Answer: Lack of fruit production can be caused by high temperatures (over 90 degrees), or lack of pollination. If you've sprayed for insects, there may not be any flying insects around to transfer pollen; or if the daytime temps have been 90 or above, pollen will die and pollination will not occur. If you think it is due to lack of insect activity, try gently shaking each plant so the pollen will drop from the male to the female part of the flower. There's not much you can do about the weather - except wait it out.
Best wishes with your tomatoes!
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