This butterfly is a real menace in the vegetable garden. It lays multitudes of eggs on the undersides of vegetable leaves - usually those of Brassicas - and when these hatch they turn into voracious caterpillars which can devour a cabbage plant in a very short space of time, leaving it with that characteristic "lacy" look.
Here is one Cabbage White caught in the act of laying eggs:-
And here is a cluster of its eggs. Fortunately, being bright yellow, they are easy to spot. I can't imagine why the eggs are that colour. Surely it would have been better for the butterfly if they were a more unobtrusive colour?
Right now the Cabbage Whites don't have a lot of choice if they want to lay eggs on brassicas in Mark's Veg Plot. I have only four Brussels Sprout plants for them to choose from (as long as they don't notice the two trays of tiny PSB and Cavolo Nero seedlings!). This means that it is easy enough for me to "patrol the brassicas" and remove the eggs. I simply rub them off with my fingers. I did consider putting a net over the plants again (I had them covered when they were small), but I think that I'll manage to control the situation OK without it.
So far I seem to be winning the battle because I have only seen a few caterpillars, despite having removed dozens of clusters of eggs. I did resort to spraying the growing tips of the plants with a proprietary bug-killer because these are the most important parts, but it is not a good idea to spray the whole of the (very large) Brussels Sprout plants if you can avoid it.
On second thoughts, I have remembered that I still have some turnips left, and they are brassicas too. Better check them as well... Cabbage White = Pieris Rapae; Turnip = Brassica Rapa!
|Cabbage White on a Turnip leaf