Citrus leprosis disease

CiLV-N RNA2 (5,847 nt) contains one ORF encoding the RNA-dependent RNA polymerase (RdRp) replication module.

The structure of the CiLV-C2 genome closely resembles the genome organization of CiLV-C. CiLV-C2 RNA1 have two ORFs encoding a large polyprotein (285 kDa), putative involve in virus replication, with five conserved domains (two methyltransferase, protease, helicase and RdRp); and a putative coat protein (CP) of 29 kDa.

[6] CiLV-N probably belongs to the proposed genus Dichorhavirus, related to the family Rhabdoviridae, which has Orchid fleck virus (OFV) as the type member.

In leaves, characteristic lesions are often circular (from 5 to 12 millimetres (3⁄16 to 15⁄32 in) in diameter), chlorotic or necrotic, colored light yellow to dark brown.

[14] In young stems, lesions are small, chlorotic and shallow; with time they become darker brown or reddish and prominent.

[14] In fruits, dark and depressed lesions are found in large numbers and affecting only the external part.

[18] Because of its widespread occurrence and potential for high damage, the disease can cause 100% yield losses, depending on the susceptibility of the citrus variety, isolate and control of the vector.

Presence of CiLV-N and CiLV-C particles in affected tissue can be confirmed by transmission electron microscopy (TEM).

[6][30][31][32] CL was initially described in what is now Philippe Park, Florida in 1907 by Fawett who called it "scaly bark" and "nail-head rust".

[33][34] However, the disease appears to have disappeared from Florida since the 1960s,[35][33] perhaps due to reduction of vector population caused by freezing weather and intensive sulfur application.

[40] CiLV-C has been detected in Bolivia, Venezuela, and Colombia, and it is spreading northward through Panama, Costa Rica, Nicaragua, Guatemala, Honduras, El Salvador, and Mexico.

[41][45] Virus inoculum can be reduced implementing some cultural practices as remove affected branches, use of windbreaks to decrease vector wind spread, control of weeds (alternative mite hosts), use of healthy plants sources, and controlling the movement of people and material in orchard.

One study developed using a hybrid population suggests that inheritance of resistance to leprosis may be controlled by only a few genes.