Survey of Italian Ryegrass in Delaware and Maryland

Kurt Vollmer, Extension Weed Management Specialist | kvollmer@umd.edu
University of Maryland Extension

Italian ryegrass seedheads. If seedheads are smaller than shown here, increase the number collected.

Problem: Control of Italian ryegrass is becoming more difficult in Delaware and Maryland.

Objective:

  • Understand why Italian/annual ryegrass is so widespread in 2023
  • Is herbicide-resistance part of the issue?
  • Which herbicides are involved in local resistance?
  • How wide-spread is resistance in DE and MD?

How you can help:

  1. Collect 50 ryegrass seedheads from the field (only seedheads are needed).
  2. Put in paper bag or paper envelope (do not use plastic bags).
  3. Write the nearest crossroads on bag or envelope.
  4. Write the crop on the bag/envelope.
  5. Note if any of the following herbicides were sprayed since last fall:
  • Glyphosate (Roundup)
  • Axial
  • Powerflex
  • Osprey
  • Select
  • Assure II
  1. Store in dry area.
  2. Deliver to nearest county extension office OR contact Mark VanGessel or Kurt Vollmer for collection or pickup.
  • Mark VanGessel: (302) 542-8160
  • Kurt Vollmer: (443) 446-4260

Specific farms or individuals will not be identified in any reports or summary.

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