Sap Beetles

8/4/2016

Sap beetles may be small, but they can be a serious threat to ripening fruit.

Sap beetle (John Tann) CC BY 2.0

Sap beetle description

Sap beetles are tiny (0.1" to 0.2" long), flat, and usually brown or black. They are active and move quickly. There may be spots on short wings and the antenna are clubbed. Larvae are white with a tan head, 3 pairs of legs and 2 horn-shaped structures on their back end. There are several varieties of sap beetle, also known as dried fruit beetles. These most common varieties are:

Dried fruit beetle (Carpophilus hemipterus)
Freeman sap beetle (C. freemani)
Confused sap beetle (C. mutilatus)

Less common varieties include:

Carpophilus marginellus
Haptoncus luteolus
Urophorus humeralis

Sap beetle damage

Sap beetles damage fruit by feeding, transmitting disease, and making fruit more appealing to other pests. Sap beetles create a hole near the stem of ripening fruit, where they enter and begin feeding. They begin by attacking fruit that has fallen on the ground, but ripe and overripe fruit left on trees can draw these pests upward. Sap beetles can act as disease vectors, spreading brown rot, Fusarium wilt and other fungal diseases. As damaged fruit begins to rot, other pests, such as navel orangeworm and vinegar flies, are attracted to the tree.

How to control sap beetles

Sanitation offers the best control of sap beetles. This means removing all fruit as soon as possible, including fruit that has fallen or mummified on the tree. Before fruit starts ripening, containers of fruit, water and yeast may be used to attract and drown sap beetles.

David Livingston

3/6/2017 09:31:09 am

Hi there, I just realized that I have a major infestation of dried fruit beetles in my compost/worm bin. I had seen the beetles for a couple months, as well as their larvae, but only yesterday did I finally get a positive identification of the beetles and realized how damaging they can be. I am trying to get rid of them, obviously, and am wondering if there is any way I can do this short of emptying and disposing of all my compost. I have heard of setting traps for the beetles with fruit and yeast, but I have an infestation that has gotten into the millions now and don't think some small traps would even put a dent into their population. Thanks and hope to hear from you soon.

Kate Russell

3/6/2017 10:17:02 am

Hello, David.

You are already halfway to the solution by identifying the pest!

Dried fruit beetles can be, as you have learned, very destructive. At the same time, they do help break down your compost. Since dried fruit beetles are attracted to ripe and rotting fruit, I think your first step should be to check the moisture level within your compost pile.

If it is too wet, you will need to dry it out a bit. Open it up and spread it out to reduce any rotting. Also, this will attract many birds who just love to eat beetles and their larva.

I, too, have heard of the sugar and yeast traps, but have never needed to try them. When I get my periodic grub infestations, I simply open up the compost pile and let my chickens do their thing! I have heard good things about the traps and urge you to give them a try. They may not be able to fix the problem completely, but you are more likely to get good results with a multi-pronged attack.

Increasing the amount of heat within your compost pile may help kill off many of the larva. Depending on where you live, this can be tricky in March. Covering the pile with a dark colored tarp and making sure to keep it at least 3 feet deep can help. Also, adding freshly cut grass clippings near the bottom of the pile can really heat things up.

Compost piles always attract critters. Some of them are good, others, not so much. As your garden starts producing again, be sure to collect fallen fruit and mummies immediately and regularly to reduce habitat options for these and other pests.

Please let me know if these ideas help. I’d love to see photos!

3/7/2017 05:35:42 am

Hello again. I just reread your question and saw that you had said compost/worm bin. That changes things. Can you describe your set up in more detail?

3/9/2017 02:02:22 pm

After contacting a worm pro, I learned a couple more tips. First, remove all the excess fruit. If the worms can't eat it rapidly enough, it creates food for the pests. You can also put everything in the bin in a bucket of water. The pests will float to the top, scoop them up, remove them, drain the water and everything should be fine.

6/2/2018 09:14:06 am

Hi Kate-Thank you very much for your reply. I have still been working on getting rid of the beetles and trying not to hurt my worms. As you stated, having too much fruit in the bin is causing the beetles to multiply, so I have cut back a lot on how much fruits I feed (I have actually stopped feeding it completely for the time being.) I made a trap with bananas and yeast and it caught a few beetles, so I will continue to use this. Also I will try your idea of soaking the compost and having the beetles float up to the top. I am getting ready to harvest my bin which is completely full of beautiful, black compost, so after this I will build a very hot pile and let it cook, hopefully killing any lingering beetles. I will let you know how things go and try to get you some pictures of my bin.

Thanks again!!!!

David

6/2/2018 10:59:36 am

Hi, David.

I'm so glad things are improving for you! As you know, if isn't one thing, it's another. I'd love to see some photos.

Kate

Guacamole Products link

4/30/2023 08:04:25 pm

Hi, thanks for posting this.

5/1/2023 04:35:11 am

I'm glad you enjoyed it!

Kate

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