While the defoliation of beloved trees, roses and other plants can be extremely frustrating, it is important to note that not all yards in a given neighborhood are equally affected by the annual Japanese Beetle invasions. Being familiar with the top 6 approaches to keeping Japanese Beetles off of your roses and other plants can put you ahead of the game the next time the dreaded season comes around.
Alter Plant Selection
Certain trees, shrubs and plants are more susceptible than others to the voracious Japanese Beetles. Whether you are planning a new landscape or looking to alter what is already there, you can select plants that are best at keeping the annoying beetles away. Instead of planting American Linden, fruit, or Birch trees, select Ash, Boxwood or Dogwood. Instead of roses, you can choose Magnolias, Hemlock, or a redbud tree.
In some cases, you may want to keep the plant and also protect it from the beetles. In such a case, there are other options besides uprooting the plant itself.
Cover Susceptible Plants
Typically the Japanese Beetle heavy foraging season is relatively short. If you are looking to protect some roses, fruit bearing trees, or other plants manageable in size, you can select certain soft or wire mesh covers for them.
When installing, ensure that the gaps are small enough to keep the beetles out. Also keep in mind that Japanese Beetles can fly so the covering has to be completely over the plant.
Japanese Beetles are slow and clumsy. In mild invasions, it can be best to just physically remove the beetles. The beetles are easy to grab and are harmless to people. Simply pull them off the plant you wish to protect. Since they can fly, relocation isn’t typically recommended, especially if your idea involves delivering the captured beetles to your neighbor’s fruit trees.
Certain products (neonicotinoids.are the most commonly used products in this regard) can be injected directly into the tree or plant in question. Typically, it can also be applied to the root system of the plant in a manner that will get absorbed up into the plant. These treatments can last 6-18 months in different kinds of plants and make the treated plant less desirable and/or lethal to the feeding beetles.
The downside to systemic treatments is that the product can become present in the flowering portion of the plants which can be harmful to pollinators such as honey bees. In addition, pay attention to labels as you don’t want the wrong products getting into fruit that is planned for consumption.
Certain sprays can be used on different kinds of plants affected by Japanese Beetles. When choosing a product to spray, make sure you choose one that is both labeled for the beetle and the specific plant. Products that can be used on general trees and bushes may not be suitable for fruit bearing plants and certain flowers.
Some sprays come in ready to use bottles that can be applied to beetles on site. Others will be available in concentrate form for mixing in larger broadcast spray applications. Especially when dealing with sensitive plants such as roses, be sure to test it on a smaller section of a smaller plant to see how it will affect them before applying to the rest.
Japanese Beetle Traps
In some situations, it makes sense to utilize some Japanese Beetle traps which are essentially a bag with a pheromone attractant. These can help pull beetles off of hard to reach places for physical removal and provide a distraction to the population that would otherwise be eating. If you utilize the traps, you have to dedicate some time and attention to emptying the bags frequently enough for them to remain effective.
In some situations, the traps may pull in additional beetles toward the yard from surrounding areas. If it seems to be compounding the situation, switch to a different method rather than adding more attractants to the area.
Keep a Good Perspective
While Japanese Beetles are annoying and can do a lot of unsightly damage, the effects are typically superficial and aesthetic in nature (obviously a huge deal if they entire purpose of your affected plants is aesthetics). Most healthy plants will recover from a Japanese Beetle feeding and do not require much interference. It is easy to get caught up in the battle and lose sight of how much time and effort is being put into the control. Ensure the effort is less than the value gained.