POTATO INVESTIGATIONS LABORATORY
Mimeo Report 59-8 October 1, 1958
PRODUCTION OF POTATOES OF GOOD QUALITY
A. H. Eddins
In favorable growing seasons high quality table pt 'k potatoes, are grown, packed
end shipped from the Hastings area which command pri h on the leading markets of the
United States which are as good as those received foio stocks cjoia and shipped from
competing potato-growing areas of the country. It illSo6l lm s difficult to ship
potatoes of good quality throughout the digging seas t Hastings,/articularly in
May, when heavy rains cause great damage in come fieli when digging of crops is
delayed beyond maturity. Tubers dug at late harvests a further exposed to infec-
tion and damage from disease-producing organisms and injurier-ftm insects, root-knot
nematodee, physiological internal necrosis, stem end browning, high soil temperatures
Practices developed at Eastings and considered essential for production of good
quality potatoes suitable for sale as table stock and for chipping are as follows:
1. Plant certified seed potatoes free of ring rot and discard seed tubers
affected with late blight, fusarium rot, soft rot, blackleg and other
diseases; and frozen and discolored tubers,
2. Store whole seed potatoes sad cut seed in a well-ventilated building
where it can be protected from freezes, drying winds, rains and the sun
until it is placed in the planter. This will help to prevent loss of seed
from soft rot and later development of blackleg in the new crop tubers.
3. Do not plant seed in wet soil and be sure it is placed in the center
of the row so that it will not be in direct contact with the bands of
fertilizer to cause chemical injury and resulting seed piece decay and
development of blackleg in tubers of the new crop,
4. Grow potatoes in new land and in the best old land where experience has
shown that tubers of good quality can be produced year after year. Do
not sidedress with nitrogen or potash late in the season which may delay
maturity of the crop. In leveling land, break and incorporate the hardpan
in the top soil, as that will Improve quality of the potatoes grown.
5. Practice rotation of crops in old land where it has been difficult to
produce good quality potatoes, Rotations suggested are (1) a winter
crop of rye or oats and a summer crop of sesbania or one of the sorghums
followed by potatoes the second year and (2) pangolagrass one or more
years followed by potatoes.
6. Maintain good drainage in potato fields from date of planting until the
crop is dug. This requires an adequate system of drainage canals and in
some areas installation of pumps to remove water rapidly from low-lying
fields during rainy weather. Nothing will contribute more to seed piece
decay and enlargement of the lenticels and rotting of tubers of the new
crop than lack of adequate drainage in wet growing seasons.
7. Irrigate potato fields as needed to maintain rapid plant growth and hasten
maturity of the crop. Experience has shown the necessity of using irriga-
tion water judielously -to avoid, damaging the yield and quality of the crop,
Overirrigation will cause lenticel enlargement, cracking of the skin and rotting
of the tubers, especially in poorly-draLined fields. Irrigation should be discon-
tinued near the end of the growing season about two weeks before digging to
mature the tubers so that they can be dug on schedule without excessive skinning.
8. Grow the Red Pontiac variety in fields or parts of fields known to produce Sebago
pol-atoes affected wi-th internal necrosis, as Red Pontiac is resistant to this
trouole; or plant the affected fields to cabbage, cauliflower or other crops.
9. Plant corky ringspot-resistant Plymouth, Pungo or Merrimack in soil known to be
infested with this disease.
10. Spray potato plants with fungicides as needed to prevent late blight plant and
11. Use soil and foliage insecticides known to reduce damage from insects which feed
on tubers of the new crop.
12. Avoid or prevent injury from root knot as indicated below.
a. Plant infested areas or fields to other crops such as cabbage or
cauliflower which should be grown during the winter and early spring
months when the root-knot nematode is inactive at Hastings.
b. Plant infested fields to potatoes in December or early January and
dig the crop prior to Nay 1 before root knot nematodes become very
active and infest the tubers.
c. As a last resort treat infested land with a soil fumigant such as
ethylene dibromide (EDB) and dichloropropane-dichloopropene (D-D)
applied in the row a month before the potatoes are planted.
13. Potato crops planted, grown and harvested during the period December 20 to May 1
usually produce the best quality tubers. Leaving the potatoes in the ground
longer than 100 to 110 days after planting the crop exposes them to conditions
which may cause rapid deterioration in tuber quality. Diseases and injuries that
may develop or increase in crops left in the ground too long, particularly in May,
include tuber-rotting diseases such as soft rot, sclerotium rot, pink rot, char-
coal rot, and watery rot; enlargement of lenticels and cracking of the skin of
tubers in wnt soil; physiological internal necrosis, stem end browning, root knot,
wireworm, cutworm and grubworm injuries; greening, yellowing and sunburn; and
sprouting of the tubers.
If it becomes necessary to plant acreages that will be harvested late in the
season (Iay), delay the planting date so that the crop will be 95 to 110 days old
when ready for harvesting late in the season.
14. Kill the vines with herbicides applied a week to 10 days before digging when
necessary to maintain a digging schedule or to fill orders with the best quality
potatoes. Herbicides used judiciously to kill the vines will mature the tubers
and set the skin and thus improve quality of the tubers.
15. Use digging, harvesting and grading machinery constructed and padded so as to
reduce tuber injuries to the minimum. Regulate the speed of the digger or har-
vester to minimize tuber injury and use methods of loading and unloading potatoes
in the field and at the packinghouse that will prevent major tuber damage. The
quality of crops is easily and quickly ruined if little or no precautions are
teken to prevent damage to the tubers when they are dug, picked up, hauled, graded
and packed for shipment. Sorting the tubers at the packing plant so as to prevent
diseased, injured and malformed ones from entering the packages is necessary to
maintain high quality.