Summer is here and fruit trees are nearer to producing their delicious cornucopia of juicy, sweet delicacies ripening in back yards across Florida.  Yet humans are not the only creatures waiting.  An amazing number of insects enjoy fruit just as much as we do. Aphid, whiteflies, scales and psyllids are potential threats to your trees, and knowing what to look for can save not only the fruit but, sometimes, the tree itself. Aphids are tiny insects that come in green, reddish-brown, black or gray.  They are identified by their small size and tendency to infest the bottom of tree leaves.  If your tree has aphids, you will likely see a sooty mold that precipitates a white sticky substance called honeydew. The whitefly is another scourge to be on the lookout for, and are very similar to aphids in behavior and result.  Their presence, in large enough numbers, will also produce mold.  They are identified by their diminutive size and white appearance. Like aphids and whiteflies, scales also produce mold.  In Florida, where fruit trees abound, there are three types:  wax scale, purple scale and soft brown scale.  Their presence leaves trees weakened and leads to a fruit of low quality.   Regular maintenance of your trees requires observation, which should happen weekly.  In most cases, once a problem is identified, it is often manageable with swift and appropriate intervention.  Asian psyllids are another issue altogether, however.  This invasive species attacks all types of citrus and once identified, the tree must be destroyed and removed.