Why Are Caterpillars Eating My Artichoke Leaves?

Artichoke plants are large and tough enough to tolerate moderate caterpillar feeding on the outer leaves without serious harm. The situation becomes a genuine problem when caterpillars bore into the developing heads — making them inedible — or when very young plants are attacked before they have established a strong root system and enough leaf area to compensate. Identifying which species is responsible helps determine the best control approach.

Painted lady butterfly larvae

Artichokes are a preferred host plant for painted lady butterfly caterpillars (Vanessa cardui). The larvae spin silky webs at the tips of leaves, drawing the tips together into a protective tent inside which the caterpillar feeds. The outer leaves show areas of dry, web-covered damaged tissue. While damaging to the affected leaf, this rarely harms an established plant seriously. The butterflies are beautiful and valuable pollinators — if the infestation is not severe, tolerating it is a reasonable response. For significant infestations, physically remove webbed leaf tips containing caterpillars.

Various noctuid moth larvae

Several species of noctuid moth (cutworms and related species) may feed on artichoke leaves, particularly at night. The damage appears as large, ragged holes or completely eaten leaf sections. These larvae are often found in the soil during the day, emerging at night to feed. Physical removal (night patrol with a torch) and beneficial nematode treatment of the soil (Steinernema carpocapsae for cutworms) are effective controls.

Protection of heads

The most problematic caterpillar damage is boring into developing heads. Once inside a head the caterpillar is very difficult to reach. Soaking harvested heads in salted water before cooking (as for aphids) dislodges any insects from between the scales. Check heads regularly — particularly between the scales of forming heads — and remove any caterpillars you find.

Biological insecticide

Bacillus thuringiensis (Bt) is a biological insecticide that kills caterpillars specifically without affecting other insects. It is approved for organic use and is available as a spray. Apply to the leaves and into any forming heads if caterpillar infestation is severe. It is most effective on young, actively feeding caterpillars.