Japanese beetles have plagued Eastern U. S. gardens for decades. Meanwhile, dimly aware of the insect's destructive potential, Minnesota gardeners battled lesser pests. Sadly, the age of innocence is ending here, especially in the Twin Cities area.
The beetles have been present in Minnesota for several years but populations have been local and numbers relatively low. This year many Twin Cities area gardeners encountered them for the first time and numbers exploded in some places. More of the same is likely to come.
The bronze and green beetles are known to feed on 300-400 kinds of plants. Rose, linden and grape are among their favored hosts. The beetles are gregarious, often gathering in clusters on chosen plants with remarkably destructive effects. Beetle activity peaks mid-July through mid-August.
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Controlling the beetles is so difficult that enduring some damage will probably be the only option for most gardeners. However, measures can be taken to reduce their numbers.
Recommended
Hand Picking: Knock beetles into a pan of soapy water.
Barriers: Cover prized plants with mesh or netting.
Plant selection: Choose plants that do not attract the beetles.
Insecticides: Use products labeled for beetle control.
Not Recommended
Milky spore: This bacterial product has been used to control Japanese beetle grubs in turf. It hasn't been proven effective in Minnesota. The beetles are strong fliers so grub control doesn't guarantee a beetle free garden.
Traps: Research shows that traps often attract more beetles than they trap, making a bad problem worse.
Here are links to more information about Japanese beetles and ways to control them:
http://www.extension.umn.edu/distribution/horticulture/DG7664.html
http://www.ca.uky.edu/agc/pubs/ent/ent5/ent5.htm
When will it end? That's what many Washington County residents are asking about the indoor presence of boxelder bugs.
Many ways have been devised to reduce or eliminate mole damage but researched-based studies show that some work better than others and a few are entirely ineffective.
Luckily I planted daffodils and not tulips! Deer love sweet tender tulips in the spring but do not touch my daffodils. I learned the hard way, so now the tulips are in the fenced-in area of the yard and the daffodils and alliums are outside the fence. ]]>
If you don't want to fence your yard or gardens, continually be spraying stinky purchased or homemade repellents, or have a yard full of smelly soap or shiny objects hanging from trees, then landscape your yard with plants rated "rarely damaged��? or "seldom severely damaged��? by deer browsing. A list of various types of plants can be found on the Rutgers University Extension website which is searchable by plant type, ratings, or specific plant name.
Many of us think we know how to take care of our trees just by observing how our cities, shopping malls, neighbors, etc. take care of theirs. We assume that a city or large commercial enterprise would know the proper methods of pruning, mulching, watering, and other plant maintenance. But think about it, how many times have you noticed an irrigation system spewing forth water while it is raining? One of the most noticeable tree care mistakes seen in our area is mounding mulch up around the tree trunk.]]>
Mulching is very important because it conserves soil moisture, suppresses weeds and grass, moderates soil temperatures, and reduces compaction. If there are no weeds and grass near the trunk of the tree there is no need to mow or weed whip near the tree trunk, thus reducing the possibility of damaging the trunk. In order to protect the trunk, it is best to have a nice wide mulched area, not a small area with mulch piled up around the trunk. If the tree looks like there is a mulch volcano around it it may develop problems because water soaked bark is susceptible to bacteria, it creates a place for insects and disease to start attacking the tree and it provides a hideout for rodents. Instead, the look you want is that of a doughnut where the mulch is pulled a couple of inches away from the tree trunk and extends out several feet from the trunk.
