Click on the link for the NEJM Journal Watch weekly update. NO paywalls on any of the links in this article. (paywalls bother me)
The Latest in COVID-19 News: Week Ending July 25
Meanwhile in Imperial County California…
For many decades, a relative few white farmers who tilled vast acreages of winter vegetables, cotton and alfalfa held that power. Ultimately, however, demography shifted power to Latinos, the sons and daughters of field workers from Mexico who are today 80% of Imperial County’s population.
Changing demography didn’t change Imperial County’s basic nature. It exists primarily to grow food and fiber with little economic diversity and always ranks high on California’s lists of unemployment and poverty.
Imperial has another distinction these days — the epicenter of California’s COVID-19 pandemic. Its infection rate is six times as high as California’s as a whole and victims are overwhelming its two hospitals.
lifeunderwriter.net 
Why is Covid so high in imperial County? It doesn’t sound as though farming should be a high-risk occupation like meat packing?
All most likely due to classic socioeconomic factors. High level of poverty, lower educational status, less access to health care, poorer quality diet, etc. While farming is lower risk than meat processing, it only takes one infected individual bringing the virus home and the whole family gets infected. Likely more multi-generational housing situations too.