Grubby Work

Recently, I’ve noticed what look like piles of tiny white droppings on some of the leaves of my lemon tree. On further investigation it became apparent that they were wood shavings which had been dropping out of tiny holes on the underside of the branches and landing on the leaves or ground beneath. Clearly there was a wood borer of some sort inside the branches of the tree, so, under the guidance of Mabel, a local organic farmer whom I buy vegetables from, I cut off a branch and found an oval tunnel right through the middle of the branch. Chopping off bits of the branch, we finally discovered the culprit – an orange grub about an inch long with a dark head. Here’s a rather poor picture of it.

Sorry, it’s such a bad picture, but the others were even worse! Later, I noticed that some holes were filled with tiny ants, which came swarming out when I cut through, but whether they had killed a grub and taken over its tunnel for themselves, or whether they were associated with the grub in some way, I don’t know. Can anybody identify it, and does anyone know of an organic method of removing the creature before my lemon tree dies? At the moment, there appears to be nothing obviously wrong with the tree, but the grub burrows right along the length of branches, which is at the very least going to make them very susceptible to the next typhoon that blows through. Waiting for a natural predator would be the ideal solution, of course, but that would be more likely to happen in a whole, intact ecosystem, whereas my garden, despite having a tremendous array of insects, amphibians, reptiles, birds and assorted soil organisms, is surrounded by wasteland which has been repeatedly disturbed by human activities – currently a flood drainage system is being built nearby. Consequently, the chances of a natural predator arriving like the cavalry over the hill, are pretty remote, I think. What can I do, and how can I stop this happening in future? One possible clue might be the fact that we’ve had an extraordinary number of wasps in the garden this year. Could one of them be responsible?

Don Latter

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About transitionsl

I've been an English teacher for the best part of 30 years, teaching in England, Tanzania, Brunei, Australia and Hong Kong. I've always been interested in nature and environmental issues, but it was the discovery of Peak Oil about five years ago that galvanised me into trying to help my local community to prepare for what will be a dramatically different world to the one many of us have been used to. I've been helping to run a transition group, following the guidelines created by Rob Hopkins's Transition Movement in the UK. This blog is an attempt to engage in discussion with a wider group of people in Hong Kong on the ways to transition from our current oil dependency to a state of fossil-free local resilience.
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2 Responses to Grubby Work

  1. Gwen Dahlberg says:

    Hi Don, Do you know Paul Aston, a fellow teacher and bird and bug expert? He lives in Wang Tong. I’ll have to dig around for his contact details. If he doesn’t know the name of this bug, he’ll know someone who does. (I believe he’s writing a book about HK bugs).

    • transitionsl says:

      Thanks, Gwen. Paul Aston has suggested it might be a jewel beetle, but the picture is pretty awful. Paul Melsom also suggested a longicorn beetle, and the grub is indeed just the same except for it being bright orange. It seems as if the main problem with them is if you want to use the wood for anything, as the wood is hollowed out. Fortunately, I don’t expect to be using the wood. Apparently, neem oil should deter the insects without actually killing them according to David at Green Patch.

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