Dr. Phyto

Green foxtail

Setaria viridis

Diseases & pests on this plant

• rice blastMagnaporthe oryzae
• Leaf spot and common root rotBipolaris sorokiniana

  Small dark brown to black leaf spots, often with a yellow halo, that enlarge and merge to blight whole leaves in warm, humid weather; on close-mown turf this becomes a general thinning and bronzing. Below ground the same fungus causes a brown rot of roots, crowns and stem bases, so plants are easily pulled up and the turf melts out in diffuse, irregular brown areas. Most damaging in warm summer spells on stressed, thatchy lawns.

• fall armywormSpodoptera frugiperdaEU-notifiable quarantine organism

  Young caterpillars skeletonise leaves and make "windowpane" patches; older ones chew ragged holes and burrow into the whorl, tassel and cobs of maize, leaving copious moist sawdust-like frass; the caterpillar has a pale inverted "Y" on the head and four dark spots in a square on the second-to-last segment. Populations build explosively and "march" between crops.

• European corn borerOstrinia nubilalis

  Small (1-2mm) shot-holes in young whorl leaves from first-instar feeding, sawdust-like frass extruded from stalk + ear entry holes, broken tassels + stalk lodging from internal tunneling, larvae visible inside split stalks (pinkish-white, 2cm at maturity), ear infestation creates entry for Fusarium ear rot.

• ergot of rye + cerealsClaviceps purpurea

  Hard purple-black curved sclerotia (5-30mm long) replacing kernels in cereal heads (very distinctive — looks like a black banana stuck in the head), honeydew (sticky yellow exudate) on flowering heads during infection phase, sclerotia drop to ground at harvest + survive winter, contaminated grain dangerous for human + animal consumption.