Little Yellow Stoneflies, often referred to as Yellow Sallies, are hatching throughout the Smoky Mountain region right now. These bright yellow insects start life as a dull brown nymph in the stream. They migrate across the stream bottom and crawl up on boulders in the middle of the stream or on dry areas along the bank to emerge from their nymph skin.
It can take quite a while for the stoneflies to emerge from their skin and their wings completely open up. It’s common to see them like this on the rocks as their wings slowly open.
Their wings will eventually lay flat on their back. Try fly patterns that imitate Yellow Sallies, but they will work best when the flies are laying eggs, not hatching. They are not usually available to the trout while they are hatching unless a breeze blows them into the water.
When Little Yellow Stoneflies lay eggs late in the evening they dive bomb the water to sink their eggs into the stream. Many will either expire on the water or get washed into the stream by the rapids. Trout will often rising voraciously during this period but it may only last twenty minutes or less.