… A newsletter this month by the Almond Board of California said the [rat] infestation in parts of the San Joaquin Valley, one of the world’s top agricultural regions, has impacted more than 100,000 acres and caused $109 million to $311 million in losses from damage to equipment and crops over a year. … Well over half a million acres of California farmland were left unplanted in the early 2020s because of a protracted drought and diminishing water supplies, which also meant no pest-control efforts in those fields. The drought finally ended in the winter of 2022-23, the beginning of a three-year spell of at least average rainfall that resulted in more vegetation growth and an abundance of food sources for wildlife.