http://www.greenharvest.com.au/pestcontrol/fruit_fly_info.html
...is intended to keep out fruit fly, codling moth, birds, fruit bats and, with any lucks, small children. Action Man knocked up a frame for it:

Apparently only 17% of the sunlight is blocked.

And here are some golden dorsetts, looking enormous compared to last week:

*rubs hands together with glee*
Cost of Pestguard: $160.
I'll add that to the total when the lunch isn't burning.