citricida, the oriental citrus aphid. Toxoptera citricida had been found in East Asia and South America, and had slowly made its way up through Central America and the Caribbean Islands. By 1993 it had reached Cuba, and in 1995 it was found in Florida. The aphids require at least 30 to 60 minutes of feeding to acquire the virus, and remain viruliferous for at least 24 hours after. T. citricida is much more efficient than the other aphids, and it can transmit CTV strains causing severe stem pitting or decline that the other aphids cannot vector. Even though A. spiraecola is less efficient, it tends to have higher populations and thus can still transfer the virus fairly well. T. aurantii has been shown to only transmit certain strains of CTV. Of the three lesser efficient aphids, A. gossypii has a 78% transmission efficiency, while A. spiraecola and T. aurantii are between 0-6%. There is laboratory evidence that the psyllid Diaphorina citri may also be a relevant vector. The main cultural practice that increases the severity of the CTV is when the citrus trees are grafted onto the sour orange rootstock. Using CTV infected budwood for grafting can transfer the CTV from the original tree to the new one. Management When CTV was first discovered quarantine was the best management strategy, now quarantining only works for areas where a small amount of trees are infected. The other approach that was adopted after T. citricida came to the U.S. was destroying any tree in which the budwood was not free of CTV. This is a more drastic measure but must be done due to how fast T. citricida can spread the virus. If there is any CTV in the area, avoid grafting trees on sour orange rootstock and instead graft on tristeza-tolerant rootstock. Since the virus has been in Asia a long time they have used rootstock from trifoliate orange, Sunki, and Shiikuwasha (C. × depressa) for many years. Some hybrids, such as Troyer citrange or Swingle citromelo, show promise as resistant root-stock. Also, using scion varieties tolerant to stem pitting is recommended. The production of virus-free trees by shoot-tip grafting or heat treatment is very important. If it is possible to keep the field permanently free of CTV, the planting of virus-free trees is practical. In areas where it is difficult to find a virus-free field, preinoculation with a mild CTV