Modeling long-term effects of pesticides on populations: Beyond just counting dead animals
2000 (English)In: Ecological Applications, ISSN 1051-0761, Vol. 10, no 1, 295-302 p.Article in journal (Refereed) Published
New highly selective pesticides are often less lethal than older pesticides and consequently leave many survivors behind. Because there are survivors, evaluating efficacy for these new pesticides requires a subtler approach than simply counting dead animals. To address this problem we developed a demographic model that incorporates the biological complexities of age structure, temperature sensitivity, and pesticide persistence. We illustrate our approach using experimental data on the activity of Margosan-O, a derivative from the neem tree, applied to the pea aphid. We found that, although the activity of Margosan-O decreased with time after spray, it persisted for similar to 2 wk at 25 degrees C. To quantify the effectiveness of Margosan-O we introduced a new measure, a delay in population growth, since the result of a spray was short-term reduction in population growth from which the population will eventually recover. The practical question is then how long is the delay? We found the delay to be >5 d at 25 degrees C for 40-60 mu L/L of Margosan-O and longer at lower temperatures. Proper estimation of the delay required including the age selectivity and persistence of Margosan-O. We suggest that generally these new less lethal chemicals demand a new approach in toxicology both theoretically and experimentally.
Place, publisher, year, edition, pages
2000. Vol. 10, no 1, 295-302 p.
demography, ecotoxicology, insecticides, Margosan-O, neem, pea aphid, pesticides, evaluating efficacy, population, stage-structure
IdentifiersURN: urn:nbn:se:liu:diva-49867OAI: oai:DiVA.org:liu-49867DiVA: diva2:270763