Legend Seeds Blog

Grasshopper Watch

As a proud distributor of Nuseed sunflowers, Legend Seeds is pleased to not only bring superior products with proven performance, but also in-field agronomy support from both Nuseed and Legend throughout the growing season.  Below is an Agronomy Alert written and published by Alison Pokrzywinski, Nuseed Product Development Manager:

Grasshoppers are moving out of their young nymph stages and are starting to cause more damage in sunflower fields. This has been more prevalent in South Dakota, but there are still pockets in North Dakota where growers are opting to spray borders. With the 10 day forecast looking hot and dry you will want to keep an eye on your fields.

Grasshopper-on-Sunflower

Grasshopper damage in sunflowers can be very apparent due to their ability to defoliate large portions of sunflower leaves. Decisions to spray should include the number of grasshoppers present in the field and level of defoliation. Sunflowers can compensate for up to 25% defoliation.
Grasshopper damage close up
Grasshoppers will typically start at field margins that border weedy patches or matured small grains. It’s important to recognize insect levels at field margins vs the inside of the field. Scouting can be done by visually estimating how many are seen in one square yard.
 

Threshold:
30-45 nymphs or 8-14 adults
25% defoliation 

Watchouts:

  • If grasshoppers are seed feeding on the heads, you are likely above threshold
  • When reducing adult populations use the highest labeled rate 

SDSU Pest Management Guides on labeled insecticides can be found here:
https://extension.sdstate.edu/south-dakota-pest-management-guides

Grasshopper damage in field

Sources:
Compendium of Sunflower Diseases and Pests, APS Press, 2016
https://extension.sdstate.edu/watch-sunflowers-grasshopper-defoliation-and-flower-feeding