Their names are similar and they’re from the same region of the world, so I can see why some people are still confused about Asian lady beetles and Japanese beetles. But when it comes down to it, there’s really no comparison. The bug pictured here – the reddish/orange lady beetle, is a beneficial insect. It feeds on aphids and other plant pests and doesn’t destroy anything, though I realize some people resent their intrusion in homes in the fall. On the other hand, the copper-colored Japanese beetle, a recent foreign invader in Iowa, is known to devour at least 300 plants, including hollyhocks, roses, raspberries, linden trees and grapes. If you see your leaves turning to lace, the likely culprit is the Japanese beetle. Japanese beetles have no known predators here, other than me. So feel free to get rid of as many as you can. As mentioned previously, the most environmentally friendly method is to knock them into a bucket of soapy water when they’re sluggish – early evening seems to be the best time. If you have other suggestions – maybe from our East Coast readers and others who have learned to cope with Japanese beetles – please add your comments below.
Posts tagged grapes
I spotted the first Japanese beetle of the season yesterday on my raspberry bushes. I went to check one of my rose bushes and sure enough, there was another one, sucking the life out of a beautiful pink bud. Unfortunately, both got away.
The beauty of these copper-colored beetles belies the devastation they wreak. Adult Japanese beetles feed on more than 300 types of plants – turning leaves into lacy skeletons. As larva, the white c-shaped grubs feed on turf grass roots.
I’ve heard some people have luck with the Japanese beetle traps that can be found at garden centers. Others say the traps just lure more beetles into your yard. When I see just a couple of the bugs, I use the squish method, but as they become more numerous, I’ll try to control their numbers with soapy water.
Take a small bucket with water and dish detergent – any kind will probably work – and knock the beetles off the plants into the bucket. The beetles are more active at certain times of day and will fly off. Othertimes, they do a drop and roll, which is the best way to get them to fall into the bucket. Early evening seems to be the time when they are more sluggish and easier to catch that way. Obviously, if you are growing crops that the beetles are attacking, such as grapes (another favorite,) you’re going to need a different method of control. They also favor certain trees, but supposedly they don’t kill the trees as do pests like the emerald ash borer. I also wonder what they will ultimately do to the monarch butterfly population, as Japanese beetles devastate the monarch’s food source, milkweed.
Since they make my top 10 bad bugs list, the Japanese beetle and different control methods can be found in several posts on this blog. Just use the search box at the right to find more from city arborist Daniel Gibbons, master gardeners and others on this foreign invader.
Richard Jauron, extension horticulturist at Iowa State University, offers the following on spring pruning of berries and other small fruits:
Small fruits that are commonly grown in home gardens include raspberries, grapes, gooseberries, currants and blueberries. For maximum production, small fruit crops need to be pruned in late winter/early spring (March/early April). Proper pruning procedures for raspberries, grapes, gooseberries, currants and blueberries are outlined below.
The pruning procedures for raspberries are based on the growth and fruiting characteristics of the plants.
Summer-Bearing Red Raspberries
Remove all weak, diseased and damaged canes at ground level in March or early April. Leave the most vigorous canes, those approximately 1/4 inch in diameter when measured 30 inches from the ground. After thinning, remaining canes should be spaced about 6 inches apart.
Also, prune out the tips of the canes that have died due to winter injury. Cut back to live tissue. If the canes sustained little winter dieback, remove the top 1/4 of the canes. Cane-tip removal or “heading-back” prevents the canes from becoming top heavy and bending over under the weight of the crop.
Red raspberries sucker profusely from their roots. Plants should be maintained in a one- to two-foot-wide hedgerow using a rototiller or spade. Remove or destroy those shoots that emerge outside the one- to two-foot-wide hedgerow.
Fall-Bearing Red Raspberries (Two Crop System)
Follow the same pruning procedures as described for the summer-bearing red raspberries. This pruning option provides both a summer and fall crop.
Fall-Bearing Red Raspberries (One Crop System)
Prune all canes back to ground level in March or early April. While the plants won’t produce a summer crop, the late summer/early fall crop should mature one to two weeks earlier. Also, total crop yield is typically larger using the one-crop system versus the two-crop system.
Maintain the plants in a one- to two-foot-wide hedgerow.
Black and Purple Raspberries
Remove the small, weak canes, leaving only four or five of the largest, most vigorous canes per clump or plant. Cut back the lateral (side) branches to 12 inches in length for black raspberries and 18 inches for purple raspberries.
Grapevines produce fruit clusters on the previous season’s growth. Before pruning, a grapevine may have 200 to 300 buds capable of producing fruit. If the vine is not pruned, the number of grape clusters would be excessive and the grapevine would be unable to ripen the large crop or produce adequate vegetative growth.
To maximize crop yields, grapevines are trained to a specific system. The most common training system used by home gardeners is the four-cane Kniffin system. The four-cane Kniffin system is popular because of its simplicity. In the four-cane Kniffin system, the canes of the grapevine grow on two wires, one located three feet above the ground and the second six feet high.
If using the four-cane Kniffin system, select four canes on the upper wire, two going in each direction. Also, select four canes on the lower wire. To aid identification, some gardeners tie brightly colored ribbons or strips of cloth on those canes they wish to retain. All remaining one-year-old canes should be completely removed.
Going back to the upper wire, select two of the remaining four canes (one going in each direction). Prune these canes back to one or two buds. These short one or two bud canes are referred to as renewal spurs. The renewal spurs provide the shoots or canes that will produce next year’s crop. Prune the remaining two canes on the upper wire back to eight to 13 buds. The number of buds left on the fruiting canes is determined by plant vigor. If the grapevine is vigorous, leave 13 buds per cane. Leave only eight buds per cane if the grapevine possesses poor vigor.
Prune the four canes on the lower wire the same as those on the upper wire. When pruning is complete, no more than 60 buds should remain on the grapevine. When counting the number of buds on the grapevine, include both the buds on the fruiting canes and those on the renewal spurs.
Gooseberries and Currants
Gooseberries and currants produce the majority of their fruit on 2- and 3-year-old shoots. Shoots that are 4 years old and older produce very little fruit. After the first growing season, remove all but six to eight vigorous, healthy shoots. The following year, leave four or five 1-year-old shoots and three or four 2-year-old canes. After the third growing season, keep three or four shoots each of 1-, 2-, and 3-year-old growth. A properly pruned, established plant should consist of nine to 12 shoots. Pruning of mature plants consists of pruning out all 4-year-old shoots and thinning out some of the new growth.
Blueberry plants are shrubs like currants and gooseberries. Blueberry yields and fruit quality decline when blueberry shoots (stems) reach 5 years of age. In late winter/early spring, prune out any dead or diseased stems. Also, prune out stems that are 5 years old and older. Allow one to two new shoots to develop each year.
The pruning of small fruits really isn’t difficult. It requires a basic understanding of plant growth and pruning techniques, proper pruning equipment and (sometimes) a little bit of courage.
I don’t hide my disdain for the Colorado potato beetles that annually devour my potato crop, but come July, I’m battling a much more formidable foe.
The deceptively handsome, copper-colored Japanese beetles are out in force, their voracious appetites turning foliage to lace throughout my backyard.
As obnoxious as they are, potato beetles are at least slower moving, and thus easier to squish than the wily Japanese beetle.
Japanese beetles have perfected the art of stop, drop and roll, and if that fails, while I’m reaching in for the death kill, they simply fly away.
Their favorite meals appear to be grapes, hollyhocks, roses and – where we do most of our battle – raspberry bushes.
Armed with a single gardening glove and a container for whatever raspberries they haven’t devoured, I make a trek to the bushes every evening after work.
Early evening seems to be the time when they are less likely to fly off and are an easier target for my gloved hand.
When one or two started appearing on the bushes in late June, this “squish” technique seemed to work, but by now, several of the beetles gather on each leaf and it’s time to move on to bigger things.
Because raspberry patches should be a place where you or a child can readily eat whatever’s ripe, as-is, I wouldn’t use any chemical means of control. The best approach has so far been to take a small bucket of soapy water to the bushes – I use liquid dish soap – and knock the beetles into the water.
Plain water doesn’t quite do the trick, as the beetles can survive, swimming around, for at least several days in it.
I’ve heard bug experts say Japanese beetles usually don’t kill anything before they end their midsummer’s rampage, but I don’t know that they’ve seen the infestation problem that my backyard seems to have. Once the beetles ravage their favorite plants, they will move on to almost any others available. They even suck the flowers of my fragrant milkweed to nothing.
I’m envious of the parts of the country where these beetles have not yet reached. Even areas of Cedar Rapids seem immune to the problem. If you’ve had any luck with other methods of control, please let me know.