Variegated Cutworm (Lepidoptera: Noctuidae): Leaf-area Consumption, Feeding Site Preference, and Economic Injury Level Calculation for Potatoes

1985 ◽  
Vol 78 (5) ◽  
pp. 1095-1099 ◽  
Author(s):  
E. J. Shields ◽  
D. I. Rouse ◽  
J. A. Wyman
Keyword(s):  
Leaf Area ◽  
Site Preference ◽  
Economic Injury Level ◽  
Feeding Site ◽  
Economic Injury ◽  
Variegated Cutworm ◽  
Level Calculation ◽  
Lepidoptera Noctuidae

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.

scholarly journals Economic injury level of Helicoverpa armigera on bean Phaseolus vulgaris L. seedlings

2020 ◽  
Vol 18 (3) ◽  
pp. 308
Author(s):  
Fernando Belezini Vinha ◽  
Lucas André Genari ◽  
Mauricio Bianchi Masson ◽  
Alexandre De Sene Pinto
Keyword(s):  
Phaseolus Vulgaris ◽  
Helicoverpa Armigera ◽  
Economic Injury Level ◽  
Phaseolus Vulgaris L ◽  
Economic Injury ◽  
Helicoverpa Armígera ◽  
Lepidoptera Noctuidae ◽  
Helicoverpa Armigera Hubner

A lagarta Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) chegou ao Brasil em 2012 e vem causando prejuízos severos aos agricultores, especialmente nas culturas do algodão, feijão, milho, soja e tomate nas regiões Norte, Nordeste e Centro-Oeste. Pouco se conhece sobre seus danos às culturas no país e o feijoeiro é uma das culturas menos estudadas dentre as citadas. Portanto, esse trabalho objetivou-se avaliar o nível de dano causado pela lagarta H. armigera de 3º ínstar em plântulas de feijão cv. BRS-Estilo. O ensaio foi semeado em 10/04/2014, em Ribeirão Preto, SP, com espaçamento de 0,5 m e 12 plantas por metro. Em um delineamento em blocos casualizados, as infestações (18/04) de 0 (testemunha), 0,1, 0,2, 0,5 e 1 lagarta por planta foram repetidas quatro vezes, em parcelas de 0,5 m2 cercadas por barreias de PVC de 20 cm de altura e com bordadura de 1 m. Após 1, 3, 7 e 14 dias após a infestação foi avaliada a porcentagem de desfolha. A porcentagem média de desfolha foi proporcional à densidade de lagartas. O nível de dano de lagartas de 3º ínstar de H. armigera é de 1,4 lagartas por planta e, dessa forma, o nível de controle deve ser de 0,7 lagartas por planta de feijoeiro.

scholarly journals Efficacy of microencapsulated nucleopolyhedroviruses from Colombia as biological insecticides against Spodoptera frugiperda (Lepidoptera: Noctuidae)

2017 ◽  
Vol 66 (2) ◽  
Author(s):  
Gloria Patricia Barrera Cubillos ◽  
Juliana Andrea Gómez-Valderrama ◽  
Laura Fernanda Villamizar Rivero
Keyword(s):  
Insecticidal Activity ◽  
Spodoptera Frugiperda ◽  
Fall Armyworm ◽  
Field Trials ◽  
Control Treatment ◽  
Economic Injury Level ◽  
Original Activity ◽  
Economic Injury ◽  
Insect Mortality ◽  
Lepidoptera Noctuidae

Wettable powder formulations by microencapsulation of viral occlusion bodies (OBs) of both Spodoptera frugiperda multiple nucleopolyhedrovirus from Colombia (SfCOL) and a genotypic variant (SfCOL-A) were evaluated for controlling the fall armyworm S. frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) in maize crops. Microencapsulation preserved OBs activity after three months of storage at 35ºC, where insecticidal activity loss was not greater than 12%. Additionally, the formulation protected the OBs against inactivation caused by UV-B radiation, retaining its insecticidal activity after 6 hours of UV laboratory exposure, in contrast to unformulated viral suspensions, which presented an Original Activity Remaining (OAR) between 12.1 and 50%. Under greenhouse conditions, the insect mortality was greater than 80% with microencapsulated viruses. In field trials, treatments reduced the percentage of damaged plants to levels below the economic injury level (35%) when the formulated and unformulated virus were applied at 8x1011 OBs/ha (800g/ha) dose, while the damage in the control treatment was close to 60%. Microencapsulation of SfCOL and SfCOL-A OBs provides useful advantages related to half-life and photostability.

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.

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