Catalpa worms also known as catawba worms are the larvae of the catalpa sphinx moth (Ceratomia catalpae). These caterpillars are well-known for their role as excellent fishing bait and their relationship with catalpa trees (Catalpa spp.).
Understanding when catalpa worms emerge can help fishermen gardeners and nature enthusiasts predict their appearance and make the most of their seasonal abundance. In this topic we will discuss the life cycle of catalpa worms their seasonal patterns and the factors that influence their emergence.
Life Cycle of Catalpa Worms
Catalpa worms go through four main stages of development:
- Egg Stage – Female moths lay eggs on the underside of catalpa leaves.
- Larval Stage (Catalpa Worms) – The caterpillars hatch grow and feed on the tree’s leaves.
- Pupal Stage – The worms burrow into the soil and form cocoons.
- Adult Stage (Catalpa Sphinx Moth) – The moth emerges mates and lays eggs to begin the cycle again.
When Do Catalpa Worms Emerge?
Seasonal Patterns
Catalpa worms typically emerge in late spring and summer depending on climate and geographical location. Their activity follows a predictable cycle:
✔ First Generation: Appears in May or June when temperatures rise and catalpa trees are in full leaf.
✔ Second Generation: Occurs in July or August especially in warm regions.
✔ Third Generation (in warmer climates): Some areas may see a final wave in September or October.
Climate and Regional Variations
✔ Southern U.S. (e.g. Alabama Georgia Florida Texas): Catalpa worms often appear earlier in spring (April-May) and may have three full generations per year due to warm temperatures.
✔ Midwestern and Northern U.S. (e.g. Ohio Kentucky Missouri): The first emergence typically occurs in late May or early June with fewer generations per year.
Temperature and Weather Effects
Catalpa worms are highly dependent on temperature. Warmer springs lead to earlier emergence while cooler or wetter conditions can delay their appearance.
✔ Mild winters and early springs = Earlier emergence.
✔ Cold or prolonged wet weather = Delayed hatching and slower development.
✔ Drought conditions = Can reduce caterpillar survival rates.
Where Do Catalpa Worms Come From?
Catalpa worms originate from eggs laid by the catalpa sphinx moth. After hatching the small caterpillars begin to feed on catalpa leaves growing quickly over a period of 2-3 weeks before dropping to the ground and pupating.
Egg Laying and Hatching
✔ Female moths lay clusters of 100-1000 eggs on catalpa leaves.
✔ Eggs hatch within 5-7 days depending on temperature.
✔ Newly hatched caterpillars start feeding immediately.
Pupation and Overwintering
✔ Mature caterpillars burrow into loose soil and pupate.
✔ If conditions are right they emerge as moths within a few weeks.
✔ In colder months pupae remain underground until the following spring.
Signs That Catalpa Worms Are Emerging
To predict when catalpa worms will come out watch for these key signs:
✔ Catalpa trees leafing out – The worms only feed on fresh catalpa leaves.
✔ Catalpa sphinx moths flying at night – More moth activity means eggs are being laid.
✔ Clusters of tiny eggs on catalpa leaves – Eggs hatch within a week.
✔ Small black-and-yellow caterpillars – The first sign of feeding larvae.
How to Attract and Manage Catalpa Worms
If you want to encourage catalpa worms for fishing bait or natural observation follow these tips:
✔ Plant catalpa trees – The worms only feed on catalpa leaves.
✔ Avoid pesticide use – Chemicals can harm both eggs and caterpillars.
✔ Check trees frequently – Look for eggs and larvae during warm months.
However if catalpa worms are defoliating your trees consider:
✔ Hand-picking worms – Effective for small infestations.
✔ Encouraging natural predators – Birds and parasitic wasps help control populations.
✔ Using organic insecticides sparingly – Only when absolutely necessary.
Why Are Catalpa Worms Important?
1. Excellent Fishing Bait
✔ Catalpa worms are highly prized by anglers especially for catching catfish bass and bream.
✔ The caterpillars’ juicy insides and strong scent attract fish effectively.
✔ Many fishermen freeze catalpa worms to use as bait year-round.
2. Natural Defoliators
✔ While they can strip catalpa trees of leaves the trees usually recover quickly.
✔ Catalpa trees have co-evolved with these caterpillars and can withstand defoliation.
3. Part of the Ecosystem
✔ Birds wasps and other insects depend on catalpa worms as a food source.
✔ Catalpa sphinx moths contribute to pollination.
Catalpa worms emerge in late spring and summer with two or three generations per year in warmer regions. Their activity depends on temperature climate and catalpa tree growth.
✔ First wave: May-June.
✔ Second wave: July-August.
✔ Third wave (if warm enough): September-October.
These caterpillars play an important role in the ecosystem and serve as one of the best natural fishing baits. By understanding their life cycle and emergence patterns you can effectively predict and utilize their appearance each year.
