Cellphones among other things are Killing Honeybees worldwide

Is the Cellphone Killing the Honeybee?
Pity the poor honeybee. Since 2003, bee colonies around the globe have declining at an alarming rate. And since bees play a vital role in agricultural production, that's bad news for us humans. Scientists suspect many factors may be responsible, including pesticides, viruses, the varroa mite, genetically modified crops, and even exceptionally cold winters. Now we can add cellphones to the list of possible culprits.
A study by Swiss researcher Daniel Favre shows that mobile phone-generated electromagnetic fields may contribute to Colony Collapse Disorder (CCD), a condition that causes worker bees to desert the hive. In most cases, the queen bee is left with eggs, immature bees, and a lot of honey. The colony survives for a short time, but soon dies out without its workers. end quote.

The bad thing about this is that no crop can pollinate without honeybees. So, if honeybees go extinct so does everything that lives on the land because no grain, no fruit, no vegetable can live without being pollinated by honeybees.

quote from wikipedia under the heading "pollination"

Pollination

Main article: Pollination

The transfer of pollen grains to the female reproductive structure (pistil in angiosperms) is called pollination. This transfer can be mediated by the wind, in which case the plant is described as anemophilous (literally wind-loving). Anemophilous plants typically produce great quantities of very lightweight pollen grains, sometimes with air-sacs. Non-flowering seed plants (e.g. pine trees) are characteristically anemophilous. Anemophilous flowering plants generally have inconspicuous flowers. Entomophilous (literally insect-loving) plants produce pollen that is relatively heavy, sticky and protein-rich, for dispersal by insect pollinators attracted to their flowers. Many insects and some mites are specialized to feed on pollen, and are called palynivores.
In non-flowering seed plants, pollen germinates in the pollen chamber, located beneath and inside the micropyle. A pollen tube is produced, which grows into the nucellus to provide nutrients for the developing sperm cells. Sperm cells of Pinophyta and Gnetophyta are without flagella, and are carried by the pollen tube, while those of Cycadophyta and Ginkgophyta have many flagella.
When placed on the stigma of a flowering plant, under favorable circumstances, a pollen grain puts forth a pollen tube which grows down the tissue of the style to the ovary, and makes its way along the placenta, guided by projections or hairs, to the micropyle of an ovule. The nucleus of the tube cell has meanwhile passed into the tube, as does also the generative nucleus which divides (if it hasn't already) to form two sperm cells. The sperm cells are carried to their destination in the tip of the pollen-tube.
end quote.
I'm still not completely clear whether  it is all plants edible to humans in grains, fruits and vegetables would not exist without honeybees or just all fruits and vegetables wouldn't exist worldwide without honey bees.

But I am clear that if honeybees go extinct none of us will be eating any fruits or vegetables ever again and neither will anything that humans eat for meat or fowl. The food chain for fish is not a part of the honeybee pollination cycle of life. However, ocean fish are threatened by overfishing all over the world at present. Therefore, I would say the biggest single problem humans have at present on earth is maintaining a food supply with all the present problems of  global warming(serious weather issues worldwide regarding the growing of food most places)  and honeybees dying in droves all over the earth.