What do yellow sticky cards tell us about beneficial insects and pests?


What do yellow sticky cards tell us about beneficial insects and pests?

Research scientists at Rodale Institute help vegetable growers combat a pest that can wipe out an entire crop in only a few days

Using a microscope, Dr. Gladis Zinati, an Associate Research Scientist at Rodale Institute, and Dr. Andrew Smith, Director of the Vegetable Systems Trial, are identifying and counting parasitoids and predators collected on yellow sticky cards from 2016 field research plots. Those plots were cropped to organic cucumber plants and integrated with flowering insectary strips.

The purpose of the inclusion of flowering insectary strips, as reported by Dr. Zinati, is to attract beneficial insects that predate or parasitize striped cucumber beetles.

Striped cucumber beetle is a pest and a vector for a bacterial pathogen (Erwinia traheiphila) that causes plant wilting and has the potential to eliminate an entire crop within a few days.

The idea is to design production systems that can be adopted by vegetable growers to manage insect pests and plant diseases. The main goal is to attract and keep natural enemies in the system by creating habitat to enhance their chances for survival and reproduction. For example, many adult predators and parasitoids feed on nectar and pollen of flowering plants, so it is essential to have a diverse suite of pollen and nectar-producing plants in production systems to provide insects with continuous resources.

These parasitoids include tachinid flies and braconid wasps. They are very small insects (refer to photo of yellow sticky card) whose immature stages (larvae) develop within the host and feed inside the host body, in this case the cucumber beetle, and ultimately kill the host. The predators found on the sticky cards include ladybird beetles, minute pirate bug, hover flies, and damsel (nabid) bugs. While these predators do not feed on striped cucumber beetle adults, their role is important in keeping many soft-bodied insects (such as mites, thrips, leafhoppers, aphids and even small caterpillars) in check.

This project funded by a Pennsylvania Department of Agriculture Specialty Crop Block Grant is beginning its second year. For more information on the project, please contact Dr. Gladis Zinati, Associate Research Scientist, Rodale Institute at Gladis.Zinati@RodaleInstitute.org | 610-683-1402

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