Japanese Beetle (Tree)

Popilia japonica

The Japanese beetle, Popilia japonica, is native to Japan, but was first found in New Jersey in 1916. Common in every state east of the Mississippi, these insects have spread as far west as California. Japanese beetle adults are gregarious, hanging out in groups, and attracting each other using pheromones. Japanese beetle infestations can defoliate an entire tree in days.

Download Japanese Beetle (Tree) Fact Sheet

Treatment Strategy

Unfortunately, no treatment will prevent Japanese beetles from visiting your yard, because the presence of beetles on a plant attracts more beetles. Hand picking the first Japanese beetle adults to arrive on a property and dropping them into a container of soapy water can be an effective Japanese beetle control method when populations are low.

Japanese beetle traps actually attract them from other areas, making the population in your yard higher, but once they are present they prefer their food source to the pheromones in the traps. You should avoid using Japanese beetle traps as a control method.

Which treatment strategy to use is primarily determined by the time of year.

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Japanese Beetle (Tree) Treatment Option 1

Lepitect is applied to the soil and will provide a quick knockdown (within 3 days). It has a residual of 30 days, so Lepitect can be applied as soon as beetles are visible. You may have to apply a second time (one month later) to maintain control.  Consider applying a long lasting insecticide such as Xytect™ when applying Lepitect™ to extend the window of protection.

Application Method - Soil injection

DIY Equipment/Product Needed:

• Lepitect

• Soil injection kit

• Gloves

• Measuring or diameter tape

Japanese Beetle (Tree) Treatment Option 2

 Xytect is applied to the soil and has a long residual (1 year), however it usually will take 30 – 60 days for the product to reach the leaves. Professional arborists will often apply Xytect™ in the fall of the year for control of Japanese beetles and other insects the following season. Spring application is also very effective. Xytect™ applications also work well when used with Lepitect™. Once the Lepitect™ has worn off, the Xytect™ will be in the leaves and provide protection.

Application Method - Soil drench or soil injection

DIY Eqipment/ Product Needed:

 Xytect

• Gloves

• Measuring or diameter tape

• Soil Drench: Watering can or soil drench kit

• Soil Injection: Soil injection kit

Japanese Beetle (Tree) Treatment Option 3

A contact insecticide such as Up-Star® Gold can be sprayed and is very effective as long as even coverage of the foliage is achieved.  Multiple spray applications are often needed to control the beetles, so be sure to wait at least 14 days in between treatments.

Application Method - Foliar spray

DIY Equipment/Product Needed:

• Up-Star® Gold

• Hand pump sprayer

• Gloves

Japanese Beetle (Tree) DIY Kit

Option 1

Application Method – Soil injection

DIY Equipment/Product Needed:

• Lepitect

• Soil injection kit

• Gloves

• Measuring or diameter tape

Option 2

Application Method – Soil drench or soil injection

DIY Eqipment/ Product Needed:

 Xytect

• Gloves

• Measuring or diameter tape

• Soil Drench: Watering can or soil drench kit

• Soil Injection: Soil injection kit

Option 3

Application Method – Foliar spray

DIY Equipment/Product Needed:

• Up-Star® Gold

• Hand pump sprayer

• Gloves

• Safety glasses

How Is It Spread?

Japanese beetle larvae overwinters in the soil at a depth of 4-8 inches. Adults emerge over a 3-4 week period during late June through August. After mating and feeding on leaf tissue for a couple days, the females lay 1- 5 eggs into the soil and return to the tree to start the feeding, mating, and egg laying cycle over again. The females will lay about 40-60 by the end of these cycles. The eggs hatch in 8-14 days and the Japanese beetle larvae feeds on roots and organic material before overwintering.

Susceptible Trees

The trees most suseptable to Japanese beetle infestations include: Japanese maple, Norway maple, Crape myrtle, Apple, crabapple, Virginia creeper, Plum, apricot,cherry, peach, pin oak, Sassafras, American mountain ash, Linden, Horsechestnut, althaea, birch, summer-sweet, hawthorn, Beech, black walnut, larch, Lombardy poplar, and willow.

Symptoms

Japanese beetles are skeletonizers, which mean they eat the “meat” of leaves, leaving only the veins behind. They also feed on both flowers and fruit. Japanese beetles begin feeding on the outermost foliage first, working their way inward towards the trunk and down towards the ground. In heavy infestations the entire tree can be affected, turning all leaves brown. Some leaves may fall off before they are completely skeletonized. From a distance, trees may look scorched, as if by fire.

Lookalikes

None

Related/Similar Problems

None

Timing

Spring or Fall

Urgency

High

Risk of Spreading

High

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