First report of Citrus tristeza closterovirus in Guadeloupe
In Guadeloupe, citrus is mainly cultivated on Basse-Terre (south and south-west of the Island). The volume of production is relatively small but citrus is nevertheless a key element in a crop diversification programme which has been initiated in Guadeloupe. The main species grown are Tahiti limes (Citrus latifolia), sweet oranges (C. sinensis), and mandarins (C. reticulata). In Guadeloupe, Toxoptera citricida (Homoptera: Aphididae - EPPO A1 list) was first identified in 1991 and rapidly colonized all citrus-growing areas. Citrus tristeza closterovirus (CTV – EPPO A2 list) was detected for the first time in 1997 on a few lime trees showing mild symptoms (leaf vein clearing and stem pitting). In 1999/2000, 506 citrus trees from 20 orchards were sampled and tested. The orchards studied had been planted before 1995, mainly with lime but also orange, mandarin and grapefruit trees grafted on rootstocks susceptible to CTV (C. aurantium and C. macrophylla). Immunoprinting tests showed that 42% of the trees were infected. CTV was found in 18 orchards and affected all Citrus species, but more particularly Tahiti lime. In 1999, CTV was also detected in mother trees and grafted trees in nurseries. Another survey done in 2002 in the previously studied orchards showed progression of the disease, as newly infected trees were found. It is concluded that CTV is now established in the main citrus-growing areas of Guadeloupe. Research and extension services are recommending growers to use new CTV-tolerant rootstocks, and financial support is provided for establishment of new orchards. In parallel, a certification programme is currently being developed to provide growers with virus-free planting material.
The situation of CTV is Guadeloupe can be described as follows: Present, first found in 1997 and now established in all citrus-growing regions, under official control.
Sources
Urbino C, Le Bellec F, Fournier F, Bruyère S, Ramassamy M, Chidiac A, Deroche J, Monnerville G (2004) La maladie de la tristeza des agrumes est en Guadeloupe. La production de plants de qualité s’impose.
Phytoma – La Défense des Végétaux, n° 573, 26-27.