The burrowing nematode,Radopholus similis, is an economically important plant-parasitic nematode that inflicts damage and yield loss to a wide range of crops. This migratory endoparasite is widely distributed in warmer regions and causes extensive destruction to the root systems of important food crops (e.g., citrus, banana). Despite the economic importance of this nematode, little is known about the repertoire of effectors owned by this species. Here we combined spatially and temporally resolved next-generation sequencing datasets ofR.similisto select a list of candidates for the identification of effector genes for this species. We confirmed spatial expression of transcripts of 30 new candidate effectors within the esophageal glands ofR.similisbyin situhybridization, revealing a large number of pioneer genes specific to this nematode. We identify a gland promoter motif specifically associated with the subventral glands (named Rs-SUG box), a putative hallmark of spatial and concerted regulation of these effectors. Nematode transcriptome analyses confirmed the expression of these effectors during the interaction with the host, with a large number of pioneer genes being especially abundant. Our data revealed thatR.similisholds a diverse and emergent repertoire of effectors, which has been shaped by various evolutionary events, including neofunctionalization, horizontal gene transfer, and possibly byde novogene birth. In addition, we also report the first GH62 gene so far discovered for any metazoan and putatively acquired by lateral gene transfer from a bacterial donor. Considering the economic damage caused byR.similis, this information provides valuable data to elucidate the mode of parasitism of this nematode.

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.

Coffee berry borer (CBB), Hypothenemus hampei, is a damaging insect pest of coffee worldwide. CBB has recently been introduced to Hawaii, so management techniques are still being developed for sustainable and cost-efficient approaches for the effective control of this pest. Field trials were conducted to evaluate the use of spinetoram on CBB infestation and bean damage compared to Beauveria bassiana and an untreated control. Initial CBB infestations were similar, and the treatments resulted in no detectable differences in subsequent new infestations. Damage to the coffee beans was reduced by both spinetoram and B. bassiana compared to controls as the mortality of adult beetles resulting from the treatments prevented them from moving into the bean (C/D position) from the berry (A/B position). The mortality of adult beetles also prevented reproduction, subsequently reducing future CBB populations in the field. When applied to infested berries, spinetoram reduced live beetle populations in the A/B position by 73% and CBBs in the C/D position by 70% compared to the water control, whereas applications of B. bassiana reduced beetles in the C/D position by 37% but had no effect on the live A/B population. An integrated pest management program is recommended for the effective control of CBBs, and the use of spinetoram applications when adult beetles are in the A/B position appears to have potential as another management tool.

Okinawan sweet potato, Ipomoea batatas, is an important food staple and export crop for the Island of Hawaii. Cylas formicarius elegantulus, sweet potato weevil, is a major quarantine pest that causes severe destruction to the crop. Root malformation and a bitter taste occur when larvae feed and tunnel within the storage root. Off-grade roots are often left in the field after harvest and serve as a reservoir for the weevils. Current management involves the unsustainable practice of moving to virgin land for the next cropping cycle. Strains of Heterorhabditis indica isolated from the Hawaiian Islands were tested for their efficacy at causing mortality of C. formicarius and reducing the emergence of adults from infested roots. In well plate assays, H. indica caused mortality of 88% larvae, 96% pupae, and 4% adults after 48 h. When applied to infested roots, the nematodes caused an average mortality of 78% larvae, 66% pupae, and 32% adults. Greater mortality was observed at the highest inoculum levels (10,000 infective juveniles per storage tuber) but a reduction of 90% inoculum density was still effective at weevil management. In simulated field trials, infestation of storage roots was reduced by 42–99.6% when planted among infested roots that had been inoculated with H. indica. Rates of 2.5 billion IJs/hectare were just as effective as 5 billion IJs/hectare. Application of local H. indica strains in sweet potato production has the potential to manage C. formicarius populations and allow for consecutive cropping seasons.

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.

Anthurium amnicola is in the monocot family Araceae, subfamily Pothoideae and is a contributing species in Hawaii floriculture industry hybrids. To support future genetic improvements to this commodity, we sequenced and assembled the A. amnicola genome to chromosome-scale using PacBio HiFi and short-read Hi-C sequencing. A total of 98.51% of the 4.79 Gb genome is anchored into 15 chromosomes, with 99.2% gene completeness and a high LTR assembly index (LAI) score of 21.73, indicative of a complete, high-quality assembly. Annotation reveals the presence of 20,380 protein-coding genes, with 78.52% of the genome composed of repetitive sequences, predominantly long terminal repeat retrotransposons (LTR-RT). Phylogenetic analysis identified evolutionary relationships between A. amnicola and representative species in the Araceae and other plant families. This study provides the first reference genome sequence for the neotropical genus Anthurium and insights into Araceae evolution, benefiting the floriculture industry and evolutionary studies.