The economic injury level and action threshold in stored-product systems

2011 ◽  
Vol 7 (3) ◽  
pp. 1-8 ◽  
2018 ◽  
Vol 151 (1) ◽  
pp. 85-93
Author(s):  
H.A. Cárcamo ◽  
S.B. Meers ◽  
C.E. Herle

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.


2020 ◽  
Vol 73 (2) ◽  
pp. 9213-9220
Author(s):  
Paola Vanessa Sierra-Baquero ◽  
Edgar Herney Varón-Devia ◽  
Lucimar Gomes-Dias ◽  
Buenaventura Monje-Andrade

Mango is a tropical fruit with great production and market worldwide. In Colombia, it is an important crop with high export potential. There are many arthropods affecting mango production, such as thrips that feed on leaves, flowers, and small fruits, causing damage such as deformations, scars, and premature fall of fruits. This study aimed to establish the economic injury level (EIL) of Frankliniella cf. gardenia Moulton in mango (Mangifera indica L. var. yulima and var. tommy) in Guamo and San Luis (Tolima, Colombia). The methods employed included a weekly sampling of thrips in mango inflorescences during two productive periods (B-2015 and B-2016) using the structure tapping technique in a deep tray with mesh. Three preliminary thresholds per productive period were established: [B-2015: ≥10 thrips per inflorescence (TpI), ≥30 TpI, and ≥60 TpI. B-2016: ≥5 TpI, ≥10 TpI, and ≥15 TpI]. The variables density, costs, and yield were recorded. The EIL was calculated statistically using linear regressions and the final action threshold was estimated. An EIL of 11 TpI and an action threshold of 7 TpI were estimated for var. tommy in Guamo in the second semester of 2016. There was a risk of losing 220 kg ha-1 for each increase in insect unit in var. tommy. Therefore, thrips in mango behaved as an occasional pest, requiring control in var. tommy in Guamo, when the crop is flowering, and the population exceeds the action threshold of 7 TpI.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Natalie Hoidal ◽  
Robert L Koch

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.


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 ◽  
...  

Agronomy ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 291 ◽  
Author(s):  
Maja Meseldžija ◽  
Miloš Rajković ◽  
Milica Dudić ◽  
Milica Vranešević ◽  
Atila Bezdan ◽  
...  

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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