scholarly journals Economic Injury Level for Bermudagrass Stem Maggot (Diptera: Muscidae) in Bermudagrass Forage Production in Texas

2019 ◽  
Vol 112 (5) ◽  
pp. 2215-2221
Author(s):  
Allen E Knutson ◽  
Forrest Mitchell
Keyword(s):  
Vascular Tissue ◽  
Cynodon Dactylon ◽  
Forage Yield ◽  
Economic Injury Level ◽  
Forage Production ◽  
Market Values ◽  
Economic Injury ◽  
Stem Damage ◽  
And Control ◽  
The Impact

Abstract The bermudagrass stem maggot, Atherigona reversura Villeneuve (Diptera: Muscidae), was first reported damaging bermudagrass Cynodon dactylon (L.) Pers grown for forage in 2010 in the southeastern United States. Injury results from individual larvae feeding internally on the vascular tissue just above the terminal node of the grass stem. Injury slows plant growth and reduces forage accumulation. To address the need for economic guidelines to manage this new pest, the relationship between the percent of stems damaged by bermudagrass stem maggot and forage yield was measured in commercial bermudagrass hay fields in northcentral Texas. Yield loss was estimated to be 9.97 kg/ha (8.90 lbs /acre) for each percentage of stems with bermudagrass stem maggot damage. This relationship was used to calculate economic injury levels for a range of hay market values and control costs. The impact of stem damage on protein content, energy, and digestibility of bermudagrass hay was also investigated. Although there was a significant trend for declining forage quality with increasing stem damage, stem damage explained very little of the model’s variability.

Trap-Based Economic Injury Levels and Thresholds for Euschistus servus (Hemiptera: Pentatomidae) in Florida Peach Orchards

2020 ◽  
Vol 113 (3) ◽  
pp. 1347-1355 ◽  
Author(s):  
Cory Penca ◽  
Amanda C Hodges ◽  
Norman C Leppla ◽  
Ted E Cottrell
Keyword(s):  
Stink Bug ◽  
Economic Injury Level ◽  
Late Season ◽  
Growing Seasons ◽  
Management Actions ◽  
Economic Thresholds ◽  
Euschistus Servus ◽  
Economic Injury ◽  
And Control ◽  
Time Of Harvest

Abstract Populations of the brown stink bug, Euschistus servus (Say), in Florida peach orchards were monitored during the 2017 and 2018 growing seasons using yellow pheromone-baited pyramid traps. Peaches were evaluated at harvest for the presence of stink bug injury. A relationship between E. servus trap capture and fruit injury was used to estimate the economic injury level (EIL) for varying scenarios of crop price, per-hectare yield, and control costs. Economic thresholds were then set based on observed E. servus population trends and expected rates of increase. Thresholds were lowest in the period immediately following shuck split due to the rapid increase in E. servus populations during this period. Euschistus servus trap capture trended downward at the time of harvest. Therefore, increased E. servus management early in the Florida peach season provides the greatest overall benefit, whereas late season populations decline independent of management actions. The proposed EIL for Florida peaches determined by this study is 5.53 E. servus per trap over a 14-d trapping period, which was surpassed in only 16 of the 60 recorded trapping periods. This suggests that the current recommended spray frequency may not be economically justified.

scholarly journals The Effect of Limestone and Stabilized Nitrogen Fertilizers Application on Soil pH Value and on the Forage Production of Permanent Grassland

2016 ◽  
Vol 64 (4) ◽  
pp. 1239-1244
Author(s):  
Pavel Ryant ◽  
Petr Škarpa ◽  
Lenka Detvanová ◽  
Lucie Taušová
Keyword(s):  
Soil Ph ◽  
Ph Value ◽  
Forage Yield ◽  
Nitrogen Fertilizers ◽  
Dolomitic Limestone ◽  
Forage Production ◽  
Permanent Grassland ◽  
Small Plot ◽  
Experimental Treatments ◽  
The Impact

The changes of soil pH and dry forage yield of permanent grassland after application of dolomitic limestone and stabilized nitrogen fertilizers are described in this paper. The small‑plot experiment was located on semi‑natural grassland at Bohemian‑Moravian Highlands, near village Kameničky (Czech Republic), with poor and acidic soil. The experiment was divided into two blocks, within one of whose dolomitic limestone was applied in autumn 2013. In each block, 4 experimental treatments were applied: 1. control (untreated), 2. Urea, 3. Urea with inhibitor of urease, 4. Urea with inhibitor of nitrification. After liming, the pH/CaCl2 soil values increased in both the first as well as the second year after application. Fertilizing by urea, namely urea with inhibitors, did not significantly influence the pH/CaCl2 values. Dry forage productions in both years were comparable. In comparison to the untreated variants, significant increase in dry forage yield was achieved after application of urea and urea with urease inhibitors. The impact of stabilized fertilizers on the yield was not proven. In case of the limed variants, yield drop by 1.12 t/ha (average of both years) was observed; the yield decrease may be connected with disturbance of production potential of the stable community of plant species that had been adapted to acidic locations.

Evaluation of Leaf Consumption and Determination of Economic Injury Level Caused by Plutella xylostella (L.) (Lepidoptera: Plutellidae) in Brassica oleracea var. acephala (Brassicales: Brassicaceae)

2019 ◽  
Vol 112 (4) ◽  
pp. 1805-1811
Author(s):  
Angélica Massarolli ◽  
Bruna Camila Gualda Bersani ◽  
Fernando Henrique Dalla Roza ◽  
Alessandra Regina Butnariu ◽  
Mônica Josene Barbosa Pereira ◽  
...  
Keyword(s):  
Pest Control ◽  
Plutella Xylostella ◽  
Yield Reduction ◽  
Economic Injury Level ◽  
Control Cost ◽  
Collard Greens ◽  
Market Values ◽  
Leaf Consumption ◽  
Economic Injury ◽  
The Mean

Abstract Plutella xylostella (L.) is a microlepidopteran found in all brassica-producing regions of the world. However, no economic injury level (EIL) has been established for this pest in collard greens. Therefore, studies evaluating the EIL of P. xylostella in this crop based on the number of caterpillars per plant can assist pest monitoring and the most effective time for pest control, ensuring profits and the use of pesticides only when required. The present study assessed leaf consumption of caterpillars at different levels of infestation and determinined the EIL for P. xylostella in collard greens. Based on the yield reduction index of collard greens for P. xylostella, EIL was estimated for different scenarios of pest control costs, setting the market value of the bunch of collard greens, and, alternatively, with prices varying and the control cost fixed. In simulated scenarios for 7 d after infestation, the number of caterpillars per plant was always below 1.38, whereas for 10 d, the maximum number was 1.25 caterpillars per plant. When simulating scenarios with different market values for the bunch of collard greens the lower the price of the collard greens bunch, the higher the mean number of caterpillars per plant to compensate the application cost. The mean number of caterpillars per plant ranged from 4.59 to 0.38 in the evaluation for 7 d, and from 4.17 to 0.35 caterpillars per plant for 10 d according to the price of the bunch of collard greens.

scholarly journals Establishing Defoliation Thresholds for Insect Pest of Peanut in Mississippi

2019 ◽  
Vol 46 (1) ◽  
pp. 1-7 ◽  
Author(s):  
C. C. Abbott ◽  
J. M. Sarver ◽  
J. Gore ◽  
D. Cook ◽  
A. Catchot ◽  
...  
Keyword(s):  
Photosynthetic Capacity ◽  
Plant Biomass ◽  
Insect Pest ◽  
Canopy Height ◽  
Growth Stages ◽  
Economic Injury Level ◽  
Pod Yield ◽  
Economic Injury ◽  
Plant Emergence ◽  
The Impact

ABSTRACT Defoliation of peanut by foliage-feeding insects reduces photosynthetic capacity, and in turn, may reduce pod yield, particularly when canopy loss occurs at critical growth stages, i.e., 40 or 80 d after full plant emergence (DAE). The objective of this research was to determine the impact of peanut defoliation levels of 0, 20, 40, 60, 80, and 100%, at 40 or 80 DAE on canopy height and width, plant biomass, pod grade and yield, and economic injury level. Research was conducted in Stoneville and Starkville MS in 2015 and 2016. The experimental design was a six (defoliation level) by two (defoliation timing) factorial arranged in a randomized complete block. Up to four wk after defoliation, canopy height, canopy width, and plant biomass were negatively correlated with defoliation level regardless of defoliation timing (40 and 80 DAE). Neither defoliation level nor timing had an effect on peanut grade or maturity. Similarly, defoliation at 40 DAE did not affect pod yield but when damage occurred 80 DAE, pod yield was reduced 18.6 kg/ha for every 1% increase in defoliation. Considering average crop value and insect control costs, the economic injury for peanut defoliation at 80 DAE is 5% defoliation. These data indicate that control of canopy-feeding insects is only economically viable when defoliation exceeds 5% defoliation at 80 DAE.

Short-term impacts of winter bale grazing beef cows on forage production and soil nutrient status in the eastern Canadian prairies

2021 ◽  
Author(s):  
Gwen Donohoe ◽  
Don Flaten ◽  
Faith Omonijo ◽  
Kim Ominski
Keyword(s):  
Untreated Control ◽  
Perennial Grass ◽  
Soil Nutrient ◽  
Nutrient Status ◽  
Large Mass ◽  
Forage Yield ◽  
Forage Production ◽  
Soil Nutrient Status ◽  
Canadian Prairies ◽  
The Impact

The impact of winter bale grazing on forage productivity and nutrient cycling was determined near Winnipeg, MB. Variable distribution of nutrients and forage yield within bale grazed plots on a perennial grass-legume forage field was identified using an intensive grid sampling method. In bale-grazed plots, mean dry matter (DM) yield of forage decreased 68% in year one following bale grazing, with no difference in DM yield in year two following bale grazing, relative to an untreated control. Decreased yield was attributed to the large mass of waste feed and feces (21% of feed delivered) that remained at the centre of each bale-grazed plot, where each bale was placed. Concentrations of crude protein, total digestible nutrients, phosphorus (P), and potassium in forage increased in the first growing season following winter bale grazing compared to the control, particularly at the centre of each bale-grazed plot. Concentrations of residual nitrate-nitrogen and Olsen P in soil were 15 and 2.5 times greater, respectively, at the centre of the bale-grazed plots compared to untreated control plots. Dispersion of waste feed packs when bale grazing in sub-humid climates on clay soils is recommended to minimize smothering and encourage rapid decomposition of waste feed and feces. Long-term studies are needed to determine the potential benefits and risks of bale grazing to forage productivity and soil nutrient status in the eastern Canadian prairies.

Managing cabbage seedpod weevils (Coleoptera: Curculionidae) in canola (Brassicaceae) – are Lygus (Hemiptera: Miridae) affected?

2018 ◽  
Vol 151 (1) ◽  
pp. 85-93
Author(s):  
H.A. Cárcamo ◽  
S.B. Meers ◽  
C.E. Herle
Keyword(s):  
Insect Pest ◽  
Economic Injury Level ◽  
Action Threshold ◽  
Southern Alberta ◽  
Economic Injury ◽  
Flower Stage ◽  
Significant Yield ◽  
Cabbage Seedpod Weevil ◽  
The Impact ◽  
Early Flower

AbstractCabbage seedpod weevil (Ceutorhynchus obstrictus Marsham; Coleoptera: Curculionidae) and Lygus Hahn (Hemiptera: Miridae) species are part of the late season insect pest complex of canola (Brassica Linnaeus; Brassicacea) in the southern prairies of Canada. From 2010 to 2013, large strips in 73 commercial fields were studied in southern Alberta to validate action thresholds for cabbage seedpod weevil and assess the impact of insecticide spraying at the early flower stage for cabbage seedpod weevils on abundance of Lygus at the pod stage. Only fields planted in April accumulated the damaging populations of cabbage seedpod weevils, such that the application of an insecticide resulted in significant yield protection. The economic injury level for the cabbage seedpod weevil was calculated at 20 cabbage seedpod weevils per 10 sweeps, but an action threshold of 25–40 is recommended because sampling mainly occurs along the edge where cabbage seedpod weevils are initially concentrated. At the pod stage, Lygus were lower in strips sprayed with insecticides at the early flower stage than in those not sprayed, but the differences were not statistically significant. Furthermore, Lygus were generally below economically damaging levels in early seeded fields. Therefore, there is no benefit of spraying early seeded fields to attempt to prevent Lygus outbreaks when cabbage seedpod weevils are below thresholds because Lygus may pose a risk only in fields planted later in the season.

EFFECTS OF APPLYING INORGANIC FERTILIZER AND FARMYARD MANURE ON FORAGE PRODUCTION AND ECONOMIC RETURNS IN EAST-CENTRAL SASKATCHEWAN

1985 ◽  
Vol 65 (3) ◽  
pp. 597-607 ◽  
Author(s):  
N. W. HOLT ◽  
R. P. ZENTNER
Keyword(s):  
Farmyard Manure ◽  
Forage Yield ◽  
Inorganic Fertilizer ◽  
Forage Production ◽  
Comparable Rate ◽  
Total N ◽  
Crested Wheatgrass ◽  
Soil P ◽  
Market Values ◽  
Net Returns

Over a 4-yr period, annual application of inorganic fertilizer (IF) at 55 kg/(ha∙yr) nitrogen (N) plus 12 kg/(ha∙yr) phosphorus (P) and two times this rate or farmyard manure (FYM) at 11 or 22 tonne/(ha∙yr) significantly increased dry matter (DM) yields, nitrogen (N) and phosphorus (P) uptake and P content of alfalfa, bromegrass, crested wheatgrass and the grass-alfalfa combinations. Inorganic fertilizer produced larger yield increases of bromegrass, crested wheatgrass and their mixtures with alfalfa than FYM containing slightly more N and P. Each fertilizer form was as effective at increasing forage P, but IF increased the N content of crested wheatgrass or bromegrass by 0.1–0.5% more than a comparable rate of FYM. Utilization of P was 14–20% of that applied as IF and 6–13% of P applied as FYM. Utilization of N by the grasses was 44–52% for IF and 7–29% for FYM. At the relatively low levels applied, each fertilizer form increased bicarbonate-extractable soil P, but had no significant effect on total soil N, P or carbon. Based on forage market values that were related to the nutritional requirements of beef cattle, the net returns for the fertility treatments ranged from $121 to $261/ha for alfalfa, from $53 to $237/ha for grass-alfalfa mixtures and from a $48/ha loss to a $135/ha gain for grass only treatments. Application of IF was equally or more profitable than no fertilizer for all forage types. When FYM was priced on the basis of its total N and P contents, net returns for the 11 and 22 tonne/ha rates of FYM averaged $54/ha or 33% and $112/ha or 62% lower than those for the comparable IF treatments, respectively, and $25/ha or 19% and $65 or 39% lower than for the check treatments. When considering the alfalfa and alfalfa-grass treatments, the break-even value of FYM as a substitute for IF varied from $0 to $6/t of DM.Key words: Inorganic fertilizer, farmyard manure, forage yield, forage protein, economic worth of forage

MODELING OF THE PREVENTION AND CONTROL OF FOREST PEST

2007 ◽  
Vol 15 (04) ◽  
pp. 539-550 ◽  
Author(s):  
WEIJIAN XU ◽  
SHIDONG CHEN ◽  
LANSUN CHEN
Keyword(s):  
Pest Control ◽  
Prevention And Control ◽  
Existence Condition ◽  
Impulsive Effect ◽  
Forest Pest ◽  
Economic Injury Level ◽  
Economic Injury ◽  
Finite Period ◽  
Pest Density ◽  
And Control

In most models of pest control, the time of prevention and control is always assumed to be unrestricted. In practice, however, it is usually required in agriculture and forestry that we control the pest density to be lower than the economic injury level in a given time. By constructing the dynamics of logistic differential equation with impulsive effect, this paper describes the process of pest control through impulsive spraying pesticide in a given time, and then the existence condition of the solution to the boundary value problem of the dynamics is obtained, with which we solve the problem of pest control on a finite period of time and discuss the governing strategies.

scholarly journals On determination of ETL – a distributional approach

2013 ◽  
Vol 50 (2) ◽  
pp. 107-116
Author(s):  
Satyabrata Pal ◽  
Arunava Ghosh ◽  
Tapamay Dhar
Keyword(s):  
Real Life ◽  
Threshold Level ◽  
Control Measures ◽  
Economic Injury Level ◽  
Pest Population ◽  
Data Set ◽  
Real Life Data ◽  
Economic Injury ◽  
And Control

Summary Economic threshold level (ETL) is an important component in pest management and control. Usually, it is determined by the grower/technologist utilizing his experience on a crop; however, for cereals the values of these indices are available. Knowledge of ETL helps reduce crop loss (and ensure less pesticide application), and as a consequence, profit is increased. Also substantial knowledge is required on the dynamics of the pest population, in order to determine the density at which the economic injury level (EIL) may be prevented (Weersink et al. 1991). This paper is devoted to the development of an analytical method (probabilistic) for determination of ETL, which is defined as the density at which control measures should be determined to prevent an increasing pest population from reaching the economic injury level. A method to model the dynamics of the pest population is also proposed. The above method is demonstrated on a real life data set on pest (whitefly) incidence on betelvine, obtained from an experiment designed for that purpose.

Suppressed, but Not Forgotten

2011 ◽  
Vol 70 (1) ◽  
pp. 5-11 ◽  
Author(s):  
Beat Meier ◽  
Anja König ◽  
Samuel Parak ◽  
Katharina Henke
Keyword(s):  
Memory Trace ◽  
Thought Suppression ◽  
Test Phase ◽  
Indirect Test ◽  
Final Test ◽  
Test Experiment ◽  
And Control ◽  
Cue Words ◽  
The Impact

This study investigates the impact of thought suppression over a 1-week interval. In two experiments with 80 university students each, we used the think/no-think paradigm in which participants initially learn a list of word pairs (cue-target associations). Then they were presented with some of the cue words again and should either respond with the target word or avoid thinking about it. In the final test phase, their memory for the initially learned cue-target pairs was tested. In Experiment 1, type of memory test was manipulated (i.e., direct vs. indirect). In Experiment 2, type of no-think instructions was manipulated (i.e., suppress vs. substitute). Overall, our results showed poorer memory for no-think and control items compared to think items across all experiments and conditions. Critically, however, more no-think than control items were remembered after the 1-week interval in the direct, but not in the indirect test (Experiment 1) and with thought suppression, but not thought substitution instructions (Experiment 2). We suggest that during thought suppression a brief reactivation of the learned association may lead to reconsolidation of the memory trace and hence to better retrieval of suppressed than control items in the long term.

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