First off, have some faith in science and know that they will find the reason. Good People are working on it.
That said, this has happened before. Link:
http://www.ento.psu.edu/MAAREC/FAQ/FAQCCD.pdfAlbert Einstein estimated that the human race would last 4 years without bees...
Quote of Albert Einstein: "If the bee disappeared off the surface of the globe, then (wo)man would only have four years of life left. No more bees, no more pollination, no more plants, no more animals, no more (wo)man." Link:
http://melbourne.indymedia.org/news/2007/04/143402.phpSome affected crops, READ SOME...
PDF Link:
http://maarec.cas.psu.edu/PDFs/Pollination_PM.pdfForage and Legume Crops - *Alfalfa; buckwheat; clover
(alsike, berseem, crimson, Egyptian, *Ladino, *red, rose,
strawberry, and white); *crown vetch; sweet clover (*Hubam,
*white, *yellow); lespedeza (bush); *trefoil; vetch (*hairy
and purple).
Fruit Crops - *Apple; apricot; *avocado; berry (blackberry,
*blueberry, *cranberry, gooseberry, raspberry, and *strawberry);
carambola; *cherry; citrus (*grapefruit, lemon, *mandarin,
nectarine, *tangelo, and *tangerine) *kiwi, mango,
passion fruit, *peach; *pear; persimmon, *plum, and prune.
Nut Crops - *Almond, cashew, chestnut, coconut, and *macadamia.
Oilseed Crops - *Cotton, flax, *rape, *safflower, soybeans,
*sunflower, tung.
Vegetable Seed Crops - Asparagus, *broccoli, *brussel
sprouts, *carrots, *cauliflower, celery, Chinese cabbage,
collard, cucumber, dill, eggplant, garlic, kale, kohlrabi, leek,
*lima beans, mustard, *onion, parsley, *pepper, pumpkin,
*radish, rutabaga, *squash, and *turnip.
Vegetable Crops - Beans, *cucurbits (canteloupe, cucumbers,
muckmelon, pumpkin, squash and watermelon), eggplant,
lima beans, and peppers.
However, there are a lot of people investigating this and I am sure that they will discover the reason.
I edited this to tone down the fear mongering and added the line above.