Why do you always see Japanese beetles in swarms?

Plant odors attract both sexes to potential food sites. Japanese beetle feeding produces odors which act as pheromones to attract other Japanese beetles to the area to feed and mate. Pheromones are chemical odors used by insects to communicate.

Where did they come from?

Originally from Asia, Japanese beetles were brought over to the United States in 1917 into New Jersey. Currently the insect can be found establish in all  states east of the Mississippi River, except Florida and Louisiana.

How can I kill Japanese beetles?

To kill the adult stage Japanese beetle contact insecticides that can be used are:

  • Cyonara
  • Bifen
  • Malathion

Always read the label for instructions and apply as directed from the label for any pesticide.

What about Japanese beetle traps?

Japanese beetle traps do work in that they capture adult beetles. However, placement is critical. DO NOT place the traps near any plant material you do NOT want the beetles feeding on. Although the trap is quite effective in attracting the beetle, only about 70 percent of the beetles end up in the trap. In addition, pheromone traps attract more beetles to your property than would have visited your property naturally. Research has shown that putting the traps in the perimeter of the property well away from valuable plantings or vulnerable crops may be the best use of the traps. Traps work better if you also get your neighbors to set out traps. Use a community-wide approach of 25 to 50 traps per square mile.

To kill the grub stage of Japanese and Southern chafer beetle or white grub, timing of the application is critical.

Japanese Beetle Life Cycle
  • Preventative Control for grubs is Long Lasting Grub Control Designed to be applied before a potential grub problem develops. Normally applied in late June to early July and effective against the baby grubs as they hatch. 
  • Curative control for grubs is Quick Kill Grub Control containing Dylox. Normally applied in August or September, after the eggs have hatched and grubs are present. Very fast acting with a short active life. Water heavily after application to penetrate thatch.

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