A Comparison of Acute Mortality and Population Growth Rate as Endpoints of Toxicological Effect

Walthall, William K.; Stark, John D.

doi:10.1006/eesa.1997.1521

Cited by 125 publications

(68 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…For lime sulphur, recent studies showed the same tendency (Tuelher 2006, Soto 2009). The use of demographic studies together with lethal concentration is recommended to evaluate the toxicity of products (Walthall & Stark 1997, Teodoro et al 2005, Stark et al 2007. For neem based products, this approach is especially important due to their special mode of action and delayed effects on arthropods (Scmutterer 1990).…”

Section: Discussionmentioning

confidence: 99%

Alternative control of Tetranychus evansi Baker & Pritchard (Acari: Tetranychidae) on tomato plants grown in greenhouses

Soto¹,

Venzon²,

Oliveira³

et al. 2010

Neotrop. entomol.

View full text Add to dashboard Cite

-Tetranychus evansi Baker & Pritchard is an important pest of solanaceous plants, including tomatoes. This mite is characterized by a high reproductive rate, which leads to high population growth in a short period of time causing important economic damage. Control of T. evansi is mainly through synthetic acaricides. In searching for environmentally friendly control measures, we evaluated the effi ciency of alternative products to control T. evansi on tomato plants under greenhouse conditions. The products tested were lime sulphur and neem based products. We fi rst estimated the lethal concentration (LC) and instantaneous rate of increase (r i ) of T. evansi exposed to different product concentrations in laboratory conditions, and later tested the effi cacy of LC 95 and the concentrations that restrained mite population growth (r i = 0) in greenhouse conditions. The following treatments were repeated three times: NeemPro (81.0 and 71.6 mg a.i./l), Natuneem (31.1 and 20.4 mg ai/l), Organic Neem (39.1 and 30.4 mg a.i./l), lime sulphur (1.0 and 0.6%) and water (control). For all products, control provided by LC 95 was higher than provided for lower concentrations (r i = 0) one day after spraying. However, after fi ve days, for both concentrations, the percentage of T. evansi population reduction was superior to 95% and increased over time. Only plants sprayed with Natuneem (31.1 mg a.i./l) showed symptoms of phytotoxicity. Lime sulphur and neem based products, applied in appropriate concentrations and formulations, bear out as a viable alternative to control T. evansi on tomato plants.KEY WORDS: Acari, Azadirachta indica, lime sulphur, effi ciency, phytotoxicityThe tomato red spider mite, Tetranychus evansi Baker & Pritchard, is an important pest of solanaceous plants, especially tomatoes (Flechtmann 1983, Bonato 1999, Ferragut & Escudero 2002. This mite is characterized by a high reproductive capacity, which leads to high population levels in a short time, causing important economic damage (Moraes & McMurtry 1986). Additionally, the mite produces large quantities of webs on the infested plants, hampering the action of natural enemies (Gerson 1985, Sabelis & Bakker 1992. The control of T. evansi in tomato is done mainly with application of synthetic pesticides. Despite its relative effi ciency, chemical control has several negative impacts as the selection of resistant individuals due to the continuous use of certain active ingredients, the reduction or elimination of benefi cial species, the high toxicity of products to applicators, and the presence of residues in food (Picanço et al 2007, Maniania et al 2008.A viable alternative to the problems arising from excessive use of synthetic pesticides in tomato production is the use of methods that provide control with social and environmental safety. In the search for such methods, natural enemies are being evaluated as biological control agents of T. evansi (Wekesa et al 2005, Furtado et al 2007, Brito et al 2009. Another strategy that has been used where con...

show abstract

Section: Discussionmentioning

confidence: 99%

Alternative control of Tetranychus evansi Baker & Pritchard (Acari: Tetranychidae) on tomato plants grown in greenhouses

Soto¹,

Venzon²,

Oliveira³

et al. 2010

Neotrop. entomol.

View full text Add to dashboard Cite

show abstract

“…Few studies have been published that compare population growth and the LC 50 of species exposed to chemicals (Bechmann, 1994;Walthall and Stark, 1997b). Clearly, studies that address population growth versus individual mortality after exposure to potential environmental pollutants are needed so that relationships, or the lack thereof, among different levels of biological organization can be elucidated.…”

Section: Introductionmentioning

confidence: 98%

Reproductive Potential: Its Influence on the Susceptibility of a Species to Pesticides

Stark

Tanigoshi

Bounfour

et al. 1997

Ecotoxicology and Environmental Safety

Self Cite

151

View full text Add to dashboard Cite

“…Although more theoretical than the previous methods, they are by no means less realistic, and they can be validated with experimental work appropriately designed for that purpose. Common population endpoints used are abundance, population growth rate [160,161] and the chance of population extinction [162]. Two types of models have been suggested: simple life-history models distinguishing between life-history stages of juveniles and adults [163] and spatially explicit individual-based landscape models [164].…”

Section: Population Modellingmentioning

confidence: 99%

Environmental Risk Assessment of Agrochemicals — A Critical Appraisal of Current Approaches

Sánchez‐Bayo¹,

Tennekes²

2015

Toxicity and Hazard of Agrochemicals

View full text Add to dashboard Cite

This chapter provides insights into the difficulties and challenges of performing risk evaluations of agrochemicals. It is a critical review of the current methodologies used in ecological risk assessment of these chemicals, not their risks to humans. After an introduction to the topic, the current framework for ecological risk assessment is outlined. Two types of assessments are typically carried out depending on the purpose: i) regulatory assessments for registration of a chemical product; and ii) ecological assessments, for the protection of both terrestrial and aquatic ecosystems, which are usually site-specific. Although the general framework is well established, the methodologies used in each of the steps of the assessment are fraught with a number of shortcomings. Notwithstanding the subjectivity implicit in the evaluation of risks, there is scepticism in scientific circles about the appropriateness of the current methodologies because, after so many years of evaluations, we are still incapable of foreseeing the negative consequences that some agrochemicals have in the environment. A critical appraisal of such methodologies is imperative if we are to improve the current assessment process and fix the problems we face today. The chapter reviews first the toxicity assessment methods, pointing to the gaps in knowledge about this essential part of the process and suggesting avenues for further improvement. Deficiencies in the current regulations regarding toxicity testing are discussed, in particular the effect of the time factor on toxicity and the issue of complex mixtures.

show abstract

A Comparison of Acute Mortality and Population Growth Rate as Endpoints of Toxicological Effect

Cited by 125 publications

References 19 publications

Alternative control of Tetranychus evansi Baker & Pritchard (Acari: Tetranychidae) on tomato plants grown in greenhouses

Alternative control of Tetranychus evansi Baker & Pritchard (Acari: Tetranychidae) on tomato plants grown in greenhouses

Reproductive Potential: Its Influence on the Susceptibility of a Species to Pesticides

Environmental Risk Assessment of Agrochemicals — A Critical Appraisal of Current Approaches

Contact Info

Product

Resources

About