Spray but not sway - Roundup damage on tomatoes

Ajay Nair
Department of Horticulture, Iowa State University

We are obsessed with things that are round.....cookies, pizza, pies, and now ROUNDUP !  Weed control had never been easy until the formulation called Glyphosate which is a non-selective, broad-spectrum, systemic herbicide and an active ingredient in Roundup. Care should be taken to minimize spray drift while applying this herbicide. Roundup spray drift can cause serious injury to non-target plants.

Pictures below show roundup damage on tomato plants growing inside high tunnels (compare with the rows behind). The entire row of plants growing on the outer edge of the tunnel was damaged due to roundup drift from adjacent field. Symptoms include distorted new growth with cupped leaflets. Extent of damage on tomato crop depends on factors such as  stage of growth, amount of exposure, cultivar, etc.

Precautions to avoid such damage:

1. Avoid spraying under breezy conditions

2. Utilize a shield to prevent drift over to non-target plants. 

3. When applying roundup near or in vegetable gardens, increase droplet size to minimize mist and possible drift.