All together now … aw … so cute! And, unfortunately, a pest. Seems the little coqui frogs—as adorable as they may be—are a problem in Hawaii, where their numbers have increased exponentially following an unintentional introduction, presumably from their native Puerto Rico, in the late 1980s. They’re not necessarily damaging to plants, but they do have a voracious appetite for the state’s unique insects (and spiders), and so they compete with the islands’ native birds that rely on insects for food. Other fauna unique to Hawaii also are duking it out with these minute creatures—adults are about the size of a quarter—for food sources. It’s also feared that they may become the preferred meal for nonnative snakes, allowing the slithering pests to become established and further jeopardize Hawaii’s ecosystem.
A sad state of affairs, but what’s the fuss in the green industry? Coqui frogs are tree dwellers and, because of their size, easily nestle into foliage where it’s hard to spot them. Their characteristic—and shrill—nocturnal call helps searchers find them, but otherwise they’re easily and unknowingly transported among plants and in containers, often hidden between the pot and the potting soil. Tiny, 5 mm eggs are easily missed.
About 90 percent of the frogs captured and eliminated on the island of Oahu between 2001 and 2002 were concentrated in five locations, three of which were nurseries. A significant land population was eradicated in 2012, but frogs are still found at nurseries; nursery owners are cooperating with the Oahu Coqui Frog Working Group.
Legislation recently introduced would regulate the movement around the state of growing and landscaping materials, such as potting media and mulch, and would levy fines on those individuals or companies who move these materials if they’re infested with coqui frogs. (Little fire ants also would be subject to regulation.) House Bill 1994 HD1 (Relating to Civil Liability for the Intrastate Transport of Invasive Species) passed the House Agriculture Committee in January and the Finance Committee in February, and it’s opposed by the Hawaii Export Nursery Association (HENA) and the Hawaii Floriculture and Nursery Association. Industry advocates state that nurseries already are cooperating with current eradication efforts and a new program is unnecessary. HENA president Thomas Martin told http://bigislandnow.com, “This bill places the blame for invasive pests to the Big Island ornamental growers who are already working so diligently to eradicate these pests and prevent the spread of same.”
Photo courtesy of Eli Sarnat; Bugwood.org
Pretty sneaky plant
It was a challenging winter for much of the country, but apparently not nasty enough to kill off several pests—one of which lies dormant in South Carolina. Benghal dayflower (Commelina benghalensis) was confirmed in several Lowcountry areas last fall, and has recently been confirmed in Orangeburg and Calhoun counties. Investigators from Clemson University’s Department of Plant Industry are trying to determine how the invasive plant found its way into the area, speculating that it hitched a ride either with container plants or was carried by birds in seed form. Benghal dayflower previously was identified in a container of liriope at a South Carolina nursery in 2005.
Variously called tropical spiderwort, Indian dayflower and jio, this pest is a particularly successful weed in field nurseries as well as in row crops. It is tolerant of many herbicides. It also is difficult to remove by cultivation or by hand; succulent stems root at each node, and pieces of stem left on the ground can easily become established and produce new plants. It also develops underground stems, allowing the vigorous plant to spread vegetatively.
Photo courtesy of Herb Pilcher, USDA Agricultural Research Service; Bugwood.org
Benghal dayflower is not just a prolific seeder, capable of producing in excess of 1,000 seeds per square foot; it produces four different types of seed, practically assuring its successful germination.
Prevention is your best bet: Practicing good hygiene is no guarantee against invasion, but it beats the frustration—and the cost—of eradication.