This beautiful butterfly is no fairy. The larvae of the white cabbage moth and her wicked step-sister, the diamond backed moth, can decimate brassica crops in days. The only way to control the diamond-backed wrigglers is to spray and spray and spray. Every five to seven days for the life of the crop! I’m no buddhist but this is a level of chemical use that scares me (and blows any hope of profitability at the same time).
For this reason, I’m falling out of love with rape. This obscenely-named brassica has long been the darling of dry-land dairy farmers. We’ve come to rely on it for high-quality lush green feed in the height of summer; when little else worthy of our cows’ refined (read “udderly spoilt”) palates will grow without irrigation.
I used to stagger plantings over a dozen hectares of brassicas to provide a constant feed source from January through to early March. Not any more. I’ve planted the oat paddock with Hunter rape and that’s it. Unlike the more hardy Winfred variety, Hunter is safe to graze at any age and when the larvae get a wriggle on, I’ll simply send in the cows and let the caterpillars have the rest. No spraying, no searching under leaves for stealthy marauders and no cow health worries.
5 thoughts on “Little monsters in a crop”
What can you grow other than grass that is fairly sustainable?
For summer, Beeso, there’s fairly limited choice without irrigation. Millet is probably the best but we find it still needs quite a bit of moisture – paddocks that will support ryegrass growth anyway. A lower quality option is sorghum but we don’t need any extra fibre. Chicory and plantain are being used by some farmers but I found chicory flopped in paddocks with elevated aluminium levels, so it won’t suit this paddock.
Ugh! These little critters are laying waste to my garden at the moment too. My kids and I dance around the garden every morning, vainly trying to reduce their numbers and then pick as many of the larvae off before they do too much damage. We are fighting a losing battle though, I fear.
We don’t grow rape but those same butterflies wreak havoc in our garden…one reason I hate organic broccoli and don’t eat Kale until after several hard frosts.
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