Narcissus Bulb Fly - Merodon

Roy Herold
Tue, 30 Oct 2007 07:50:22 PDT

The biggest problem I have with narcissus fly is on/in cyrtanthus. I lost the majority of bulbs in several pots this summer after I decided to give them a break from the greenhouse and put them outside. The results were, to say the least, disgusting. I took to pulling the grubs from the bulbs with tweezers, and found they had excavated quite sizable cavities. I wound up throwing the majority of the damaged bulbs onto the compost pile, where they proceeded to generate rings of little bulblets around the basal plate. One had a bulblet inside the cavity. A new propagation technique?

This wasn't the first time they got into the cyrtanthus--it seems to happen every other time that I put them outside, but not always. As for narcissus, they probably get into these from time to time, but I don't dig the bulbs that often to check. I've never seen them in pot grown bulbocodium types, perhaps because they go dormant earlier. As Mark mentioned, a grower in western Massachusetts has an ongoing problem, but that doesn't stop him from sending wonderful narcissus bulbs.

I'm wondering if there is a magic date after which the flies stop laying eggs, and the amaryllids can safely be brought outside to enjoy the summer weather. Ideas?

NW of Boston, down to 29F,  but no real frost/freeze yet

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