Question
QUESTION: Hello Mr DeAngelis,
Thank you for taking the time to anwser my question. I have a linden tree that was infested with aphids for a couple of years now. This year June bugs started showing up in large numbers. They seem to be all around the tree. My grass is healthy and green. Can it be that they are attracted to the aphids? Is there a correlation betwee the two. Is it necessary to cut down the tree before it gets out of hand.
Once again I thank you in advance for your time and your expert advice.
Regards.

ANSWER: Danny,

There's no association between June bugs (June beetles) and aphids that I know of. Both insects can be very abundant in early summer. June beetles are a type of scarab beetle, larvae are called white grubs. White grubs live in soil feeding on roots and adult beetles emerge in early summer. Here's some information about white grub control http://www.livingwithbugs.com/white_grub.html that may be useful.

Aphids feed on plant sap. If the linden tree is small and heavily infested with aphids you might consider treating it with insecticidal soap. Large trees usually can't be treated but most will tolerate aphid feeding.

Jack DeAngelis, PhD
Extension Entomologist (ret.)
My website about home and garden pests: http://www.livingwithbugs.com



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QUESTION: I thought there might have been. Let me explain. With the aphid infestation I get alot of honeydew that falls on the grass and on the surrounding plants. The honeydew seems to stunt the growth of the grass and thus attracts the grubs.

ANSWER: Danny,

I also considered the honeydew but I could not think of a mechanism that would link the two. Scarabs are not attracted to weakened stands of grass because the larvae are dependent on healthy root growth.

The stunting of the grass may be due to the honeydew using up the available nitrogen. The carbohydrates in the honeydew stimulates microbial growth which needs nitrogen hence soil nitrogen is sequestered and not available to the grass. A bit more water and fertilizer might help.

Jack DeAngelis



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QUESTION: Hello Mr DeAngelis,
I have the city now addressing the problem with the excessive honeydew dripping from the tree. They tried spraying it with an insecticide soap the last few years but that di d not work. I heard that there is a way of getting rid of the problem by injecting the tree with a insecticide that will travel through but the tree and kill the aphids. Do you have any comment on this. Will it work or is it temporoary? Once again I thank you kindly for your time and effort devoted to anwsering my question.
Redards,  

Answer
Danny,

Injecting trees with insecticide is usually only done for certain wood boring beetles and is both expensive and potentially hazardous for the tree. There are some systemic insecticides that are absorbed by the roots and are effectively moved through the vascular system to the leaves. They can be very effective against aphids. One such insecticide is Merit. Here's a link to more information about Merit http://www.livingwithbugs.com/merit_insecticide.html and how it is used.

If you decide to use a systemic insecticide it is best to apply it early in the season before the aphid population builds too much. Merit is also effective against white grubs when applied to soil.

Jack DeAngelis