Making a Stink About Bugs

The introduction of new insect pests damaging to grapes is an ongoing threat for California’s grape growers.  Light brown apple (LBAM) and European grapevine (EGVM) moths are two recent examples of introduced insects the presence of which has been very costly to growers.  Although safe and effective conventional and organic control methods are available to manage moths, these particular insects are considered ‘quarantine’ pests, so extra special measures must be taken in the vineyard and throughout the fruit distribution and processing network.  Quarantine pests are a particular concern for the trade of fresh fruits, such as table grapes, due to import restrictions in some domestic and international markets.  Exactly how these insects made it to California is not presently known, but past insect introductions have come from contaminated plants and plant products.  Thus, it is critically important that everyone recognize the potential danger of violating plant protection and quarantine regulations.

Just as grape growers learn they have made excellent progress toward eradicating EGVM, officials are expressing concern over a new exotic insect pest, the brown marmorated stink bug (BMSB).  The BMSB is now found in 33 States.  Although not established in California, it has been identified in Los Angeles and Solano Counties.  BMBS can fly, but they primarily move into new areas by hitchhiking on vehicles and equipment.  Native to Asia, its thought that BMSB arrived in packing crates shipped to the Eastern US.  It has a large host range that includes grapes and many of the fruits and vegetables grown in California.  Damage can be substantial when BMSB populations are not identified early and managed appropriately. Apple growers in the Mid-Atlantic States have reported losses of $37 million representing 18% of their fresh apple market.  Growers and wineries are also concerned that the “stink” from any bugs accidentally crushed in wine or juice grapes could taint the product with off flavors. This insect should concern homeowners as well, since people in the Mid-Atlantic States have reported large populations of BMBS overwintering in their homes and becoming a nuisance.  

BMSBs resemble some other California stinkbugs such as the rough stink bug, a beneficial predator of other insects.  If you think you’ve found a BMSB, or any other odd or unique looking insect pest, you should collect it and bring it to your local university advisor, ag commissioner or state ag department entomologist for proper identification.  Early identification of invasive pests is critical for protecting California’s billion dollar agricultural industries.

You can learn more about the BMSB and current research here.