Recovery of ‘Zinfandel’ Grapevines from Feeding Damage by Willamette Spider Mite (Acari: Tetranychidae): Implications for Economic Injury Level Studies in Perennial Crops

1991 ◽  
Vol 20 (1) ◽  
pp. 104-109 ◽  
Author(s):  
Stephen C. Welter ◽  
Rachael Freeman ◽  
Delbert S. Farnham
Keyword(s):  
Spider Mite ◽  
Feeding Damage ◽  
Economic Injury Level ◽  
Perennial Crops ◽  
Economic Injury

scholarly journals The influence of the two-spotted spider mite (Tetranychus urticae Koch.) and irrigation on yield of 5-years-old apple trees

2013 ◽  
Vol 55 (2) ◽  
pp. 113-119
Author(s):  
Wojciech Warabieda ◽  
Remigiusz W. Olszak
Keyword(s):  
Tetranychus Urticae ◽  
Spider Mite ◽  
Fruit Weight ◽  
Economic Injury Level ◽  
Apple Trees ◽  
Economic Injury ◽  
Apple Cultivars ◽  
Effect On Yield ◽  
Two Spotted Spider Mite ◽  
Tetranychus Urticae Koch

The influence of the two-spotted spider mite (<i>Tetranychus urticae</i>) on yield of apple trees was investigated. The experiment was conducted on rrigated and non-irrigated 5-years-old apple trees of 'Close' and 'Jonagold' cultivars grafted on M.9. The population size of the pest exceeded four and two times the valid (in Poland) economic injury level on trees of 'Close' and 'Jonagold' cultivars respectively. No significant influence of mites on yield and its quality (mean fruit weight and fruit colour) was observed on both apple cultivars. Irrigation had positive effect on yield and quality of 'Jonagold'. On the contrary, trees of ' Close' cultivar were positively influenced by irrigation only regarding fruits colour. Results of the study support opinion that the economic injury level for apple orchards, with respect to two-spotted spider mite, should be higher than it is up to now.

Growth and yield of barley in relation to grasshopper feeding damage

2008 ◽  
Vol 88 (1) ◽  
pp. 219-227 ◽  
Author(s):  
Sultan H. Begna ◽  
Dennis J. Fielding
Keyword(s):  
Surface Area ◽  
Dry Matter ◽  
Growth And Yield ◽  
Plant Responses ◽  
Feeding Damage ◽  
Economic Injury Level ◽  
Hordeum Vulgare L ◽  
Leaf Stage ◽  
Economic Injury ◽  
Below Ground

Grasshoppers are common pests of barley (Hordeum vulgare L.) in subarctic Alaska and cause substantial crop loss during outbreaks, but there is little information about the growth response of barley to grasshopper feeding damage. In two growth chamber experiments, we studied the effect of four densities (0, 1, 2, and 3 pot-1, equivalent to 0, 25, 50 and 75 grasshoppers m-2) of grasshoppers (Melanoplus sanguinipes F.) on the above-and below-ground growth of barley (eight plants per pot). Plants were exposed to grasshoppers beginning in the 3rd to 4th leaf stage (exp. 1) and in 1st to 2nd leaf stage (exp. 2). Plants were harvested and growth variables were measured shortly after anthesis and at maturity. Generally, the reduction in above-ground dry matter, at the highest density was 29 and 47% for exp. 1 and exp. 2, respectively. Effects of grasshoppers on below-ground growth (dry matter and surface area of roots) was less consistent than on above-ground variables; however, at the highest grasshopper density in exp. 2, dry matter and surface area of roots were reduced by about 40–53%.Grain yield (pooled over experiments) decreased by 19 and 36% for grasshopper densities of 2 and 3 pot-1, respectively. Most of the yield loss was accounted for by reduced seed weights, while protein content per seed remained nearly constant. The proportion of total above-ground dry matter represented in harvested grain and root:shoot ratios were not affected by grasshopper feeding. These results provide greater understanding of plant responses to insect feeding damage and will lead to more accurate estimates of economic injury levels. Key words: Cropyield loss, economic injury level, harvest index, Insecta

scholarly journals Damage assessment and economic injury level of the two-spotted spider mite Tetranychus urticae in soybean

2020 ◽  
Vol 55 ◽  
Author(s):  
Guilherme Padilha ◽  
Rubens Alex Fiorin ◽  
Alberto Cargnelutti Filho ◽  
Henrique Pozebon ◽  
John Rogers ◽  
...  
Keyword(s):  
Grain Yield ◽  
Tetranychus Urticae ◽  
Spider Mite ◽  
Grain Weight ◽  
Economic Injury Level ◽  
Control Cost ◽  
Economic Injury ◽  
Four Levels ◽  
Two Spotted Spider Mite ◽  
Whole Plants

Abstract: The objective of this work was to quantify the reduction of soybean grain yield caused by Tetranychus urticae damage, and to propose an economic injury level (EIL) for this pest in the crop. The experimental design was set up in randomized complete blocks, with four replicates and a 4x2 factorial arrangement with four levels of mite infestation, with or without mite control. Chlorotic symptoms were evaluated using a damage scale of 1 to 4. Soybean grain yield, number of pods, number of grains, and 1,000-grain weight were quantified for each segment of plant canopy (lower, middle, and upper) and for the whole plants. The chlorophyll content in the leaves was evaluated using the SPAD index. The population density of one two-spotted spider mite per cm2 of leaf area caused the following reductions: one pod per plant, two grains per plant, 0.7 g of 1,000-grain weight, and 0.35 g of grain yield per plant or 42 kg ha-1. Based on the equation y = 4,369 - 41.99x, the EIL of one two-spotted spider mite per cm2 is determined by considering a control cost of US$ 20.00 ha-1 and a soybean crop value of US$ 350.00 Mg-1. As to chlorotic symptoms, the EIL is set between damage scores 1 (no apparent mite damage) and 2 (yellow mottling beginning to appear).

scholarly journals Perception and Use of Economic Thresholds Among Farmers and Agricultural Professionals: A Case Study on Soybean Aphid in Minnesota

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Natalie Hoidal ◽  
Robert L Koch
Keyword(s):  
Soybean Aphid ◽  
Educational Outreach ◽  
Economic Injury Level ◽  
Economic Thresholds ◽  
Foundational Principle ◽  
Economic Injury ◽  
Fundamental Misunderstanding ◽  
The Difference ◽  
Commercial Pesticide ◽  
Agricultural Professionals

Abstract Economic thresholds (ETs) are a foundational principle of integrated pest management but are not always widely accepted by farmers and agricultural professionals. This article reports on a survey of Minnesota farmer and agricultural professional perceptions of the ET for soybean aphid, Aphis glycines Matsumura (Hempitera: Aphididae). We discuss insights for Extension programs on how to frame the importance of thresholds and teach stakeholders to use them effectively. Key takeaways include farmers and agricultural professionals often worry about combined effects of insect, disease, and physiological pressures, whereas effects of interactions with these other stressors are seldom discussed in educational outreach. Across groups, there is a fundamental misunderstanding about the difference between ETs and economic injury level. Many survey participants reported believing in the ET but lacked the time and capacity to fully implement it. Sales agronomists and farmers were the least likely groups to trust the university-determined soybean aphid ET, whereas commercial pesticide applicators and independent consultants were the most likely groups to trust it. Based on these results, we recommend adapting communication about ETs based on the target audience to address common misconceptions and barriers to ET use that are unique to each group.

Economic injury level for sequential sampling plan of Frankliniella schultzei in bell pepper crops

2019 ◽  
Vol 123 ◽  
pp. 30-35 ◽  
Author(s):  
Jhersyka da S. Paes ◽  
Tamíris A. de Araújo ◽  
Rodrigo S. Ramos ◽  
João Rafael S. Soares ◽  
Vitor C.R. de Araújo ◽  
...  
Keyword(s):  
Sequential Sampling ◽  
Sampling Plan ◽  
Bell Pepper ◽  
Economic Injury Level ◽  
Frankliniella Schultzei ◽  
Sequential Sampling Plan ◽  
Economic Injury

scholarly journals Economic Feasibility of Chemical Weed Control in Soybean Production in Serbia

Agronomy ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 291 ◽  
Author(s):  
Maja Meseldžija ◽  
Miloš Rajković ◽  
Milica Dudić ◽  
Milica Vranešević ◽  
Atila Bezdan ◽  
...  
Keyword(s):  
Weed Control ◽  
Block Design ◽  
Economic Feasibility ◽  
Economic Injury Level ◽  
Weed Species ◽  
Soybean Crop ◽  
Economic Justification ◽  
Randomized Block Design ◽  
Effective Combination ◽  
Economic Injury

The aim of this study was to investigate the efficacy and phytotoxicity of herbicides in combinations and to determine their economic feasibility in the soybean crop. The trials were placed at two locations, Pobeda and Budisava (Serbia), during 2016 and 2018, organized in a randomized block design with four replicates of all herbicide combinations (metribuzin + S-metolachlor; imazamox + oxasulfuron + typhenesulfuron-methyl; metribuzin + S-metolachlor + imazamox + oxasulfuron + typhenesulfuron-methyl; and bentazon + imazamox + typhenesulfuron-methyl). At the first location, 16 weed species were determined, while in the second location, 14 were determined. The highest reduction in the number of weeds was achieved at the first location, using a combination of herbicides metribuzin + S-metolachlor + imazamox + oxasulfuron + typhenesulfuron-methyl with a total efficacy that ranged from 96.98% to 97.40%. Only on the second location bentazone + imazamox + tifensulfuron-methyl showed passable phytotoxicity on soybean, during both years. Based on the established economic justification, in the combinations of metribuzin + S-metolachlor + imazamox + oxasulfuron + typhenesulfuron-methyl, yield was increased for 2350 kg/ha or 1.91 times more, according to the untreated variant at first location. The economic injury level at the most effective combination of herbicides was 52.70 weeds/m2.

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