Coffee berry borer (CBB), Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae) is a serious pest of coffee worldwide and a new invasive pest in Hawaii. Adult flat bark beetles, mainly Leptophloeus sp. (75%) and Cathartus quadricollis (21%) (Coleoptera: Laemophloeidae and Silvanidae, respectively), were found inside CBB-infested coffee beans on the tree and molecular marker studies confirmed feeding on CBB. Research was conducted to better understand the ecology of these predators and explore ways to increase their role in suppressing CBB populations in coffee. Laboratory feeding assays demonstrated the capacity for adult and larval flat bark beetles to feed on all CBB life stages. The predators are widely distributed in the coffee growing areas on the island of Hawaii, but feed mainly in dried coffee on the tree rather than in ripening berries where initial crop damage occurs. Berlese funnel extraction of flat bark beetles from dried beans on the tree indicated that predator numbers can be relatively high (up to 23 adult predators per 150 bean sample). C. quadricollis was not susceptible to infection by the fungal biopesticide Beauveria bassiana which is used for field control of CBB in coffee. Leptophloeus sp. and C. quadricollis can be raised easily on a diet of cracked corn and cornmeal. Augmentative releases of generalist flat bark beetle predators like Leptophloeus sp. and C. quadricollis may be a useful component of integrated pest management programs against coffee berry borer and other scolytine pests.

Coffee is one of the most economically valuable specialty crops for which Hawaii is famous. It is produced commercially on >6,900 acres across six islands by more than 1,470 growers. It has a raw crop value of $55.9 million, while the value-added benefits of coffee-related industries exceed $148.5 million (USDA, 2021). In addition to high product quality, Hawaii also has the distinction of being the last major coffee growing region that is free of coffee leaf rust (CLR), a highly damaging disease caused by the obligate parasitic fungus Hemileia vastatrix Berk. & Broome. On October 21, 2020, a coffee grower in Maui County, Hawaii reported the presence of coffee leaf rust-like symptoms on coffee plants (var. ‘Typica’) at their farm with many trees heavily defoliated. Foliar symptoms consisted of yellowish-orange, circular lesions that often coalesced. On abaxial surfaces, these lesions appeared powdery. Urediniospores were mostly reniform, (25)27-34(36) × (17)18-28(29) µm, strongly echinulated on the upper (convex) surface and smooth on the lower (concave) surface, with hyaline to pale yellow-orange walls. Urediniospores incubated in molecular grade water for 10 min at 95 oC served as template for PCR targeting the internal transcribed spacer region of fungi using primers ITS1/ITS2, ITS3/ITS4, and ITS1/ITS4 (White et al., 1990). Amplification products underwent direct Sanger-based sequencing. Following primer sequence trimming, the sequence reads were assembled using CAP3 (Huang and Madan, 1999) and deposited in GenBank (Accession MW228837). Blastn analysis revealed > 99% nucleotide identity with isolates of H. vastatrix from Mexico (eg. KX260251) and Brazil (eg. MF627828). A voucher material from which both the morphological and molecular assays were performed was deposited in the National Fungus Collection (BPI 924818). Subsequent surveys on the islands of Hawaii, Lanai, and Oahu revealed the presence of coffee plants with symptoms of coffee leaf rust. To confirm pathogenicity, urediniospores from a symptomatic plant growing in Holualoa, Hawaii, were collected in gelatin capsules using a G-R Electric Manufacturing Portable Vacuum Pump with a mini cyclone spore adapter. The concentration of spores was adjusted to 1 x 105 spores/ml in sterile water using a Brightline Hemocytometer. The spore suspension was brushed onto the abaxial side of leaves from two C. arabica var. ‘Typica’ plants using a camel hair paintbrush. Two control plants were mock-inoculated with sterile water. Plants were placed in a dark humid chamber set at 22 oC for 48 hours, after which it was adjusted to 12 hours light under cool white fluorescent lighting. After 20 days small, chlorotic spots were visible on the adaxial leaf surface and a few spots contained orange urediniospores on the abaxial surface. Lesions expanded by day 34, followed by necrosis of the center area of several leafspots and leaf abscission was observed at day 70. The experiment was conducted twice. H. vastatrix was confirmed by both morphological and molecular examination of urediniospores recovered from the observed lesions. All mock-inoculated control plants remained asymptomatic. To our knowledge, this is the first report of CLR on coffee in Hawaii. This discovery is of great concern since CLR threatens not only the yield and quality of Hawaii-grown coffee, but also the economic viability of this historic and culturally important industry. Statewide monitoring for CLR continues and further work is needed to mitigate the impact of this discovery through the development of short- and long-term management strategies.

Integrated pest management strategies were adopted to combat the coffee berry borer (CBB) after its arrival in Hawaii in 2010. A decision tree framework is used to model the CBB integrated pest management recommendations, for potential use by growers and to assist in developing and evaluating management strategies and policies. The model focuses on pesticide spraying (spray/no spray) as the most significant pest management decision within each period over the entire crop season. The main result from the analysis suggests the most important parameter to maximize net benefit is to ensure a low initial infestation level. A second result looks at the impact of a subsidy for the cost of pesticides and shows a typical farmer receives a positive net benefit of $947.17. Sensitivity analysis of parameters checks the robustness of the model and further confirms the importance of a low initial infestation level vis-a-vis any level of subsidy. The use of a decision tree is shown to be an effective method for understanding integrated pest management strategies and solutions.

Hawaii has a multitude of scolytine (Coleoptera: Curculionidae: Scolitinae) pests including Hypothenemus hampei, coffee berry borer, which is apest of coffee, Hypothenemus obscurus, tropical nut borer, a significant pest of macadamia nut, and Xylosandrus compactus, black twig borer, a pest of many tropical and ornamental crops. The flat bark beetles, Carthartus quadricollis (Coleoptera: Silvanidae) and Leptophloeus sp. (Coleoptera; Laemophloeidae), are known to predate on coffee berry borer and tropical nut borer but their natural history (feeding habits, reproduction and movement) are poorly understood. Studies were conducted using molecular, field, and laboratory assays to examine 1) flat bark beetle reproduction and movement in coffee and the broader agricultural landscape, 2) establishment of augmentative releases for biological control, and 3) predation rates on H. hampei, H. obscurus and X. compactus. Various life stages of C. quadricollis and Leptophloeus sp. were found in seven different plant species common to the agricultural landscape around coffee farms, suggesting these predators are feeding and reproducing on theses hosts. Molecular analysis indicated that C. quadricollis and Leptophloeus sp. predated on H. hampei, H. obscurus and X. compactus in coffee, macadamia nut, and mixed coffee-macadamia nut farms. Laboratory reared predators were recaptured near release sites on coffee farms at 1, 2, and 7 weeks after augmentative releases. Predation of C. quadricollis on H. hampei eggs placed inside artificial coffee berries in coffee farms was about 40%. Predators C. quadricollis and Leptophloeus sp. are natural enemies of some significant agricultural scolytine pests in Hawaii and have excellent potential for biological control with augmentative releases.

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.

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.

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Photoselective shadecloths that manipulate light quality may enable nursery growers to achieve desired plant growth. This ability to manage plant habit could give growers an additional nonchemical tool to improve potted plant quality. The objective of this study was to determine growth and flowering responses of potted Dracaena and Anthurium plants to four shadecloths. Dracaena deremensis `Janet Craig' and Dracaena marginata `Colorama' cane top-cuttings were placed in 70% black cinder: 30% peat moss media. Anthurium `Lola' liners were transplanted into 100% black cinder medium. Plants were grown in a greenhouse under 70% shadecloths: black, gray, red, and blue. Four months after planting, Dracaena `Janet Craig' had more new leaves under red shadecloth (10.4) compared to other shadecloths (8.9–9.3). Leaf area was less with red shadecloth (340 cm2) than other treatments (380-388 cm2). Plants under the red shadecloth had the lowest grower evaluation scores (5.4; 1 = poor, 10 = excellent) than those under other shadecloths (7.2–8.2), but all plants were considered marketable. Dracaena `Colorama' plants under red shadecloth had the greater plant height increase (20.1 cm) than those under other shadecloths (10.1–13.2 cm). Red shadecloth resulted in more new leaves (26.2) compared to other treatments (18.0–21.4). Anthurium `Lola' flower height 9 months after transplanting was less under red shadecloth (23.0 cm) than under black (33.0 cm). The number of flowers/pot was greater under red shadecloth (3.17) compared to those under other shadecloths (0.50–1.33). Flower size was greater (35.2 cm2) under red shadecloth than under black (20.0 cm2). Photoselective shadecloths may be used to nonchemically manipulate plant growth and improve the quality of potted Dracaena and Anthurium plants.