The Garden Community for Garden Lovers

County Durham , United Kingdom Gb

A number of Male ferns (Dryopteris filix-mas) came up in my containers, and some of them have grown to be enormous. Yesterday l noticed that the curved spore-covers have been infested with tiny fat cream-coloured grubs that are generating rust-coloured frass the same colour as the emerging spores, and turning the surface of the pinnae brown. I’ve been unable to find out what these larvae might be. Can anyone help?

Eacf9339_539b_4503_b5b6_0a59b465e148 56e8b7f5_7192_4700_849e_8257a3a2136c



see the answers above.

22 Jul, 2020


Thank you— l followed up the fern smut moth suggestion across several sites, went and inspected the ferns again, and am now certain that’s what it is. You get a different point of view depending on whether you’re a gardener (Eeek! Something’s destroying my beautiful plant! Quick, slash and burn the infected leaves!) or an entomologist (Wow, just look at these clever little camouflaged burrows!).
I checked the other susceptible fern varieties, which are also setting spores at present, and they are clear.
Thank you for your speedy response, Bamboo, and the extra links, Seaburngirl.

22 Jul, 2020


you are welcome.
my daughter has just graduated in wildlife conservation and has a particular interest in moths. since March 31st she has recorded 91 different species just in our back garden in East yorks. My skills have as a consequence improved too. so I recognised it as a micro moth. we now have lots of extra native plants to complement the ones I grew before.

I will check my ferns and see if I have any of these ones lurking. The perk though is you will get more predators in the garden.

22 Jul, 2020

How do I say thanks?

Answer question


Not found an answer?