Hymenopteran parasitoids of black-headed caterpillar Opisina arenosella Walker (Lepidoptera: Xyloryctidae) in South India

The coconut Black Headed Caterpillar (BHC), Opisina arenosella Walker (Lepidoptera: Xyloryctidae), poses a significant threat to coconut plantations in South India. The present study investigates the diversity and prevalence of hymenopteran parasitoids associated with O. arenosella. BHC larvae and pupae were collected from 15 locations spread across 9 districts of Tamil Nadu. Life stages of BHC were reared to observe the emergence of parasitoids. A total of six parasitoids viz., Antrocephalus hakonensis (Ashmead), Brachymeria nephantidis Gahan, Kriechbaumerella sp. (Family: Chalcididae), Apanteles sp. (Family: Braconidae), Goniozus nephantidis Muesebeck (Family: Bethylidae) and Xanthopimpla punctata Fabricius (Family: Ichneumonidae) were found to be associated with larvae and pupae of BHC. This study provides the first documented evidence of Kriechbaumerella sp. parasitizing BHC pupae. The level of natural parasitisation by various parasitoid species varied across different sampling locations. Highest natural parasitisation (31.64 %) of BHC was noticed in Tiruppur district. Field surveys and laboratory rearing of collected specimens highlight the potential of these parasitoids for biological control, contributing valuable data towards integrated pest management strategies. Further research into the life cycles, host specificity and ecological interactions of these parasitoids is recommended to enhance their utilization in sustainable agriculture practices

Management of the maize weevil (Sitophilus oryzae L.) using turmeric (Curcuma longa) essential oil

Among the various insect pests infesting stored maize, the rice weevil, Sitophilus oryzae L. (Coleoptera: Curculionidae), is one of the most destructive pests, capable of causing 100 % infestation and significant qualitative losses. Essential oils (EOs) from botanicals are considered eco-friendly as they show promise against several stored product pests including S. oryzae without leaving any non-toxic residues in the final product. This study aims to evaluate the potential insecticidal effects of essential oil of turmeric, Curcuma longa against S. oryzae under laboratory conditions. A maximum adult mortality of 90.0 % was recorded in fumigant toxicity tests at 65 μL/96 cm³ after 5 days of exposure. Under contact toxicity conditions, 99.13 % mortality was observed at 70 μL after 5 days. Fumigant and contact toxicity tests revealed an LC50 of 60.39 μL and 65.61 μL, respectively, against adults of S. oryzae. At the same concentration (70 μL),turmeric EO observed complete reduction of oviposition and adult emergence. These findings indicate that turmeric EO possesses strong insecticidal properties and could serve as an effective and environmentally safe alternative to synthetic fumigants for the management of S. oryzae in stored maize grains

Essential oil of garlic, Allium sativum L.: A promising alternative for the management of Sitophilus oryzae (L.)

The study evaluates the effectiveness of garlic essential oil as a fumigant and contact toxicant against adult rice weevils (Sitophilus oryzae L.) (Curculionidae: Coleoptera). Garlic essential oil demonstrated significant fumigant toxicity, causing 56.67% adult mortality at a concentration of 3 µl/96 cm³ air on the first day, which increased to 99.13% by the fifth day after treatment (DAT). In addition, garlic essential oil exhibited contact toxicity, achieving up to 100% mortality at doses of 4 and 5 µl/40 g seeds. Even at lower concentrations (1 µl), mortality rates were as high as 78.33%. The calculated LC50 value was 2.58 µl/40 g of seeds. Garlic essential oil also had a considerable effect on reproduction, as no adults emergence was observed from seeds treated with 4 µl/40 g. GC-EAD analysis identified 39 compounds in garlic essential oil, with male and female S. oryzae exhibiting different antennal responses. Females displayed stronger reactions to alcohols and esters, while males were more responsive to alkenes and alkanes. The presence of chemical constituents in garlic essential oil that influence insect behaviour underscores its potential as a viable pest management solution against stored-product pests. Further exploration of these compounds for their insecticidal properties using GC-EAD studies and their development into the formulations could provide significant benefits to farmers and contribute to sustainable pest management practices

Abundance and diversity of Odonata in temporary water bodies of Coimbatore and Salem districts in Tamil Nadu

Odonata diversity was assessed in 13 temporary water bodies of Coimbatore and Salem districts in Tamil Nadu. Assessment revealed the presence of 21 species of Odonata (14 species of Anisoptera and seven species of Zygoptera) belonging to 17 genera under four families. Libellulidae (Anisoptera) was represented by the maximum number of species and individuals. Pantala flavescens (Libellulidae) was the most abundant among 21 species. Among the temporary water bodies, the maximum number of individuals as well as species was recorded from Utkulam tank (Coimbatore district). Odonata diversity was higher in Kamalapuram tanks 1 and 2 (Salem district) and lower in Ukkadam tank (Coimbatore District). Diplacodes trivialis (Rambur), Orthetrum sabina (Drury) and Pantala flavescens (Fabricius) were identified as temporary water body specialists because of their presence in all the 13 temporary water bodies sampled

Abundance and Diversity of Odonata (Insecta) in Some Hilly Regions of Tamil Nadu

Volume: 105Start Page: 352End Page: 35