first year Brussels had some kind of worm/caterpillar. Spraying with Bt worked great, but they never produced very well. We then bought Brussel starts that same year for a fall harvest from Burpee. They send them according to your zone. Plants were very healthy, and bug free, but shipped too late to produce more than tiny sprouts. Last year, tried a different variety started from seed. these grew ok, but got the caterpillar (nixed with Bt), then infested with tiny black bugs-assuming an aphid. I try not to use much in the way of pesticides, unless really need it, and decided not to treat them. Instead pulled one a day and gave them (stalk and all) to the chickens. So, this year, I’ll start them in late June from seed and plant in Late July or early August and should have a hopefully bug free, hearty crop.