July 1, 2015
July has arrived, and soon you will see the arrival of the Japanese Beetles. From past experience, there is no way to be sure if there will be a problem in a particular area. Some years, I will have customers who will ask me where have all the beetles gone and then the next customer will tell me they have never seen the beetles so bad in their yard.
The Japanese beetles come from the grubs that eat the roots of your lawn. During June, the grubs form a cocoon around them and eventually turn into Japanese beetles. The beetles will emerge from the ground and will eventually head toward plants that they like to eat. You will find the beetles in your vegetable garden. They also like to eat the leaves of any plant that bears fruit. They also like the leaves of your ornamental fruit trees. This would include flowering pear, flowering cherry and crabapple trees. They also like rose flowers and many other annual and perennial flowers. At some point in time, the females give off a scent to attract the males. The males will mate with the females and then the females lay eggs in your lawn. The eggs hatch out as the grubs that feed on the roots of your lawn. The eggs usually hatch out some time in early to mid September.
The adult beetles can cause major damage to your plants in the two months that they are feeding on your plants. You can apply insecticides to the leaves of your plants. If you are applying the insecticides to your vegetable plants, you need to know if the product is recommended for use on vegetables. The label on the product will tell you if it can be used on vegetables and the label will also tell you how many days you must wait from the last spraying until you can eat the vegetables.
You must also be aware that many of the products that kill the beetles, including some of the organic products, can also kill the honeybees that will help to pollinate the flowers in your vegetable garden. It is best to apply the products when the bees are not present. These same precautions apply to using an insecticide on your annual and perennial gardens.
One way to control the beetles is to set up Japanese beetle traps. I know that the traps have received a bad rap over the years. I have heard all the comments about how they can attract beetles from your neighbors yard etc. Let me tell you a short story. Back in the late seventies, I had purchased a home in West Newbury. In the backyard there was a grape vine and some blueberry bushes. During the first summer we were there, the beetles arrived in droves. I set up beetle traps near the plants and the traps filled up with beetles. It got to the point were we were emptying the traps every few days. Over the years, we would set up the traps and fewer beetles would be in the traps. By about the fifth year, we had very few beetles in the traps. Soon, I did not have to set up the traps any more.
The traps use a strong floral scent to attract the females, and the traps use a scent that mimics the scent given off by the females to attract the males. If the traps are set up early in the season, they will attract hundreds, if not thousands of beetles before they even have a chance to attack your plants. It is important to set up the traps in an appropriate location to draw the beetles away from the plants and not to your plants. We have these traps for sale in our store.
Please check your plants for signs of the arrival of the Japanese beetles – and once you see them, start your spraying program. It is always best to have the traps set up in early July. This will help to catch the maximum numbers of beetles. The more beetles you trap and kill, the fewer you will have to lay eggs in your lawn and the fewer grubs you will have in your lawn.
Well, that’s all for this week. Have a safe 4th of July. We will be open on the 4th and the 5th, if you need help with your gardening problems or if you need to fill your propane tank for your cookout.
I’ll talk to you next week.