Is this a beneficial ladybug? Or other insect? - Ask Extension
I noticed that these beetles are on my tomato plants in the past week or so, as the plants are starting to die due to the end of season. Would like he...
Knowledgebase
Is this a beneficial ladybug? Or other insect? #728995
Asked October 06, 2020, 12:36 AM EDT
I noticed that these beetles are on my tomato plants in the past week or so, as the plants are starting to die due to the end of season. Would like help identifying this beetle and if they are beneficial or cause gardening issues? Thanks so much!
Washington County Oregon
Expert Response
The insect is a small lady beetle with the the common name of 20-Spotted Lady Beetle and the impressive scientific name of Psyllobora vigintimaculata.
Here's an interesting link which describes two other similar small, white lady beetles: "White Ladybug?" -- https://ladybugplanet.com/white-ladybug-identify-types-it-could-be/.
The link says that Psylllobora is a rare lady beetle.
Well, I don't know where the author lives, but at my place in Portland, Oregon, I would see several every year on my lilac leaves late in the season. The reason: These little champs feed on powdery mildew!
If you look closely at your tomato leaves, you may see narrow trails on the leaves where these lady beetles cleaned off the powdery mildew spores.
Unfortunately, there's a major hitch with these small Garden Good Samaritans -- they never eat enough of the mildew to do any good. (Oh, well.)
