International Journal of Tropical Insect Science (2006) 26, 48-56

G.V.P. Reddy and P. Baskaran (2006)
Damage potential of the spider mite Tetranychus ludeni (Acari: Tetranychidae) on four varieties of eggplant
International Journal of Tropical Insect Science 26 (1), 48-56
Abstract: The damage potential of the spider mite Tetranychus ludeni Zacher was studied on 20-65-day-old seedlings of four eggplant Solanum melongena varieties: Madurai (MDU₁), Coimbatore (CO₁), Annamalai and Panruti at introduction levels of 2, 5, 10 and 15 mites/leaf. The average seedling mortality among varieties was lowest at the introduction level of two mites and maximum at the introduction level of 15 mites/leaf. The overall seedling mortality was 23% when the four levels of mite population were introduced on 20-day-old seedlings, and only 14% on 30-day-old seedlings. Among the different varieties, the MDU₁ seedlings recorded higher mortality (1.6%) and Panruti the lowest (0.3%). The percentage losses in total plant height, number of leaves, number of flowers and fruits and fruit weight due to mite attack were highest (37-50%) in MDU₁ and lowest (7-11%) in the variety Panruti. The other two varieties CO₁ and Annamalai were found to be intermediate between Panruti and MDU₁. The inoculated mites at different levels multiplied greatly on the variety MDU₁ followed by CO₁, Annamalai and Panruti. The extent of damage was higher in 35-day-old plants, when mites were introduced on 35- and 65-day-old seedlings. Therefore, the variety Panruti is recommended for cultivation in the study area in view of its resistance to T. ludeni.

On a e´tudie´ les de´ga^ts potentiels de l' acarien Tetranychus ludeni Zacher sur des plantules d' aubergine Solanum melongena, a^ge´es de 20 à 65 jours, sur les quatre varie´te´s Madurai (MDU₁), Coimbatore (CO₁), Annamalai et Panruti et pour des niveaux d'infestation de 2, 5, 10 et 15 acariens/feuille. La mortalite´ moyenne des plantules est minimale pour 2 acariens/feuille et maximale pour 15 acariens/feuille. La mortalite´ totale des plantules est de 23% sur des plantules a^ge´es de 20 jours et seulement de 14% sur des plantules a^ge´es de 30 jours. Parmi les diffe´rentes varie´te´s, on a enregistre´ la plus forte mortalite´ (1.6%) sur les plantules de MDU₁ et la plus faible (0.3%) sur les plantules de Panruti. Les pourcentages de pertes en taille, nombre de feuilles nombre de fleurs et fruits et poids des fruits sont maxima (37-50%) sur MDU et minima (7-11%) sur Panruti. Sur les deux autres varie´te´s, CO₁ et Annamalai , on a enregistre´ des pertes interme´diaires. Les de´ga^ts sont maxima sur les plantes a^ge´es de 35 jours, lorsque les acariens ont e´te´ inocule´s sur des plantules a^ge´es de 35 à 65 jours. En conse´quence, la culture de la varie´te´ Panruti est recommandee´ dans la zone d'e´tude compte tenu de sa re´sistance à T. ludeni.
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Link to article at publishers website
Database assignments for author(s): Gadi V. P. Reddy

Research topic(s) for pests/diseases/weeds:
damage/losses/economics
resistance/tolerance/defence of host

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Tetranychus ludeni	Eggplant (Solanum melongena)