Sanitation by removal of diseased trees to reduce insect vectors of laurel wilt

Ambrosia beetle breed in tree trunks, where their immature stages feed upon symbiotic fungi. Xyleborus glabratus Eichhoff (Coleoptera: Curculionidae: Scolytinae) carries a phytopathogenic symbiont, Raffaelea lauricola T.C. Harr., which causes laurel wilt, a lethal disease of trees in some Lauraceae species. Other ambrosia beetles emerging from a R. lauricola infected tree can also carry this pathogen. The effectiveness of tree removal and destruction as a cultural control tactic to reduce the infestations of ambrosia beetles in avocado groves was studied. Wood chipping was an effective control measure to kill beetles and reduce infestations. However, the totality of the tree cannot be chipped because large portions of the tree trunk exceed the capacity of the wood chipper used to destroy the trees. We determined that a large number of beetles survive in large portions of the tree left on the field. Moreover, some of the beetles that survive in these logs can carry the laurel wilt pathogen. Four paint wood covers were tested to determine their effectiveness to reduce ambrosia beetle infestations. Roofing tar reduced beetle emergence from infested logs and prevented ambrosia beetles from boring into the wood better than other paint treatments. To be effective in interrupting the spread of the disease by ambrosia beetles, stems and branches of avocado-laurel wilt infected trees must be destroyed, or be applied with a tar paint as a treatment.