A Severe Outbreak of the Ailanthus Webworm, Atteva fabriciella Swederus (Lepidoptera: Attevidae), on Ailanthus triphysa (Simaroubaceae) in Kerala, India: Taxonomy, Distribution, Biology and Damage Symptoms

A sudden and severe outbreak of the ailanthus webworm, Atteva fabriciella Swederus (Lepidoptera: Attevidae), was recorded on Ailanthus triphysa (Simaroubaceae) at Parakkadavu, Kozhikode district, Kerala, India, between 25 January and 1 February, 2026. Larvae constructed extensive silken leaf webs, resulting in pronounced defoliation and foliar damage. Field surveys revealed abundant caterpillars, pupae, and adult moths. Several individuals who visited the site reported intense itching after contact with dense larval aggregations, suggesting possible dermal irritation linked to larval setae. After feeding, larvae migrated to accumulated dried foliage on the ground or pupated among residual silk masses or under the leaves. The affected host tree was a mature specimen (~60 years old) with a large branching structure. This paper provides anan integrated account of the outbreak, including updated taxonomic context of A. fabriciella, along with global and regional distribution records, known host associations, key aspects of its biology, characteristic damage symptoms, and parasitoids reported from the species. The observations offer valuable baseline data for future monitoring and management of A. fabriciella in forestry, agroforestry, and urban landscape systems. Keywords: Atteva fabriciella; Attevidae; Ailanthus triphysa; outbreak; taxonomy; defoliation; dermal irritation; parasitoids; India