If they are present in your area, you will never be able to eradicate them. At best you can keep them to manageable levels.

It takes at least a year for milky spore to become effective so you need to be patient with that. And the timing of nematode applications is tricky - the soil needs to be warm enough to foster the nematodes (above 45-50F) and the beetle larvae need to present and active.

Neem oil is fully organic and is good treatment for most plants (even edibles) but needs to be applied before feeding really gets going. It is considered an antifeedant - it does not need to come into direct contact withe beetles but only on the foliage that they like to eat. Otherwise, you need to resort to hand picking and drowning :-)

Verbascum thapsus (Mullein) is a JB magnet around here. I go to it with my bucket of soapy water and kill dozens at a crack. I allow some to grow each year mainly for this reason.

tj

I have had good results from using Milky Spore but as gardengal said it takes a good year to see results. And you have to apply it over a wide area including adjacent lawns, not just the gardern itself. Each successive season shows further decrease in numbers.

Dave

Traps are very organic. They can kill not only 'your' JBs, but the neighbors too.

Some think that that is a negative, but I see it as very positive.

Milky Spore does take a while. How much Milky Spore did you use, when did you apply it, and where did you apply it?

Dave, I understand that the eggs are laid in sod. Putting Milky Spore on the Garden might be a waste of time and money for any appling it.

Wayne, thank you. I used a 10 oz box of milky spore in the spring, followed by 10 million nematodes. I applied Nematodes in the fall, as well. I read somewhere that the Nematodes help. Distribite the milky spore. Regarding the milky, I sprinkled a teaspoon in every 4 square ft of grass, moving out from the garden beds until I ran out. Now, I wish I had used the big 40 Oz box, because it did go quickly. But at the time (and now), $85 plus shippong feels like a big blow to the ol' pocketbook! Especially in the spring when I spend so much money on everything garden! I thibk I should keep a look out for a sale and do another major application.

Maybe I should also check out neem oil and a trap. I am just afraid the trap will tell all the JBs from the neighborhood that the party is at my house!

"I am just afraid the trap will tell all the JBs from the neighborhood that the party is at my house!"

Strangely enough, that is exactly what you need to happen. If you kill only the local ones this year...remember, they have wings and if you have desirable plants for the JBs,, they will come...from wherever.

I think the time to apply Milky Spore is August 1st.

Use natural predators.

Those "traps" were originally meant to monitor Japanese Beetles and they come with a pheromone that tells male beetles that there are females around so the males move in. The presence of the males then attracts more females. Putting those traps in your yard means you will attract more Japanese Beetles into your yard and garden.

The eggs the beetles lay hatch in mid to late august and Milky Spore diseases is effective on the larva when they are quite small so the best time to spread it around is late July to early August so the spores will have time to get down to the beetle larva when they hatch. As numerous researchers will tell you there needs to be a community wide effort to control these pests, one yard will do little.

I used the traps for a few years and went from about 300,000 beetles in '03 to 5, 8, 11, 25 for a while. I also used a small amout of Milky Spore.

Proper trap placement is important. Once I placed one too close to silking sweetcorn. I discovered it quickly and it was ok.

One man I know has a trap with a plastic bag with the bottom funneling into a one gallon milk container...when full, cap the bottle...neat

Wayne - sod maybe but I used to find the JB grubs all over the gardens too. Maybe mine just aren't as picky as we have no sod per se.

Dave

Dave, Since there are grubs and then grubs, do you know that the garden grubs are JBs. We had grubs long before JBs showed up here.

I've spoken about Surround® WP for years. It's an organic kaolin clay that when mixed with water and applied in two or three coats, forms a porous (breathable) film that works beautifully to prevent chewing, sucking, and egg laying pests from damaging plants.

I first used it for JBs, but graduated to applying it on my garden crops against flea beetles, leaf hoppers, squash bugs......well, just about all of the pests. It also reflects scorching sun, preventing sun scald and over heating to my tomatoes, squash, greens, and more.

Yes, the film is white and looks scary, especially on ornamental plants. It wears away with a few rains or frequent overhead watering cycles and needs to be reapplied. But with JBs, you'll need just a few short weeks of protection.