Sydney NSW, Australia
Identification request
6 years ago
   1
Sweet potato discoloured skin for identification - Pohnpei, Federated States of Micronesia
Dear Pestnetters

Does anyone know why the skin of the sweet potato has dark areas. Is it caused by poor handling or is it a disease? This sweet potatoes were imported from Papua New Guinea to Pohnpei, Micronesia.

Kind regards
Konrad Englberger

Posted on user's behalf
Pohnpei
Scurf
Sweet_potato
Federated_states_of_Micronesia

Responses

   0
6 years ago
Hi Konrad,I think you have both factors in play here.Scurf (Monilochaetes infuscans), a fungus, is quite common in PNG, particularly in areas that have very short crop rotations. In some areas of Eastern Highlands, it is so common that I have had farmers tell me it is a sign of maturity.  Usually it is restricted to the skin, so is more a visual effect. Spread is often through infected planting material, something that I have clearly noticed in trials comparing pathogen tested vines and field collected vines. It survives in the soil for 1-2 years. The post-harvest handling of sweetpotato in PNG is terrible. Roots are thrown around, packed as tightly as possible into unventilated 80+ kg woven  plastic stock feed bags. These are then manually lifted on and off trucks a number times. If going to Port Moresby they are then loaded into shipping in containers and then unloaded and transferred to storage depots before being reloaded and distributed to sales points.  There are levels of damage at all points along the supply chain.CheersMike 

 

Michael Hughes

Farming Systems Development  Officer,
Department of Agriculture and Fisheries
Please note changed  office telephone numbers.T 07 4017 0716 M 0427 602 156 International +61 7 4017 0716 / +61 427 602 156
E michael.hughes@daf.qld.gov.au  
W www.daf.qld.gov.au
28 Peters Street, Mareeba Q 4880


Posted on user's behalf

   0
6 years ago
Hi Konrad

The scurf sweet Kumala is common in Tonga, especially the variety
"Mele-Fakahau" also, when you have a plantation over-matured on the
ground... better harvest when it is on the right time of maturity.
Sione Foliaki

Posted on user's behalf
   0
6 years ago
Malo aupito Konrad,

Now it is good to know that it is present. No need to hide it.
Has been here for awhile now, since Kumala was becoming as major cash crop. It is common in "Kumala-Hawaii" and "Kumala-MeleFakahau" when you store the kumala roots in bags for awhile, also on over-mature Kumala plantation.
Will share photos when I have time on to the fields.

Sione Foliaki

Posted on user's behalf
   0
6 years ago
Dear Konrad

Your sweet potatoes look as if they have scurf, Monilochaetes infuscans, a fungus.
It is common on sweet potato in PNG. 
There is a fact sheet on scurf (260). Go to the Pestnet website and click on Pest Fact Sheets in the menu. The fact sheets are listed alphabetically

Best wishes
grahame

Posted on user's behalf
Pohnpei
Scurf
Sweet_potato
Federated_states_of_Micronesia