What's That Bug? does not endorse extermination

Mystery bug
Location: San Diego, CA
October 1, 2011 8:54 pm
Dear WTB,
These bugs have recently appeared in large amounts and are prolifically mating. It is late September and the weather has been hot and dry. I have recently planted a field of Protea flowers. Can you tell me what they are and if they will harm my plants?
Thank you!
Signature: Darwin

Red Bug

Hi Darwin,
The Red Bug,
Scantius aegyptius, is a non-native introduced species that was first reported in California in 2009.  According to the UC Riverside Center for Invasive Species Research website:  “The most noticeable impact of S. aegyptius in California will likely be the presence of large numbers of nymphs and adults migrating from drying annual weeds into adjacent developed areas.  These migrations consisting of thousands of individuals can be very conspicuous and lead to large aggregations on small patches of host plants causing concern to local residents who notice these obvious aggregations.“  That would indicate your Protea flowers are not in danger.

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What's That Bug? does not endorse extermination
Location: California

27 Responses to Red Bug: Introduced species spreading in California

  1. susan says:

    These bugs have been in my yard a few years and I live in the bay area.

  2. jodi hanby says:

    we have had them in riverside county for a few years too the best way to get rid of them is laundry soap and and water in a sprayer you can use cheap liquid detergent we have animals and dont like pestisides or poisons .

  3. Paul Vincent says:

    They’re called Firebugs. Just located a huge population of them here in Huntington Beach at the Bolsa Chica Wetlands.

    • bugman says:

      The Red Bugs commonly called Firebugs, Pyrrhocoris apterus, are a different, but similar looking species from Europe. Several years back, we received a report of Firebugs from Utah, and as of now, BugGuide only reports Firebugs from Utah. Since Firebugs and Mediterranean Red Bugs look similar, we would not venture to speculate that you truly observed Firebugs in Bolsa Chica without an image.

      • bay says:

        I live in DC near a grave yard and they are EVERYWHERE. Including my storage, but there are 3-4 different kind. Thou some are really pretty, the others are scary looking.

  4. Kathy Fortenberry says:

    I have planted milkweed to attract Monarch butterflies and have just recently notice these red bugs on the milkweed. Will they harm my caterpillars or are they just after the aphids or are they targeting the milkweed plant?

  5. E S says:

    Large aggregation of red bugs here in the foothills 10-15 miles east of Santa Maria, CA in field of dead weeds.

  6. Kady says:

    I’ve been watching these red bugs for a couple of weeks. It is very dry here (southern Tulare County, CA) and all the surrounding fields are dry. Although my mostly fallow garden is full of these guys. I have not seen them showing any interest in eating veggies. Nor do the chickens show any interest in eating them! This evening I found a dry dandelion stalk completely covered with tiny red nymphs(?). I sure hope they don’t acquire a taste for greens.

  7. gina says:

    We have been seeing many of these bugs the past few weeks in Baja California, Mexico. I don’t recall seeing any last year. We are about 40 miles South of the CA border.

  8. Laurie says:

    I saw one for the first time today. I live in Granada Hills, Ca. (San Fernando Valley).
    I do have a pest control service.

  9. JennP says:

    Hi, saw these everyone on the cliffs of Palos Verdes Callifornia

  10. Isaiah says:

    These bugs are in my back yard in ventura ca how can I get them out

  11. Stacy says:

    We have these all over our property in San Benito County. There are 1000’s of them. They have moved from around the yard to the horse manure piles in my pasture. Lots of aggregations still. A few under the water troughs, one in a dying tree and some on the sides of my horse shelters.

    • Stacy says:

      After the invasion last two years I have yet to see one after winter. I am so surprised since we had 1000’s and 1000’s. I can’t see that they did any damage.

  12. Sam Lang says:

    I have several thousand in my yard.. Bleach did not kill them.. I will try the soap.. Are there any ideas to kill them in mass,,,, break cleaner, wd40, and engin bright did not work…. Someone Help

  13. Kady says:

    Sam – I, too, had thousands in my yard and garden for the last 2 summers of the drought, But for the life of me, I could never discover any damage done by them. I just left them alone (organic gardening purist :P), except for taking a few pics. We had LOTS of rain this last winter, and now I only see an occasional straggler. We live out in the country, so maybe they just have room to spread out (or drowned). Hope you survive.

  14. Kurt Walters says:

    k. walters: 10/2017. I am in the foot hills east of Fresno @1600 ft. Nine months ago I found a Blue Oak tree, killed by the drought, infested with these bugs. I have since cut the tree down and removed the wood. The bugs have started to infest various weeds, some areas of the barn, and seem to nest under dried piles of horse manure. Breeding locations? How or where do these bugs breed, subterranean? They have dispersed to about a half acre area.
    Any help on controlling their breeding environment and and substances that kill them is appreciated. Laundry soap is my next step for killing them. Thanks, Kurt

    • bugman says:

      We don’t provide extermination advice. The Center for Invasive Species Research states: “The most noticeable impact of S. aegyptius in California will likely be the presence of large numbers of nymphs and adults migrating from drying annual weeds into adjacent developed areas. These migrations consisting of thousands of individuals can be very conspicuous and lead to large aggregations on small patches of host plants causing concern to local residents who notice these obvious aggregations.” There might be other helpful information for you there.

  15. Bert the Biologist says:

    I see hundreds of them at a park near my house in Santa Clarita. They emerge en masse from Argentine ant nests. I wonder if they are feeding on the ant larvae and then planting their eggs in the nests…

    • bugman says:

      That would really be wishful thinking.

      • Bert the Biologist says:

        Well there used to be numerous Argentine ants there and now that the nests have been taken over by the Reds, there are no ants at all.

        One possibility is the Reds may have entered to feed off the grains stored by the ants and disrupted their reproduction.

  16. Roxan Coffman, gardener says:

    I planted Milkweed two years ago and have watched these little red and black beetles increase in numbers . They are even crawling up the walls of our house. I don’t use bug spray because I have a lot on Hummers and bees coming to my plants. I have ants like crazy too and they don’t seem to be bothering them. I’m going to try the dish soap and water and spray on the ground around the plants.

  17. mrsndavis says:

    We having a migration of them coming into our community. We actually live a mile from UC Riverside. I guess as long as they eat weeds we’ll let them be.

  18. James says:

    I’m in Fresno CA and just killed a bunch of these that were mating in my backyard. If someone could email me, I would be happy to send pictures.

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