Depth: 2.5 cm, or even less in retentive soils with plenty of moisture.
Inoculation: recommended unless a well nodulated lupin crop was grown the
previous year, but note “rotation” above ie only grow lupins in a 3–4 year rotation
with other crops.
GROWTH CONDITIONS
Day length: most varieties are long-day, though this aspect is not well researched.
Growth period: about 105–180 days for most improved varieties. Some older types
need six months or more in which to mature.
Temperature: lupins are semi-hardy and generally need a five month period with
average temperatures of 15–25°C. The optimum for growth is 18–24°C. There is
variation between spp.:
- L. angustifolius—best in cool conditions, and can withstand minus 6°C in the
vegetative state. - L. luteus—only tolerates light frosts.
- L. cosentinii—susceptible to frost and needs heat for good growth.
Rainfall: lupins should have 400–1000 mm of evenly distributed water, as they
suffer during any period of extended drought. L. cosentinii is the most drought
resistant, and L. mutabilis also has some drought resistance.
Altitude: in Kenya lupins grow between 1500 and 2400 m. In the Andes L.
mutabilis grows at 1800–4000 m.
Pests: Aphids—especially on sweet varieties of L. luteus, they attack at the bud
stage; they also transmit virus diseases. Can be controlled with sprays (eg Bidrin)
though reinfestation can occur. - Budworm (Earworm)—the larvae enter pods and eat the seeds. Controlled by
Other pests which can create problems are: Thrips, Red-legged Earth Mites, Lucerne
Fleas, Root Weevils, Lupin Maggots, White-fringed Beetles, Grasshoppers, Root-
knot nematodes, slugs and snails.
Diseases: these can be serious and cause large loss of yield. Lupinosis can be big
trouble:
- Anthracnose and Mildew—especially in warm, humid conditions. Some varieties
have some resistance. - Grey Leaf Spot—especially with L. angustifolius. Neither L. albus nor L. luteus
are infected.
early planting, using early varieties and sprays (eg Dipterex or carbaryl compounds).
L. luteus is the most susceptible to attack, and L. angustifolius the least susceptible.
- Lupinosis—caused by Phomopsis leptostromiformis fungus which can produce a
toxin that damages the liver of ruminants which eat the infected seed (or stems);
sometimes fatal. The danger increases in the days following heavy rain. Controlled
with resistant varieties and/or fungicides such as benomyl just before pod formation. - Brown Leaf Spot—especially in cool, humid conditions. L. albus is very sus-
ceptible. The disease is seed-borne, and also survives on crop residues, which should
be removed and destroyed. No effective control methods are available.
280 TONY WINCH
- L. albus and L. mutabilis—fairly frost tolerant.