Things have cooled off greatly since the hot spell that we had a couple weeks back, but its effects are still evident around the farm. The two-spotted mites, which are one of the largest pest problems for strawberry growers in this area, reproduce at a much greater rate when temperatures are high. We’ve had to release more of the beneficial, predatory, persimilis mites to combat them than we normally would have. To date we have released close to 600,000 on our 3.75 acre plot and there are still areas that have sustained considerable damage. Fortunately, we planted almost an acre more strawberries than last year, so we are still harvesting a substantial amount of fruit.
Hot weather can also have the effect of greatly speeding up the lifecycle of many crops. Lettuces, chicories (radicchio, escarole etc.), and umbelliferous crops like carrots, cilantro and fennel, all have the tendency to prematurely bolt (send up a seed stalk) when they are under heat stress. We had a lettuce crop at our Lewis Road site that went from being too small to harvest to having an elongated central core in about three days—even though we were watering on a daily basis. We’ve also seen premature bolting in some of our fennel, escarole, carrots and cilantro.
Perhaps the most dramatic effect of the heat spell for us was an outbreak of “fireblight” in our pears. This bacterial disease moves down the tree’s vascular system and leaves twigs, branches and sometimes entire trees blackened to the point that the origin of its name becomes perfectly obvious. Antibiotics like Streptomycin and Oxytetracycline are commonly used to combat this disease in large production orchards, but the National Organic Standards Board appears to be on the verge of prohibiting their use in organic systems—a move that we support. Next season we will likely try out a yeast based organic treatment from Europe that sounds promising. It’s too late for preventative measures this year.
I was happy to see our beloved fog coming in on the horizon at the end of the heat spell, like the Mormon’s seagulls that rescued them from a plague of locusts. The temperatures have stayed close to our seasonal norms since then and things are on the mend. The persimilis mites seem to have gained the upper hand on the two-spotted. And the spread of fireblight seems to have slowed down dramatically.
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