|
Onion & Leek Troubles |
|
Trouble |
Symptoms |
Treatment |
Prevention |
|
Onion Fly |
Yellow, drooping leaves. Maggots burrow into the
bases and kill young plants. |
None. Lift and burn affected plants. |
Rake Chlorophos into soil before showing or planting.
Sets are less prone than seeds. |
|
Bolting |
Premature production of flower-heads. |
Cut off flower stalks and lift as usual. Do not
store. |
Don't sow or plant too early in the season. Ensure
soil is firmed well before sowing or planting |
|
Stem & Bulb Eelworm |
Swollen, distorted foliage. Young plants die and
older plants product soft bulbs. |
None. Lift and burn affected plants. |
Do not grow onions, peas, beans or strawberries on
land previous infected with this disease. |
|
Saddleback |
On harvesting, bulbs are split at the base. Caused by
heavy rain or watering after a dry period. |
None. Use affected bulbs immediately. |
Keep well watered during dry spells. |
|
Set Division |
Onions from sets produce twin bulbs. |
None |
Plant sets in good soil and keep well watered in dry
spells. |
|
Smut |
Black spots and blotches on leaves and bulbs of young
plants. Twisted and thickened leaves. More likely in leeks than
onions. |
None. Lift and burn affected plants. |
Don't grow leeks or onions on affected ground for
eight years. |
|
Rust |
Orange spots and blotches on surface of leaves. More
likely in leeks than onions. |
Remove and burn affected leaves. |
Don't grow leeks or onions on affected ground for one
season. |
|
White Tip |
Tips of leek leaves turn white and papery in autumn. |
Spray with Dithane at first signs. Lift and burn
badly affected plants. |
Don't grow leeks or onions on affected ground for one
season. |
|
Bull Neck (Thick Neck) |
Abnormally thick necks means the bulbs will not store
successfully. |
None |
Don't use too much manure. Use a feed with more
potash than nitrogen. Don't sow seed too deeply. |
|
Downy Mildew |
Downy, grey mould covering leaves. Leave die back
slowly and shrivel. Bulbs are soft and don't store well. |
Spray with Dithane at first signs. Repeat
fortnightly. |
Grow onions on a difference site each year and ensure
soil is well drained. |
|
Leek Moth |
Tunnelled leaves. Caterpillars feed inside young
leaves leaving the outer skin. Also attacks leeks. |
Spray with a contact insecticide at first signs of
attack. Destroy badly affected leaves. |
None |
|
White Rot (Mouldy
Nose) |
Foliage turns yellow and wilts. Fluffy white mould on
base of bulbs and round black bodies appear in the fungus. |
None. Lift and burn affected plants. |
None. Don't grow onions on affected land for eight
years. |
|
Shanking |
The centre leaves turn yellow and collapse, outer
leaves follow later. Evil-smelling slime within scales. |
None. Lift and burn affected plants. |
None. Don't grow onions on affected land for several
years. |
|
Neck Rot |
During storage a grey mould appears near the neck.
Bulbs are soft and rotten. |
None. Remove rotten bulbs. |
Dist seeds and sets with benomyl before planting. Dry
bulbs thoroughly before storing. Don't store soft bulbs or bulbs
with green necks. |