Each summer since the release of information about Northern giant hornets being found in Washington state in 2020, Texas A&M AgriLife entomologists have been inundated with questions and reported sightings.

Many insects are being mistaken for the Northern giant hornet.

But these sightings of Northern giant hornets, which were formerly named the Asian giant hornet and commonly called “murder hornet,” are nothing more than cases of mistaken identity, said Molly Keck, Texas A&M AgriLife Extension Service integrated pest management specialist and entomologist, San Antonio.

People are most likely mistaking cicada killers, which are large native Texas wasps, for Northern giant hornets.

Northern giant hornets are not in Texas, and from reports, agencies in Washington state have done a very good job of controlling their numbers and preventing their spread,” she said. “It would be a far leap for them to be in Texas.” Keck said she is mostly receiving phone calls about sightings. But she also receives photos of native cicada killers, also known as ground hornets, submitted as suspected Northern giant hornets.

It’s a bird, it’s a plane … it’s a cicada killer

The Northern giant hornet was recently renamed by the Entomology Society of America and added to the group’s Common Names of Insects and Related Organisms List.

Cicada killer wasp commonly mistaken for the Northern giant hornet

A cicada killer wasp and burrow. These are being confused for Northern giant hornets.

While state agencies want to encourage Texans to be vigilant in watching for the Northern giant hornet, also known as murder hornet, they also want to help provide guidance that will help narrow the focus.

Northern giant hornets are native to Japan and South Korea and have only been found in parts of British Columbia, Canada and the northwestern corner of Washington state.

Summer, cicadas and cicada killers

Summer months are the normal time for the cicada killer wasp, a common large wasp in Texas, to be seen. They typically start showing up in June as their offspring’s main food source – cicadas – emerge.

Cicada killer sightings continue to prompt phone calls, emails, and posts on social media and in news feeds with mistaken identifications.

I don’t know that cicada killers are in higher numbers this year, but people are noticing them and swear they are seeing an Asian giant hornet. It looks like this could happen every summer, especially when cicada killer numbers are peaking.

Pat Porter, Ph.D., AgriLife Extension entomologist in Lubbock, developed a short video explaining the differences between the “murder hornet” and several common lookalikes here in Texas.

To date, we have identified hundreds of insects that people in Texas suspect might be Northern giant hornets (murder hornets). Eighty percent of these have been either the eastern cicada killer or western cicada killer. But it is understandable how non-entomologists might think they saw a Northern giant hornet.

How to tell the difference

There are a number of Texas native species of wasps, hornets, yellow jackets and bees, but what really separates Northern giant hornets and a few of our native species is their size. The flying insects most likely to be confused with Northern giant hornet are the native species of cicada killers and the pigeon horntail.

The Northern giant hornet is the world’s largest known hornet measuring 1.5-2 inches in length. It has a head as wide as its shoulders, where the wings and legs are located, or wider, and it is a bright orange or yellow. The thorax, or shoulder portion where the wings and legs are connected, is a dark brown, as are the antenna. It has a much smaller or pinched waist and then smooth looking brown and orange stripes cover the abdomen.

The cicada killer, of which there are three different species in Texas, are also quite large, measuring 1-1.5 inches in length. But they all typically have a head that is narrower than the thorax. The head and the thorax are typically the same color, a darker orange or brown color. It does also have a pinched waist. But the stripes on the abdomen are irregular and will be jagged and sometimes look like mountains.

The eastern cicada killer tends to be black and yellow. The western cicada killer is closer in color to the Asian giant hornet, being reddish brown and yellow.

The easiest way to identify a cicada killer wasp is the irregular markings on the abdomen.

Not harmful, just alarming

The cicada killer and wood wasps, however, are solitary and thus do not aggressively protect their nesting sites by attacking in large numbers, Keck said. Cicada killers, however, may cause alarm due to the males’ territorial behavior, dive-bombing or buzzing people and animals that walk into their territory.

Although cicada killers are solitary, numerous individuals can often be found in areas with sandy soils where females dig nests in the ground, she said. Nests appear as dime to quarter sized holes in the ground. Females come and go, provisioning their nest with cicadas they paralyze with a sting and carry back to their nests.

Males are more interested in mating. Males are territorial and may try to chase off intruders they perceive as a threat to their mating opportunities. But male wasps are not capable of stinging and are not dangerous.

Cicada killers can be a nuisance for a few weeks out of the year during the nesting season, but they are not a threat to us. Females can sting but are very docile, and reports of stings are rare.

Horntails and wood wasps may have what appear to be very long stingers, but they are unable to sting.

Testing Forages and Hay for Hydrogen Cyanide (Prussic Acid) Potential

In some situations, there may be a desire to test forages or hay for hydrogen cyanide or prussic acid potential. Hydrogen cyanide (HCN) or hydrogen cyanide potential are more appropriate terms and will be used throughout this document. Free hydrogen cyanide is not routinely found in the plant. Instead, the plant contains one or more cyanogenic glycosides that can be converted to hydrogen cyanide by enzymes in the plant or enzymes in the rumen of cattle, which is why the term hydrogen cyanide potential is used.

To evaluate the full hydrogen cyanide potential, it is critical that the testing procedure includes a beta-glucosidase enzyme. The inclusion of this step is necessary because it allows for the most accurate measurement of hydrogen cyanide potential and more closely represents the conditions and changes that would occur within the rumen. ServiTech Laboratories (servitech.com) is the only commercial lab that we are aware of that currently includes both steps and is the lab our group has used to test research and producer samples.

Research conducted near Amarillo in 2021 (Bell and Banta, unpublished data) revealed both hydrogen cyanide potential and nitrates in pearl millet, corn, forage sorghum, and sudangrass samples grown in the same trial. Based on this research and other sampling, if forages are being tested for hydrogen cyanide potential it would be advisable to also test them for nitrates as well. The same sample can be used for both. Cost for hydrogen cyanide, nitrates, and dry matter analysis are currently running about $43 per sample. $25 for prussic acid only.

Interpreting results:

Results should be expressed and evaluated as mg/kg or ppm on a 100% dry matter basis (1 mg/kg = 1 ppm). Unfortunately, testing results can’t guarantee that a forage will be safe to feed. There is limited research in cattle regarding toxic levels of hydrogen cyanide. Additionally, toxicity is a function of cyanogenic glycoside concentration in the forage, rate of forage consumption, and rate of hydrogen cyanide detoxification in the animal. Mammalian species including cattle and humans can detoxify some level of hydrogen cyanide. Toxicity becomes an issue when absorption of hydrogen cyanide exceeds the bodies’ ability to detoxify it. Although testing cannot guarantee safety, knowing the level of hydrogen cyanide potential provides valuable information to make informed decisions regarding the risk level of a particular forage.

Collecting samples:

Hay samples: Use a hay probe to collect and composite samples from at least 8 to 10 representative bales from each cutting or lot of hay, just like would be done for other hay testing analysis. Mix the samples and place the composite sample in a quart sized plastic bag for shipping. Contrary to what has historically been thought, hydrogen cyanide potential can be an issue in some dry hay, even following a substantial post-harvest storage period. Research results from 4 experiments published by Dr. Stuart indicate that increased drying time, conditioning hay, or double conditioning hay did not lower hydrogen cyanide potential when compared with plant samples taken just prior to cutting.

Fresh forage samples: When collecting fresh forage samples, try to minimize bending or cutting of plant tissue until after the plants are dry. Plants should be cut approximately 2 to 4 inches above the ground and collected at random across the field. The number of plants to collect will vary by size. See below for size-dependent reference numbers of plants to collect. Generally, it would be desirable to collect enough sample to provide at least 100 grams of dry tissue for analysis.

• Fresh plant samples can be shipped overnight to the lab. Cut plants into 12 to 24 inch pieces so they will fit into a brown paper grocery bag (preferred) or trash bag. Place the bag in a cardboard box for shipping. Cut samples into as few pieces as possible. Samples absolutely should not be frozen and should not be placed on ice. Placing samples on ice could cause tissue freezing and cell rupture resulting in lower hydrogen cyanide values.

• Alternatively, samples can be dried or partially dried prior to shipping. Partially drying samples by placing them in the sun for a few days works well in many situations. It reduces shipping weight and allows for samples to be shipped with lower cost options compared to overnight shipping. If samples are dried, they can be cut or bent to help with shipping.

Amount of fresh forage sample to collect:

• Plants less than 12 inches tall: Collect about 40 to 60 plants.

• Plants 18 to 30 inches tall: Collect about 15 to 20 plants.

• Plants over 30 inches tall: Collect about 6 to 10 plants.

For additional questions about sampling please contact Dr. Jason Banta, [email protected], or one of the other authors of this publication.

Results usually take about 3 days.

Note: This document reflects the current information and understanding of hydrogen cyanide potential in forages, testing, and risks to cattle and other livestock. However, there is still much to learn about these topics and additional research and technology advancements may change scientific understanding and recommendations in the future.