Project Overview

Reports

Commodities

• Fruits: berries (brambles)

Target Pests

• Target Pests: insects, lepidoptera, other

Practices

• Pest Management: behavioral control, monitoring/scouting, traps

Raspberry crown borer (RCB, Pennisetia marginata) is the most significant native pest of blackberries and raspberries in the eastern United States. Larval feeding on crowns and roots reduces yield, vigor, and ultimately kills plants 3 to 5 years after infestations begin. The only management tools available to conventional growers are preventative soil applications of broad-spectrum insecticides targeting larvae before they tunnel into crowns; organic growers have no known effective control options. Blackberries are an increasingly important specialty crop in the southern U, and are grown by 9560 farmers across 19,507 acres with a value of up to $250 million. Raspberries are less commonly grown in the south because most varieties are not heat tolerant.

A key barrier to developing integrated pest management tools for RCB has been the difficulty of sampling and monitoring. Adults RCB are day-flying clear wing moths which resemble wasps, but they are difficult to observe within fields. Eggs are laid on leaves and canes but hatch within a few days after which larvae drop the soil and after which larvae tunnel into crowns and roots. Damage from root-feeding larvae is cryptic and difficult to observe without killing plants. There has been no effective means to monitor adults RCB, but recently, sex pheromones for adult RCB have been identified and these have been used to develop commercially available lures. This project will determine if recently developed commercially available pheromone lures can be used to effectively monitor RCB, and in turn, if monitoring can enable more targeted pest management action and reduce pesticide applications. We expect that more effective monitoring tools will reduce and more effectively time pesticide use and enable the development of non chemical and organically acceptable tools.

The overall goal of this project is to evaluate the effectiveness of pheromone lures for monitoring raspberry crown borer (RCB) in southern blackberries, and to share this information with stakeholders affected by this pest. We will achieve this via the following two objectives and associated activities:

1. Determine if commercially available lures can be used to efficiently monitor RCB.

           1.1. Compare commercial lures to laboratory-formulated pure compounds.

           1.2 Track seasonal fluctuation and compare local abundance between sites.

           1.3 Relate pheromone trap captures of adult moths to larval infestation.

3. Train blackberry growers and extension agents to monitor raspberry crown borer.