Cabbage Centre Grub (Hellula sp.) Larvae attack leaves and flowers in Brassica crops. They are known to combine leaves together with webbing and may tunnel into the growing points of plants. Adult moths are about 12 mm long with light and dark brown markings and are rapid fliers. Larvae are a creamish colour with dark heads, are up to 12 mm long and have longitudinal reddish-brown stripes along the body. Check crop for leaf damage and silken webbing.