Item Details

Title: Tritrophic effects of plant growth regulators in an aphid-parasitoid system

Date Published: 2013
Author/s: Sara G. Prado, Steven D. Frank
Data publication:
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Affiliation: Department of Entomology, North Carolina State University, Campus Box 7613, Raleigh, NC 27695-7613, USA
Keywords: Aphidius colemani
Biological control
Myzus persicae
Percent emergence
Sex ratio


Plant growth regulators (PGRs) have the potential to negatively affect the outcome of biological control
via plant architectural changes and plant chemical changes. Despite studies demonstrating the negative
effects of PGRs on herbivore survival and development, to date, no studies have investigated the tritrophic effects of PGRs on parasitoid life history traits. In this study we investigated the effect of four commonly used PGRs on Myzus persicae abundance and suppression, and Aphidius colemani fitness in a
greenhouse experiment. None of the PGRs reduced aphid abundance alone or affected aphid suppression
by A. colemani. However, paclobutrazol reduced the number of mummies that developed on plants. PGRs
had a range of negative effects on parasitoid fitness. No adult parasitoids eclosed from mummies on
ancymidol treated plants. Paclobutrazol reduced parasitoid size, and paclobutrazol and uniconazole
reduced female:total ratio. This study shows that PGRs can negatively affect parasitoid fitness, and reduce
parasitism, suggesting the potential for negative long-term effects on the efficacy of biological control.