Every year, California receives, on average, six new exotic invasive pests of concern; that's about one new pest every 60 days. These may be plants, insects or other arthropods, mollusks, plant pathogens such as fungi and bacteria, vertebrates, or any other organism not native to our state and with the capacity to negatively impact agriculture, urban environments and/or natural ecosystems. These invasive pests enter California on plant material and other biological substrates, as hitchhikers on trade goods and in ship ballast water, and sometimes even because of smuggling operations. Without the natural enemies that kept them in check in their native lands, they are free to reproduce and wreak havoc. Such pest invasions may then lead to destruction or alteration of habitat, loss of agricultural trade revenues, pronounced losses in agricultural production, and increases in pesticide applications.
The best way to combat such invasions may be through robust exclusion, inspection, early detection, and quarantine programs. Once established, they are best managed using classical and conservation biological control and the decision-making process of integrated pest management (IPM), described in detail in an earlier blog post. Urban agricultural environments are not immune to these invasions and may even be more at risk since urban environments contain many likely routes of introduction and have often been identified as point sources for invasive pests. In this article we will review the biology, ecology, and management of three recent pests that may increasingly be found in urban gardens and other urban ag environments.
UC IPM PEST NOTE: Asian Citrus Psyllid and Huanglongbing Disease
Center for Invasive Species Research: Asian Citrus Psyllid
UC scientists release a natural enemy of Asian citrus psyllid
Brown marmorated stink bug (BMSB): This large (5/8”) stink bug from eastern Asia has been an established pest in the eastern United States since 2001. Though it has been intercepted many times in California over the years, probably because of its ability to hitchhike on and in outdoor household items (such as patio furniture) and firewood, it has only recently (sometime between 2006 and 2013) become established in the state. The BMSB, Halyomorpha halys, is a key agricultural pest, reportedly attacking over 100 plant species using piercing mouthparts to suck juices and inject tissue-damaging enzymes. Damage is expected to be worst on pome fruits (apples, pears), stone fruits (peaches, nectarines), legumes, corn, tomatoes, and peppers. Stink bugs are known to aggregate in large numbers in fall, sometimes entering homes and other structures to escape harsh winter conditions. BMSB can be distinguished from several native stink bug species by two white bands on the antennae. The current distribution in California is unknown, so if you think you find BMSB you should contact your County Agricultural Commissioner's office to confirm and document its presence. To learn about BMSB identification and management, please visit the following links:
UC IPM PEST NOTE: Brown Marmorated Stink Bug
Pest Alert - UC IPM Online: Brown Marmorated Stink Bug
Center for Invasive Species Research: Brown Marmorated Stink Bug
Pest Alert - UC IPM Online: Bagrada Bug
Center for Invasive Species Research: Bagrada Bug
[Reposted from the original article on the UC ANR's Urban Agriculture blog, Sept. 25, 2014]
Author - Integrated Pest Management Advisor