Dynamic economic thresholds for the management of vegetable leafminer on glasshouse cucumber estimated by simulated defoliation

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.

A, The ESTIMATION OF ECONOMIC THRESHOLDS OF JUNGLE RICE (ECHINOCHLOA COLONA L.) AND FALSE AMARANTH (DIGERA ARVENSIS FORSSK.) IN DIRECT SEEDED RICE

JOURNAL OF WEED SCIENCE RESEARCH ◽

10.28941/pjwsr.v26i4.890 ◽

2020 ◽

Vol 27 (2) ◽

pp. 507-523

Author(s):

Amir Ehsan ◽

Muhammad Ehsan Safdar1 ◽

Amjed Ali

Keyword(s):

Block Design ◽

Dry Weight ◽

Field Trials ◽

Research Area ◽

Growth And Yield ◽

Rice Grain ◽

College Of Agriculture ◽

Competitive Index ◽

Economic Thresholds ◽

Direct Seeded

ABSTRACT There is little understanding about ecological interference of weeds in direct-seeded rice. To get estimates of economic thresholds of two weeds in direct seeded rice, two-year field trials were conducted at research area of College of Agriculture, University of Sargodha, Punjab-Pakistan. Treatments included 0, 22, 44, 66 and 88 plants m-2 densities of each of Echinochloa colona and Digera arvensis laid out in randomized complete block design. Augmented densities of E. colona (0, 22, 44, 66 and 88 weed plants m-2) enhanced its plant dry biomass up to 348 and 353%; and relative competitive index maximally to 80 and 77% in years 2015 and 2016, respectively. While the corresponding increases in plant dry weight and relative competitive index of D. arvensis were 367 and 360% and 79 and 82%. The enhancement in N (up to 258 & 257 %), P (up to 220 & 232%) and K (up to 293 & 301%) uptake in years 2015 and 2016, respectively were made by E. Colona whereas the corresponding increases in N, P and K assimilation by D. arvensis were as far as 265 & 257%, 238 & 233% and 305 & 298%, respectively. The declines in growth and yield of rice were observed in response to growing number of both the weeds. Rice grain yield losses ranged between 9.8 to 80% and 28 to 80% by E. Colona and D. arvensis. The economic thresholds of false amaranth and jungle rice were estimated to be 1.6-1.4 plants m-2 and 2.2-2.6 plants m-2, respectively.

Influence of Simulated Defoliation and N Fertilization on Compensatory Growth of Gmelina arborea Seedlings

Journal of Applied Life Sciences International ◽

10.9734/jalsi/2020/v23i1230205 ◽

2020 ◽

pp. 59-66

Author(s):

Titus Fondo Ambebe ◽

Anjah Grace Mendi ◽

Abubakar Ali Shidiki

Keyword(s):

Compensatory Growth ◽

Interactive Effect ◽

N Fertilization ◽

Stem Volume ◽

Total Biomass ◽

N Availability ◽

Gmelina Arborea ◽

Leaf Production ◽

Increasing Trend ◽

Simulated Defoliation

To investigate the effect of artificial defoliation and N availability on growth of Gmelina arborea, seedlings were subjected to three artificial defoliation levels (0, 25, 50%) and four N regimes (unfertilized, 1 g N plant-1, 3 g N plant-1, 6 g N plant-1) in a field trial. The results showed that height increment was 24.09% lower in the 50% defoliation than the undefoliated and 25% defoliation treatments which were not significantly different from each other. On average, the 25% and 50% defoliation treatments reduced stem volume increment by 44.34%. Increments of diameter and biomass and leaf production were not reduced by defoliation. In terms of response to N, increments in height and stem volume rose from 8.98 cm and 8.23 mm at unfertilized to 11.39 cm and 12.13 mm at 3 g N plant-1, respectively, while number of new leaves increased by a margin of 1.51 from unfertilized to 6 g N plant-1. Total biomass increment that was unaffected by defoliation showed an increasing trend from 0.55 g at unfertilized and 1 g N to 0.83 g at 3 g N and 0.94 g at 6 g N plant-1. There was no significant interactive effect of treatments on any parameter, suggesting that the adverse effect of defoliation on growth of G. arborea seedlings may not be alleviated by N fertilization. It is encouraged that a similar study be conducted for a longer duration to ascertain if the responses are sustained or modified.

Yield-Based Economic Thresholds for Grape Berry Moth (Lepidoptera: Tortricidae) in Juice Grapes

Journal of Economic Entomology ◽

10.1603/ec12298 ◽

2013 ◽

Vol 106 (2) ◽

pp. 905-911 ◽

Cited By ~ 2

Author(s):

Craig R. Roubos ◽

Keith S. Mason ◽

Luís A. F. Teixeira ◽

Rufus Isaacs

Keyword(s):

Grape Berry ◽

Economic Thresholds

Estimation of economic thresholds for weed control in soybean (Glycine max (L.) Merr.)

Crop Protection ◽

10.1016/0261-2194(95)00114-x ◽

1996 ◽

Vol 15 (1) ◽

pp. 63-68 ◽

Cited By ~ 26

Author(s):

I. Sartorato ◽

A. Berti ◽

G. Zanin

Keyword(s):

Glycine Max ◽

Weed Control ◽

Economic Thresholds ◽

Glycine Max L

Dynamical analysis of plant disease models with cultural control strategies and economic thresholds

Mathematics and Computers in Simulation ◽

10.1016/j.matcom.2009.10.004 ◽

2010 ◽

Vol 80 (5) ◽

pp. 894-921 ◽

Cited By ~ 36

Author(s):

Sanyi Tang ◽

Yanni Xiao ◽

Robert A. Cheke

Keyword(s):

Plant Disease ◽

Control Strategies ◽

Cultural Control ◽

Dynamical Analysis ◽

Disease Models ◽

Economic Thresholds

Trophic interactions between three species of cereal aphid (Hemiptera: Aphididae) and spring wheat (Poaceae): implications for pest management

The Canadian Entomologist ◽

10.4039/n07-004 ◽

2007 ◽

Vol 139 (6) ◽

pp. 850-863 ◽

Cited By ~ 2

Author(s):

Samuel M. Migui ◽

Robert J. Lamb

Keyword(s):

Spring Wheat ◽

Trophic Interactions ◽

Plant Biomass ◽

Rhopalosiphum Padi ◽

Aphid Species ◽

Economic Damage ◽

Cereal Aphids ◽

Cereal Aphid ◽

Economic Thresholds ◽

Specific Impact

AbstractThe susceptibilities of genetically diverse Canadian spring wheats, Triticum aestivum L. and Triticum durum Desf., to three aphid species, Rhopalosiphum padi (L.), Sitobion avenae (Fabricius), and Schizaphis graminum (Rondani), were investigated. Trophic interactions measured as changes in biomass of aphids and wheat plants were used to quantify levels of resistance, components of resistance, and impact of aphids on yield. Plants in field cages were infested with small numbers of aphids for 21 days at heading. These plants were usually more suitable for the development of S. avenae and S. graminum than of R. padi. Partial resistance, measured as seed production by infested plants as a proportion of that by a control, varied from 11% to 59% for different aphid species and wheat classes when all wheat plants were infested at the same stage. Cultivars within wheat classes responded similarly to each of the aphid species. None of the wheat cultivars showed agriculturally effective levels of antibiosis. The specific impact of each aphid species and wheat class varied from 5 to 15 mg of plant biomass lost for each milligram of biomass gained by the aphids. Canadian Western Red Spring wheat had a lower specific impact and therefore was more tolerant to aphids than the other two classes, but not tolerant enough to avoid economic damage at the aphid densities observed. Plants did not compensate for feeding damage after aphid feeding ceased, based on the higher specific impacts observed for mature plants than for plants that were heading. The interactions between aphids and plants show that current economic thresholds probably underestimate the damage caused by cereal aphids to Canadian spring wheat.

Western Bean Cutworm Survival and the Development of Economic Injury Levels and Economic Thresholds in Field Corn

Journal of Economic Entomology ◽

10.1603/ec12436 ◽

2013 ◽

Vol 106 (3) ◽

pp. 1274-1285 ◽

Cited By ~ 21

Author(s):

S. Paula-Moraes ◽

T. E. Hunt ◽

R. J. Wright ◽

G. L. Hein ◽

E. E. Blankenship

Keyword(s):

Field Corn ◽

Economic Thresholds ◽

Western Bean Cutworm ◽

Economic Injury

Principles of Integrated Pest Management

Turfgrass Insects of the United States and Canada ◽

10.7591/cornell/9781501747953.003.0025 ◽

2020 ◽

pp. 370-380

Author(s):

Patricia J. Vittum

Keyword(s):

Integrated Pest Management ◽

Pest Management ◽

Economic Value ◽

Crop Damage ◽

Pest Population ◽

Economic Thresholds ◽

Activity Setting ◽

Economic Injury ◽

A Site ◽

The Cost

This chapter examines the principles of integrated pest management (IPM). IPM often is defined as a program that, in the context of the environment and the population dynamics of pests, uses many different techniques and strategies in as compatible a manner as possible to maintain pest population levels below those causing economic injury. The concept of IPM was initially developed in traditional agriculture, where the success of a crop was measured in economic yield (quantity and quality of produce). The key to such agricultural IPM programs has always been establishing consistent and reliable “economic thresholds” — pest populations at which the cost of expected crop damage exceeds the cost of implementing control. In turf, the expected economic benefit from reducing a pest population usually is much more difficult to measure than in agriculture. It is difficult, if not impossible, to determine the economic value of suppressing pest insects. As a result, “economic thresholds” in turf IPM usually are more accurately described as “tolerance levels,” or “action thresholds.” In a turf IPM program, the turf manager must determine what pest populations can be tolerated without incurring unacceptable damage. The basic components of an IPM approach include assessing a site, monitoring and predicting pest activity, setting thresholds, managing turf stress, identifying and optimizing management options, and evaluating the results.