Everglades Research and Education Center

West Palm Beach, FL, United States

Everglades Research and Education Center

West Palm Beach, FL, United States
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Cherry R.,Everglades Research and Education Center | Nuessly G.,Everglades Research and Education Center
Florida Entomologist | Year: 2010

The neem tree Azadirachta indica A. Juss produces numerous allelochemical compounds. The most effective active ingredient in A. indica based insecticides is azadirachtin. We found that azadirachtin did not cause mortality, antifeeding responses, or change growth rate of Melanotus communis (Gyllenhal) wireworms. However, azadirachtin treated soil was repellent to the wireworms. This is the first report of azadirachtin being repellent to any of the large and economically important family of Elateridae.

Adams C.B.,University of Florida | Erickson J.E.,University of Florida | Singh M.P.,Everglades Research and Education Center
Field Crops Research | Year: 2015

Optimizing nutrient management practices in cropping systems is essential to improve economic and environmentally sustainability. Sweet sorghum [Sorghum bicolor (L.) Moench] is a crop that is capable of high sugar, grain, and lignocellulosic biomass yields, but a synthesis of published nutrient response curves reveals gaps in our knowledge. We therefore evaluated responses of sweet sorghum on a marginal North Florida sandy soil to ranges in nitrogen and potassium application rates and combined the nitrogen data with literature datasets to provide a broadly useful assessment of the relationship between nitrogen uptake and yield. There were no significant effects of the application of potassium observed. In response to nitrogen, leaf SPAD and photosynthesis were less with 20kgNha-1 than with more nitrogen (60, 100, and 140kgha-1), reflecting end-of-season crop responses in total biomass, estimated sugar, and grain yield. A linear plateau model indicated that application of 70kgNha-1 was sufficient to optimize total biomass yield at 20.8Mgha-1, although aboveground nitrogen uptake reached 120kgNha-1. These results are aligned with other reports on this topic showing similarly small optimal nitrogen fertilization rates and a strong capacity to extract soil nitrogen. In a combined analysis of this and three other published studies, crop nitrogen uptake reached approximately 127kgha-1 at the plateau in biomass production (19.7Mgha-1) with a slope of 0.13Mgkg-1. Sustainable management plans for sweet sorghum should include strategies to replenish the often considerable soil nitrogen removed by the crop. © 2015 Elsevier B.V.

Cherry R.,Everglades Research and Education Center | Karounos M.,Everglades Research and Education Center | Sakr B.,Everglades Research and Education Center
Journal of Entomological Science | Year: 2016

The rice water weevil, Lissorhoptrus oryzophilus Kuschel, is the most widely distributed and destructive insect pest of rice, Oryza sativa L, in the United States. The objective of this study was to determine overall damage levels of rice water weevils in Florida rice fields. Fifty rice fields were sampled over 2 yr for adult foliar damage. These damage data were used as the criteria for determining when control measures are justified. Although the weevils were widespread in Florida rice fields, damage levels at which control is required occurred in only 2% of fields sampled. An increase in adult feeding damage was observed as the rice season progressed. And, there was a significant correlation of feeding damage among fields within a paddy. These data suggest that Florida rice growers may not have to sample all fields in a paddy to estimate weevil damage in the paddy.

Odero D.C.,Everglades Research and Education Center | Mesbah A.O.,Powell Research and Extension Center | Miller S.D.,University of Wyoming | Kniss A.R.,University of Wyoming
Weed Science | Year: 2011

Redstem filaree is a troublesome weed for sugarbeet growers in northern Wyoming and southern Montana. Field studies were conducted in Powell, WY, in 2006 and 2008 to determine the influence of season-long interference of various redstem filaree densities and the duration of interference on sugarbeet. Root and sucrose yield decreased with increasing redstem filaree density. The rectangular hyperbola model with the asymptote (A) bounded at 100% maximum yield reduction characterized the relationship between redstem filaree density and sugarbeet yield reduction. The estimated parameter I (percent yield reduction per unit weed density as density approaches zero) was 5% for root and sucrose yield reduction. Sugarbeet root yield decreased as the duration of redstem filaree interference increased. The critical timing of redstem filaree removal to avoid 5 and 10% root yield reduction was estimated to be 25 and 32 d after sugarbeet emergence, respectively. Redstem filaree interference did not affect the sucrose content percentage. These results demonstrate that redstem filaree is competitive with sugarbeet and should be managed appropriately to reduce negative effects on yield.

Erickson J.E.,University of Florida | Helsel Z.R.,Rutgers University | Woodard K.R.,University of Florida | Vendramini J.M.B.,Range Cattle Research and Education Center | And 3 more authors.
Agronomy Journal | Year: 2011

Sweet sorghum [Sorghum bicolor (L.) Moench] is a potential bioenergy crop that is capable of high biomass and sugar yields, but production for biofuel in the Southeast is not well understood. The present study examined the effects of planting date (three dates from mid-March to mid-June) on primary and ratoon crop fresh biomass, brix, and estimated sugar yield of three sweet sorghum cultivars ('Dale', 'Topper 76-6', and 'M-81E') grown at three sites from North (29°24′ N) to South Florida (26°40′ N). Across all treatments, primary crop fresh biomass, brix and estimated sugar yields were 70 Mg ha -1, 148 g kg -1, and 5.69 Mg ha -1, respectively. Primary crop yields were greatest for the two earliest planting dates (mid-March to mid-May), and for our southernmost site. The yield potential for ratoon crops was in general only about half as much as the primary crop across all years, sites, and cultivars for the earliest planting date. An exception, however, was ratoon crop yields at the southernmost site, which were in some cases equal to or greater than primary crop yields. Low primary crop brix values were found for all cultivars on the muck soils in South Florida compared to the other two sites, and for M-81E compared to Dale and Topper 76-6. These low brix values were correlated with greater fresh biomass production. Further research is needed on planting dates for optimizing primary and ratoon crop yields along with varietal development with improved ratoon crop yields.

Cherry R.,Everglades Research and Education Center
Florida Entomologist | Year: 2011

The parasitic wasp Eumicrosoma benefica has year round activity and was found at all southern chinch bug infestations that were sampled in southern Florida. This parasite is an important, if not the most important, biological control agent in reducing southern chinch bug populations in southern Florida.

Bhadha J.H.,Everglades Research and Education Center | Daroub S.H.,Everglades Research and Education Center | Lang T.A.,Everglades Research and Education Center
Geoderma | Year: 2012

Equilibrium phosphorus concentration (EPC) is the aqueous phosphorus (P) concentration at which no net adsorption or desorption occurs when a soil is in contact with water; and are typically determined experimentally by plotting the measured amount of sorption versus initial concentration of P. In this study we evaluated the effect experimental parameters such as equilibration time, soil:solution ratio (SSR), and solution electrolyte may have on EPC values for two distinctly different soil types, (i) organic muck soil, and (ii) loamy mineral soil. Results indicate that there is a significant difference in emerging EPC values with changing equilibrium time, SSR, and electrolyte. For the muck soil, we observed up to 97% decrease in EPC while increasing equilibration time from 1 to 8h using 1:10 SSR. For the same soil the most profound effect of SSR was observed for 1h equilibration where EPC value decreased from 0.19mgL -1 using 1:2 SSR to 0.03mgL -1 using 1:20 SSR, corresponding to an 84% change. The EPC of the loamy soil decreased by 94% while increasing equilibration time from 24 to 72h using 1:20 SSR, whereas the same soil change in SSR was highly variable. Overall there was a 38% increase in EPC values using 0.01M CaCl 2 compared to KCl as the solution electrolyte in the experiment. These results indicate that experimental conditions can significantly affect EPC values (besides other factors) and therefore need to be standardized especially when used as a tool to assess P loading in natural systems. © 2012 Elsevier B.V.

Wang Y.,Texas AgriLife Research Center | Wang Y.,Everglades Research and Education Center | Pinson S.R.M.,U.S. Department of Agriculture | Fjellstrom R.G.,U.S. Department of Agriculture | Tabien R.E.,Texas AgriLife Research Center
Molecular Breeding | Year: 2012

F2:3 families from crosses between three rice indica introgression lines and their common japonica recurrent parent were used to evaluate two quantitative trait loci (QTL) for sheath blight (SB) resistance. Three selected TeQing-into-Lemont backcross introgression lines (TILs) were more resistant than their susceptible parent (Lemont) in inoculated field plots, and were molecularly verified to contain TeQing alleles at qSB9-2 and/or qSB12-1. F2 individuals homozygous for qSB9-2 and qSB12-1 provided F2:3 families that fit four genotypic classes: containing the resistant TeQing allele for qSB9-2 TQ alone, qSB12-1 TQ alone, both qSB9-2 TQ and qSB12-1 TQ, and neither SB QTL introgression. By comparing the SB resistance of these four genotypic classes in micro-chamber evaluations and inoculated field plots, the phenotypic values of the QTL were measured. Under both study conditions, disease resistance ranked qSB9-2 + qSB12-1 > qSB9-2 > qSB12-1 > no QTL, with both qSB9-2 and qSB12-1 acting as dominant resistance genes. In micro-chamber studies, qSB9-2 TQ reduced disease an average of 1. 0 disease index units and qSB12-1 TQ by 0. 7 using a scale of 0-9. Field effects of qSB9-2 TQ and qB12-1 TQ were less pronounced, with average phenotypic gains of 0. 5 and 0. 2 units, respectively. TIL:642 proved to contain qSB9-2 TQ in an introgression so small it was tagged by just RM205 on the tip of chromosome 9. These studies verify that the indica introgression of qSB9-2 TQ or qSB12-1 TQ can measurably improve resistance to sheath blight disease in a highly susceptible tropical japonica cultivar, and fine-mapped the qSB9-2 locus. Markers presently verified as linked to these QTL can support marker-assisted breeding to improve disease resistance. © 2011 Springer Science+Business Media B.V. (outside the USA).

Frederick P.,University of Florida | Campbell A.,Florida Atlantic University | Jayasena N.,University of Florida | Borkhataria R.,University of Florida | Borkhataria R.,Everglades Research and Education Center
Ecotoxicology | Year: 2011

Although methylated mercury (MeHg) is known to have neurological, immunological, reproductive, and endocrine effects on vertebrates at low environmental exposure levels, effects on survival of exposed birds have not been demonstrated in the wild. Here, we report on survival of the same group of White Ibises (Eudocimus albus) during exposure to 4 levels of dietary MeHg in captivity and later as depurated free-ranging animals. Ibises were chronically exposed in captivity to dietary MeHg in groups at 0 (control), 0.05 (Low), 0.1 (Medium) and 0.3 (High) ppm MeHg ww for 43 months. No differences in annualized survival among captive MeHg groups were seen within age classes. Survival of all ages taken together was significantly lower for Control birds than for Low or Medium dosed birds, but was not different from High dosed birds. While this might be evidence of a hormetic effect, none of the captive results support the prediction that MeHg impairs survival. Using a mark-recapture analysis we found no effects of dose group or of Hg exposure on survival or resight probabilities during the first 99 days post-release to the wild. The latter results suggest that there is no lasting, post-depuration effect of even high MeHg exposure (0.3 ppm ww dietary) on survival. While these results agree with a variety of studies of survival of free-ranging birds, we suggest many survival studies have been confounded by seasonal depuration through molt, and variation in exposure rates. We suggest future studies concentrate on evaluating survival effects during nonmolting periods in species for which methylmercury exposure is relatively constant. © 2010 Springer Science+Business Media, LLC.

Cherry R.,Everglades Research and Education Center | Grose P.,King Ranch | Barbieri E.,King Ranch
Journal of Pest Science | Year: 2013

Wireworms in Florida are primarily a pest in newly planted sugarcane, and growers usually apply a soil insecticide at planting to protect germinating seedpieces from wireworm damage. However, studies have suggested that this application in many cases may not be necessary. The objective of this research was to test a sequential sampling method to determine the need for soil insecticide at sugarcane planting. Testing was conducted on fields located on King Ranch near South Bay, Florida. Wireworm samples were taken in a transect across the length of each field. We used an economic injury level of nine or more wireworms per 25 samples. Sugarcane yield parameters for each whole field were obtained through standard commercial harvesting procedures. Using our sampling method, 38 fields were judged as not needing insecticide application. There was no significant difference in yield in these fields with versus those without insecticide application. © 2011 Springer-Verlag.

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