The caddis worm can be collected and destroyed at the same time

George OrdishGarden pests, Londres, Hart-Davis, 1956, p. 39.

Cadis Flies (Phryganeidae). A number of « caddis worms » may often be found moving about the bottom of old lily ponds. They live in tubular cases made of silk and  grains of sand, small stones and old leaves. These «  worms » live on the leaves, stalks, and buds and can do much damage. Control Measures. Clear out old ponds and clean the rubbish from the bottom. The caddis worms can be collected and destroyed at the same time.