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Kona coffee root-knot nematodes (Meloidogyne konaensis) cause severe declines in ‘Kona Typica’ arabica coffee (Coffea arabica) trees in Hawaii. Defoliation and destruction of the root system result in significant yield losses and can kill the host. Grafting with other coffee (Coffea) species that exhibit tolerance to kona coffee root-knot nematodes is a viable solution for mitigating damage in the field. An infested field was established in 2006 with ‘Kona Typica’ scions grafted on seven accessions of promising rootstock and nongrafted ‘Kona Typica’ as the control. Four grafted trees of each accession were planted per plot with four repetitions. Yield data were assessed for the 2016–17, 2017–18, and 2018–19 seasons. Three liberica coffee (Coffea liberica) accessions [‘Arnoldiana’ (‘Arnoldiana’ 1 and ‘Arnoldiana’ 2), ‘Dewevrei’, and ‘Fukunaga’ 1], demonstrated higher yields of coffee cherry compared with nongrafted ‘Kona Typica’ in the 2016–17 season. In the 2017–18 and 2018–19 seasons, five accessions of liberica and ‘Nemaya’ robusta coffee (Coffea canephora) exhibited higher cherry yields than ‘Kona Typica’. Plant vigor was greater in trees grafted on ‘Arnoldiana’ and ‘Fukunaga’ compared with other accessions and nongrafted ‘Kona Typica’, with taller trees, higher vertical branches, thicker trunk circumferences, and overall better health. After 13 years in the field, nongrafted ‘Kona Typica’ showed the highest mortality, with 81% of trees lost. Liberica rootstocks performed consistently well in the presence of kona coffee root-knot nematodes, with the healthiest trees, highest yields, and least mortality of the coffee species evaluated.

Nuclear and chloroplast genetic markers have been extensively used for plant identification and molecular taxonomy studies. The efficacy of genetic markers to be used as DNA barcodes is under constant evaluation and improvement with identification of new barcodes that provide greater resolution and efficiency of amplification for specific species groups as well as distantly related plants. In this study, chloroplast DNA genetic markers for Anthurium, the largest genus in the Araceae family, were adapted from chloroplast markers previously designed for Lemna minor, a member of the same plant family. Primers for chloroplast region trnH-psbA, previously used for molecular systematic studies in Anthurium, as well as primers for the rpoB, rpoC1, psbK-psbI, matK, rbcL, and atpF-atpH regions, all located within the large single copy sequence in the chloroplast genome, were evaluated and found to efficiently amplify target sequences when using DNA of varied quality and concentration extracted from silica-dried leaves of selected accessioned species of Anthurium. The trnH-psbA, psbK-psbI, and atpF-atpH intergenic region primers were further evaluated using Anthurium species spanning different subgeneric groups. Of the intergenic region primers tested, psbK-psbI primers were the most robust, yielding well-defined amplicons across Anthurium species that were consistent, with exceptions, within sectional groupings. Application of the psbK-psbI region amplicon as a visual marker for surveying sectional relationships in Anthurium is novel and serves as a model for the development of a diagnostic method for genotyping plants and testing for sample integrity from among species or germplasm collections. This work further demonstrates the use of dried plant tissue banks as a genetic reference and information resource to support basic research as well as ornamental plant characterization and improvement.

Burrowing nematode (Radopholus similis) causes severe stunting and yield reduction in anthurium (Anthurium andraeanum) cut flower production. Two field trials were conducted at commercial grower farms to test the efficacy of fluopyram or fluopyram + trifloxystrobin for managing burrowing nematodes. Nematode population densities in roots and cinder media were evaluated during the trial in addition to cut flower yield and canopy cover. In the first trial, the nematode population in roots was reduced by 57% after two applications of fluopyram 3 months apart. As plant health improved, the increasing anthurium root weight supported higher nematode populations. After 14 months, fluopyram-treated plots had 43% more green canopy cover and a 53% increase in flower production compared with the untreated control plots. At a second location, population densities of burrowing nematode were reduced in roots after one application of fluopyram + trifloxystrobin and remained low with quarterly applications. Nematode populations were initially reduced in fluopyram-treated plots followed by a resurgence as demonstrated in the other trial. Ten months after the initial treatment, flower yield was greater in fluopyram + trifloxystrobin-treated plots with more large and extra-large flowers produced. Canopy cover was 45% and 22% greater with fluopyram + trifloxystrobin and fluopyram applications, respectively. Fluopyram shows potential for management of burrowing nematodes in anthurium by improving plant vigor and cut flower production.