| Species: | Tetranychus ludeni | |
| Genera: | Tetranychus | |
| Family: | Tetranychidae | |
| Distribution: | Kenya, Madagascar, Malawi, Mauritius, Mozambique, South Africa, Swaziland, Zambia, Zimbabwe, Australia, New Zealand, Fiji, USA, France, Mexico, Argentina Brazil, Chile, Colombia, Costa Rica, El Salvador, Honduras, Nicaragua, Paraguay, Venezuela, China, India, Japan, Taiwan, Thailand, Algeria, Spain, Egypt, Germany, Greece, Iraq, Israel, Portugal, Morocco, Spain | |
| Host Crops: | More than 330 crops belonging to families Acanthaceae, Aizoaceae, Amaranthaceae, Apiaceae (Umbelliferae), Apocynaceae, Araceae, Araliaceae, Arecaceae (Palmae), Asteraceae, Balsaminaceae, Bignoniaceae, Brassicaceae (Cruciferae), Caprifoliaceae, Caricaceae, Caryophyllaceae, Chenopodiaceae, Commelinaceae, Convolvulaceae, Cucurbitaceae, Dipterocarpaceae, Euphorbiaceae, Fabaceae, Geraniaceae, Gesneriaceae, Iridaceae, Juglandaceae, Lamiaceae (Labiatae), Lardizabalaceae, Lobeliaceae, Malvaceae, Moraceae, Musaceae, Myoporaceae, Myrtaceae, Nyctaginaceae, Oleaceae, Oxalidaceae, Passifloraceae, Piperaceae, Poaceae, Polypodiaceae, Pontederiaceae, Primulaceae, Proteaceae, Rosaceae, Rubiaceae, Rutaceae, Salicaceae, Sapindaceae, Saxifragaceae, Scrophulariaceae, Solanaceae, Tiliaceae, Ulmaceae, Urticaceae, Verbenaceae, Violaceae, Vitaceae Important crops are anjeer, beans, ber, brinjal, castor, coconut, cowpea, cucurbits, mulberry, okra, potato, pumpkin, tori, water melon and many other vegetable and fruit crops. | |
| Nature of Damage: | The mites often infest the upper surface of the leaves causes yellowing of leaves followed by formation of necrotic patches and drying up. Yellow-bronze leaves in beans due to mite infestation. In mulberry, white specks are formed which are enlarged to form large patches and give rusty, dry look. It is also a vector of Dolichos Enation Mosaic Virus. Losses in total plant height, number of leaves, number of flowers and fruits and fruit weight due to mite attack. The extent of damage was higher in 35-day-old egg plant seedlings. Penetration of cells by mite stylets and injection of saliva cause both mechanical damage and changes in cell cytology and physiological and biochemical processes of non-punctured adjacent cells. In leaves damaged by mites, degeneration of chloroplast structure, reduction in stomatal (day time) transpiration and increase in cuticular (night time) transpiration occur thereby reducing leaf gas exchange and inhibition of photosynthesis. It becomes more severe during summer months particularly during April to June, resulting in significant yield loss. Stratawise, maximum population of mites was recorded from the middle strata followed by top and bottom strata. | |
| Life Cycle: | There are five stages in the life cycle of these mites i.e. egg, larva, protonymph, deutonymph and adult stage. This polyphagous mite lays 165 eggs/ female on French beans with male: female ratio of 1:27. Pre oviposition and developmental period is recorded as 1.54 and 11.5 days, respectively. The parthenogenetic development required comparatively shorter duration than sexual ones. The larva/nymph entering quiescence selected a suitable site under the webbing and moved in close proximity and gradually became stationary close to each other. The process of moulting is completed within 20 to 25 minutes. Copulation in this species occurred immediately after the final moult of the female deutonymph. The males emerged earlier than the females and were found guarding the quiescent female deutonymphs and copulating with the female immediately after the emergence of the latter. | |