Galls, Diseases, and Pests - Fruit Fly Gall
Trupanea signata
The Trupanea signata Fruit Fly generally feeds only on cudweeds, laying its eggs in the plant's buds. As the larvae grow, they eat the insides of the stems, which helps form the plant gall. The insect sheaths visible in some of the photos are the exuviae or exoskeletons of insects that have moulted.
On Pink Cudweed (Pseudognaphalium ramosissimum).
On Pink Cudweed.
On Pink Cudweed.
On Wright's Cudweed (Pseudognaphalium microcephalum).
On Wright's Cudweed.
On Wright's Cudweed. The black grains are called "frass"--basically the insect's excreta or droppings.
On Wright's Cudweed.
On Wright's Cudweed. Here you can see frass, exuviae, and I'm not sure what the brown is!