Insect Update

Outside of the early problems we had with red lettuce aphids, we have had very light insect pressure so far this season. The cabbage aphids, which were so bad last year that we had to disc in several plantings before harvest, have only appeared in a few areas and in light numbers. And I have yet to see a single flee beetle this year. These tiny black beetles can be so destructive that we usually have to cover up all of our direct seeded Cruciferous crops (radishes, broccoli raab, turnips, arugula, mustard greens etc.) with floating row cover to keep them from being riddled with tiny holes. I’ve seen some spotted cucumber beetles (often mistaken for “yellow lady bugs”) but none of the striped. It’s primarily the striped ones that can congregate on newly planted squash plants in such dense numbers that they take down entire plantings.

I am not taking any of these positive developments for granted. For now I’ll work under the assumption that these pests can and probably will return at any time. I think that people are often a little too eager to attribute changes like these to long term changes in our climate—the one thing that I have learned is that, as the cliché goes; the only thing you can count on is change itself.

When it comes to insects and disease, some things change over extended periods and some, like the aphids and beetles, vary from year to year. When I first started working for my Uncle back in the mid 90’s, one of his main crops was garlic. He grew lots of types of heirloom, stiff-necked garlic that was very popular at farmer’s markets.  Then came the El Nino winter of 97-98, when serious rainfall continued into the months of April and May. Along with it came a disease commonly known as garlic rust, which hadn’t been seen in this area for many decades. The garlic bulbs that year only reached the size of a large persons thumb before the plants were covered with the rust-orange pustules that eventually killed them off. Garlic rust has been with us here on the coast ever since and it is one of the reasons that we only grow “green” garlic instead of matured garlic bulbs.

Another disease that often determines what we can and cannot successfully grow is downy mildew. Because we live in an area with high humidity (winter rain and summer fog) where lettuce and spinach is intensively grown almost year around, inoculum for downy mildew is almost ever-present—floating on the wind. The only way we can successfully grow these crops is by using varieties selected for their natural resistance. The problem with using resistant varieties is that they are only resistant for a short period of time. Every 2-4 years a new race of mildew comes along (in lettuce the current prevalent race is number 28) which the current varieties no longer have resistance to. The companies that market seed to growers in the Salinas and Pajaro Valleys have progressive breeding programs and are continuously developing new varieties to keep pace with the new mildew races.

When I read about other businesses in industry and manufacturing, with their relatively fixed set of variables, at times I get envious. But if I am truly honest with myself, I think I would find those circumstances a bit boring. Good farming is as much an art as it is science and dealing with an ever changing landscape is part of what always keeps it interesting.