Monday 31 May 2021

Moth Trap: mark II

Now that it has finally stopped raining, its time to get the moth trap out.


But wait, I've had a idea for a better design.

So here is my mark II.

Its been a very strange spring here, in sunny southern England. We had some hot days in March, then it turned really cold, and then it rained and rained and rained.

But with a few dry days ahead, and mild nights with not too much wind, I decided to dust off my simple moth trap from 2020. Designed around an old roller-paint-bucket, the only slight problem was the lack of space behind the two clear polycarbonate sheets. This meant that I had to really mangle a couple of egg-boxes to get them behind the sheets. So I wondered whether one of my existing Really Useful Storage Boxes might be a better option.

It quickly became clear that a 35 litre box (480mm Long x 390mm Wide x 310mm High) was ideal for my needs, not least because the 2 polycarbonate sheets from the old design fitted almost perfectly.

The mkII, deployed & waiting for its first moth!



The first step was to add a couple of support blocks to hold the 2 sheets at an angle, with a gap between them of about 30mm.

Each block is just a 3" length of 1" x 1.75" wood, with corner cutouts to leave a 30mm gap (...yes, of course I mix metric and imperial measures...don't you?).

All I had to do with my existing polycarbonate sheets was to round-off the corners a little bit so that they sat better in the box (i.e. the box corners are rounded, not square).

Now the egg boxes are a much better fit!

I was also very lucky with my existing lamp holder. I only had to shorten it by a few inches and reverse one of the short cross-bracing pieces. I cut a small section of the box for the cable entry point.

These modifications allow the lamp holder to rest on a ledge inside the box so I can refit the lid (in the morning) once the trap is populated with moths.


The long lead is an aggravation in the morning, when I shut the lid and bring the trap inside. So I think I'll just cut it shorter and rely on an extension lead from garage power socket to garden 'trapping' position.



So far, not so good. On the first night we only got 3 moths and a huge cockchafer beetle.

However, this was not really a surprise, as everyone else seems to be getting poor results at the moment. I guess it all comes back to that funny spring weather!


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