When do cabbage moths lay their eggs?

Question

I just transplanted my kale starts and I'm going to put my cabbage & broccoli plants in next. Last year we had some significant damage & developmental delays from cabbage moth caterpillars and I want to avoid that this year.

From what I've been reading, row cover looks like a good option for me. However, I haven't come across information about when the plants need to be covered or for how long. Where can I find this information.

(FYI, I'm in northern VT, zone 3-4. For reference, the lilacs are just now beginning to bloom.)

Answer 1

Where I am the cabbage moth was active the whole summer until mid autumn. In fact people said it was such a good summer that we had several generations of cabbage moths this year.

I tried row covers over hoops but found the following issues.

1. I couldn't easily inspect the plants so missed seeing insect damage
2. Moths still managed to get in possibly because they hatched inside the covers, or just crawled through some cracks
3. The mesh size was small enough to largely exclude them but kept aphid predators out as well while allowing aphids to flourish.

I am going to try BT next year instead of covers.

Answer 2

I'm far from expert on the subject, but covering when you set them out is advisable; the white cabbage moths are active in cooler weather, and I'm certain I saw the little beasts the very day transplanted my first cabbages out (into wall-o-waters once I refreshed my information enough to realize that they only take freezing well when mature, not as seedlings.) As far as I know, for anything that does not need pollinated, you can keep them under cover the whole season, but I gather that the moths may be less active in hot weather.

I've only started growing cabbage this year, after getting into making sauerkraut last year (I like that, I don't like unfermented cabbage) and I have tried growing broccoli once before with poor results (trying that again this year - we'll see.) Mine is not covered, but that's because I'm 6 ways behind and disorganized this year so that didn't happen; I'm hoping to be more organized when I get the crop for late fall/winter harvest in place. Ha! I can dream...