February is Hawaii Invasive Species Awareness Month! The theme for this year is Mythbusters! There are so many misconceptions about invasive species, now is the time to hear the facts that are backed by science. Throughout the month there is going to be a variety of webinars and live events throughout the state! Webinars range from how to ID plants to information about inivasive animals. Check out the full list and sign up now!
It’s a sweet potato bug.
Throughout the late winter and early spring, you may notice an odd-looking bug in your garden. Although a healthy garden will draw many critters (some beneficial, and some not), this one stands out: it’s on the large side at nearly 1 inch long, with noticeably large “thighs”. You’ve spotted a sweet potato bug (Physomerus grossipes)! This is a type of true bug in the Coreidae family, or leaf-footed bugs. Members of the Coreidae have enlarged showy parts on their hind legs – these guys do not skip leg day.
If you’re a sweet potato grower or neighbors with one, then this is probably an unwelcome guest. Generally however, sweet potato bugs are considered a minor agriculture pest and are not dangerous to humans or animals.
- Adults are approximately 1 inch long
- Brown grey mottled color
- Wings fold over each other at the end of the body making a dark colored diamond
- Orange lines along the edge of the body
- Large distinct ‘thighs’
- Like to cluster together in large numbers
This insect has a piercing mouthpart that is used to suck sap from leaves of their preferred food plants, members of the morning glory family (like sweet potatoes) and legumes. One or two insects won’t harm the plant, but a large number of them will cause leaves to yellow and wilt. Even when under attack by a huge number of sweet potato bugs it’s likely that the plants won’t completely die, but the attack will reduce plant production and leave it susceptible to other insects and diseases. The bugs can often be found resting on other plants, but this does not indicate feeding.
Photo: Alistair Bairos
Sweet potato bugs are rather resilient and most insecticides are ineffective on them. The best method for removal is to simply pluck the bugs off the plants and dunk them into a container filled with soapy water. Their clustering habit makes them easy to collect in large numbers. They are docile and can’t bite, sting, or release stink smells, so hand capturing them is non-hazardous and the most effective method to protect your sweet potatoes. While your picking away at the adult insects don’t forget to smash any egg masses you may also come across.
Join us as we celebrate our love for ʻōhiʻa and Hawaiʻi’s unique forest ecosystems. The theme of this year’s festivities is Mōhala, the unfurling, and blossoming of the lehua. Not only does it refer to a particular life stage of the ʽōhiʽa lehua it also represents how our Big Island community has blossomed in the midst of volcanic eruptions and a pandemic. The ʻōhiʻa lehua has also blossomed with its new official designation as the State Endemic Tree of Hawaiʻi earlier this year.
Kīpaepae: opening ceremony
When: Monday, November 14 (9am to 9:30am)
Where: Live on Facebook
We will begin this year’s festivities with a Kīpaepae (ceremony) guided by haumāna of Hālau ‘Ōhi‘a, a Hawai‘i Lifeways Stewardship Training program with Lonoa Honua. The Kīpaepae will immerse you in the Native Hawaiian cultural tradition of hula and oli (chant).
Webinar: Go Plant ʻEm: A Journey to Understand ʻŌhiʻa Seedling Survival and Growth at ROD-Impacted Sites on Hawaiʻi Island
When: Wednesday, November 16th (6pm to 7pm)
Corie Yanger from the US Geological Survey will be sharing the research being done to understand the survivability of ʻōhi’a in a time of deadly disease, and how we can help to protect and nurture these trees for the future. Streaming live on Zoom and BIISC’s Facebook page. For more info, visit: https://fb.me/e/29uNu6Ld7
Workshop: Ōhiʻa Seed Conservation
When: Thursday, November 17 (8am to 11am)
Where: Terraformation, Makai Meeting Room Gateway Center at Hawaiʻi Ocean Science and Technology Park (73-4485 Kahilihili St. Kailua-Kona, HI 96740)
This free workshop, hosted by Terraformation, is for anyone who wants to learn how to properly collect, handle, and process ʻōhiʻa seeds using methods that protect seed viability and ensure conservation value for future restoration efforts. Seats are limited. Pre-registration is required. Register today! If you have any questions, contact Marian Chau at email@example.com
ʻŌhiʻa Love Fest Fair:
When: Saturday, November 19th, 2022 (10am to 2pm)
Where: Pāhoa Community Center – Pahoa District Park (15-3022 Kauhale St. Pāhoa, HI 96778) – directions
A free event for the whole family to celebrate ʻōhiʻa! Join us for raffles, giveaways, demonstrations, crafts, and more. This event is brought to you with funding by Vibrant Hawaii MicroGrant in partnership with the Big Island Invasive Species Committee, the College of Tropical Agriculture and Human Resources, the Department of Land and Natural Resources, and many other partners.
*Special ʻŌhi’a Planting Workshops: Learn how to properly plant and care for ʻōhi’a on your property. Participants will pot an ʻōhi’a seedling to take home. Two workshops are being offered: one at 9 am and one at 1 pm. Pre-registration is required – sign up here.
The ramie moth is a destructive caterpillar that can completely defoliate native māmaki. This caterpillar was first discovered in November 2018 on Maui where it was destroying māmaki plants. Since then, it has spread to the Big Island and was found on the east side in November 2020. This is the first record of this pest in the United States. It’s known to feed on members of the nettle family (Urticaceae). Besides harming the māmaki plant, this caterpillar also poses a threat to the native Kamehameha butterfly as it competes for the same food resources.
The young ramie caterpillar will start by chewing holes in the middle of the leaf and create even larger gaps as they grow, leaving only the main veins. Kamehameha caterpillars start eating from the edge of the leaves. Young Kamehameha caterpillars will fold over the edges of the leaf to make a tent for protection.
Photo of Kamehameha caterpillar by Forest and Kim Starr
Adult ramie moth
Ramie Moth: appearance
Ramie moth (RM) eggs are about 1mm in diameter and are a clear-white color. The eggs are laid individually on the underside of leaves.Â Kamehameha butterfly (KB) eggs are more brownish in color. The first instar of RM caterpillars are green and black. As they get larger, they change color to become yellow and black with red/orange spots and thin white hairs. There is also a black variant of the RM caterpillar, but it still has the iconic red spots and white hairs. The RM caterpillar can look very similar to the KB caterpillar and they are found on the same plants, so it is important to make a positive identification before taking any action! Young KB caterpillars also have black-colored heads, but they turn green or brown as they get older.
Unlike KB caterpillars, the ramie caterpillars are aggressive…at least, relatively aggressive for a caterpillar! When disturbed the caterpillar may lift its head and start wiggling around, and might even vomit a green fluid. These actions are to dissuade predators but are not displayed by KB caterpillars.
The adult ramie moth is about 3 cm long with a 6-9 cm wingspan. It is mostly brown, with black markings on the scalloped wings. Hindwings have silvery-blue markings. They can be challenging to identify, so please send a picture of your suspect caterpillar to BIISC or your local HDOA or CTAHR office for identification.
Be careful when moving māmaki and olonā plants, and do not move them interisland. Always inspect your plants before moving them.
If you see a ramie moth caterpillar, please capture it and report it to 643-pest.org.
A critical part of the work we do at BIISC is looking for new, potentially damaging, arrivals, In late 2017, BIISC botanists collected a mystery plant on a trailside early detection survey on the Kona side near the Makaula-O‛oma State Forest Reserve. It was at first easy to overlook, with no eye-catching characteristics to make it stand out from the lush greenery around it. However, trail users had reported its aggressive tendency, and its persistence even after they tried to control it. The BIISC team realized that this plant did not match any known introduced or native species on the island, and observed that it was reproducing naturally – and quickly – throughout the area: an alarm bell indicating a potential invasive species.
However, before declaring a new species invasive, careful investigation must be done – and the first step is ensuring a definitive identification of the organism. But this seemingly simple question became more vexing as the team pored over botany records: just what WAS this plant? With hundreds of thousands of plants in the world, many with little published information available, plant ID is not an easy task. The team reached out to plant experts on the island and across the state, but no one recognized this one. Samples and photos made their way to various botanists until in 2020 a Smithsonian botanist, working with colleagues from Europe, was able to pronounce that a little-known, low-profile shrub from Central America, Phenax hirtus, had somehow arrived in Hawai‛i.
Phenax taking over the understory
Phenax leaves and growth pattern
Like another recent invader, the Queensland Longhorn Beetle, Phenax hirtus wasn’t known to be a pest anywhere else in the world before it appeared on the Big Island. It is unknown how either arrived here, but most likely it was a “keiki form” (larvae in the case of the beetle, seed for the plant) as an accidental stowaway, quietly arriving in some kind of soil, plant material, or packing crate. These sleeper species will often quietly proliferate and spread, unnoticed until they begin to cause a problem. This can make it difficult to enact a successful eradication plan; without previous research, we don’t always know how to control the pest. Information about the species’ life cycle, reproductive strategies, seed viability, climate tolerance limits – all can be critical to making sure control efforts are effective.
Phenax hirtus has many of the classic characteristics associated with invasive plants: it is shade-tolerant and can grow in undisturbed vegetation, including under a native forest canopy. It has a climbing nature, able to pull itself up over other vegetation to seek light and space. It even finds a way to grow amongst aggressive Himalayan (kāhili) ginger – a known “space hog”! Seeds are tiny and can spread easily on wind or water.
Phenax hirtus overtaking residential landscaping. (Photo: JB Friday)
BIISC crews are working now to control outlier populations of Phenax in the Kaloko Mauka community where it was found and limit it from continuing to spread. Big Island residents are also being asked to be vigilant and take pictures of any suspect plants in other areas of the island. It is a nettle, the same large family as the native māmaki, so the leaves are similar, but generally skinnier and more green (not so much of the reddish veins that are generally present in māmaki). The best way to tell them apart: māmaki produces seeds in a distinctive fleshy white fruit at the end of the leaf node, while Phenax will have a dry brown ball of seeds.
Mamaki fruits (left) are fleshy and white, while Phenax fruits (right) are dry and brown. (Forest & Kim Starr; JB Friday).
In today’s world, some invasive pests are nearly household names in dozens of countries: Asian longhorn beetle, spotted lanternfly, red imported fire ants, giant hogweed. These pests make headlines the minute they appear in a new area. But Hawai’i, while at risk of these notorious invaders, is also uniquely vulnerable to taking a bad turn to invasive behavior. Life in Hawai’i evolved in isolation over millions of years, with a barrier of 2500 miles of open ocean dissuading colonization by new life forms. Biologists estimate that before human contact, a new species established in Hawai’i only about once every 10,000 years. Without the fierce biological competition and predation found on an African savannah or South American rainforest, our native species evolved without many of the defenses and protections that their continental counterparts had long developed.
The year-round temperate weather, novel native ecosystems with open niches, and multiple climate zones of the islands all provide opportunities for introduced species to become problematic in Hawai’i. With more introduced species reaching our shores today than ever before, it is critical to be vigilant and keep an eye out for anything new that appears unexpectedly, potentially posing a problem.
Mamaki leaves (left) tend to be more oval with reddish petioles while Phenax leaves (right) tend to be more narrow and green throughout. Photos: Forest & Kim Starr; JB Friday