ANTRACHNOSE

Question 1

Also know as

Answer 1

Swartroes

Question 2

Causative organism

Answer 2

Gleosporium ampeloghagum

Question 3

LEAVES

Answer 3

light grey spots with a reddish-brown to purple on the edge (bigger than in dead arm disease)

older leaves - round appearance

significant sizes

tearing and shedding from spots because of dead tissue cause leaves to assume a broken appearance

Question 4

SHOOTS

Answer 4

• small and dark brown to black spots
• sunken in the middle with raised edges
• as spots become bigger and join each other it cause shrivelling and destruction of tissue so that shoots die-back
• these shoots appear black and dry with a hard texture

Question 5

BUNCHES

Answer 5

• before flowering
• when it occurs on the peduncle or pedicel, young bunches become entirely shrivelled and die-back
• after berry set and enlargement dark spots appear on the peduncle and cause die-back

Question 6

BERRIES

Answer 6

-older berries: round spots with pale grey centres, surrounded by dark edge spots

Question 7

Areas affected

Answer 7

Summer rainfall areas

Question 8

How does it spread?

Answer 8

Spores hibernate on infected wood.

When warmer moist conditions happen these spores are released and infect any green part of the vine

Question 9

Can it spread from vine to vine

Answer 9

Yes, very slowly and only through water