First, the silkworms stop eating. Then they spin their cocoons. Once inside, they molt several times. They grow wings and teeth. If the caterpillars are allowed to evolve, they change into moths. Then these moths bite through the silk and fly off, ruining it for the market.
This quote is the turning point in the story for Kitsune. She was obsessed with the color of her silk changing and finally, after hearing about Chichibu, she realizes that she is able to control her silk. She has the power to control the market. I find it fascinating that she is not concerned about what is causing her silk to change so much as what effect the change is having on the quality of her silk. Once she realizes that she has the power to shape her silk, she makes it higher quality. It could be said that the lower quality was because she was worrying too much. This quote pulls the fantastic part of this story into reality. It connects what is occurring, and what is about to occur, with these girls to common knowledge. It also gives power to the rest of the story. Kitsune now has a purpose outside of filling her quota. She can save the others and herself. She knows she has the power to do this because she was the one who signed her own fate away. She willfully drank the tea. She can tap into the natural instincts that came along with her transformation to change the future for the kaiko-joko. Her transformation into a silk reeler was horrifying in its own manner, but her later transformation into a true silkworm is horrifying yet inspiring.