The other day I noticed signs of aphids on my Brussels sprouts. All of the brassicas will get them if given enough time in the garden. I might have swarms of hoverflies, wasps, and preying mantises in my garden, but I cover the brassicas to keep out the dreaded white butterfly. So all those beneficial insects don't do me any good when I keep them out.
So I have to spray. I use liquid soap to kill them. Dr. Bronners is my current soap of choice in the house, so I just use it in the garden too. I used a quarter cup per gallon. I could go as far as one more tablespoon, but we will see how this dilution works. To work, you have to totally cover all the aphids, which means getting to the underside of the leaves where most of them are.
My old sprayer was failing, so I got a new one this year. I like that it is smaller - one gallon as opposed to two, but my last one had an angled sprayer which made getting under the leaf so much easier. This one does not. So I have to lift each leaf to get to the insects. While I was at it, I checked the broccoli, which is the only other brassica that will stick around all summer long. I found some on one leaf, which I sprayed, but the rest seemed clean. For one leaf I could probably just wipe them off. It is what I do for the growing point of my espaliered apples. I just squish them with my fingers.
I also tested the soap spray on the raspberries just to make sure they don't mind the soap. They were just fine the next day. Mites are hurting the poor things. If I have extra spray next time I do the Brussels sprouts, I'll spray the raspberries too. I'm not as worried about the mites as I am about the aphids. The aphids will spread and infest every sprout if I'm not careful. They make it inedible. The mites will slow my raspberry production down, but mites aren't big pests here as we tend to be wet.
I'm hoping I won't have to spray the broccoli again. I found one of my myriad preying mantises and put him under the broccoli row cover. I hope they eat aphids, but what are the odds it will eat all the spiders first? Mantids aren't very discriminating when it comes to eating.
My Brussels sprouts were also trying to burst out of their cover. So I sewed up a bigger one for them. If this gets too small they are out of luck. I don't have supports that are taller, but the cover is so light it shouldn't matter. The cover is nice and loose and the sprouts could push it up another foot if they want.