Go to National Library of New Zealand Te Puna Mātauranga o Aotearoa Go to Te Ao Hou homepage
No. 29 (December 1959)
Previous Section | Table of Contents | Next Section
– 58 –

THE HOME GARDEN
BLACK ROT IN KUMARA

by R. G. Falconer, Horticulturist, Department of Maori Affairs, Tauranga

Over the past few years, owing to the onslaught of black rot in kumara beds, production has gradually receded to a stage when drastic measures must be taken if the Maori people are to continue to produce economical quantities of this most desirable sweet potato. However, if growers are prepared to go to a small amount of trouble they can be assured of reasonable success and once again produce good clear tubers.

Infection of this disease comes originally from the soil in the tuber, therefore infected tubers give rise to infection on young plants or slips in the propagation beds, and when planted out in the field, spread the disease until harvesting when the crop is stored. Breakdown of the tuber occurs and, in some cases, the crop is a total loss. Black Rot fungus over-winters on dead vines and other decaying vegetation.

Kumaras should be carefully sorted at harvesting time and any doubtful tubers destroyed by burning or feeding to pigs. All vines should be gathered and when dry enough, burnt. If infection is present in crops, land should not be used again for four or five years. Seed beds should also be changed to a new area.

PREVENTION OF INFECTION

1.

Spray store houses or pits with Bordeaux 3–4–50 before storing crop.
2.

Dip Kumaras in Bordeaux mixture before storing and allow to dry thoroughly before sorting.
3.

After sorting seed for planting in seed beds in the spring again, dip before planting.
4.

After pulling plants for setting out in field again, dip and allow to dry before planting.
5.

Crop rotation and use of disease free sets should be carried out.
6.

Planting out healthy slips into ground that has not grown Kumaras for at least three years or longer if possible is the best means of avoiding infection.

PREPARATION OF BORDEAUX
MIXTURE

Quantities required for four gallons: —

  • 4 ozs. Bluestone

  • 5 ½ ozs. Hydrated Lime

  • 4 gallons water

Preparation:

Dissolve bluestone in 2 pints of hot water in an earthenware or wooden vessel. Mix the hydrated lime to a thin paste in 2 pints of cold water. When bluestone is dissolved, add 3 ½ gallons of cold water, and then mix in the lime with the bluestone solution, stirring rapidly. Bordeaux must be used within 8 hours after mixing.

All quantities given in this spray programme are for 4 gallons of spray.

Letter to the Editor
TE TAKUATE A KAWITI

Sir,—In issue 26 of Te Ao Hou a letter by Envious of Manaia, Taranaki asks where Te Toka o Mapuna is located in the Hokianga Harbour. I was also interested to know of a Mapuna near the Cavalli Islands. Browsing through a school Journal Part 4 of this year I came across mention of a Tokomapuna between Kapiti Island and the mainland more towards Wellington.

This raises an interesting point in my mind, which is that it seemed the olden Maoris gave any rock over which the tide surged and placed in a prominent location the name Mapuna. Maybe there are other Mapunas on other parts of N.Zs. coastline.

It is rather difficult to pinpoint by words exactly where the Hokianga Mapuna is. Suffice to say it is definitely in the Hokianga Harbour. As you go north by the west coast highway through the Waipoua State Forest about six miles past the northern boundary you ascend a steep hill. Right on top of this hill is a deep cutting. When you get through this cutting a panoramic view of the Hokianga Harbour is before you. I think it is second to none in the north.

Looking towards the harbour itself if the tide is ebbing or rising the eddy over Mapuna is quite plain if the sea is calm. If rough a wave is sure to be seen breaking over it. It is located about half-way between the bar and the inner harbour which is plainly discerned by the hills and cliffs rising from the high-water mark. It is more to the north heads. We call it the Nor-west and a very good fishing ground for schnapper.

I have been right over the rock in a dinghy but believe me it was a rather hair-raising experience as the sea seems to drop over the rocks and you are looking at a solid wall of water.

PIWAI TOI.