Larry K. Binning

Aldicarb immunomodulation in mice: An inverse dose-response to parts per billion levels in drinking water

The effects of aldicarb (a carbamate insecticide and nematocide) on selected immune and non-immune parameters of mice were examined. The primary objective was to determine whether exposure to low levels of aldicarb through drinking water could affect selected immune functions. Aldicarb was administered via drinking water either at 10, 100, and 1,000 parts per billion (ppb)2 for 14 days or at 1, 10, 100, and 1,000 ppb for 34 days. The 34-day experiment was repeated twice with minor variations. Aldicarb significantly and repeatedly suppressed the splenic plaque forming cell response to sheep red blood cells at the lowest concentrations tested: the 1 ppb level elicited greater suppression of plaque forming cells and other immune factors than did 1,000 ppb of aldicarb. This inverse dose-response represents a dramatic departure from the classic toxicologic dose-response curve, where toxicity increases with increasing dose levels.

Phenology of common lambsquarters growth parameters

Abstract Research was conducted to characterize the phenology of common lambsquarters growth parameters as influenced by climatic variation among years. Treatments included soybean or corn grown alone, common lambsquarters with soybean or corn, and common lambsquarters grown alone. Common lambsquarters leaf area and plant height phenology differed among years and was variable within treatments. Conversely, crop leaf area and plant height phenology did not differ among years and was less variable within a treatment than common lambsquarters. Weed relative leaf area and relative volume differed among years because of differences in crop and common lambsquarters leaf area and plant height phenology. Differences in common lambsquarters relative leaf area and relative volume among years may explain differences in previously reported crop yield responses to weed infestations between sites and years. Although common lambsquarters relative leaf area and relative volume differed among years, variability as indicated by regression coefficients of determination was also high within year and treatment. Crop leaf area and plant height phenology were well described by regression equations, with r2 values greater than 0.68. Therefore, low coefficients of determination for relative leaf area and relative volume models were attributed to variability in common lambsquarters within a treatment. Nomenclature: Common lambsquarters, Chenopodium album L. CHEAL; field corn, ‘Dekalb DK493SR’, Zea mays L.; soybean, ‘Asgrow XP19505RR’ and ‘AG2101RR’, Glycine max L. Merr.

Predicting soybean yield loss in giant foxtail (Setaria faberi) and common lambsquarters (Chenopodium album) communities

Abstract Widespread use of crop yield loss models based on weed density has been limited on account of spatial and temporal variability. Furthermore, research characterizing crop yield loss associated with two or more weed species is lacking for many cropping systems. Therefore, research was conducted to characterize giant foxtail and common lambsquarters leaf area, height, and shoot volume in soybean, to quantify the relative competitive ability of giant foxtail and common lambsquarters in a mixed–weed species environment, and to assess weed density, weed relative leaf area, and weed relative volume as predictors of soybean yield loss. Based on weed density, coefficient estimates of percent soybean yield loss as giant foxtail or common lambsquarters densities approached zero differed between years. In contrast, coefficient estimates of maximum soybean yield loss were similar between years. Based on weed relative leaf area, estimates of giant foxtail or common lambsquarters damage coefficients differed between years. Similarly, estimates of maximum soybean yield loss associated with common lambsquarters leaf area differed between years, whereas estimates of maximum soybean yield loss associated with giant foxtail leaf area did not change over time within a growing season or between years. Based on weed relative volume, estimates of giant foxtail or common lambsquarters damage coefficients differed between years. Similarly, estimates of maximum soybean yield loss associated with common lambsquarters volume differed between years, whereas estimates of maximum soybean yield loss associated with giant foxtail volume did not change over time within a growing season or between years. Based on weed density, weed relative leaf area, or weed relative volume, giant foxtail was more competitive than common lambsquarters in terms of soybean yield loss. Temporal variability of weed density, weed relative leaf area, and weed relative volume indicates that additional parameters may be required to accurately predict weed–crop interactions in a multiple–weed species community. Nomenclature: Giant foxtail, Setaria faberi Herrm. SETFA; common lambsquarters, Chenopodium album L. CHEAL; soybean, Glycine max (L.) Merr. ‘Asgrow AG2101’.

Growth interactions in communities of common lambsquarters (Chenopodium album), giant foxtail (Setaria faberi), and corn

Abstract The relative competitive ability of common lambsquarters and giant foxtail in mixed weed–corn communities was characterized in 1998 and 1999 using empirical models that described late-season weed biomass on the basis of weed density, early-season relative leaf area, or early-season relative shoot volume. Competition coefficients estimated from weed density were inconsistent between years because they indicated that giant foxtail was more competitive than common lambsquarters in 1998 but that common lambsquarters was more competitive than giant foxtail in 1999. In contrast, the competition coefficients based on relative leaf area and relative volume were consistent between years. Competition coefficients estimated from relative leaf area indicated that giant foxtail was more competitive than common lambsquarters in each year. Competition coefficients estimated from weed relative volume indicated that the relative competitive ability of each weed species was similar in each year. Weed relative competitive abilities were characterized further by describing the mechanisms of competition related to shoot height and width growth. Giant foxtail was taller than common lambsquarters shortly after emergence each year, but plasticity of common lambsquarters growth resulted in reduced height differential between the weed species over time. Even so, giant foxtail was taller than common lambsquarters at physiological maturity each year. Coefficients that described the ability of each weed species to crowd neighbors indicated that giant foxtail shoot width was affected more by increased common lambsquarters density and proportion than was common lambsquarters shoot width by giant foxtail. The greater ability of common lambsquarters to crowd neighbors relative to giant foxtail was attributed to the greater leaf area density (LAD) of common lambsquarters compared with that of giant foxtail. Although characterization of shoot height, width, LAD, and biomass elucidated in part the mechanisms of competition between these species, models that accounted for differences in early-season relative plant size were consistent between years, indicating that giant foxtail was equally or more competitive than common lambsquarters in corn. Nomenclature: Common lambsquarters, Chenopodium album L. CHEAL; giant foxtail, Setaria faberi Herrm. SETFA; corn, Zea mays L. ‘Dekalb DK493SR’.

Estimating giant foxtail cohort productivity in soybean based on weed density, leaf area, or volume

Abstract Understanding weed–crop interactions is critical in predicting crop yield loss, but it is also important to understand how these interactions affect weed productivity. Therefore, research was conducted to characterize the weed relative leaf area and weed relative volume of several giant foxtail cohorts in soybean, and to assess weed density and cohort emergence time, weed relative leaf area, and weed relative volume as predictors of giant foxtail shoot biomass and fecundity. Giant foxtail cohorts emerged at VE (emergence), VC (cotyledon), V1 (first node), and V3 (third node) soybean growth stages and were thinned to densities of 0, 4, 16, 36, and 64 plants m−2. Based on weed density and cohort emergence time, the maximum shoot biomass per square meter or the maximum fecundity per square meter differed between years. In contrast, shoot biomass or fecundity per plant, as weed density approached zero, and the rate at which shoot biomass or fecundity decreased exponentially, as time increased, were similar between years. Based on the weed relative leaf area, the cohort effect on giant foxtail shoot biomass differed between years, whereas the cohort effect on giant foxtail fecundity was similar between years. Maximum giant foxtail shoot biomass per square meter or fecundity per square meter differed between years when estimated from weed relative leaf area. Based on the weed relative volume, the cohort effect on giant foxtail shoot biomass per square meter or fecundity per square meter was similar between years, as was the maximum giant foxtail shoot biomass per square meter or fecundity per square meter. The temporal stability of weed relative volume, used to describe giant foxtail shoot biomass or fecundity, may aid in improving bioeconomic weed management models. Nomenclature: Giant foxtail, Setaria faberi Herrm. SETFA; soybean, Glycine max (L.) Merr. ‘Asgrow AG2101’.

Empirical corn yield loss estimation from common lambsquarters (Chenopodium album) and giant foxtail (Setaria faberi) in mixed communities

Abstract Corn yield loss associated with common lambsquarters and giant foxtail in mixed-weed species communities was estimated from empirical equations based on early-season weed density, weed relative leaf area, or weed relative shoot volume in 1998 and 1999. The estimated maximum corn yield loss ranged up to 20% in 1998 but was 50% or more in 1999. Competition coefficients estimated from weed density (I values) or weed relative shoot volume (qV values) indicated that the weed species were equally competitive in 1998 but that common lambsquarters was more competitive than giant foxtail in 1999. In contrast, the relative leaf area–based competition coefficients (qL values) indicated that common lambsquarters and giant foxtail were equally competitive in both years. Weed species emerged at the same time as corn in 1998, whereas in 1999, common lambsquarters emerged 3 d earlier than corn and 1 d earlier than did giant foxtail. Earlier emergence of common lambsquarters was associated with greater cumulative intercepted photosynthetically active radiation (IPAR) per plant compared with that of giant foxtail. Competition coefficients estimated from weed relative leaf area were similar between years for common lambsquarters but differed for giant foxtail. Similarly, the relationship between cumulative estimated IPAR and early-season relative leaf area was stable between years for common lambsquarters but not for giant foxtail. Consequently, competition coefficients were more consistent for common lambsquarters than for giant foxtail in mixed communities. The results suggest that the competitive ability of common lambsquarters and giant foxtail may not differ greatly in corn, but variability in corn yield loss between years was not adequately explained by these empirical models. Nomenclature: Common lambsquarters, Chenopodium album L. CHEAL; giant foxtail, Setaria faberi Herrm. SETFA; corn, Zea mays L. ‘Dekalb DK493SR’.

A canopy development model for potatoes

Potatoes (Solanum tuberosum) in Wisconsin are predominately grown on soils that have a high potential for agrichemical leaching. Weed control strategies are not designed for season long control from a single high rate herbicide application but for reduced rates combined with mechanical and cultural strategies. The current recommended herbicide rates provide 7–9 weeks of efficacy. Mechanical measures provide effective early season control, but development of crop canopy prevents cultivation after about four weeks. Past studies have shown that shade levels comparable to those in a potato canopy can significantly reduce weed biomass. This study was initiated to develop a canopy development model and evaluate the difference between Superior and Russet Burbank potatoes. Plots were established in 1988–1992 at the Hancock Agricultural Research Station on Plainfield loamy sand (mixed, typic Upsidaments). Light readings were taken both under the crop canopy and in full sunlight to determine the amount of shading provided by the crop. Physiological Degree Days (P-days) were used to monitor the development of the potato varieties. Regression analysis was used to determine if P-days could be used as a predictor for canopy development. Superior reached maximum canopy (88% shade) at seven weeks after emergence (WAE) and maintained it until 9 WAE. Russet Burbank reaches maximum canopy at 8 WAE (98% shade) and maintains shading above 80% until 13 WAE. The canopy model is an empirical relationship estimated using regression techniques, and is currently being utilized in a weed management module for the WISDOM

Effect of cultivar, row spacing, and weed management on weed biomass, potato yield, and net crop value

Research was conducted to quantify the effects of potato cultivar, row spacing, and weed control treatments on weed biomass, crop yield, and net crop value. Cultivars evaluated included Russet Burbank, Russet Norkotah, Goldrush, Dark Red Norland, Snowden, and Atlantic. Inter-row spacings of 76 and 91 cm with an intra-row spacing of 30 cm were evaluated in 1996 and 1997. Weed control treatments included a herbicide tank-mix of metribuzin and metolachlor, cultivation, and a hilling-only control. Common lambsquarters and total weed biomass were greater in the 76-cm row spacing than in the 91-cm row spacing across all cultivars in 1996 and 1997. In 1997, chemical control resulted in less weed biomass than both the hilling-only and cultivation treatments. Total marketable yield was greater in the 91-cm row spacing than in the 76-cm row spacing across cultivars in 1996, but was similar across row spacings in 1997. Net crop value was greater across cultivars in the 91-cm row spacing than in the 76-cm row spacing in 1996. Reduced weed biomass in 1996 and 1997, coupled with greater total marketable yield and net return in 1996, indicated that the 91-cm row spacing was the optimal row spacing for Russet Burbank, Goldrush, Russet Norkotah, Snowden, and Atlantic cultivars in 1996 and 1997. Similar yields and net crop value among weed control treatments in 1996 and 1997 indicated that cultivation and possibly even hilling-only areas within fields can be viable alternatives to herbicide use.ResumenLa investigación fue conducida para cuantificar los efectos de los cultivares de papa, el espaciamiento entre hileras y los tratamientos de control de malezas sobre la biomasa de maleza, rendimientos del cultivo y valor neto del cultivo. Los cultivares evaluados incluyeron Russet Burbank, Russet Norkotah, Goldrush, Dark Red Norland, Snowden y Atlantic. Durante 1996 y 1997 se evaluaron espaciamientos de 76 y 91 cm entre hileras, con un espaciamiento interior de 30 cm. Los tratamientos de control de malezas incluyeron una mezcla en tanque de los herbicidas metribuzin y metolachlor, labores culturales y sólo un aporque como control. La quinua silvestre común(Chenopodium album) y la biomasa total de maleza fueron mayores en los espaciamientos entre hileras de 76 cm que en los de 91, en todos los cultivares en 1996 y 1997. En 1997, el control químico resultó en menos biomasa de maleza que la obtenida con aporque y tratamientos del cultivo. Los rendimientos comerciales totales fueron mayores en los espaciamientos entre hileras de 91 cm que en los de 76 en todos los cultivares en 1996, pero fueron similares en todos los espaciamientos entre hileras de 1997. El valor neto del cultivo fue mayor en los cultivares con espaciamientos entre hileras de 91 cm que en los de 76 cm en 1996. La biomasa reducida de maleza en 1996 y 1997, conjuntamente con el mayor rendimiento comercial total y el retorno neto en 1996, indicaron que 91 cm era el espacio óptimo entre hileras para los cultivares Russet Burbank, Goldrush, Russet Norkotah, Snowden y Atlantic en 1996 y 1997. Los rendimientos y valores netos de cultivo similares obtenidos con los tratamientos de control de malezas en 1996 y 1997 indicaron que las labores culturales y posiblemente aún sólo el aporque en áreas dentro de los campos pueden ser alternativas viables frente al uso de herbicidas.

Common lambsquarters photosynthesis and seed production in three environments

Abstract Research was conducted in 1998 and 1999 to characterize common lambsquarters photosynthesis and seed production as influenced by biotic (crop environment) and abiotic (climate) factors. Treatments were common lambsquarters in soybean, in corn, and in common lambsquarters monoculture. Common lambsquarters net photosynthesis was variable among treatments and differed between years. In 1998, early-season common lambsquarters net photosynthesis did not differ in soybean, corn, or common lambsquarters monoculture. In 1999, early-season common lambsquarters net photosynthesis was greater in corn than in soybean, but did not differ from that of common lambsquarters in monoculture. By midseason in both years, common lambsquarters net photosynthesis was less in soybean than in corn or in common lambsquarters monoculture. By late season in both years, common lambsquarters net photosynthesis was greater in common lambsquarters monoculture than in soybean or corn. Common lambsquarters seed production per plant was greater in common lambsquarters monoculture than in soybean or corn. Common lambsquarters seed production was variable among plants and between years. Practical applications of models to predict weed fitness that are based on photosynthetic capacity will be limited until variability in net photosynthesis and in seed production are better understood. Nomenclature: Common lambsquarters, Chenopodium album L. CHEAL; corn, Zea mays L. ‘Dekalb DK493SR’; soybean, Glycine max L. Merr., ‘Asgrow AG2101RR’.

Pest management for potatoes in Wisconsin— A pilot program

A potato integrated pest management program was conducted from 1979–82 by University of Wisconsin-Extension in two of Wisconsin’s major potato producing areas. The program utilized trained field scouts for intensive pest monitoring, and economic thresholds for pest control recommendations; also a grower fee to pay for the scouting service. The program scouted between 1360 ha and 3240 ha during 1979–1982 growing seasons on a weekly basis for pest problem development in the field and worked with approximately 50 commercial potato growers each year. In general, program participants used more fungicide applications and fewer insecticide applications than the control group.The pesticide usage pattern on potatoes by the IPM grower group supports the integrated pest management concept of ‘fine-tuning’ pesticide usage to individual fields, weather conditions and pest problems.ResumenUn programa de control integrado de piagas fue conducido entre 1979 y 1982 por el grupo de Extensión de la Universidad de Wisconsin en dos de las areas principales de producción de papa. El programa utilizó jóvenes con entrenamiento de campo para llevar un registro contínuo e intensivo de plagas, establecer recomendaciones sobre niveles básicos económicos de control y determinar una cifra a pagar por el agricultor por este servicio. El programa registró semanalmente entre 1360 ha y 3240 ha durante las campañas de 1979 y 1982 para el desarrollo de problemas de plagas y utilizó alrededor de 50 productores comerciales cada año. En general, los participantes usaron más aplicaciones de fungicidas y menos aplicaciones de insecticidas que el grupo usado como control.El patrón de uso de pesticidas en papa por el grupo de productores participantes del programa de mayor apoyo al concepto de “afinamiento” en el uso de pesticidas en manejo integrado de plagas de acuerdo a campos individuales, a condiciones climáticas y plagas presentes.