Expert: Mike Mascio - 6/10/2010

Question
I live in Minnesota and have a wave petunia planted in my back yard.  This year it was doing beautifully but suddenly something is eating the blooms.  The leaves and plant itself seem to be fine but every one of the blooms is eaten down to the stem.  What is doing this and how do I stop it?  Thank you.

Answer
The most likely culprit are aphids. Whiteflies are also a possibility.

The best alternative for aphids (and whiteflies) is insecticidal soap. You can buy this product commercially at most garden centers, or you can make your own by adding 3 tbs. of lemon dish soap (non-concentrated)to one gallon of water. The fatty acids from the soap will kill the aphids.

Two organic insecticides include pyrethrum and rotenone. These can also be purchased at most reputable garden centers or online through companies such as Planet Natural or Gardens Alive. They are highly effective and non-toxic to humans and the environment.

To prevent aphids from infesting the outdoor garden, plant garlic throughout the bed. I plant garlic bulbs around my rose bushes, and I have not had an aphid problem for years. The smell deters them.

I hope this information helps. Please write again if I can ever provide assistance.

Regards,

Mike