Field Efficacy of Spinetoram for the Management of Coffee Berry Borer (Hypothenemus hampei).

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.

Targeted transcriptomics reveals signatures of large-scale independent origins and concerted regulation of effector genes in Radopholus similis.

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 of R. similis to 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 of R. similis by in situ hybridization, 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 that R. similis holds a diverse and emergent repertoire of effectors, which has been shaped by various evolutionary events, including neofunctionalization, horizontal gene transfer, and possibly by de novo gene 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 by R. similis, this information provides valuable data to elucidate the mode of parasitism of this nematode.

Effects of fluopyram and azadirachtin integration with sunn hemp on nematode communities in zucchini, tomato and sweet potato in Hawaii.

Fluopyram (Velum® One) is a synthetic nematicide and azadirachtin (Molt-X®) is a biological nematicide. Both have shown promise against plant-parasitic nematodes on several agriculturally important crops. There is a lack of information on integration of pre-plant sunn hemp (Crotalaria juncea) cover crop with these post-plant nematicides, aiming to improve plant-parasitic nematodes management and mitigate any detrimental effects on free-living nematodes. Three field trials were conducted to investigate the effects of fluopyram alone or in combination with pre-plant sunn hemp cover crop, and azadirachtin combined with pre-plant sunn hemp on Rotylenchulus reniformis and Meloidogyne spp., and free-living nematodes. Zucchini (Cucurbita pepo) and tomato (Solanum lycopersicum) were grown in Trials I and II, and sweet potato (Ipomoea batatas) only was grown in Trial III. In all three trials, early applications of fluopyram at crop planting were effective in suppressing the abundance of Meloidogyne spp. (M. incognita and M. javanica) but it was not effective in reducing R. reniformis in the soil. Combining sunn hemp with fluopyram was suppressive to R. reniformis on short-term zucchini crop, but not on longer term tomato and sweet potato crops. In addition, application of fluopyram at transplanting was the key to successful suppression of Meloidogyne spp. as later fluopyram chemigation (at 2 weeks after planting in Trial II or 1 month after planting in Trial III) had no effect against Meloidogyne spp. On the other hand, planting of sunn hemp followed by monthly post-plant azadirachtin application consistently suppressed R. reniformis, but this treatment did not suppress Meloidogyne spp. Integrating sunn hemp with fluopyram increased zucchini yield by >2.3 folds and that with azadirachtin increased the zucchini yield by >1.7 folds. Although no yield improvement was observed on tomato in Trial II, integrating sunn hemp with azadirachtin and fluopyram increased tomato yield by 0.23 and 1.12 folds, respectively, in Trial I. Marketable yield of sweet potato was increased by 4.5-6.4 folds in all the fluopyram treatments but was only increased 61.5% by sunn hemp plus azadirachtin treatment. While fluopyram alone often reduced the abundance of free-living nematodes, integrating with sunn hemp mitigated the negative impacts of fluopyram on soil health.

Reduced Emergence of Cylas formicarius elegantulus (Coleoptera: Curculionidae) from Sweet Potato Roots by Heterorhabditis indica.

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.

Integrated Pest Management of Coffee Berry Borer in Hawaii and Puerto Rico: Current Status and Prospects.

The coffee berry borer (CBB), Hypothenemus hampei, is the most significant insect pest of coffee worldwide. Since CBB was detected in Puerto Rico in 2007 and Hawaii in 2010, coffee growers from these islands are facing increased costs, reduced coffee quality, and increased pest management challenges. Here, we outline the CBB situation, and summarize the findings of growers, researchers, and extension professionals working with CBB in Hawaii. Recommendations for the Integrated Pest Management (IPM) program for CBB in Hawaiian Islands and Puerto Rico include: (1) establish a CBB monitoring program, (2) synchronize applications of insecticides with peak flight activity of CBB especially during the early coffee season, (3) conduct efficient strip-picking as soon as possible after harvest and perform pre-harvest sanitation picks in CBB hotspots if needed, (4) establish protocols to prevent the escape of CBB from processing areas and when transporting berries during harvest, and (5) stump prune by blocks. Progress achieved includes the introduction of the mycoinsecticide Beauveria bassiana to coffee plantations, the coordination of area-wide CBB surveys, the establishment and augmentation of native beetle predators, and an observed reduction of CBB populations and increased coffee quality where IPM programs were established. However, CBB remains a challenge for coffee growers due to regional variability in CBB pressures, high costs, and labor issues, including a lack of training and awareness of CBB management practices among growers.

Organ-specific transcriptome profiling of metabolic and pigment biosynthesis pathways in the floral ornamental progenitor species Anthurium amnicola Dressler.

Anthurium amnicola Dressler possesses a number of desirable and novel ornamental traits such as a purple-colored upright spathe, profuse flowering, and floral scent, some of which have been introgressed into modern Anthurium cultivars. As a first step in identifying genes associated with these traits, the transcriptome from root, leaf, spathe, and spadix from an accession of A. amnicola was assembled, resulting in 28,019 putative transcripts representing 19,458 unigenes. Genes involved in pigmentation, including those for the metabolism of chlorophyll and the biosynthesis of carotenoids, phenylpropanoids, and flavonoids were identified. The expression levels of one MYB transcription factor was highly correlated with naringenin 3-dioxygenase (F3H) and dihydroflavonol-4-reductase (DFR) in leaves, whereas a bHLH transcription factor was highly correlated with flavonoid 3'-monooxygenase (F3'H) and a DFR in spathes, suggesting that these two transcription factors might regulate flavonoid and anthocyanin synthesis in A. amnicola. Gene sequence and expression data from four major organs of A. amnicola provide novel basal information for understanding the genetic bases of ornamental traits and the determinants and evolution of form and function in the Araceae.