Question
We have Japanese beetles in most of our plants and trees. It is extremely frustrating to deal with them. Generally, I am against killing animals and insects. Therefore, I tried every other possibilities to prevent them. The following are the steps I tried.
1) Murphy organic soap.
2) Neem oil.
3) Vegetable oil.
4) Baking soda.
5) Vinegar.

I tried a mix of all of the above. Nothing changed. They go away during the application and then come back with in a day or two.

Besides Japanese beetles, the spider mites are eating several of our ornamental plants. Most of them are half gone.

Could you please let me know your suggestions. I prefer saving the plants without killing those insects if that is possible. Otherwise, I would like to do whatever required to save my plants and trees.

By the way, should I also consider apply grub-ex every where because of these beetles presence. If so, please guide me when would be a right time to do that and any specific way I need to apply?

Thanks in advance for your timely help.

Rog

Answer
Rog,

Thanks for re-submitting your questions. Japanese beetles are extremely difficult to control so your goals should be realistic. You can manage damage but you'll never be completely rid of these landscape pests. Start by treating the larvae (soil) with milky spore disease (see http://www.livingwithbugs.com/japanese_beetle.html). This will take several years but eventually the bacterium will buildup in the soil to affect some control. Then, treat adult beetles with neem oil insecticide (see http://www.livingwithbugs.com/neem_oil.html) by spraying the foliage that the beetles are feeding on. Over time you should see a gradual reduction in damage and beetle activity.

By comparison spider mites are fairly easy. Insecticidal soap (see http://www.livingwithbugs.com/insecticidal_soap.html) is very effective or simple overhead irrigation to dislodge mites is often enough. Don't let plants get dry as they become more susceptible to damage when water-stressed.

Post a follow up if you have questions.

Jack DeAngelis