|Geographic variation in the mycangial mycoflora of Xyleborus glabratus in Florida|
A. S. CAMPBELL (1), R. C. Ploetz (1), P. E. Kendra (2), W. S. Montgomery (2). (1) University of Florida, Homestead, FL, U.S.A.; (2) Subtropical Horticulture Research Station, USDA-ARS, Miami, FL, U.S.A.
Laurel wilt kills <i>Persea borbonia</i> and other American members of the Lauraceae. It is caused by <i>Raffaelea lauricola</i>, a fungal symbiont of an exotic ambrosia beetle, <i>Xyleborus glabratus</i>. <i>R. lauricola</i> and other fungi were quantified in <i>X. glabratrus</i> collected from three locations in Florida. A Miami-Dade Co. (MDC) site, 25.8<i>º</i>N, was populated by <i>P. palustris</i>, a Highlands Co. (HC) site, 27.9<i>º</i>N, by <i>P. borbonia,</i> <i>P. humulis</i> and <i>P. palustris</i>, and an Alachua Co. (AC) site, 29.8<i>º</i>N, by <i>P. borbonia.</i> Mycangia from individual females were macerated and plated on CSMA and ½ PDA. Seven putative taxa were identified based on identical LSU genotypes and colony phenotypes. With the exception of <i>R. lauricola</i> and <i>Zygozyma oligophaga</i>, it was not possible to match LSU genotypes/sequences with those deposited in GenBank, as the remaining taxa were 98 to 99% similar to two or more species of <i>Fragosphaeria</i>, <i>Leptographium</i>, <i>Grosmannia</i> and/or <i>Ophiostoma</i>. The numbers of <i>R. lauricola</i> colony forming units (CFUs) in <i>X. glabratrus</i> varied by location (p<0.0003), as beetles from MDC had more CFUs (3,532) than those from HC (2,593) and AC (1,829). The numbers of fungal species also differed by location (p<.0001), as 80% of the individuals from AC and MDC carried ≥3 species, compared to 31% of those from HC. The results indicate that climate and vegetation may affect fungal diversity and the relative abundance of <i>R. lauricola</i> in the mycangia of <i>X. glabratus</i>.