GROWTH CONDITIONS (Groundnuts)
Day length: day-neutral.
Growth period: from planting to dry pods, about 120–160 days for slower growing
Runner type varieties, 90–110 days for faster growing erect Bunch varieties. The
plants are ready to harvest when the leaves turn yellow and the insides of the pods
show dark markings.
It is important to harvest in a dry spell and at the correct stage, since the nuts,
even on a single plant, do not mature simultaneously. Fresh pod moisture of 30–40%
must be dried to around 8–10% for storage.
Temperature: high temperatures favour high yields, around 15C average is
needed, and there should be no frost during the growing season.
Rainfall: about 600 mm per year is the minimum, with at least 500 mm during the
growing period. Most varieties are grown where annual precipitation is 1000–1200
mm. Some varieties can produce some yield with only 300 mm per year. In Asia and
elsewhere it is grown under irrigation.
Pests: rarely a problem, though the following insects may cause some damage:
thrips, termites, ants, nematodes, leafhoppers, velvet bean caterpillars, corn
earworms, cutworms & armyworms.
Diseases: at least five diseases can reduce yields:
become distorted and plants are stunted. Control: plant early at high plant densities,
spray aphicides and use resistant varieties.
- Leaf Spot—a fungal disease, causing dark brown or black spots on both sides of
the leaves. Control: plant early, dress/treat seed, destroy infected plants; fungicides
are generally not cost effective.
rapidly dry the seed to a minimum of 10% moisture content.
may die, especially in humid conditions. Can be controlled with seed dressings.
- Bacterial Wilt—caused by the bacteria Pseudomonas solanacearum.
YIELD
Groundnuts can yield well in the warmer arid and semi-arid regions as well as in its
more traditional homeland of the humid tropics.
The global average in 2004 was 1.45 MT/ha, according to FAO statistics.
6.7 MT/ha in Israel (Figures are for groundnuts in the shell).
°
- Groundnut Blight—plants become wilted, and stems and even the whole plant
- Rosette—a viral disease, spread by aphids, where leaves turn yellow, shoots
The lowest average yield reported was 336 kg/ha in Zambia, and the highest wasnotably Aspergillus flavus and A. parasiticus, which can develop rapidly in humid
- Aflatoxins are naturally occurring mycotoxins produced by species of Aspergillus,
They are most dangerous with young animals and poultry, and are thought to be the
conditions. They are carcinogenic to animals and humans, affecting mainly the liver.
cause of high rates of liver cancer in parts of Africa and Asia. The only control is to