Friday, June 5, 2015

Natural Aphid Control

Queen Composter is dealing with a perennial garden pest. 

Due to an abnormally warm and dry spring, my garden is way ahead of where it would be in a typical year. I have more garden greens, my tomatoes are exploding, and the squash are loving the heat. But the garden pests and problems are ahead of schedule too. Climate change anyone?

I have been battling powdery mildew on my plants (and sadly had to pull up all of the kale), which isn't usually a problem for me until late July or August. Also, the dreaded aphids have been causing me problems since early May. 

There is little that I can do about the powdery mildew (and I've tried the milk spray and the baking soda spray with no luck. It's just something I have to live with; it makes the plants look ugly and slows their growth, but that's about it as far as I can tell.

But there are a few things I can do for the aphid problem. 

Do Nothing

I love lazy gardening and often this is my default plan. This sometimes works because the aphids are a natural food source for ladybugs and other aphid predators, and they take care of the problem for me by attracting them to the plants to eat the aphids. 

Encourage Natural Predators

Sometimes, like this year, laziness does not pay off and the aphids take over and start to kill my plants, so I need to do things to encourage predators, like ladybugs, to the aphid buffet. Ladybugs need pollen as well as aphids as a food source so it is important to plant flowers that they like to eat, like marigolds, carrot, dill, fennel and chives. Don't pull up all your plants; make sure you leave some of your plants go to flower. The bonus is you get seeds for next year!

There are other natural predators that love eating aphids, and many of you probably don't want to hear that the hated wasps love eating aphids. I have seen some wasps this year, but not enough to make a dent in my crazy aphid problem. Hover flies, which come in abundance once my carrot flowers open, also love eating aphids. 

But sometimes, like this year, the ladybugs, wasps and hover flies have not arrived before the aphids have taken over, so I need to find ways to remove them from the plants myself. 

This is my compost bin after pulling up half a dozen plants that were
absolutely encrusted with aphids and dumping them in here. I'm not that
squeamish about bugs, but these make me itchy all over!

Just Spray Away

If the plant is hardy enough I just blast the aphids with a jet stream of water to force them off the plants. This is somewhat labour intensive and doesn't guarantee that they won't return (you are just moving them to a different location, after all). Sometimes, like now, I just want the aphids gone, so I move to the last resort: insecticidal soap.

Garden Soap Spray

There are commercial non-toxic insecticidal soaps you can buy in the garden shops, but it is so easy and cheap to make at home that it isn't worth the trip to the store. 

I am a castille soap addict and use it for all kinds of DIY products, and it is perfect for insecticidal soap. A soap bar works, but I love castle soap in liquid form. 

I'm not a measurer so I don't have a precise recipe (a quick google search will bring up many if you are interested). I add about a tablespoon of soap to a spray bottle and fill it with water. I've begun adding a tablespoon of oil (like olive oil) to it to help it stick. Other recipes talk about adding baking soda or garlic to the spray, but I like to keep it simple. Spray it directly onto the aphids and they should die almost instantly. 

I suppose I should be more precise in my measurements because my last batch of insecticidal soap was a bit strong and it has burnt the leaves a bit. The rest of the plant is fine, so I'm not concerned. 

The yellowed parts were burnt from my spray
and the grey parts have been damaged by
aphids (the holes are from the caterpillars).

Good luck and I wish everyone an aphid free growing season!

2 comments: said...

Cinnamon sprinkled under the leaves may help the powdery mildew issue

Green Bean said...

I really need to get in touch with my inner Castille soap!

And @brenda - cinnamon sprinkled under the leaves for powdery mildew! Do tell!!


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