Posts tagged Japanese beetle

Good vs. Evil: Asian lady beetles and Japanese beetles

Asian lady beetle

Asian lady beetle - a good bug (photo/Cindy Hadish)

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.

Japanese beetles (photo/Cindy Hadish)

Japanese beetles - not a good bug, or just plain evil? (photo/Cindy Hadish)

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Japanese beetles are back

They’re back.

Japanese beetles

Japanese beetles

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.

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Getting ready for Japanese beetles

   I’ve been keeping a careful watch for Japanese beetles in my garden and enjoying my roses before the pesky beetle begins its annual invasion. The city of Cedar Rapids sent out the following today, (June 8, 2009) which made me wonder if Japanese beetles had already emerged. City arborist Daniel Gibbons, who wrote the article, assured me that he hadn’t seen any. Yet.

Japanese beetles

Japanese beetles

But, they will arrive, worse in some areas than others. If you haven’t seen this foreign invader yet, be grateful. Whether or not you have, read the following from Daniel Gibbons to learn more:

Japanese beetle has become one of the most destructive and frustrating pests for gardeners, farmers, and green industry professionals.  A transplant from Japan during the early 1900’s, Japanese beetle (Popillia japonica Newman) populations have enjoyed explosive growth across the East and Midwest.  Damage inflicted by various stages in the beetle’s life cycle can be severe to turf grasses, agricultural crops, and over 300 ornamental trees and landscape plants.  The USDA estimated in 2007 that control measures alone cost over $460 million.

Success of the non-native Japanese beetle can be primarily attributed to a lack of natural predators and a supportive climate and food source.  Although eradication is not feasible, successful management leading to reduced populations will minimize pest damage.  Those who succeed in managing Japanese beetle do so by gaining local cooperation, using an integrated approach to natural and chemical control, and by shrewdly selecting plant material when designing a garden or landscape.

Local cooperation is critical because of Japanese beetle mobility.  Despite the best efforts of one property owner, beetles from neighboring yards are usually a significant problem.  Success will increase if adjoining neighborhoods and property owners cooperate with sound management techniques.

Integrated Pest Management (IPM) is simply the use of multiple control techniques to reduce the comprehensive use of pesticides.  When properly used, IPM creates a healthy biotic environment in which populations of undesirable pests are reduced over time by the introduction of predatory elements, resistant plants, and targeted use of pesticides when necessary. 

Natural predators of Japanese beetle include microscopic nematodes (Heterorhabditis bacteriophora), naturally occurring soil bacteria (Bacillus thuringiensis), and the spores of Bacillus popillae (referred to as “Milky Spore”).  The success of these and other products can be effective, but depends on adherence to application and storage directions, climatic and soil conditions, and the presence of other pesticides or chemicals which may be harmful to these living organisms.  Products such as Milky Spore will become more effective over the span of several years when the bacterium has had time to establish.

Application of pesticides may be used to reduce heavy infestations, but should be performed by competent and trained applicators.  Some chemicals may only be used by licensed pesticide applicators.  Considerations in choosing insecticides to control Japanese beetle will include application method, seasonal timing, location, type of plant material being protected, and the presence of sensitive environment features such as waterways.  Assistance in choosing the latest formulation of pesticide for a particular site may be obtained from local garden shops or government extension agencies.

Finally, avoiding plants and trees that are susceptible to Japanese beetle is the best method to reduce the pest’s impact on a particular landscape or garden.  Keeping landscape plants healthy will also increase resistance.  The following trees are specifically targeted by Japanese beetle: Linden, Birch, Norway and Japanese maple, pin oak, beech and horse-chestnut.  Trees that show resistance to the beetle include hickory, red maple, tulip poplar, dogwood, northern red oak, pine, spruce, arborvitae and hemlock.  Resistant herbaceous plant groups include: Columbine, ageratum, coreopsis, coral-bells, showy sedum, hosta, and forget-me-not.  Herbaceous plants to avoid in areas where beetle populations are high include: rose, hibiscus, evening primrose, clematis, sunflower, peony, zinnia, asparagus and morning-glory.

Despite recent challenges with Japanese beetle, thoughtful management can reduce the impact to community gardens and landscapes.  Education, cooperation and savvy IPM practices will also reduce the impact on our pocketbooks, while promoting a healthy and vibrant growing season.

More information on Japanese beetle may be obtained through the following online sources: “Managing the Japanese Beetle: A Homeowner’s Handbook”    http://www.aphis.usda.gov/publications/plant_health/content/printable_version/JB3-07.indd.pdf

Iowa State University – Iowa Insect Information Notes http://www.ipm.iastate.edu/ipm/iiin/node/125

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Bugged by bugs?

  

Japanese beetles

Japanese beetles

 Spring in Iowa is too fleeting. Rare are those 70-degree days with cool nights before the air explodes with humidity and bugs begin their annual invasion. I can look at healthy green potato plants today and know that in a week or so the Colorado potato beetle will begin its defoliation quest. Same is true of the lush rose bushes that succomb ever earlier to the dreaded Japanese beetle, a copper-colored foreign invader.

   Because of the devastation they wreak on my plants, the Japanese beetle and potato beetle rank number one and two on my list of “bad bugs.” I was enjoying my backyard garden last night trying to think of others when a mosquito bit my leg. Mosquitoes= #3.

Colorado potato beetle

Colorado potato beetle

   Here are the others: 4) gnats or whatever those little black bugs are that bite behind the ears. 5) chiggers – not an insect, but larvae of a specific family of mites – the Trombiculidae. If you’ve ever suffered through chigger bites, you’ll know why these are on my list. 6) wasps – I try to leave them alone, but they seem ubiquitous this year and more aggressive – building wherever they take a liking, which includes my back porch and my sons’ club house.  7) ticks – again, not an insect, but my general worry over them keeps me from enjoying the outdoors at times. 8) Ants – luckily we don’t have  fire ants like they do in the south, but they’re just a pain when they decide to come in the house. 9) termites – again a general anxiety thing. 10) Emerald ash borer – not here in Iowa yet, but a preemptive disdain for a foreign invader that will someday devastate our ash trees. 

Emerald ash borer

Emerald ash borer

   What makes your list? I’m sure I’ll think of more, now that our perfect spring days are in the past.

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Letting milkweed grow

A monarch caterpillar makes its way along a milkweed plant in late July in Cedar Rapids, Iowa.

A monarch caterpillar makes its way along a milkweed plant in late July in Cedar Rapids, Iowa.

  

 

This monarch caterpillar was munching on common milkweed at my garden this weekend. As noted below, habitat destruction has reduced the amount of milkweed growing in the Midwest, which is the only food source for the graceful Monarch butterfly. That’s one of the reasons I don’t kill off all the milkweed in my gardens. Another reason: the scent of milkweed flowers, as another gardener once described it to me, is intoxicating. Unfortunately, my nemesis, the Japanese beetle, has managed to suck all the milkweed flowers to brown this year. More plants are springing up, and hopefully will bloom after the destructive beetle has gone underground. Though the caterpillars look a bit ominous, they won’t bother your tomatoes or other plants, so don’t poison or otherwise kill them off, as Monarchs already face a number of obstacles to survival.

 

 

 

 

 

 

   For more information on milkweed, the following came from the Monarch Watch Web site at www.monarchwatch.org

    Monarch larvae appear to feed exclusively on milkweeds in the genus Asclepias and several other genera of viny milkweeds in North America. Milkweeds are perennial plants, which means an individual plant lives for more than one year, growing each spring from rootstock and seeds rather than seeds alone. In the Midwest, milkweeds were historically common and widespread on prairies, but habitat destruction has reduced their range and numbers.

    Milkweeds belong to the family Asclepiadaceae, derived from Asklepios, the Greek god of medicine and healing. Though most members of the genus Asclepias are tropical, there are approximately 110 species in North America known for their milky sap or latex contained in the leaves. Most species are toxic to vertebrate herbivores if ingested due to the cardenolide alkaloids contained in the leaves and stems.

    When Monarch larvae ingest milkweed, they also ingest the plants’ toxins, called cardiac glycosides. They sequester these compounds in their wings and exoskeletons, making the larvae and adults toxic to many potential predators. Vertebrate predators may avoid Monarchs because they learn that the larvae and adults taste bad and/or make them vomit. There is considerable variation in the amount of toxins in different species of plants. Some northern species of milkweed contain almost no toxins while others seem to contain so much of the toxins that they are lethal even to monarch caterpillars.

 

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