Two Ingredient Japanese Beetle Spray

My gardens have been overrun with Japanese beetles. While I generally like bugs, I’m not a fan of having my plants destroyed.

Our raspberry bushes were especially affected, with some leaves being absolutely covered with those awful beetles, and the leaves surrounding them looked like sad little leaf skeletons. I don’t like spraying pesticides in my yard since we’re outside a lot and also have lots of beneficial insects like bees and butterflies that I wouldn’t want to harm.

I remembered a soap spray I made a couple years ago and whipped some up, and it really did the trick. My daughter sprayed the leaves liberally with the mixture one evening and then we waited to see what would happen. Well, the next morning, I went out to check on the plants and was amazed- the beetles were gone (well to be honest I did see two on one of the plants, but the previous day the plants were literally covered with beetles)!

I would definitely recommend mixing some of this up, it’s inexpensive, non-toxic, and it really works! It’s also helpful for other garden pests.

Supplies Needed:

1 Spray Bottle

1-2 tbs. Dr. Bronner’s Liquid Castile Soap

1-2 tbs. Cooking Oil (I used canola oil)  

Put the liquid soap and oil in the bottom of an empty spray bottle and then fill slowly the rest of the way with water. Hold the bottle up to the faucet when filling since too much agitation will cause soap bubbles.

Spray your affected plants liberally. Try to spray either in the morning or evening rather than in the strong midday sun. If your mixture does not spray correctly, reduce the amount of soap in your mixture. Measuring isn’t really necessary, just squirt a bit of soap and oil in the bottom of your empty bottle before filling with water.

Neem Oil Spray for the Garden

Neem oil is wonderful to use in the garden as a natural insecticide that is safe for beneficial bugs, as well as having anti-fungal properties which prevent mildew and other fungal diseases on plants. Neem oil works against chewing and sucking insects like aphids, whiteflies, and mealybugs, without harming bees and other pollinators. 

Neem as a general preventative:

1/2 tsp neem oil
1/4 tsp Dr. Bronner's Castille Soap
2 cups warm water

For a stronger batch, with more severe pest problems, increase the amount of neem oil:

1 tsp neem oil
1/4 tsp Dr. Bronner's Castille Soap
2 cups warm water

It is best to make this in small batches because it loses its effectiveness over time when the ingredients are mixed together. I usually make a single use spray each time since I think that way the neem keeps its top effectiveness (the beneficial properties in neem oil begin to break down 2-3 hours after mixing).

Single use spray:

1/4 tsp. neem oil (15- 18 drops)
1/8 tsp. castile soap (my measuring spoon doesn’t go that small, so I just estimate)
4 oz. warm water

Neem begins to turn to a solid at room temperature, so if you open your bottle and see clumps of oil, run the bottle under warm water for a minute before using.

Mix all the ingredients in a spray bottle and shake well before use. Spray liberally on affected plant foliage.

Neem oil is only bad for bugs that chew on leaves (because of this, I would not use it on host plants for butterflies like milkweed).

The neem oil spray should be used early in the morning or in the evening since it's best not to spray plants when the sun is at its strongest. Morning and evening are also when pollinators are less active. This neem spray will not harm beneficial insects unless they are directly sprayed.

Spray every few days for intensive insect problems, once every two or three weeks for prevention. I was having a really bad time with some sort of insect sucking and curling the new leaves on my phlox plants, so I sprayed those plants every day for a few days and now the new leaves seem to be growing in healthy without any curling.

Neem is safe to use on vegetable plants, but it's best to discontinue its use five weeks before harvest.