Bananas and Food Security - Bioversity International

Asie/Pacifique - Asia/Pacific : A. Molina and R.V. Valmayor
infected leaves. The effects of Sigatoka leaf spot infection are small bunches, few and
small fingers. These, however, are acceptable by farmers as their fruits are consumed
locally. Thus, Sigatoka is perceived as a tolerable disease unlike BBTV and Fusarium wilt,
which cause total loss on affected plants.
Moko/blood disease
Moko/blood disease caused by Pseudomonas solanacearum is a major disease affecting
bananas in Indonesia and the Philippines. In Indonesia, blood disease is ranked the
number one disease. Reported as early as in the 1930’s in Sulawesi, disease epidemic
resulted to quarantine regulation that prohibited the translocation of planting materials
to other islands of Indonesia. The disease seriously devastated a very popular cooking
banana of balbisiana genomic constitution, Pisang Kepok. Recently, the disease is
already wrecking havoc in West Java and the southern island of Sumatra. The same
disease, called “Bugtok”, is seriously affecting the cultivar Saba, an important cooking
banana in the Philippines. While it was not originally ranked in the top three banana
diseases, Moko or Bugtok has now become a major threat to small growers and banana
farms in Central and Southern Philippines. In a recent survey in affected provinces,
60-90% of Saba plants are affected with “Bugtok”. This disease cause fruit rotting
rendering the fruits unfit for human consumption.
The bacterium is transmitted by insect feeding on male buds. Subsistent banana
farms are most affected as farmers do not sanitize and remove male buds. Thus, insect
transmission is efficient. On the other hand, large commercial plantations manage the
disease quite effectively as they remove the male buds as soon as the false hands appear.
At the same time, fruits are protected with plastic bags. Moreover, strict monitoring and
eradication of infected plants are implemented.
In a field demonstration trial conducted in farmers field in the Philippines, the
simple removal of the male buds as soon as the false hands appear, reduce incidence to
0-5%. This technique is being adapted for blood disease in Indonesia. It is interesting to
note that a variety of Pisang Kepok that does not produce fully developed male buds are
not affected by blood disease.
Nematodes
The burrowing nematode, Radopholus similis, is the most important nematode species
affecting banana in the region. The root-knot nematode is also present to a lesser extent.
Practically, no nematode control is employed by subsistent small growers. On the other
hand, large commercial plantations apply nematicides to manage nematodes. Nematode
control is essential to prevent yield loss not only due to fruit weight reduction but most
importantly, to prevent toppling down as a result of weakened root systems.
The continued use of nematicides, however, had caused concerns on environmental
and ground water contamination and workers’ safety. Biological control such as the use
of the fungus, Phaecilomyces lilacinus, which has been demonstrated under
experimental fields to be effective, has not yet found wide usage even among commercial
plantations.
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