Cargo ships and air travel are two of the biggest global highways for invasive pests because they move goods — and the hitchhikers hiding in them — faster and farther than ever before.

Here’s why they’re such major spreaders:

1. Pests Hide in Cargo and Packaging

• Wooden pallets, cardboard boxes, and shipping containers are perfect hiding spots for insects like termites, beetles, and ants.
• Soil clinging to machinery or plants can harbor eggs, larvae, or fungal spores.
• Rodents can stow away in food shipments or storage holds.

Example:
The Asian longhorned beetle is believed to have arrived in the US in solid wood packaging from Asia.

2. Global Trade = Global Pest Network

• Cargo ships carry millions of containers each year, linking continents.
• Once a pest reaches a new port, it can escape into local environments where it may have no natural predators.

Example:
The brown marmorated stink bug spread from Asia to Europe and the Americas largely through shipping containers.

3. Speed of Air Travel

• Insects, seeds, and pathogens can survive the short duration of a flight, even without food or water.
• Airplanes also move pests during their peak breeding seasons — spreading them before local authorities detect outbreaks.

Example:
Mosquito species like Aedes aegypti and Aedes albopictus (which transmit dengue and Zika) have been found in aircraft cabins and cargo holds.

4. Ballast Water in Ships

• Cargo ships take in ballast water in one port and release it in another.
• This water can contain invasive aquatic species like zebra mussels, which have caused billions in damage to North American waterways.

5. Lack of Inspection or Detection

• Many pests are microscopic or live deep inside cargo, making them hard to detect during routine inspections.
• Customs authorities can’t inspect every single shipment due to sheer volume.

6. Year-Round Risk

• Unlike natural migration, which follows seasons, trade and air travel happen year-round — giving pests constant opportunities to spread.