Terrestrial Fly Patterns: A guide to why, when, and how

Updated: Oct 14


Terrestrial fly patterns are a subcategory of dry flies used to imitate non-aquatic insects that have crawled out of or fallen into the water. These include ants, beetles, crickets, and grasshoppers among others.

In this guide we will cover the following about terrestrial fly patterns:

Why do terrestrial patterns work

Best time of year to fish terrestrials

How to fish terrestrials

Best terrestrial patterns to use

Why do Terrestrial patterns work?

Give them what they want:

Of course trout feeding preferences vary among regions and water types, but according to Mike Lawson's book "Spring Creeks", terrestrials can make up as much as 40% of a trout’s diet during peak months.

While this may be a little less than half of their overall meals, according to a study conducted in 2011 and 2012 by Patrick M. O'Rouke of the Georgia Department of Natural Resources, it represents over 50% of the surface insects they consume. By not fishing terrestrial patterns, you might be missing out on a major portion of dry fly fishing opportunities.

*Click here to see the entire contents of the study by O'Rouke*

Larger Trout:

During times of the year when terrestrials are most prevalent, larger fish often have the tendency to hide lower in the water column. The same study by O'Rouke, found that more than 8 out of 10 of the total terrestrials eaten were by trout over 8 inches long. Showing one way to entice larger trout to the surface is by presenting something packed with calories.

Explosive action:

Trout feeding on terrestrials have a tendency to attack their prey with considerable force, creating splashy rises that are exhilarating to witness. Check out this video from one of our favorite fishing duos!

When is the Best Time of year to Fish Terrestri

al Patterns?

Summer is the best time of year for terrestrial patterns. Seasons can vary greatly among geographic regions, but generally speaking, June, July and August are the best months to fish terrestrials. According to O'Rouke's study, nearly 70% of all terrestrials consumed by a trout in a given year are during these Summer months.

Not only are the vast majority of the terrestrials eaten during the Summer, trout also seem to have a distinct preference for them during that time of year. Of the numerous food options, over 25% of a trout’s diet is made up of terrestrials during the summer months. As the chart below shows, this is distinctly different from the other 3 seasons.

Weather conditions: Windy cloudless Summer afternoons are the best conditions for terrestrials. Since they don’t live or typically spend time in the water, being blown in by the wind is a primary way they get there. Any time you’re walking to a stream and see grasshoppers jumping all around you, it’s time to tie on a terrestrial pattern.