The MGS Forum
Gardening in mediterranean climates => Pests and diseases => Topic started by: JTh on October 09, 2016, 06:40:06 PM
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I planted a tree today (a persimmon), and mixed the rather poor soil we have with soil bought in a large bag this summer. I was surprised when I saw the first big larvae and found that it came with the soil in the bag, then I found a lot more, I believe around 50 in about a 1/3 of the bag. They were quite large, the largest ones around 5 cm long, around 1 cm in diameter, greyish with a paler underside, slightly hairy. They moved in a very strange way, creeping on their backs. The bag had been opened this summer, but the larvae were spread around in the whole bag and I believe they were there when I bought the soil.
I would very much like to know if anybody could identify these.
(https://c2.staticflickr.com/6/5644/29587342233_abb4a645ce_z.jpg) (https://flic.kr/p/M5wS3e)
_A093689 What did I find in a bag of soil?.jpg (https://flic.kr/p/M5wS3e) by Jorun Tharaldsen (https://www.flickr.com/photos/46063510@N03/), on Flickr
I got one photo of the underside of a larva:
(https://c8.staticflickr.com/6/5188/30216615535_fc9d4db176_z.jpg) (https://flic.kr/p/N3944V)
_A093688 Unidentified grub.jpg (https://flic.kr/p/N3944V) by Jorun Tharaldsen (https://www.flickr.com/photos/46063510@N03/), on Flickr
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Jorun, I don't know what this grub is or whether it is harmful to plants. However, in earlier days when I was preparing pots sometimes I did not make the drainage holes large enough and the contents of the pot soon became waterlogged, even flooded. Grubs like those you show would come to the surface and die. And that was a bought-in potting mix.
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Joanna, I'm not very concerned about these, I'm just curious and want to know what they are. They are probably beetle larvae, but they were exceptionally big. I just picked them out and threw them away, I don't think they are necessarily harmful.
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Could they be Chafer grubs which are the larvae of the Cockchafer?
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Yes, larvae of the genus Melolontha, cockchafer, is definitely a possibility, the development is very slow and the larvae can grow to a size of about 4–5 cm. I am glad I picked them before adding the soil to the newly-planted tree.
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If you search for Chafer on the compost page of the MGS website [urlhttp://www.mediterraneangardensociety.org/compost.html][/url] you'll find that they are useful in compost making. In a discussion about the larvae in TMG a long time ago there were many suggestions how to kill them including getting a hen, but I seem to recall that the last contributor was convinced that they are harmless in the garden. I wouldn't want to put them in a planting hole, though.
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Thank you, Fleur, lot's of useful information there. I think it is safer not to put them in the planting, as well, I read that cockchafer larva: 'Feeds on fresh roots, does great damage'