SUMMER WEEK 3

BOUQUET INGREDIENTS

zinnias, cosmos, basil, celosia

Since we don't use any pesticides on our farm, we've come to know many of Kansas' most common garden pests. Each year around the start of August we start seeing partially severed sunflower heads in our garden, thanks to this guy—the sunflower head-clipping weevil.

Sunflower head-clipping weevils are mischievous pests that wreak havoc on the garden by chewing around the stems of maturing sunflowers just below the bloom. In large sunflower fields, damage is usually confined to outside borders, but on our small farm the damage can be more severe because our beds are so small. Even farms that spray for bugs don't usually spray for this pest, but it's an interesting case study to consider how, as farmers and stewards of the land, we can prevent costly crop loss without doing damage to the unseen and often forgotten ecosystems we rely on.

We manage this pest (and all pests) on our farm with biological and cultural control methods instead of chemical controls. Biological control means leveraging the natural relationships that exist within an ecosystem, and we do this by creating the conditions that enable beneficial predators to thrive in our gardens (e.g. not using any pesticides and allowing populations of pests, which are food for beneficials, to exist in our gardens). In this case, head-clipping weevil larvae are consumed by many of our favorite generalist garden predators like spiders, ground beetles, and parasitic wasps.

Cultural control means changing our behavior to prevent pests. We took the time to learn about the head-clipping weevil life cycle, so we know that there's only one generation of this insect per year and adults are active from around mid-July to mid-August. Because their reproductive period is so short, we tailored our sunflower planting schedule to mitigate any potential damage. For most of the season, we plant single-stem varieties of sunflowers—for each seed, we get just one flower. And if that one is beheaded, nothing.

Since we knew the adult weevils would be active around this time, we planted branching sunflowers for the succession we knew would be maturing now. This way, we can cut back any clipped heads and these branching varieties will produce new stems, ensuring we'll have a harvest from these beds. We also make sure to dispose of the clipped heads, as the weevil eggs and larvae grow in the heads of sunflowers before eventually burrowing into the soil, where they'll develop until they emerge the following July.

Thanks for enabling us to steward our land thoughtfully and for supporting flourishing ecosystems in our community. Enjoy your blooms this week and make sure to smell the basil!