Plant mediated effects on parasitoid efficacy in a banker plant system

Project Overview

Project Type: Graduate Student
Funds awarded in 2011: $9,930.00
Projected End Date: 12/31/2013
Region: Southern
State: North Carolina
Major Professor:
Dr. Steven Frank
North Carolina State University

Annual Reports


  • Additional Plants: ornamentals


  • Crop Production: biological inoculants
  • Education and Training: extension, focus group, workshop
  • Pest Management: biological control

    Project objectives from proposal:

    The overall goal of this project is to develop a banker plant system using A. colemani as a sustainable, effective, and economical biological control agent for aphids in greenhouses. To achieve this, the specific objectives are to: 1) Determine the effect of plant architecture on parasitoid attack rate and aphid pest suppression Rationale: Currently plant growers utilize PGRs to alter plant aesthetics and growth rate. PGRs alter plant architecture affecting herbivore placement on the plant and consequently parasitoid foraging efficiency. For instance, plants with more compact leaves are likely to provide refuges for the pest aphids. The drop in parasitoid foraging efficiency negatively affects parasitoid population growth as A. colemani cannot reproduce without its aphid host. Because so little is known regarding these topics, more research is needed to investigate PGR impacts on herbivore hosts and parasitoid attack rate. 1.1) Determine the effect of plant architecture on parasitoid attack rate and parasitoid and aphid development; Rationale: This first experiment will be carried out in order to determine the variation in A. colemani’s attack rate as related to the different plant architectures. This experiment is conducted to stimulate an augmentative biocontrol setting where the parasitoids are released right after purchase. 1.2) Determine how crop-plant architecture affects banker plant efficacy Rationale: This second experiment is to test whether or not the banker plant is providing sufficient parasitoids to decrease aphid numbers. When comparing the results from 1.1 to 1.2, we will be able to determine if parasitoids reared on the banker plant are capable of suppressing pest aphid population numbers at the same rate as the ‘simulated’ augmentative biocontrol methods are. 2) Determine parasitoid preference for and attack rate of pest aphid species compared to BCOA on banker plants. Rationale: This experiment will be conducted in the lab to determine if, when given the choice, A. colemani attacks M. persicae more than R. padi. Past studies on A. colemani have demonstrated that the parasitoid exhibits preference for the host aphid on which it was reared (van Emden et al. 2002). Because past studies have shown that A. colemani reared on banker plants do indeed suppress pest aphid populations, this choice experiment will show what percentage of parastoids preferentially forage on the pest aphid versus their non-pest host aphid. The data from this study will also demonstrate the efficacy of a banker plant system in comparison to augmentative control. 3) Determine the efficiency of aphid banker plant systems in commercial greenhouse production Rationale: To this date, the number of banker plants to place in a greenhouse has not been properly established. This experiment will help determine the correct density of banker plants needed within a commercial greenhouse. Banker plant placement and number is important because parasitoids emerging from banker plants must be able to locate and travel to pest aphids on crop plants throughout the greenhouse.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.