Using bee pollinators as a novel means for vectoring Beauveria bassiana to greenhouse peppers and tomatoes for pest control

Project code: MU03-ENT5

Project Lead

Les Shipp - Agriculture and Agri-Food Canada.

Objective

To investigate and develop the use of bumblebee pollinators as a new application technology for the microbial biocontrol agent Botanigard® in control of insect pests of greenhouse crops.

Summary of Results

Fungal pathogens of insects (in particular, Beauveria bassiana) have been demonstrated to effectively control certain greenhouse pests including whiteflies, aphids, thrips, and Lygus. This project investigated the use of a new application technology by which the microbial biocontrol agent is picked up by bees as they exit the hive, and is then dispersed to flowers and leaves during pollination of the crop by the bees. This method of application continuously provides the biocontrol agent inoculum to greenhouse insect pests, as compared with spray techniques which target only a single point in time.

Trials were conducted in cages to evaluate the effects of the fungal agent on insect pests under commercial greenhouse tomato production conditions, and to assess the impact of Beauveria on bee activity and its pollination efficiency. Three concentrations of Beauveria conidia in the inoculum were tested for controlling pest insects. A randomized complete block design was applied to all treatments for all experiments. Results showed that the middle concentration of Beauveria killed similar numbers of insect pests as did the high concentration (70 % Lygus and 54 % whiteflies) but more than the low concentration (33 % Lygus and 18 % whiteflies). Bee mortality was greater in the high versus the middle Beauveria concentration (44 % vs 13 %), but no significant difference was found between the latter and the low concentration or controls. Thus, the middle Beauveria concentration (6.24 X 1010 conidia / gram inoculum) is considered the optimal treatment concentration, because it killed the similar proportion of pest insects as did the high concentration, but with less negative impact on the bees. In the commercial trials, bee activity (trips to and from the hive) was the lowest when the bumble bees were exposed to the highest concentration of Beauveria. However, pollination level was satisfactory at all commercial greenhouses and harvested tomato fruit quality met commercially recommended standards.

Preliminary studies to investigate the feasibility of delivering a fungal insect biocontrol together with a plant health inoculum for management of disease (Endofine®, Clonostachys rosea) were undertaken as well, with very promising results. These studies have been continued in a subsequent project funded by the Pest Management Centre of AAFC, MUR06-300.

This study has demonstrated that bee vector technology is feasible as a new integrated pest management tool that can be used to deliver microbial fungal control agents and plant health inocula, singly or in combination, for insect pest control and plant disease suppression for greenhouse tomato and sweet pepper. Following the registration of the biopesticide Botanigard® in Canada, feasibility of label expansion to register this novel application technology will be discussed with the product registrant and regulator.

Factsheet on Hands-Off Method for Application of Microbial Agents

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