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Pests of narcissus | AG0186 |
David Williams, Knoxfield
June, 2000 |  |
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Narcissus species suffer from virus diseases that are transmitted by aphids. Aphids are slow moving, plump-bodied insects. The colour varies with the species and green, yellow, pink, brown and black forms occur. Very few chemicals are registered specifically for use against aphids on Narcissus, but they may have a general registration covering use on ornamentals. It is the grower's responsibility to check that any chemicals used are registered for the purpose. Current registrations can be checked at district offices of DPI. Bulbs may be attacked by bulb mite and the lesser bulb fly.
Bulb mite Rhizoglyphus echinopus
This slow-moving mite is about 0.5 mm long, globular, and yellow-white with brownish legs. Infested bulbs produce stunted plants with yellow and distorted leaves. Early infestations are found around the basal plate of the bulb. Roots are destroyed first and bulb scales and stems are attacked later. Bulbs can be completely destroyed by the combined action of the mites and micro organisms that invade the damaged bulbs. Hot water treatment will kill the mites but good sanitation is very important when digging up or planting out bulbs.
Lesser bulb fly Eumerus tuberculatus
The adult flies are about 8 mm long, black, with three pairs of white crescent-shaped marks on the body and white lines on the thorax. They lay their eggs on damaged bulbs near the neck, in folds of the coat or on the ground near the bulb. The maggots are a yellowish color and about 8 mm long when fully grown. They are commonly found in the neck of the bulb even if the whole bulb is rotted.
This pest usually attacks the bulbs when the foliage dies down at the end of the season. Frequency of attack can be reduced by filling the holes left by the dead leaves with soil. Bulbs that produce grasslike foliage and poor flowers should be inspected for lesser bulb fly.
For effective pest and disease control, correct diagnosis is essential. A commercial diagnostic service is available at the Institute for Horticultural Development. For further information, contact the Diagnostic Service. ph: (03) 9210-9222 or fax (03) 9800 3521.
The advice provided in this publication is intended as a source of information only. Always read the label before using any of the products mentioned. The State of Victoria and its employees do not guarantee that the publication is without flaw of any kind or is wholly appropriate for your particular purposes and therefore disclaims all liability for any error, loss or other consequence which may arise from you relying on any information in this publication.
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