Blossoms falling off

by Grace
(Ocean City, NJ)

The tomatoes were planted about 4 weeks ago and have produced many flowers. However, the flowers turn brown and fall off.

I have inspected it with a magnifying glass and do not see any bugs. None of the pics of the problem tomatoes resemble our problem. Our neighbor sprayed the plants with Sevin.

If you have any ideas, they would be greatly appreciated. Thank you.