Family. Tenthredinidae.
Order. Hymenoptera.
Common name. Mustard sawfly, kerawai daun sawi (Indonesia).
Distribution. Japan, South China, South India, Indonesia, Korea, Myanmar, Taiwan.
Host plants. Plants of the family Brassicaceae such as Brassica juncea (L.), B. napus L., B. nigra (L.), B. rapa L., Lepidium sativum L., and Raphanus rapanistrum L.
Description and biology. The adult wasp is orange-yellow with black markings on the body. It has smoky wings with black veins and a body length of 7-8 mm (Figure 1).
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| Figure 1. Adult of Athalia proxima (Photo: © Aunu Rauf) |
Each egg is laid individually and inserted into leaf tissues using a saw-like ovipositor. The eggs have a cream color and typically hatch within 3-4 days. The larvae are dark gray and have three thoracic legs and eight pairs of abdominal legs (Figure 2). When fully grown, the larvae can measure between 16-20 mm in length.
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| Figure 2. Larvae of Athalia proxima (Photo: © Aunu Rauf) |
They pass through five instars in males and six instars in females. When touched, the larvae suddenly fall to the ground and display feign death behavior. The total duration of the larval stage varies from 20 to 30 days. Pupation occurs in an oval cocoon in the soil, and the pupal stage lasts for 8 to 12 days. The entire life cycle of these insects is completed within 30 to 38 days.
Nature of damage. Larvae are active during the day and typically feed on all leaves except the midrib (Figure 3), mostly in the early morning and evening hours.
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| Figure 3. Radish crop damaged by Athalia proxima (Photo: © Aunu Rauf) |
Remarks. Sawflies are rare insects in Indonesia. I only found Athalia proxima in the highlands at an altitude of 1,500 meters.
Abe M. 1988. A biosystematic study of the genus Athalia Leach of Japan (Hymenoptera: Tenthredinidae). Esakia (6): 91-131.
Atwal AS, Dhaliwal GS. 1997. Agricultural Pests of South Asia and Their Management. New Delhi: Kalyani Publishers.
Haris A. 2007. Sawflies (Hymenoptera: Symphyta, Tenthredinidae) from Indonesia, Malaysia and Vietnam. Zool Med Leiden 81(8): 149-159.
Muniappan R., Shepard BM, Carner GR, Ooi PAC. 2012. Arthropod Pests of Horticultural Crops in Tropical Asia. Oxfordshire (UK): CABI.
Park B, Choi J-K, Wei M, Lee J-W. 2017. A taxonomic review of the genus Athalia (Hymenoptera: Tenthredinidae: Athaliinae) from South Korea. Anim Syst Evol Divers 32(2): 100-111.
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