By Claregauden
Shropshire,
United Kingdom 
my lemon tree has produced flowers which have since dropped off with my show of fruit
Also a friend has a courgette whose flower has dropped off snapped at the stem and no sign of fruit
Something is eating the leaves of courgette, cucumbers, and gunnera boring small holes in leaves but cant see anything and runner bean leaves have been stripped but not from slugs or snails
7 Jul, 2011
Sometimes citrus drop their flowers without forming fruit. Common culprits include overfertilization, overwatering, and wild temparature swings.
Sometimes a courgette will lose its flowers if they aren't pollinated, though more often, the female part of the flower will hang on, gradually turning yellow and brown from the tip.
Small holes would make me suspicious of flea beetles--little metallic green, blue or black beetles, which jump when disturbed. Generally pyrethroids or carbaryl are recommended as control, though actual pyrethrin can also be effective, if it is sprayed thoroughly enough.
8 Jul, 2011