Effect of temperature and
fungicides on black-end rot of
banana
Suren Samuelian, Lynton Vawdrey
Introduction & Objectives
Black-end rot caused by Ceratocystis (Chalara,
Thielaviopsis) paradoxa is an important postharvest disease of banana worldwide
Fungus invades the surface of the crown cut,
advancing into the finger stalk
Infected fruit show an uneven black discoloration of
the skin, and the pulp is reduced to a wet dark
brown soft consistency
Infected fruit ripens prematurely, fingers drop off
when handled
Aim: to study the effect of temperature on the
development of C. paradoxa, and its sensitivity to
post-harvest fungicides
Materials & Methods
• Fungal isolates were identified from diseased fruit and cultured
onto Potato Dextrose Agar (PDA)
• Crowns of three finger clusters were infected with 103 conidia
• Infected fruit was incubated at 10, 13, 15, 18, 22, and 26oC in
the dark and black-end rot disease index (BERDI) assessed 6
dpi
• In vitro assessment of fungicide sensitivity was conducted with
imazalil, fludioxonil, thiabendazole, and prochloraz at 0.001
µg/mL
2
5
7
BERDI
Results
Black-end rot 6 dpi
Mycelium growth at 0.001 µg/mL
e
c
7
d
6
100
d
80
BERDI
5
c
4
60
b
b
fludioxonil
imazalil
%
3
b
40
2
1
20
a
0
a
0
10oC
o
10 C
13oC
o
13 C
15oC
o
15 C
18oC
o
18 C
22oC
o
22 C
26oC
o
26 C
prochloraz
thiabendazole
BERDI: 0 = no discoloration or mycelial growth on crown, 1 = discoloration or mycelial growth limited on surface of cut crown, 2 = discoloration or mycelial growth
less than 10 % of crown area, 3 = 11–40 % discoloration or mycelial growth on crown area, 4 = 41–70 % discoloration or mycelial growth on crown area, 5 = 71–
100 % discoloration or mycelial growth on crown area, 6 = discoloration or mycelial growth advanced to finger stalks, 7 = finger-stalk rot occurs, causing fingers to
drop off when handled (after Alvidia (2013) J Gen Plant Pathol 79:136-144)
Discussion
Optimal temperature for development of black-end rot was
18oC (storage conditions) with pathogen invading fruit pulp
within 6 days.
Black-end rot did not develop at 10oC; slow mycelial growth
was observed at 22 and 26oC
Prochloraz was the most effective post-harvest fungicide
tested, and at concentration 0.001 µg/mL reduced the
radial growth of C. paradoxa by 90%