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Fruit flies (Diptera: Tephritidae) are important quarantine pests that may cause even up to 100 per cent yield losses in cucurbits. Among them, Zeugodacus cucurbitae (Coquillett) and Dacus ciliatus Loew are the serious pests of cucurbits. Survey was conducted in Coimbatore (11°14'60.00"N; 77°18'60.00"E) and Dharmapuri (40°26.767'N; 79°58.933'W) districts of Tamil Nadu, India, during 2017-2018, in the fields of snake gourd, ridge gourd and bitter gourd. Approximately 10 infested fruits from each vegetable ecosystem were collected and placed in glass cages for 15-20 days. Emerged flies were identified by using the taxonomical keys and confirmed through molecular characterization. The overlapping abdominal tergites are the key character to distinguish the Bactrocera genus from Dacus. Further, the presence of median vittae, r-m cross vein on forewing pecten on the male's abdomen and black facets on the face are the identification characters for Z. cucurbitae. Whereas, D. ciliatus with two facial spots. The amplicon size of collected fruit flies was found to be 480 bp. The population of both Z. cucurbitae and D. ciliatus showed a significantly positive correlation with rainfall and relative humidity. Whereas, it was negative with respect to maximum temperature and sunshine hours in both the locations. [ABSTRACT FROM AUTHOR]

Background: Little leaf disease caused by phytoplasma infection is a significant threat to eggplant (also known as brinjal) cultivation in India. This study focused on the molecular characterisation of the phytoplasma strains and insect vectors responsible for its transmission and screening of brinjal germplasm for resistance to little leaf disease., Results: Surveys conducted across districts in the Tamil Nadu state of India during 2021-2022 showed a higher incidence of phytoplasma during the Zaid (March to June), followed by Kharif (June to November) and Rabi (November to March) seasons with mean incidence ranging from 22 to 27%. As the name indicates, phytoplasma infection results in little leaf (reduction in leaf size), excessive growth of axillary shoots, virescence, phyllody, stunted growth, leaf chlorosis and witches' broom symptoms. PCR amplification with phytoplasma-specific primers confirmed the presence of this pathogen in all symptomatic brinjal plants and in Hishimonus phycitis (leafhopper), providing valuable insights into the role of leafhoppers in disease transmission. BLAST search and phylogenetic analysis revealed the phytoplasma strain as "Candidatus Phytoplasma trifolii". Insect population and disease dynamics are highly influenced by environmental factors such as temperature, relative humidity and rainfall. Further, the evaluation of 22 eggplant accessions revealed immune to highly susceptible responses where over 50% of the entries were highly susceptible. Finally, additive main effect and multiplicative interaction (AMMI) and won-where biplot analyses identified G18 as a best-performing accession for little leaf resistance due to its consistent responses across multiple environments., Conclusions: This research contributes essential information on little leaf incidence, symptoms, transmission and resistance profiles of different brinjal genotypes, which together ensure effective and sustainable management of this important disease of eggplants., (© 2024. Crown.)