JBs on Earth Song
To get to know the JB enemy, let's consider again where JBs originate. The adult beetles mate in the process of feeding on their favorite foods (like roses, many trees and other flowers like zinnias) and you can see this happening if you observe them clustering. The female JB then finds a lush bit of turf and deposits her eggs. The eggs hatch as grubs and feed on the grass roots. If enough JB grubs populate your lawn, you will develop areas of dead turf, which, when dug up, will have one-inch, white, JB grubs clustered in the roots. That whole area of your lawn will die unless you apply grub control in the fall or early spring. This is one of the things that golf course managers have learned and why they have been using huge amounts of imidacloprid, as the most effective grub control, over the last several years here in Minnesota. I had this problem myself, several years ago, and applied granular imidacloprid to save my lawn. You can bet that this is part of the reason that we have seen such an upswing in bee colony collapse disorder, which has been directly linked to imidacloprid. One extreme example of this is Orem City, Utah, which applied imidacloprid across all neighborhoods of the city, several years ago, when JBs began to affect the floraculture and nursery industries. They even went so far as to warn homeowners not to eat any of the produce of their fruit trees, because of the systemic nature of imidacloprid. It worked, but I can't even contemplate the extent of the damage to honey bees and other beneficial insects, like lady beetles, in Utah, as the result of this extreme measure. Here's the Utah story:
I also want to point out that as soon as we began to see JBs in the Twin Cities, I made the rather sizable investment in Milky Spore, with a special tubular applicator and all, and went all over my lawn and portions of my neighbors' lawns laboriously applying patches of it, exactly as specified (and I breathed-in a lot of it, as well). I watched, hopefully, for the next few years to see what the milky spore infection would do to the JB population on my roses and I can say with certainty that it did virtually nothing to significantly reduce the population of beetles in my gardens! Oh, I'm sure that Milky Spore and a subsequent, equally expensive, application of nematodes knocked off a bunch of JB grubs in my lawn over the next few years, and they still may be doing so, but that's not where the great majority of JBs landing in my gardens are originating.
Please see quotes from the University of Minnesota about the ineffectiveness of Milky Spore here:
Fact: JBs travel amazing distances, from where they pupate, to find the plant foods they relish (like your roses). There is evidence that they may fly as much as five miles to reach your plants, so unless all the turf within a five-mile radius of your garden is treated with Milky Spore or imidacloprid (like in Utah!) there is no way that what you alone do to your lawn will stop JBs from invading your gardens. Milky Spore and imidacloprid can protect your lawn from dying, but they can't stop the vast majority of JBs from flying your way each summer. Save your money and concentrate on killing the JBs as they arrive, before they can lay eggs in your lawn. As I point out in my earlier blog posts, pyrethroid insecticides, like Demand CS, work well, but they also kill beneficial insects such as lady beetles and pollinators. That is why I advocate the organic approach of manually drowning JBs. Either way you decide to go, it's far more important to concentrate on attacking and killing JBs than it is to try and prevent them from hatching on your property.
Fact: If you haven't already figured this out, JBs are amazingly canny critters. To effectively attack them, it's useful to observe what they do as they approach your garden. When you have as many as I do, it's interesting to observe their behavior (just before drowning them!). When a JB arrives in one of my rose beds it hovers around the bed, like a helicopter, looking for a suitable place to land. Almost always, it will land on a flower or leaf that has one or more JBs already on it, or on a flower or leaf that has been previously chewed by other JBs. So, obviously, the JBs arriving in my garden, from some distance, perhaps miles away, are attracted to the scent of other JBs, presumably by the female sexual pheromone, which is all kind of amazing to me. So, it's important to get rid of tainted leafs and flowers, whenever possible. I know how hard it is to pluck a brand new bud that has two JBs imbedded in it, but it's important to do that in order not to let it attract incoming beetles (I did it just a few minutes ago and it is painful). Interesingly, when they can't find an old leaf or flower to land on, they seem momentarily confused and can be easily picked off. Also, believe it or not, while they are hovering around looking for a place to land, I have been quite successful in grabbing them in mid-air! That actually makes the whole exercise kind of fun once in a while.
The good news is that JB season should soon be over. They started early this year (June 19th) so they should soon be finished. Better days ahead.
July 21, 2016