Economic Injury Level and Demography-Based Control Timing Projection of Spodoptera litura (Lepidoptera: Noctuidae) at Different Growth Stages of Arachis hypogaea

2017 ◽  
Vol 110 (2) ◽  
pp. 755-762 ◽  
Author(s):  
Shu-Jen Tuan ◽  
Chung-Chieh Lee ◽  
Li-Chen Tang ◽  
Pavel Saska
Keyword(s):  
Arachis Hypogaea ◽  
Spodoptera Litura ◽  
Growth Stages ◽  
Economic Injury Level ◽  
Economic Injury ◽  
Lepidoptera Noctuidae ◽  
Different Growth Stages

scholarly journals Pest status of the leafhopper Empoasca dolichi Paoli on groundnut (Arachis hypogaea L.) in the Zaria area of northern Nigeria

2010 ◽  
Vol 41 (No. 4) ◽  
pp. 158-164 ◽  
Author(s):  
E.A. Egwurube ◽  
O. Ogunlana M ◽  
C. Dike M ◽  
I. Onu
Keyword(s):  
Arachis Hypogaea ◽  
Growth Stages ◽  
Northern Nigeria ◽  
Economic Injury Level ◽  
Pest Status ◽  
Growing Seasons ◽  
Economic Injury ◽  
One Year ◽  
Empoasca Dolichi ◽  
Different Growth Stages

Population studies and tests on the relationship between density and damage were conducted in 1999 to 2001 to determine the pest status of <I>Empoasca dolichi</I> on groundnut (<I>Arachis hypogaea </I>L.) in the Zaria area of northern Nigeria. Analyses showed that <I>Empoasca</I> numbers varied significantly from one year to another, and within each year the numbers of leafhoppers observed at the different growth stages of the plant were significantly different (<I>P</I> = 0.01). There was an inverse and highly significant relationship between the mean kernel yield and the <I>Empoasca </I>damage at the different growth stages of the plant. When natural population densities were plotted against economic injury level (EIL), the densities did not reach the EIL throughout the groundnut growing seasons. The insect was thus not an economic pest on groundnut in Zaria during the period of the study.

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.

Determination of an Economic Injury Level for Old World Bollworm (Lepidoptera: Noctuidae) in Processing Tomato in Brazil

2020 ◽  
Vol 113 (4) ◽  
pp. 1881-1887
Author(s):  
Nayara C M Sousa ◽  
Miguel Michereff Filho ◽  
Paloma A Silva ◽  
Jorge B Torres
Keyword(s):  
Helicoverpa Armigera ◽  
Control Program ◽  
Yield Reduction ◽  
Economic Injury Level ◽  
Field Cage ◽  
Tomato Plants ◽  
Processing Tomato ◽  
Economic Injury ◽  
Helicoverpa Armígera ◽  
Lepidoptera Noctuidae

Abstract Tomato plants host various herbivores, including the Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), recently introduced into South and Central America. It is a harmful pest for tomato crops, damaging mainly the flowers and fruits. The assessment of losses and the establishment of economic injury level (EIL) and economic threshold (ET) are core steps toward establishing a control program. We determined losses caused by H. armigera on processing tomato and estimated EIL/ET values. Trials were run during two growing seasons using tomato plants caged in the field. The field cage experiment consisted of six densities of H. armigera second instar larvae (0, 1, 3, 6, 12, and 24 larvae per row meter) at two infestations periods spaced 15 d apart with the first infestation done 90 d after transplanting. The larvae were placed individually on the third upper fully developed leaf. The number of healthy and damaged fruits, size, and weight of the fruits were measured. Yield losses as a function of infestation of 1–24 larvae per row meter ranged from 4 to 34% and resulted in a yield reduction of 1.22–12.77 kg per row meter. The EIL ranged from 1.41 to 1.72 and from 2.11 to 2.58 larvae per row meter of plants in 2017 and 2018 cropping seasons, respectively. Helicoverpa armigera causes significant reduction of tomato yield. These EIL values will enable better control decision-making in processing tomato.

ECONOMIC THRESHOLDS AND ECONOMIC INJURY LEVELS OF CEREAL APHIDS ON BARLEY IN SOUTHWESTERN QUEBEC

1980 ◽  
Vol 112 (8) ◽  
pp. 759-764 ◽  
Author(s):  
S. A. Ba-Angood ◽  
R. K. Stewart
Keyword(s):  
Grain Yield ◽  
Chemical Control ◽  
Growth Stages ◽  
Cereal Aphids ◽  
Economic Thresholds ◽  
Rate Of Increase ◽  
Economic Injury ◽  
Ripe Stage ◽  
Different Growth Stages ◽  
Percentage Protein

AbstractArtificial infestations of cereal aphids in caged plants were made at different growth stages of barley in the field in 1978 and 1979. Forty, 80, 160, and 200 aphids/tiller reduced grain yield significantly (P < 0.01) when introduced into caged plants at flowering and milky stages for 2 weeks. Only the 150 and 200 aphids/tiller-treatments gave significant reductions in yield when introduction was at the mealy ripe stage. Twenty aphids/tiller gave a significant reduction in yield only when they were introduced at the beginning of ear emergence and flowering, but not at the milky ripe stage. Significant reduction in percentage protein was obtained only when 160 and 200 aphids/tiller were introduced at flowering and milky ripe stages. The economic injury and threshold levels were calculated as 10–18 and 8–16 aphids/tiller, respectively, depending on rate of increase of aphids, costs of chemical control, and the value of the crop in 1978 and 1979.

Response of canola to simulated diamondback moth (Lepidoptera: Plutellidae) defoliation at different growth stages

2000 ◽  
Vol 80 (3) ◽  
pp. 639-646 ◽  
Author(s):  
Suresh Ramachandran ◽  
G. David Buntin ◽  
John N. All
Keyword(s):  
Diamondback Moth ◽  
Maximum Yield ◽  
Field Trials ◽  
Crop Growth ◽  
Growth Stages ◽  
Economic Injury Level ◽  
Leaf Stage ◽  
Filling Stage ◽  
Crop Development ◽  
Economic Injury

In field trials conducted during 1995–1998, canola cultivar "Falcon" was subjected to different levels of simulated insect defoliation at four stages of crop growth. Plants were 0, 33, 67 and 100% defoliated at rosette and flowering stages during the 1995–1996 season as well as 2–4 leaf stage during the 1996–1997 and 1997–1998 seasons. Plants were 0, 50 and 100% defoliated at pod filling stage during all seasons. Over all seasons, defoliation did not consistently affect the number of plants per unit area, plant height, 1000 seed weight, and oil content of seeds for most of the defoliation treatments. However, defoliation at the 2–4 leaf and rosette stages made plants more susceptible to cold injury. Generally, canola could withstand a higher level of defoliation as crop development progressed. Maximum yield reductions occurred for defoliations at the 2–4 leaf stage followed by the rosette and flowering stages of the crop. No significant yield losses were recorded for defoliations at the pod filling stage. Results suggest that canola is most sensitive to defoliation in its early stages of growth. Greater amounts of defoliation can be tolerated as crop development progresses. The relationships between defoliation and yield loss were used to establish diamondback moth economic injury levels for canola at different crop growth stages. Key words: Canola, Brassica napus, oilseed rape, simulated defoliation, economic injury level

Reevaluating the Economic Injury Level for Brown Stink Bug (Hemiptera: Pentatomidae) at Various Growth Stages of Maize

2020 ◽  
Vol 113 (5) ◽  
pp. 2250-2258
Author(s):  
Tim B Bryant ◽  
Seth J Dorman ◽  
Dominic D Reisig ◽  
DeShae Dillard ◽  
Roger Schürch ◽  
...  
Keyword(s):  
Grain Yield ◽  
Growth Stage ◽  
Early Stage ◽  
Growth Stages ◽  
Stink Bug ◽  
Infestation Level ◽  
Economic Injury Level ◽  
Euschistus Servus ◽  
Economic Injury ◽  
Late Stages

Abstract Economic yield loss and reduction in grain quality from brown stink bug, Euschistus servus (Say), feeding injury in early and late stages of maize, Zea mays (Poales: Poaceae, Linnaeus), development was assessed in Virginia and North Carolina in 2018 and 2019. Varying levels of stink bug infestations were introduced to seedling maize (V2—early stage), and a range of late-stages of maize, including 1) the last stage of vegetative development (V12/V14), 2) prior to tasseling, 3) at tasseling (VT), and 4) across all tested late growth stages. Euschistus servus infestation levels included 33, 67, and 100% of maize seedlings, and 25, 50, 100, and 200% of plants during later stages. Infestations were maintained on seedling maize for 7 d, and 8 or 16 d in reproductive stages. Infestation level in seedling maize had an impact on grain yield. Infestation level and growth stage both had an impact on grain yield in reproductive maize. The percentage of discolored kernels was also affected by infestation level, but not growth stage. Regression analysis between grain yield and infestation level indicated that the average economic injury level is 7% in seedling maize (7 bugs/100 plants) and 12% (12 bugs/100 plants) from the last vegetative stages (V12/V14) through pollination (VT). The economic injury level in the late vegetative stages is only applicable when infestations are present for an extended period of time (16 d), emphasizing the need for continued scouting of maize throughout the season to make informed management decisions.

Sign in / Sign up

Export Citation Format

Share Document