One of the most important tools in detection, pest eradication and integrated pest management systems is diagnostics. When dealing with Insects, traditional taxonomy has relied on morphological characters of various life stages as the primary means of identification. As we learn more about insects and the relationships of species groups, we discover that there are some groupings in which species level separation is extremely difficult (if even possible) when utilizing morphological characteristics. Recent examples of this particular problem can be seen with Bemisia tabaci biotypes (B vs Q) and also with the discernment of passion vine mealybug (Planococcus minor) vs citrus mealybug (Planococcus citri). In the case of the biotype issue, morphological characterstics cannot be used to distinguish the biotypes. Only through the use of molecular techniques can this level of taxonomy be accomplished. In the case of the mealybug, a morphological scoring matrix has been used in the past to distinguish the two species, however a recent scare resulted in the exposure of some inaccuracies in the scoring matrix. Currently, it appears that molecular techniques may be the best option for identifying this invasive species which has not been reported in the United States as of yet.