Dear Ina, Here we have a bunch of white butterflies. We also grow a lots of Brassicas. Some of the white butterflies don't feed on cabbages, so it is hard to tell if the flour was useful, even if they were flying there that doesn't mean it is their host plants. I took my time and watched them for a while, and from around 10 butterfly pairs only 1 started to lay eggs. The other thig is that here we have some very good parasitoids. In one autumn a professor wanted to raise Pieris brassicae from the caterpillars, and collected around 50. In a few days time all caterpillars started to "grow" a kind of wooly mass, there were the cods of the parasitoids. He got hundreds of adult parasitoids but no white butterfly. Unfortunately i don't know if there is any kind of repellent or biological pest control for daffodil grubs. Here we have only 1 generation in a year, and it is said that it feeds only on weak or disease infected bulbs. Hope this helps. Jan Z5a, Hungary