SJC and Delta Field Crops

Wireworms are the soil-dwelling larvae of click beetles. They feed on the seeds and roots of various crops and are a particular pest of field corn in the Sacramento-San Joaquin River Delta region (Figure 1).

California agriculture is successful, in large part, because of the Mediterranean climate and irrigation infrastructure. While irrigating crops is the norm, there are growers who practice dryland, or rainfed, farming. These growers utilize winter rainfall to produce the crop.

I was speaking with a colleague a few weeks ago about field drainage in the Delta. Our conversation reminded me of a farm visit that I made a couple of years ago. I visited a corn field that was not growing well, and sections of the field had standing water.

In late August, I visited a kidney bean field that was exhibiting stress symptoms, like necrotic leaves and stunting. Even though the field was near harvest, the consultant asked if I would take a look at it.

In late August, I was requested by a crop consultant to visit an alfalfa field in the Delta that was exhibiting symptoms like those in the picture. The leaves had little white spots near the margins, and generally, the plants had not grown well after the previous cutting.