So I’ve been noticing, upon up-close inspection of several plants, that some have a bevy of flies. At first I was impressed that they stayed so still when I was looking at them so up close, then I wondered if they were doing something gross like mating since they seemed so totally oblivious to me. Then the horrible truth that they were dead dawned on me. It’s strange that I work so hard on slaughtering any beady eyed flyer who frequents my home space but upon spying one dead on a flower stem seized from me a gasp of compassion. It was sad, disturbing, intriguing.
It happened the first time several days, maybe a week ago. I’d noticed my rose bush in the ground out front wasn’t doing so great. So I went out there to give it some extra care: a little compost littering, removing some yellowed leaves, and the like. That’s when I saw a fly very near where a flower once was. The fly was very still. The fly, I realized, was dead.
A few days later, I was out back paying some attention to a potted lavender plant when I saw several of them, then some more. Again, at first I thought they were live flies, just hanging out enjoying some sun. Then I realized they were dead. All of them, dead as door nails (why is it door nails would be deader than any other nail, I wonder). And after a wave of nausea and the creeps, it just made me very sad. They were clinging toward the top of the stem, just as the rose-loving flower had been. Then I also found them on the rosemary. It was a garden invasion of dead flies. Day of the dead … flies. Zombies of the insect world.
I didn’t know whether to try to remove them or just let them be. Then I wondered if they were doing the plants any harm. So then I did what any other earth loving naturalist would do – I left the great outdoors for the glowing screen of my smartphone and looked it up online. This is what I found out.
Seedcorn maggot flies or delia platura may sometimes be found dead on twigs or stems of flowers, typically toward the top of the stem, close to the flower. Their larvae may damage vegetables but typically don’t have a negative effect on flowers, trees, or vines. According to the research (and now that I’m not there I cannot personally confirm this), if you look closely you likely will see a pink stripe around the flies’ abdomens. The pink stripe is why the fly died. It’s the spores of entomophthera fungus. Once infected, the fly’s coordination is affected. They land on a leaf, vine, twig, or plant and die. It seems they are unable to fly away but it wasn’t clear to me if they sense the end is near. Maybe not, since they get all coordination-confused. This usually happens in the spring but can appear throughout the summer since the flies can breed five generations in one year.
What confuses me is why I’ve never noticed this before. Anyone else seeing this? Anything else strange and kinda gross and not totally wonderful happening in the garden? As for the dead flies, they don’t easily flick off. Should they stay or should they go? Go ahead…gimme the dirt.