Last night, I was reading about Avocados, and this is what I found...

http://www.hort.purdue.edu/newcrop/morton/avocado_ars.html#Spacing

Quote:

Generally small amounts of fertilizer are given every 2 months with the amount gradually increasing until fruiting begins. Bearing trees need, on the average, 3 to 4 lbs (1 1/2-2 kg) 3 times a year, beginning when the tree is making vegetative growth. No fertilizer should be given at blooming time; one must wait until the fruits are firmly set.

And I was wondering, why my Avocado isn't setting any fruits, for the flowers are all dropping. There's literally hundreds of flowers on my Fuerte Avocado, which is flowering for the first time, but no fruits are setting.

I had given extra fertilizer in the beginning of March when I saw all the flowers on my tree.

Are citrus trees also like this? And any other fruit trees that do not like fertilizers when fruiting?