐resistant high‐yielding soybean cultivars.

Asian soybean rust (ASR) caused by Phakopsora pachyrhizi Sydow is one of the most destructive diseases of soybean. The first detection of ASR in Mississippi on soybean was in Adams Co. on 16 November 2004. As of November 2006, ASR was found in Claiborne, George, Issaquena, Jackson, Jefferson, Lee, Warren, Washington, and Yazoo counties in 20 locations. Accepted for publication 22 May 2007. Published 17 September 2007.

Dr. A. Forest Robinson , USDA Agricultural Research Service, Southern Plains Agricultural research Center, College Station, TX Dr. P. Agudelo , Clemson Univ., Clemson, SC Mr. C. A. Avila , Univ. of Arkansas, Fayetteville, AR Dr. A. A. Bell , USDA-ARS, College Station, TX Dr. F. E. Callahan , USDA-ARS, Mississippi State, MS Dr. C. G. Cook , All-Tex Seed/Leveland Delinting, Inc., Victoria, TX Dr. N. D. Dighe , Dep. Soil and Crop Sciences, College Station, TX Dr. O. A. Gutierrez , Dep. of Plant and Soil Sciences, Mississippi State, MS Dr. R. W. Hayes , USDA-ARS, Mississippi State, MS Dr. J. N. Jenkins , USDA-ARS, Mississippi State, MS Dr. J. T. Johnson , Bayer CropScience, Leland, MS Dr. R. Kantety , Fac. Forestry, Normal, AL Dr. G. W. Lawrence , Dep. Entomology and Plant Pathology, Mississippi State, MS Dr. K. S. Lawrence , Dep. Entomology and Plant Pathology, Auburn, AL Ms. L. Mangineni , Dep. Agronomy and Soils, Auburn, AL Dr. J. C. McCarty , USDA-ARS, Mississippi State, MS Dr. M. A. Menz , Dep. Soil and Crop Sciences, College Station, TX Dr. W. A. Meredith Jr. , USDA-ARS, Stoneville, MS Dr. R. N. Nichols , Cotton Incorporated, Cary, NC Dr. R. T. Robbins , Dep. of Plant Pathology, Fayetteville, AR Dr. E. Sacks , USDA-ARS, Stoneville, MS Dr. B. Scheffler , USDA-ARS, Stoneville, MS Dr. G. L. Sciumbato , Dep. Entomology and Plant Pathology, Stoneville, MS Dr. C. W. Smith , Dep. Soil and Crop Sciences, College Station, TX Dr. J. L. Starr , Dep. Plant Pathology and Microbiology, College Station, TX Dr. D. M. Stelly , Dep. Soil and Crop Sciences, College Station, TX Dr. S. R. Stetina , USDA-ARS, Stoneville, MS Dr. J. McD. Stewart , Univ. of Arkansas, Fayetteville, AR Dr. P. M. Thaxton , Dep. Plant and Soil Sciences, Mississippi State, MS Dr. T. P. Wallace , Dep. Plant and Soil Sciences, MIssissippi State, MS Dr. D. B. Weaver , Dep. Agronomy and Soils, Auburn, AL Dr. M. J. Wubben , USDA-ARS, Mississippi State, MS Dr. L. D. Young , USDA-ARS, Stoneville, MS

Thirty-nine commercial cotton (Gossypium hirsutum) cultivars were evaluated to identify those with tolerance to reniform nematode (Rotylenchulus reniformis). Trials were conducted for three years at two west-central Mississippi field locations naturally infested with reniform nematode. Main plots were cultivars and subplots were either not treated or treated with nematicide. Reniform nematode soil population densities were assessed throughout the growing season. At harvest, seed cotton yields were determined, and fiber quality was evaluated for select samples. Data were pooled from all years and locations, and t-tests were used to identify tolerant cultivars. Cultivars were judged tolerant if nematicide did not improve yield, although the nematode population was reduced at a midseason sampling interval. Only Deltapine 449 BR, Paymaster 1218 BR, and Suregrow 215 BR met these criteria. Additionally, tolerance indices were calculated for nine cultivars showing suppressed nematode populations in nematicide-treated plots at any point during the growing season. The three tolerant cultivars identified based on the t-tests ranked first (Suregrow 215 BR), second (Paymaster 1218 BR), and fifth (Deltapine 449 BR) with respect to tolerance index. Because they do not appear to suffer significant yield loss due to reniform nematode, these three cultivars may benefit growers. Accepted for publication 12 January 2009. Published 12 March 2009.

Our objective was to determine if tillage (disk fall and spring, disk fall only, or no tillage) affected rice diseases, plant population density, and yields in a rice monoculture system. Stem rot was the only disease that developed in plots during 1994, and the severity index was the same for all tillage treatments. Diseases did not develop in plots during 1995 and 1996. Tillage treatments did not affect rice plant population or yields. This is the first report on the effects of tillage on stand and yield in a rice monoculture system. A fall-only tillage system (stale seedbed) may be useful to some rice producers in the central USA because yields are similar to those in a conventional tillage system. Ruts in the field due to harvest equipment could be eliminated by fall tillage, and tillage in the spring would not be necessary prior to planting and application of a burn-down herbicide.

Twenty samples of unpolished (rough) rice collected in Arkansas and Texas during the 1995 harvesting season from fields exhibiting Fusarium sheath rot disease or panicle blight were previously shown to include 8 samples positive for fumonisin B 1 (FB 1 ) in the range 2.2–5.2 ppm, and moniliformin (MON), but no beauvericin (BEA), deoxynivalenol, its derivatives or zearalenone were detected. Fifteen cultures of F. proliferatum were established from the 20 rough rice samples. Single spore isolates of each culture were grown on rice and tested for the production of fumonisins (FB 1 , FB 2 , FB 3 , etc.), MON and BEA. All 15 isolates produced FB 1 , FB 2 , MON and BEA in culture on rice. No deoxynivalenol, its derivatives orzearalenone were detected. Seven cultures produced FB 1 at >50ppm (range 80–230 ppm), with therest producing FB 1 in the range 14–43 ppm.FB 2 was produced in the range 5–47 ppm, and those cultures which produced the most FB 1 also produced the most FB 2 . Of the 15 cultures producing MON, 11 produced it at >100 ppm in the range 188–6018 ppm, with the rest producing in the range 7–64 ppm. BEA was produced in the range 109–1350 ppm. Other derivatives of fumonisins, including FA 1 , FA 2 and partially hydrolyzed FB 1 , as well asseveral unknown metabolites including a compound with MW 414, were identified in culture extracts by continuous flow fast atom bombardment with ion spraymass spectrometry (CF/FAB/MS). Further study is needed to identify the factors that control production of FB 1 , MON and BEA by F.proliferatu in culture and in field samples.

Twenty samples of rough rice (Oryza sativa) (unpolished kernels) collected during the 1995 harvest season from Arkansas (seven samples) and Texas (13 samples) were obtained from rice fields known to include plants with symptoms of Fusarium sheath rot putatively caused by Fusarium proliferatum. Samples were analyzed for fumonisin B1 (FB1) at three laboratories using three different extracting solvents by high-performance liquid chromatography (HPLC) or enzyme-linked immunosorbent assay (ELISA) methods. Forty percent of the samples were positive for FB1 at levels ≤4.3 μg/g by HPLC. The same samples contained FB1 at ≤3.6 μg/g when measured by an ELISA method. Most samples that were positive for FB1 were positive for fumonisin B2 (FB2) and fumonisin B3 (FB3) by HPLC at levels ≤1.2 μg/g. Very good agreement was obtained among the two laboratories using HPLC methods and the third using ELISA. Shelling of the unpolished rice results in hull and brown rice fractions. In a sample that contained 4.3 μg/g in whole kernels, the fumonisin level was very high in hulls (≤16.8 μg/g) and low in brown rice (≤0.9 μg/g). Milling of brown rice results in bran and white rice fractions. Fumonisins were found in bran at a level of ≤3.7 μg/g but were below the level of detection by HPLC in white rice. The presence of fumonisins (FB1, FB2, and FB3) was confirmed by fast atom bombardment/mass spectrometry. This is the first report of fumonisins in naturally contaminated rice in the United States.

Soybean cyst nematode (SCN) (Heterodera glycines Ichinohe) infests soils throughout the mid and lower Mississippi River Valley and the southeastern Coastal Plain in the USA, a region where irrigation is widely practiced. This study was conducted to determine the effect of irrigation on number of SCN cysts and seed yield of three soybean [Glycine max (L.) Merr.] cultivars that have varying levels of SCN resistance when grown in monoculture on SCN‐infested Dundee silt loam (fine‐silty, mixed, thermic, Aerie Ochraqualf) that has a perched water table. Cultivars (all Maturity Group V) were Forrest (resistant to SCN Race 3), A5474 (resistant to SCN Races 3 and 4), and Bay (susceptible to SCN). Bay was grown with and without nematicide applied after planting. Irrigation treatment was either with or without supplemental water during reproductive development of soybean. Neither seed yield nor number of SCN cysts at planting or harvest were significantly (P = 0.05) affected by irrigation on this soil. Application of nematicide to Bay plots reduced the number of SCN cysts at harvest, but did not significantly affect seed yield. Number of SCN cysts was lowest in A5474 plots, and seed yield of A5474 was highest in the second and third year of the study. Irrigation did not significantly interact with cultivar or nematicide to affect cyst number or seed yield. We conclude that irrigation during reproductive development of soybean did not affect (i) cultivar response to infection with SCN, (ii) the capability of SCN to maintain cysts on any cultivar, or (iii) the yield‐limiting effect of SCN on susceptible cultivars. This suggests that SCN effects on soybean are more complex than simply restricting water uptake by roots.

Soybean [Glycine max (L.) Merr.] producers are often faced with the dilemna of using expensive inputs with little or no assurance of an economic return. In order for these inputs to be feasible, a resonable expectation of success as measured in either increased quality or quantity of seed yield is required. One such production input that has gained increased attention is the use of foliar‐applied fungicides. An experiments using ‘Centenniala’ and ‘Tracy‐M’ soybeans was planted in the field on 15 May 1981 and 9 May 1983 on Sharkey clay (Vectic Haplaquept, very‐fine, montmorillonitic,thermic) Stoneville, MS, to determine the effect of benomyl [methyl 1‐(butylcarbamoyl‐2‐benzimidazolecarbamate] fungicide on seed yield of irrigated and nonirrigated soybeans. Irrigation treatments were nonirrigated (NI), and irrigation started at beginning of bloom(R1) and continued whenever soil water potential (SWP) at the 30 cm (T30) and 60 cm depths (T60) dropped to between −50 and −100 kPa. Irrigation was continued through the full‐seed stage (R6) in both T30 and T60. Two irrigation methods, furrow and overhead, were used. The fungicide was sprayed onto the foliage in equal amounts (0.28 kg a.i. ha−1) at Stages R3 and RS. Significant yield increases of 194 kg ha−1 in 1981 (P < 0.10) and 145 kg ha−1 in 1983 (P < 0.05) resulted from applying the fungicide to the most frequently watered treatment (T30). Use of the fungicide did not significantly affect yield in the less‐watered treatment (T60) or the nonirrigated treatment. Type of irrigation had no significant effect on yield response to fungicide. Yield increases resulting from optimum (T30) irrigation were large (> 1500k g ha−1) and significant in both years, and most of the increase was attributable to increased number of seed. The yield increase that was obtained from the benomyl‐treated T30 treatment was the result of about equal percentage increases in both seed weight and number of seed. These results indicate that benomyl foliar fungicide should be used only on those soybeans that will receive adequate water throughout reproductive development.