Neither insects nor wind: ambophily in dioecious Chamaedorea palms (Arecaceae).

Pollination of Neotropical dioecious trees is commonly related to generalist insects. Similar data for non-tree species with separated genders are inconclusive. Recent studies on pollination of dioecious Chamaedorea palms (Arecaceae) suggest that species are either insect- or wind-pollinated. However, the wide variety of inflorescence and floral attributes within the genus suggests mixed pollination mode involving entomophily and anemophily. To evaluate this hypothesis, we studied the pollination of Chamaedorea costaricana, C. macrospadix, C. pinnatifrons and C. tepejilote in two montane forests in Costa Rica. A complementary morphological analysis of floral traits was carried out to distinguish species groups within the genus according to their most probable pollination mechanism. We conducted pollinator exclusion experiments, field observations on visitors to pistillate and staminate inflorescences, and trapped airborne pollen. A cluster analysis using 18 floral traits selected for their association with wind and insect pollination syndromes was carried out using 52 Chamaedorea species. Exclusion experiments showed that both wind and insects, mostly thrips (Thysanoptera), pollinated the studied species. Thrips used staminate inflorescences as brood sites and pollinated pistillate flowers by deception. Insects caught on pistillate inflorescences transported pollen, while traps proved that pollen is wind-borne. Our empirical findings clearly suggest that pollination of dioecious Chamaedorea palms is likely to involve both insects and wind. A cluster analysis showed that the majority of studied species have a combination of floral traits that allow for both pollination modes. Our pollination experiments and morphological analysis both suggest that while some species may be completely entomophilous or anemophilous, ambophily might be a common condition within Chamaedorea. Our results propose a higher diversity of pollination mechanisms of Neotropical dioecious species than previously suggested.

First Report of Multiple Species of the Botryosphaeriaceae Causing Bot Canker Disease of Indian Laurel-Leaf Fig in California.

Indian laurel-leaf fig (Ficus microcarpa L.) is a commonly used indoor and outdoor ornamental tree. F. microcarpa is most frequently encountered as lining city streets, especially in warmer southern California climates. A disease known as 'Sooty Canker,' caused by the fungus Nattrassia mangiferae (Syd. & P. Syd) B. Sutton & Dyko, is particularly devastating on F. microcarpa. Disease symptoms are characterized by branch dieback, crown thinning, and if the disease progresses to the trunk, eventual tree death (2). Recent taxonomic revisions have renamed Nattrassia mangiferae as Neofusicoccum mangiferae (Syd. & P. Syd.) Crous, Slippers & A. J. L. Phillips (1). An initial survey conducted during the spring of 2011 across four cities in Los Angeles County included, Culver City, Lakewood, Santa Monica, and Whittier. Five symptomatic branches per city were collected from trees showing branch cankers and dieback. Pieces of symptomatic tissue (2 mm2) were plated onto one-half-strength potato dextrose agar. Most isolates initially identified by morphological characteristics, such as growth pattern, speed of growth, and colony color, resembled those in the Botryosphaeriaceae (4). Two representative isolates from each site location were sequenced. Sequences obtained from amplification of the internal transcribed spacer region (ITS1-5.8rDNA-ITS2) and the ß-tubulin gene were compared in a BLAST search in GenBank. Results identified isolates as Botryosphaeria dothidea (identity of 99% to EF638767 and 100% to JN183856.1 for ITS and ß-tubulin, respectively); Neofusicoccum luteum (100% to EU650669 and 100% to HQ392752); N. mediterraneum (100% to HM443605 and 99% to GU251836); and N. parvum (100% to GU188010 and 100% to HQ392766) and have been deposited in GenBank with the following accession numbers: JN543668 to JN543671 (ITS) and JQ080549 to JQ080552 (ß-tubulin). Pathogenicity tests were conducted in the greenhouse on 6-month-old F. microcarpa with one isolate from each previously listed fungal species. Five plants per isolate were stem-wound inoculated with mycelial plugs and wrapped with Parafilm. Uncolonized agar plugs were used as a control. Inoculations were later repeated a second time in the same manner for a total of 10 plants per isolate. Plants were observed for 6 weeks and destructively sampled to measure vascular lesion lengths. Mean vascular lesion lengths were 26, 22, 54, and 46 mm for B. dothidea, N. luteum, N. mediterraneum, and N. parvum, respectively. The mean lesion lengths for all isolates were significantly different (P = 0.05) from the control. Each species was consistently recovered from inoculated plants, except the control, thus fulfilling Koch's postulates. To our knowledge, this is the first report on the pathogenicity of multiple Botryosphaeriaceae species causing branch canker and dieback on F. microcarpa in California. These results are significant since trees along sidewalks in southern California are often crowded and undergo extensive root and branch pruning and some Botryosphaeriaceae spp. are known to enter its host through wounds caused by pruning or mechanical injury (2,3). Further sampling is imperative to better assess the distribution of these canker-causing fungal pathogens on F. microcarpa. References: (1) P. W. Crous et al. Stud. Mycol. 55:235, 2006. (2) D. R. Hodel et al. West. Arborist 35:28, 2009. (3) V. McDonald et al. Plant Dis. 93:967, 2009. (4) B. Slippers et al. Fungal Biol. Rev. 21:90, 2007.