The fly normally is not a big problem for me. I loose perhaps 3 per cent of the daffodils per year from which I have many bulbs. New seedlings or sorts with few bulbs only are protected by spraying dimethoat, a systemic insecticide. The daffodils remain in the ground for three years and are hot water treated after this time. Yesterday I made some chipping of bulbs which came out of the hot water. The chips developing little bulbs shall be treated with oryzalin for chromosome doubling.
First I chipped the bulbs of Hawera: 80 bulbs from 100 were destroyed by larvae of the narcissus fly. I was shocked and thought nearly all my daffodils were lost. The next type for chipping was a clone of N. cordubensis from Grazalema: 70 bulbs from the same field as Hawera were without any damage. In 26 Sun Disc growing quite near to Hawera I found 2 larvae. 26 bulbs of N. henriquesii, which were grown in another field, were free of maggots.
Obviously there are species or clones of daffodils for the garden, which are of no interest for the fly. Other plants are more or less attractive. Perhaps these bulbs can be protected, if some Hawera are planted in the same field. The narcissus fly seems to be especially attracted by the smell of this plant. The bulbs with the larvae can be destroyed in the end of July. Another possibility is to spray these Hawera with dimethoat. If the maggots eat from the bulb they are poisoned. Possibly the fly does not like the fragrance of dimethoat. But there are many other insecticides which could be tried for this purpose.
Theo
Has anyone ever thought of changing the smell of the bulb? How I only speculate, Chanel #5? It would be a good experiment for some eager young person. Nancy R. Wilson
While bulb fly is not a problem for me, I do use a comercial fly trap in my yard and for bait, I use a piece of raw liver. If one were to practice using a sacrficial bulb to attract the fly, and if as has been reported, Hawera attracts them, maybe a cross between Hawera and “Liver”pool festival would be a likely combo to hybridize. Denis
Nancy Wilson’s humorous suggestion about using Chanel #5 to ward off narcissus flies may not be all that impractical. Might it not be effective to use neem oil for this purpose? The stuff may not kill the flies, but it sure smells and tastes bad enough to ward them off, and it is environmentally friendly.
Hello Theo,
Very interesting observations. I too have observed that the large Narcissus fly seems to be selective. I did not record findings accurately but my local flies seemed to have a preference for Div. 3W -R or flowers with signs of N. poeticus genes still fairly obvious. Also, on one occasion a batch of selected seedlings from Hillstar x N. triandrus triandrus was severely attacked.
Thankfully, in this years dig of 3 year down selected seedlings and named varieties I found only a few bulbs with grubs. I put this down to the inclusion of Dursban in the Hot Water Cocktail 3 years ago before planting and a single annual spraying with the same chemical.
When I started growing daffodils Mrs Richardson told me that Aldrin in the HWT cocktail would protect the bulbs for 2 years – a recommendation that I accepted. For years I had little problem, until Aldrin was banned and I did not have a ready alternative – then flies appeared seemingly from nowhere and many bulbs were attacked. In those days I used dimethoate as a spray but did not find it as effective as the aldrin and subsequently the Dursban in the HWT dip.
My only other precaution is to ensure that the the dying foliage is raked off the beds and that the holes left above the bulbs are filled by raking or hoeing.
Another observation – Meredon equestris also seems to be selective of your best new seedling or most expensive acquisition – best not to label them!!!! :-)
Brian
Well said Brian. I have lost some very good seedlings to the critters. One, a Foundling X Pink Div 2 seedling that I won rose ribbons with in the Div 2 category.
Clay