Pest Management Professional, August 2017
Photo wikimedia Commons h Zell Rodent management Roof rats with a sweet tooth Rattus rattus might be associated with grain but they love citrus fruit too follow the clues the rats leave behind as they feast on orange trees By Dr Hanif GulmaHamaD BCE EmEritus PCa Contributor A t one time three color variants of roof rats were recognized They were known by the following subspecies names Roof gray bellied or Alexandrine rat Rattus rattus alexandrinus Black or ship rat R rattus rattus White bellied rat R rattus frugivorus These are no longer considered to be valid subspecies because all of these color variants interbreed What is interesting however is the name frugivorus indicates this group feeds on fruits Over the years I have had customers who insisted on referring to roof rats as fruit rats because their experiences with this rodent in southern California have been of these animals depredating fruits in backyard trees The roof rat is essentially an arboreal species that travels and navigates dexterously in trees shrubs vines and other woody ornamentals It has extra footpads on the bottom of its feet that enable it to maintain footing on narrow vines and branches Its tail is longer than its head and body combined and although its not prehensile capable of grasping the tail aids in balancing when this rodent navigates in high locations and travels on wires The problem Early this spring I began to notice hollowed out Valencia oranges under one of my backyard trees see Fig 1 I examined a number of these oranges and had some difficulty figuring out who was responsible for the damage I knew what pest it wasnt In the past a possum had visited our yard at night and eaten some orange fruits that had fallen to the ground A possum has 50 teeth which is more than any other land mammal Eighteen of these are incisors which are located in the front of its jaws These teeth did not evolve for the purpose of eating fruits As a result possums are messy eaters when they try to eat citrus fruits This time around the oranges were picked clean I also knew it wasnt a bird Fig 2 shows four citrus fruits on the left that were damaged by roof rats The nectarine on the right was damaged by a house finch Carpodacus mexicanus one of the most injurious bird species of soft fruits in California Note the peck marks on this fruit Beakers tend 48 August 2017 Pest Management Professional mypmp net
You must have JavaScript enabled to view digital editions.
