Sampling pollen beetle (Brassicogethes aeneus) pressure in oilseed rape: which method is best?

Area of Science:

• Agricultural Entomology
• Crop Protection

Background:

• Pollen beetle (Brassicogethes aeneus) is a major oilseed rape pest causing yield loss.
• Adults damage closed flower buds, leading to bud abscission and fewer pods.

Purpose of the Study:

• Evaluate the robustness of current pollen beetle sampling methods.
• Compare the results of different monitoring techniques.
• Understand pollen beetle damage mechanisms to refine assessment methods.

Main Methods:

• Experimental evaluation of sampling methods for pollen beetle pressure.
• Comparison of adult counting, bud damage quantification, and podless stalk counts.
• Analysis of pollen beetle feeding behavior on different bud sizes.

Main Results:

• Adult abundance methods lack robustness.
• Pollen beetle damage is concentrated on small buds (<3mm).
• Podless stalk counts are a robust indicator of pest pressure.

Conclusions:

• Standardized assessment methods are crucial for comparing pest management strategies.
• Counting podless stalks provides a reliable measure of pollen beetle pressure.
• Development of alternative control strategies can be facilitated by robust monitoring.