The cotton bollworm, also called the Old World bollworm, is a moth whose caterpillars are among the world's worst crop pests, boring into cotton bolls, tomatoes, corn ears, and chickpea pods. It is not established on US farms, though a few moths have been detected in Puerto Rico, Florida, and Illinois since 2014. It looks nearly identical to the native corn earworm.
Appearance
- Appearance
- A stout moth with a wingspan of about 1.2–1.6 in (30–40 mm). Females tend to have yellowish-orange forewings and males greenish-gray ones. The hindwings are pale yellow with a dark brown border.
Look-alikes
You can't tell them apart from photos. The two look nearly identical at every life stage, and only a trained specialist can separate them; the first US record was confirmed with molecular (DNA) methods.
Why they get mixed upThe native corn earworm, found across most of North America, looks the same and feeds on many of the same crops.
Where it lives
- Typical habitats
- crop fields
- vegetable gardens
- greenhouses
- Range
- Native across Europe, Africa, Asia, and Australia. It reached Brazil around 2013 and has since spread through much of South America and into the Caribbean. In the US, a single male moth turned up in a Puerto Rico bean field in 2014, and a few males were trapped in Manatee County, Florida, in 2015; a year of surveys found no more in Florida. Adults were detected next to O'Hare airport in Illinois in 2019, and an eradication program is underway there. It has not been found in US farm areas.
- Migration
- A strong, migratory flier that can travel long distances, which is part of why it spreads to new regions so easily.
Behavior
- Diet
- Caterpillars feed on a very wide range of plants, especially tomato, cotton, pigeon pea, chickpea, rice, sorghum, and cowpea. They burrow into fruits, pods, bolls, and ears.
Life cycle
- Clutch size
- A female can lay several hundred eggs.
- Larva
- Grows to about 1.6 in (40 mm) long. Color ranges from green and yellow to reddish brown, with dark stripes along the back and a pale stripe on each side. Caterpillars sometimes eat each other. Mature caterpillars pupate in the soil about 1.5–4 in (4–10 cm) deep, or inside cotton bolls or corn ears.
Name and classification
- About the name
- Populations in Australia and the Pacific islands are treated as a separate subspecies, H. a. conferta.
Conservation
- IUCN Red List
- NENot EvaluatedNot yet assessed
- Threats
- Many populations already resist common insecticides and several crop toxins, which makes it especially hard to control.
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