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 Incorporation of radioactive products of photosynthesis into lignin and cellulose of Scots pine (Pinus sihestris L.) seedlings

2015 ◽  
Vol 42 (4) ◽  
pp. 555-565
Author(s):  
Igor Góral
Keyword(s):  
Scots Pine ◽  
Growth Stages ◽  
Pine Seedlings ◽  
Photosynthetic Products ◽  
One Year ◽  
Different Growth Stages

Distribution of radioactive photosynthetic products as well as their utilization in biosynthesis of lignin and cellulose in one-year-old pine seedlings was investigated at different growth stages. It was found that time of metabolization and the rate of photosynthetic products incorporation into lignin and cellulose depends on the organ and -on the kind of polymer synthetized.

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 A field study of Bactericera cockerelli feeding timing in potato crops

2017 ◽  
Vol 70 ◽  
pp. 320
Author(s):  
J.N. Furlong ◽  
J. Vereijssen ◽  
A.R. Pitman ◽  
R.C. Butler
Keyword(s):  
Growth Stages ◽  
Insect Vector ◽  
Bactericera Cockerelli ◽  
Zebra Chip ◽  
Growing Seasons ◽  
Yield And Quality ◽  
Zebra Chip Disease ◽  
Candidatus Liberibacter ◽  
Potato Crops ◽  
Different Growth Stages

Since its 2006 detection in New Zealand, the tomato potato psyllid (TPP), Bactericera cockerelli, has been responsible for yield and quality-reducing damage to potatoes as well as to other solanaceous crops. TPP is best known as the insect vector for the zebra chip disease-associated bacterium Candidatus Liberibacter solanacearum (CLso), but feeding by CLso-negative TPP on potatoes is also linked to damaging effects. An improved understanding of which potato plant physiological stages are most affected by feeding of CLso-negative TPP will allow for more directed integrated pest management (IPM) plans. As part of a two-year repeated eld study to assess the effect of TPP feeding timing on potatoes, CLso-negative TPP were released into mesh cages over outdoor potato (‘Moonlight’) plantings at ve different growth stages: post-emergence, owering, post- owering, late-season, and pre-harvest. Tubers were grouped by plant at harvest. (Un)marketable numbers and weights, marketable dry matter and zebra chip severity were determined. Results from this trial and other shadehouse trials conducted previously are still being analysed but have the potential to better target IPM plans and reduce costly, labour-intensive, and environmentally impactful pesticide spray use, which is currently relied on heavily throughout growing seasons.

scholarly journals Distribution of radioactive products of photosynthesis in Scots pine (Pinus sihestris L.) seedlings during the first vegetation season

2015 ◽  
Vol 42 (4) ◽  
pp. 541-553
Author(s):  
Igor Góral
Keyword(s):  
Scots Pine ◽  
Growth Stage ◽  
Growth Stages ◽  
Vegetation Season ◽  
Photosynthetic Products ◽  
One Year ◽  
Different Growth Stages ◽  
Needle Growth

Dynamics of translocation and distribution of radioactive photosynthetic products in one year old pine (<i>P. silvestris</i> L.) seedlings was investigated at different growth stages. It was found that the utilization of photosynthetic products in particular organs depends greatly on the growth stage. Loses of photosynthetic products as a result of respiration were the smallest at the stage of intensive needle growth and the greatest at the stage of approaching dormancy.

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.

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.

scholarly journals Effects of Foliar Applications of Boron at the Early Vegetative Stages on Plant Growth Parameters of Maize

2019 ◽  
Vol 7 (10) ◽  
pp. 1522
Author(s):  
Ömer Konuşkan ◽  
Mehmet Yalçın ◽  
Hüseyin Gözübenli
Keyword(s):  
Field Experiments ◽  
Agricultural Research ◽  
Foliar Application ◽  
Growth Parameters ◽  
Foliar Spray ◽  
Research Area ◽  
Growth Stages ◽  
Growing Seasons ◽  
Plant Characteristics ◽  
Different Growth Stages

Boron is an important micronutrient for growth and development of crop plants. Plant species differ in their requirement of boron for growth. This study was conducted to determine the effect of boron application on the plant characteristics of maize during early leaf stages. The experiments were conducted in Tel – Kaliş agricultural research area at the Mustafa Kemal University in 2015 and 2016 growing seasons. The field experiments were arranged in a split plot design with three replications. Four boron dosages (control, 4, 6 and 8 mg/m2) were applied at three growing stages (V2, V4 and V2V4 (at V2 and V4 stages in two equal parts) as foliar spray. The results revealed that the effects of foliar application of B were positive but statistically insignificant on plant characteristics. Further researches should be conducted for suitable boron application time at different growth stages of maize.

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

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