Home Invaders

Scentless Plant bug

Scentless Plant bug (Not Arhyssus barberi)
Photo: Jim Moore

Many species of Hemiptera overwinter as adults, often in locations sheltered from the elements. Some Hemiptera overwinter indoors and in large numbers. These include the boxelder bug, that can create large numbers of home invaders by releasing aggregation pheromone. The brown marmorated stink bug also uses aggregation pheromones although it is not clear what role the have in large numbers found indoors. Northeastern Oregon has a local home invader, Arhyssus barberi, that was present in massive numbers in the Fall of 2013.

Primarily a nuisance pest that creates little economic damage, this insect has recently attracted attention because of increasing complaints. Residents report bugs by the hundreds invading their homes, hiding in the furniture and flying into people. Arhyssus barberi is a “scentless” plant bug, but residents report a “piney” odor. The worst infestation in 2013 was in the area of Cricket Flats, Oregon.

Scientists are beginning to collect more information on the biology for insight into management options. Known colloquially as the “grass bug” the species identity was only recently confirmed as Arhyssus barberi. Arhyssus barberi is a native species, not an invasive, so many questions will focus on environmental factors that create such large populations. Perhaps cultural practices have changed to allow more habitat for the pest? One possible factor in increased numbers is noticeably warmer winter temperatures in the Northwestern United States. If that is the main factor, new control measures may be needed. Hemiptera are notoriously difficult to kill with pesticide sprays. Sprays are expensive and can cause environmental damage. Entomologists hope to find cultural practices or biological control that will mitigate the home invasions.

About jjneal

Jonathan Neal is an Associate Professor of Entomology at Purdue University and author of the textbook, Living With Insects (2010). This blog is a forum to communicate about the intersection of insects with people and policy. This is a personal blog. The opinions and materials posted here are those of the author and are in no way connected with those of my employer.
This entry was posted in by jjneal, Environment, Pest Management, Taxonomy. Bookmark the permalink.

5 Responses to Home Invaders

  1. Larry Hazard says:

    Jonathan, I need an entomologist “friend”. I am one of the NE Oregon Arhyssus barberi affected residents and have taken an interest in trying to help solve the infestation problems. The order of magnitude of the insects making their way into the house number in the thousands. I will keep this short until I get signed up.

    Our local OSU Extension office agronomist tried very hard to get funding for further research of the Arhyssus barberi, but funding was denied. We are on our own to try to figure these bugs out. No one has been able to identify a single host plant, so we have no idea where they are laying eggs and going through their nymph stages.

    We certainly know their destinations of choice! But again, no one has presented conclusive logic as to “why” residential structures. We know they are seeking over-wintering locations…and some have mentioned the warm temperatures of the buildings…but during infestation periods (high temperatures) everything in the countryside is hot, so again, why structures? I walk my 160 acres during heavy infestations and can find absolutely no bugs except at the house and outbuildings. I am beginning to think that some chemical in manufactured products is mimic’ing an attractant pheromone

    One resident is observing emerging bugs inside their house even now; and noticing some bugs are very small. The average adult is 8mm. The smaller bugs are about 4mm. Is it possible these scentless plant bugs can reproduce in the absence of a host plant?

    Larry Hazard

  2. Thank-you for going to the effort to blog about these critters; we are always dealing with them here in Eastern Washington. I have wondered for years what they were, and now I can show off with my “Arhyyssus barberi” knowledge, tho’ our cousins from Kansas said they call them “Democrats”. LOL

  3. Nora, you are welcome! Its been almost a year since my last post. I should be more active in posting so that others might feel more inclined to offer some observations of their own. How was you 2014 Summer as far as Arhyssus infestations?

    Jonathan, I didn’t make the “light” trap, but I made 5 traps of layered veneer plywood similar to some I saw made for the Brown Marmorated Stink Bugs. When mounted o the outside of the house or outbuilding, they worked well. The problem is, they were not an effective solution due to sheer numbers of bugs. There might be a couple hundred in each trap, but the hundreds of thousands not in the traps overwhelmed efficacy of the traps.

    The same traps, when relocated about 100 feet from the house, attracted ZERO Arhyssus. I found that to be astonishing.

    Adding to that…in conjunction with the Oregon State University Extension office, a line of insect bottle traps was set up just West of the house in our pasture. Four contained an ODA supplied pheromone, four without. In a two month test period of Aug-Sep, ZERO Arhyssus barberi were collected from the traps! Again, amazing while during the same period, hundreds of thousands were checking in to Hazard Hotels.

    Smaller grassbug specimens. Submitted specimens to ODA Entomology. Although not 100 percent conclusive on exact species, the smaller bugs are definitely not A.barberi. Suspected candidates for the smaller specimens are A.crassus or A.scutatus. Entomologist suggested sending speciment to a DNA lab for conclusive identification.

    So…the search continues for the “source” of these bugs. Many hours were spent last June-July in an attempt to find the vegetation on our property that was hosting the reproducing adults, their eggs, and the nymphs. Insect nets and beat sheets were used…to no conclusive findings. I did find a few adult A.barberi in some young pine trees far from the house. I have often wondered if the pines near our house and outbuildings could be the source, but a couple entomolgists discouraged that theory. This Spring, I am going to tree the ground at the base of our pines with a systemic insecticide that permeates the pine and purportedly would kill insects finding safe harbor therein. Then during Aug-Sep, I will be able to compare our infestation number estimates with others’ to determine efficacy…and rule in or out pine trees as hosts.

  4. jjneal says:

    Thanks for the follow up.
    They must be pretty good at hiding in their natural habitat.

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