First report on the presence of huanglongbing vectors (Diaphorina citri and Trioza erytreae) in Ghana

Scientific Reports volume 13, Article number: 11366 (2023) Cite this article

912 Accesses

1 Citations

Metrics details

As significant threats to global citrus production, Diaphorina citri (Kuwayama; Hemiptera: Psyllidae) and Trioza erytreae (Del Guercio; Hemiptera: Triozidae) have caused considerable losses to citrus trees globally. Diaphorina citri vectors “Candidatus Liberibacter asiaticus” and “Ca. L. americanus”, whereas T. erytreae transmits “Ca. L. africanus” and “Ca. L. asiaticus”, the pathogens responsible for citrus greening disease or Huanglongbing (HLB). Though HLB is a destructive disease of citrus wherever it occurs, information on the occurrence and geographical distribution of its vectors in Africa is limited. In recent surveys to determine if HLB vectors are present in Ghana, we observed eggs, nymphs, and adults of insects suspected to be D. citri and T. erytreae. Using morphological traits and DNA analyses, the identity of the suspected insects was confirmed to be D. citri and T. erytreae. Individuals of D. citri and T. erytreae were examined using qPCR for CLaf, CLam, and CLas, but none of them tested positive for any of the Liberibacter species. Herein we report, for the first time, the presence of D. citri and T. erytreae in Ghana (West Africa). We discuss the implications of this new threat to the citrus industry to formulate appropriate management strategies.

The Asian citrus psyllid Diaphorina citri Kuwayama, 1908 (Hemiptera: Psyllidae) and African citrus triozid Trioza erytreae (Del Guercio, 1918) (Hemiptera: Triozidae) are the most devastating pests of citrus. Their potential for significant negative impacts on citrus production and productivity is high due to international trade and the movement of host plant materials across borders1,2. Diaphorina citri and T. erytreae are native to southern Asia and Africa, respectively3,4. However, as of November 2022, each of them has been reported from at least 25 countries worldwide5,6,7. In Africa, D. citri occurs in Kenya and Zanzibar8, and more recently, in Nigeria, Ethiopia, and Benin9,10,11. Outside Africa, T. erytreae has been reported from Saudi Arabia, Yemen, Spain and Portugal12. Maximum Entropy and Climate Change Experiment modeling of the potential global distribution of D. citri and T. erytreae in the world suggest that parts of uninvaded regions of Africa have climate suitable areas for the proliferation of both D. citri and T. erytreae5,7.

Diaphorina citri and T. erytreae feed on citrus and non-citrus species. Specifically, a wide variety of plants, especially those in the family Rutaceae, serve as hosts for T. erytreae and D. citri. The pests are highly polyphagous, with each having at least 23 non-citrus host plants13,14. The pests attack many economically important citrus species, including grapefruit, lemon, lime, and sweet oranges. However, the most preferred host plants for D. citri are the orange jasmine Murraya paniculata (L.) Jack., and the curry leaf plant Bergera koenigii (L.)15. Orange jasmine is a commonly grown ornamental plant in residential areas for landscaping, and has therapeutic properties16. In contrast, T. erytreae prefers Citrus limon (L.) to other host plants17,18.

The development of the vectors goes through five nymphal instars. The adults of D. citri have speckled brown wings and measure between 2.7 and 3.3 mm in length19. The females of D. citri may lay a mean of 40 eggs per flush shoot per day20. The freshly laid eggs of D. citri are pale but change into yellow and orange with two unique red eye spots at maturity19. Diaphorina citri lays on tips of developing shoots on and between unfurling leaves21. Trioza erytreae is about 2.40 mm long, with females being slightly larger than males18. Trioza erytreae adults start pale but gradually darken afterwards to a light brown. Trioza erytreae female lays eggs on the margins and along the midribs of young and tender leaves22. The average number of eggs laid by T. erytreae females per day ranges from 17 in the cold to 39 in the warm seasons, respectively23. When feeding on leaves, adults rest at a body angle of about 35° and 45° for T. erytreae and D. citri, respectively12,19.

Both D. citri and T. erytreae cause direct and indirect damage to citrus. Feeding activities of D. citri nymphs and adults lead to substantial uptake of plant sap and may induce sooty mold development due to honeydew production on infested flush shoots. Sooty mold affects the photosynthetic activities of the citrus trees, thereby reducing their productivity24. Direct foliage feeding by T. erytreae results in stunted and seriously deformed leaves showing signs of pit-like galls23. Although direct feeding damage of psyllids may result in a loss of plant vigor, indirect damage via vectoring of HLB pathogens is the most economically important. All over the world, HLB is caused by the phloem-limited bacteria “Ca. L. asiaticus” (CLas) and Ca. Liberibacter americanus (CLam) transmitted by D. citri25,26. In contrast, in Africa, especially East and South Africa, T. erytreae represents an economically significant threat to the citrus industry because of its ability to vector "Ca. Liberibacter africanus" (CLaf), the causal agent of the African HLB. However, a recent study by Ajene et al.27 showed field populations of T. erytreae carrying CLas, and Reunaud et al.28 demonstrated that it also can efficiently transmit CLas. Unlike the HLB caused by CLaf, the HLB caused by CLas is the most destructive pathogen of all citrus in the world28.

D. citri have the ability to fly both long and short distances. However, its propensity to engage in long-distance flights, as well as the length and distance flown, are all affected by high heat conditions, regardless of the humidity level29. Nevertheless, the most extended flight distance and duration are shorter in females than males30. Additionally, D. citri routinely migrates between managed and unmanaged groves, covering a distance of about 60–100 m toward managed groves31. Because D. citri eggs are laid solely on young flush and nymphs develop primarily on young plant parts, population variations of this pest are highly correlated with the growth of new and young flush of the host plant32,33. According to Catling23, T. erytreae has weak dispersal powers and are incapable of sustaining flight for long hours. In contrast, Samways and Manicom34, showed that T. erytreae had a good dispersal ability and could invade orchards to locate new flush shoots.

Citrus is one of the most widely grown fruits worldwide due to its high demand and positive impact on food and nutritional security35. In terms of global trade value, it is one of the most valuable fruits36. The commonly known species of commercial importance are sweet oranges (Citrus sinensis), lemons (C. limon), limes (C. aurantifolia), grapefruits (C. paradisi), and tangerines (C. reticulata). Sweet oranges are the major species grown globally and represent more than half of the global citrus output. Annual global production of citrus was estimated at 158 million tonnes in 2020, with sweet oranges contributing to more than half of the world's total37. Africa produced 9,756,176 metric tons of sweet oranges from an estimated 514,573 ha in 2020, while production in Ghana was at 697,637 metric tons from an estimated 17,983 ha37. The health benefits of sweet oranges and other citrus fruits are well documented, especially in providing vitamin C, carotenoids, and polyphenols. Most citrus fruits in many countries, including Ghana, are consumed locally as fresh products38.

Early detection of D. citri and T. erytreae would help develop strategies and manage the pests and diseases they transmit, slowing down their spread and preventing them from becoming established. Despite reports of the presence of the invasive and deadly D. citri in neighboring Nigeria and Benin10,11, there have been no previous investigations to determine the existence of D. citri in Ghana. Given the economic importance of citrus production in Ghana, we conducted surveys for citrus commodity pests in Ghana to determine the presence of D. citri and T. erytreae and, if found, to test the samples for Liberibacter species.

To establish the presence of D. citri and T. erytreae in Ghana, surveys of residential areas and citrus orchards in the Volta Region, Ghana (Table 1), were conducted from April to November 2022. The main roads in each town were chosen for sampling. All encountered Citrus and Murraya species were visually inspected for the presence of D. citri and T. erytreae.

Each backyard hedge (Fig. S1) with a host plant was visually examined for D. citri adults and symptomatic leaves (Fig. S2). Expanding flush shoots and at high densities on the stems are where D. citri nymphs are attached (Fig. S3). In contrast, T. erytreae nymphs are usually found on the underside of the leaves (Fig. S4). To collect the nymphal stages from the plants, we thoroughly searched for the immature stages on the stems and new tender shoots. Inspection of host plant was further aided by feeding damage, such as 'epinasty', and distortion of young and fragile leaves due to the sap-feeding of D. citri nymphs and adults, and the presence of the white waxy excretions from the nymphs (D. citri)10,19. In addition, T. erytreae pit-like galls were used to detect the presence of the triozid18. In case adult insects were found, they were aspirated into plastic vials containing 95% ethanol, and nymphs were brushed into similar vials using a fine camel brush. The host plant observed was recorded for each location. Moreover, the coordinates of each sample location were recorded using a handheld Garmin eTrex® 32x device.

The insects were first identified visually using morphological characteristics4, and then a subset of samples was sent to the Texas A&M University Kingsville Citrus Center (TAMUK-CC) in Weslaco, Texas, USA, for additional morphological and molecular analyses. The suspected insects underwent a thorough morphological characterization at TAMUK-Entomology CC's laboratory, where they were compared to preserved reference voucher specimens. We used the morphological characteristics reported by Mead4, Yang39, and OEPP/EPPO40 to positively identify D. citri nymphs and adults. Moreover, Aidoo et al.18 and Cocuzza et al.12, reports on T. erytreae morphometry were used for their identification. The voucher specimens were kept at TAMUK-CC and the Central Laboratory of the University of Environment and Sustainable Development, Somanya, Ghana.

In this study, we used the method described by Dellaporta et al.41 to extract total nucleic acids (TNA) from both adults and nymphs of the psyllids. NanoDrop 2000 series spectrophotometer (Thermo Fisher Scientific Inc., Waltham, MA, USA) was used to measure the concentration and purity of the TNA extracts before they were frozen at 20 °C for later use. Two microliters (uL) of each sample was utilised as template in a 25 μL polymerase chain reaction (PCR) using the PrimeSTAR GXLDNA Polymerase, its recommended reagents, and the Rapid Protocol (Takara Bio USA, Inc., Mountain View, CA). We targeted 821-bp and 708-bp segments of the mtCOI coding region in the D. citri42 and T. erytreae43 using the primer pair DCITRI COI-L and DCITRI COI-R and Te-6U30 and Te-720L26, respectively. Positive controls consisted of DNA samples taken from TAMUK-lab-reared CC's ACPs. The 100–2000 bp Wide-Range DNA Ladder (Takara Bio USA, Inc.) and the amplified products were run on ethidium bromide-stained 1% agarose gels and then visualised using a UV-transilluminator.

Zymoclean Gel DNA Recovery Kit was used to cut out and gel-elute the appropriate size DNA bands from the sample and the target (Zymo Research, Irvine, CA). After purification, the recovered DNA was cloned into the pJET1.2/blunt vector one at a time using the CloningJET PCR Kit (Thermo Fisher Scientific). Transforming chemically competent DH5 Escherichia coli cells with the ligation products yielded two to three plasmids per cloned DNA amplicon that were PCR-verified to be the correct size (Sigma-Aldrich, St. Louis, MO). By using the Sanger sequencing technique and primers designated as pJET1.2 F and pJET1.2 R, each plasmid sample was sequenced in both directions (ELIM BIOPHARM, Hayward, CA, USA).

The pJET1.2 vector sequences were removed using VecScreen (https://www.ncbi.nlm.nih.gov/tools/vecscreen/). Each sample's forward and reverse sequences were entered into the CAP contig assembly function of the BioEdit software44 to generate a consensus sequence. To determine which species each consensus sequence belonged to, BLASTn analysis45 was performed on all the sequences of the psyllids. Multiple sequence alignments were generated between the sequences derived in this study and those obtained from GenBank using the MUltiple Sequence Comparison by Log-Expectation alignment program (http://www.ebi.ac.uk/Tools/msa/muscle/). The sequences were chosen because they are representative of the diversity of the taxonomic groups studied. The sequence identity matrices and phylogenetic analyses were calculated using the maximum likelihood approach in MEGA version 7.046, which was applied to the gene-specific alignment data. Instead of using tables of pairwise sequence identity scores, which are commonly used for this purpose, it is recommended to use the Sequence Demarcation Tool (SDT), which displays pairwise identity scores using a color-coded matrix47. This makes it easier to gain insights into the overall relationships between sequences in a dataset. Moreover, we calculated the pairwise using SDT in this study. Trioza species considered in this study included those from Percy et al.48 and Khamis et al.49.

TaqMan Multiplex Real-Time PCR tests were done on an ABI 7500 Fast Thermocycler (Thermo Fisher Scientific Inc., Waltham, MA) or a SmartCycler II (Cepheid, Sunnyvale, CA) and the DNA extracts were assayed for CLaf, CLam, and CLas as described50,51,52. All reactions included a standard set of positive and negative DNA controls, as well as a non-template water control. At a cycle threshold (Ct) of ≤ 37, it was determined that a sample was positive for the presence of a given bacterium.

This article does not contain any studies with human participants or animals performed by any of the authors.

The altitudes of all locations investigated ranged from 112 to 174 m above sea level (m.a.s.l). The field-collected insects were morphologically identified as D. citri and T. erytreae using previously published features4,12,18,39,40, and by comparison with voucher specimens (Fig. 1).

Female adults of the African citrus triozid (Trioza erytreae Del Guercio) (A) and the Asian citrus psyllid (Diaphorina citri Kuwayama) (B) detected in different locations (Table 1) in Volta Region, Ghana.

Both the TAMUK-CC Entomology Laboratory in Weslaco, Texas, and the University of Environment and Sustainable Development in Somanya, Ghana, now hold voucher specimens of these samples. Four of seven locations had adults D. citri feeding on mature and/or young growing oranges jasmine leaves during the study. We found that D. citri was more established and reasonably widespread in Volta Region than T. erytreae, given the vast dispersion of the positive detection in different locations and the observation of developing nymphs and eggs at three different sites (Table 1).

A subset of six adults each of D. citri and T. erytreae were chosen at random to represent the geographical diversity of the sampled insects, and their gene-specific DNA amplicons were found to be of the predicted sizes (Table 2).

There was a total of six sequences for D. citri COI; four using DCITRI COI-L/DCITRI COI-R and two using Te-6U30/Te-720L26. The T. erytreae samples had six sequences. D. citri sequences obtained with primers DCITRI COI-L/DCITRI COI-R showed significant matches (100.0% nt identical; 100% query coverage; E-value 0.0) using BLASTn between these sequences and corresponding gene-specific sequences of D. citri that are deposited in GenBank from different countries. When T. erytreae primers Te-6U30/Te-720L26 were used to amplify the COI gene of D. citri, the results also revealed a significant (99.30–99.58% nt identical; 100% query coverage; E-value 0.0) matches with sequences of D. citri from other countries. Trioza erytreae sequences obtained with primers Te-6U30/Te-720L26 showed a significant (100% nt identical; 100% query coverage; E-value 0.0) matches using BLASTn between these sequences and corresponding gene-specific sequences of T. erytreae that are deposited in GenBank from different countries.

Maximum likelihood (ML) phylogenetic analysis of each gene-specific sequence was performed, and the Tamura 3-parameter model was shown to have the lowest Bayesian Information Criterion (BIC) scores. As expected, it was predicted that the Ghana mtCOI sequences of T. erytreae (OR036870- OR036875) and D. citri (OR036866- OR036869) fall inside the T. erytreae and D. citri clade of the psyllid ML trees (Fig. 2). Our analysis revealed that T. erytreae samples from Ghana clustered with samples from other countries. After further analysis, it was shown that the mtCOI sequences unique to D. citri clustered strongly into the Western clade, which consists of populations from many countries. In addition, the D. citri samples from Ghana may likely represent a separate introduction event into Africa considering how distant they are from the other samples of Benin and Nigeria.

(A) Maximum Likelihood (ML) phylogenetic trees depicting the evolutionary relationships between adult individuals of Trioza erytreae and other Trioza species based on partial sequences of the maternally inherited mtCOI gene; OR036870–OR036875 derived in this study; others from GenBank. The corresponding sequences of Diaphorina citri were included as outgroup; (B) Phylogenetic placement of the D. citri isolates from Ghana into the previously described ‘Western clade’ of the insect species; OR036866–OR036869 obtained in this study; others from GenBank. The General Time Reversible and the Tamura 3-parameter models were determined as models with the lowest BIC (Bayesian Information Criterion) scores, respectively, for the figure (A) and (B) datasets and they were therefore used in the ML phylogenetic analysis for each of the gene-specific sequences (with 1000 bootstrap replications). Branches with < 50% bootstrap support were collapsed for each tree. The ML trees were generated using MEGA 7.0 (Kumar et al.46, https://www.megasoftware.net).

Possible demarcation criteria for the T. erytreae is assigned and compared to other species of Trioza. Based on the analyzed partial mtCOI sequences, the T. erytreae samples from Ghana appear to be distant relatives of the species T. erytreae based on the combination of sequence variation and geographical segregation (Fig. 3). Trioza erytreae collected from Ghana belong to the same demarcation as T. erytreae from other countries when analyzed using the SDT.

Color-coded pairwise identity matrix generated from partial sequences of the maternally inherited mtCOI gene of isolates of Trioza erytreae (blue box), other Trioza species and Diaphorina citri (orange box). The sequences obtained in this study from Ghana are denoted with black dots. The matrices were generated using the Sequence Demarcation Tool (SDT) v.1.2 (Muhire et al.47; http://web.cbio.uct.ac.za/).

For the first time, we report the presence of D. citri and T. erytreae in Ghana using both morphological and molecular techniques. However, there have been recent reports of D. citri in Nigeria (West Africa)10 and other African countries, such as Ethiopia9, Tanzania53, Kenya8 and Benin11. In response, many citrus-producing areas in eastern and southern African countries have increased the intensity of their pest surveillance and monitoring10. Herein, we initiated this study to ascertain the status of D. citri in Ghana to make early detection (if present) to inform concerted management efforts in Ghana and across sub-Saharan Africa. In addition, preventing an invasion is almost always cheaper than managing an invasive species once it has already entered an area54. Moreover, this was done due to the dangers of transporting plants around the world and the fact that citrus has been grown in Ghana for centuries.

Diaphorina citri in Ghana was confirmed at elevations of less than 200 m.a.s.l. According to Holford et al.55, in Indonesia and Bhutan, high altitudes above 1000 m.a.s.l limit the incidence and occurrence of HLB and D. citri, respectively. The entire country (i.e., Ghana) has an elevation of less than 1000 m.a.s.l. The mean annual temperatures of Ghana range between 24 to 30 °C, though it can be as low as 18 °C in the south and as high as 40 °C in the north56. Diaphorina citri prefers warm and dry climates and suitable temperatures for development range between 25 and 28 °C57. It can also tolerate temperatures above 40 °C29. However, high temperatures may decrease the flight capacity of the pest29. Average annual rainfall in the north of Ghana is below 1000 mm, whereas it averages approximately 2000 mm in the south56. Given the suitable environmental conditions in Ghana for D. citri, it is possible that the pest is widely distributed or can spread to other citrus-growing regions in the country.

Trioza erytreae was identified in one location in the Volta Region during the survey. A temperature-based phenology model study on T. erytreae predicted that optimum temperatures for the pest ranged from 20 to 25 °C58. The temperature in Ghana suggests that T. erytreae has the potential to spread in the country. However, it will be easier to manage T. erytreae than D. citri in Ghana because of its environmental requirements. In the future, it will be imprudent to ease off in developing management techniques aimed at preventing and managing agricultural pests because of their potential to adapt to the changing climates in many regions59.

A recent study, which used a species distribution model of suitability, concluded that most tropical Africa has a suitable climate for spreading D. citri and T. erytreae5,6,7. As a result of their research, they created a predictive niche map showing that many West, East, and Central African countries, including Ghana, are at high risk for D. citri establishment. Considering this, the presence of D. citri in Ghana demonstrates the severe threat posed by this invasive species to Ghana and other African countries where the pest is absent. The mtCOI of D. citri has been widely used in genetic variation and population structure studies60,61,62 because of its adaptability in diversifying insect populations across different geographical areas.

The presence of D. citri is of particular concern in Ghana, where agriculture is the backbone of the economy. Moreover, D. citri has risen to become a global threat to the viability of citrus businesses wherever the pest and the disease it transmits occur25. Agriculture remains a critical tool for sustainable development in many countries across sub-Saharan Africa, providing hundreds of millions of rural poor with new avenues out of poverty through smallholder farming, work in high-value crop production, entrepreneurial endeavors, and employment in rural and non-farming sectors. Despite efforts to ensure sustainable crop production, pests, and diseases persistently pose a threat on the continent. One such pest is T. erytreae, which is limited to Africa, the Middle East, and Europe5,6. The presence of D. citri in Ghana, which has a wide distribution in the North, Central, and South America, demonstrates that the combined effects of the HLB vectors could worsen the present losses associated with citrus pests. Trioza erytreae is heat-sensitive and develops best in the cooler highlands, while the Asiatic strain is believed to be more virulent and damaging overall63. This, however, suggests that the presence of HLB could threaten the sustainable production of citrus in Ghana due to the suitable climate suitable areas in the country7.

Huanglongbing causal agents can be disseminated via grafting and vegetative propagation. However, D. citri is implicated in much of their long-distance and within orchard distribution. Diaphorina citri can be transported over long distances by moving citrus materials like seedlings and alternate host plants. However, the psyllid may also move over long distances, and the prevailing wind direction and intensity can facilitate distance movement64,65,66. Diaphorina citri is primarily responsible for the introduction and subsequent spread of the Asian type of HLB in various parts of the world, including Brazil67, Texas68, China69, and California70.

In this study, D. citri was obtained from an alternate host plant (M. paniculata). Alternate hosts play a critical role in the dispersal and management of invasive pests71,72. Murraya paniculata is grown as an ornamental tree or hedge due to its durability, adaptability to a wide variety of soil, and suitability for larger hedges. In addition, the plant has antimicrobial, antioxidant, red blood cell membrane stabilization, and anti-inflammatory properties and is used to treat many diseases73. As a result, it has been used in many parts of the world for symptoms such as nausea, vomiting, constipation, diarrhea, stomach discomfort, headache, fluid retention, and clot formation16. In Ghana, the plant is mainly grown for its therapeutic uses, beautification and as a hedge.

Although the psyllids were collected from non-citrus host plants in Volta Region, Ghana, nationwide surveys targeting citrus and non-citrus host plants are urgently needed to define the extent of the spread in Ghana. Effective management of psyllids and HLB can only be achieved through a thorough assessment of the distribution of the pest and the disease it transmits. In addition, identifying localities that are free of infestation and where clean nursery programs can be established would offer some level of management against the psyllids. The removal of alternate host plants can be facilitated by a better understanding of areas where these plants are planted, which may also reveal the presence of previously unknown reservoirs of Ca. Liberibacter species. The farming practices in Ghana predominantly revolve around subsistence farming, which contradicts the effective implementation of recommended practices for managing HLB. These practices include establishing clean nurseries, implementing intensive psyllid management across larger contiguous blocks, and more. To effectively manage the psyllids, there is a need for regular inspection of citrus and non-citrus host plants at the Ghanaian ports of entry, and intercepted psyllids should be tested for HLB5,74. Given the confirmation of both D. citri and T. erytreae, it is essential to evaluate the existing distribution of D. citri not only in Ghana but also in neighboring regions. Coordinated regional management initiatives should be initiated promptly to eliminate these destructive pests before they become endemic or spread CLas, CLam, and CLaf, which could have severe consequences throughout the region. If found in citrus, efforts will be required to identify optimal crop management, such as crop rotation, intercropping and planting time. Also, developing resistance varieties, such as genetically engineered insecticidal types, could help control the psyllid populations in an environmentally friendly manner because resistance in field populations of D. citri has been reported in citrus groves75,76. In this study, it is important to note that D. citri was also sequenced using the T. erytreae-specific primer. This T. erytreae-specific primer used for D. citri sequencing has GenBank accession numbers OR036900 and OR036901. This information is valuable for identifying psyllids at entry points, thereby enhancing detection capabilities. Furthermore, Wenninger et al.77 reported that D. citri adults can exhibit various colorations, including gray/brown, blue/green, and orange/yellow forms, with noticeable differences in abdominal coloration. To facilitate early detection of D. citri, a combination of morphological identification and subsequent molecular studies can be useful in identifying psyllids present on planting materials at entry points.

The sequences obtained in this study have been deposited in NCBI GenBank with the following accession numbers: OR036866–OR036875 and OR036900–OR036901.

Urbaneja, A. et al. Citrus pests in a global world. In The Genus Citrus 333–348 (Woodhead Publishing, 2020).

Chapter Google Scholar

Halbert, S. E. et al. Trailers transporting oranges to processing plants move Asian citrus psyllids. Fla. Entomol. 93, 33–38 (2010).

Article Google Scholar

Van den Berg, M. A., Deacon, V. E. & Steenekamp, P. J. Dispersal within and between citrus orchards and native hosts, and nymphal mortality of citrus psylla, Trioza erytreae (Hemiptera: Triozidae). Agric. Ecosyst. Environ. 35, 297–309 (1991).

Article Google Scholar

Mead, F. W. The Asiatic citrus psyllid, Diaphorina citri Kuwayama (Homoptera: Psyllidae). Florida Department of Agriculture and Consumer Services, Division of Plant Industry, Entomology Circular. 180, 1–4 (1977).

Aidoo, O. F. et al. Predicting the potential global distribution of an invasive alien pest Trioza erytreae (Del Guercio) (Hemiptera: Triozidae). Sci. Rep. 12, 20312. https://doi.org/10.1038/s41598-022-23213-w (2022).

Article ADS CAS PubMed PubMed Central Google Scholar

Aidoo, O. F. et al. A machine learning algorithm-based approach (MaxEnt) for predicting invasive potential of Trioza erytreae on a global scale. Ecol. Inform. 71, 101792 (2022).

Article Google Scholar

Aidoo, O. F. et al. Climate-induced range shifts of invasive species (Diaphorina citri Kuwayama). Pest Manag. Sci. 78, 2534–2549 (2022).

Article CAS PubMed Google Scholar

Rwomushana, I. et al. Detection of Diaphorina citri Kuwayama (Hemiptera: Liviidae) in Kenya and potential implication for the spread of Huanglongbing disease in East Africa. Biol. Invasions. 19, 2777–2787 (2017).

Article Google Scholar

Ajene, I. J. et al. Detection of Asian citrus psyllid (Hemiptera: Psyllidae) in Ethiopia: A new haplotype and its implication to the proliferation of Huanglongbing. J. Econ. Entomol. 113, 1640–1647 (2020).

Article CAS PubMed Google Scholar

Oke, A. O., Oladigbolu, A. A., Kunta, M., Alabi, O. J. & Sétamou, M. First report of the occurrence of Asian citrus psyllid Diaphorina citri (Hemiptera: Liviidae), an invasive species in Nigeria, West Africa. Sci. Rep. 10, 1–8 (2020).

Article Google Scholar

Sétamou, M., Soto, L.Y., Tachin, M. & Alabi, O.J. Report on the first detection of Asian citrus psyllid Diaphorina citri Kuwayama (Hemiptera: Liviidae) in the Republic of Benin, West Africa. Sci. Rep. 13, 801

Cocuzza, G. E. M. et al. A review on Trioza erytreae (African citrus psyllid), now in mainland Europe, and its potential risk as vector of huanglongbing (HLB) in citrus. J. Pest Sci. 90, 1–17 (2017).

Article Google Scholar

Arengo, E. Trioza erytreae (African citrus psyllid). CABI Compend. https://doi.org/10.1079/cabicompendium.5491 (2013).

Article Google Scholar

Halbert, S. E. & Manjunath, K. L. Asian citrus psyllids (Sternorrhyncha: Psyllidae) and greening disease of citrus: A literature review and assessment of risk in Florida. Fla. Entomol. 87, 330–353 (2004).

Article Google Scholar

Subandiyah, S. et al. Colonization of Asiatic citrus psyllid and Huanglongbing development on Citrus and Citrus relatives in Indonesia. Proc. Int. Res. Conf. 1, 393 (2008).

Google Scholar

Dosoky, N. S., Satyal, P., Gautam, T. P. & Setzer, W. N. Composition and biological activities of Murraya paniculata (L.) Jack essential oil from Nepal. Medicines 3, 7 (2016).

Article PubMed PubMed Central Google Scholar

Benhadi-Marín, J., Garzo, E., Moreno, A., Pereira, J. A. & Fereres, A. Host plant preference of Trioza erytreae on lemon and bitter orange plants. Arthropod-Plant Interact. 15, 887–896. https://doi.org/10.1007/s11829-021-09862-0 (2021).

Article Google Scholar

Aidoo, O. F. et al. Size and shape analysis of Trioza erytreae Del Guercio (Hemiptera: Triozidae), vector of citrus huanglongbing disease. Pest Manag. Sci. 75, 760–771 (2019).

Article CAS PubMed Google Scholar

Hall, D. G., Richardson, M. L., Ammar, E. D. & Halbert, S. E. Asian citrus psyllid, Diaphorina citri, vector of citrus huanglongbing disease. Entomol. Exp. Appl. 146, 207–223 (2013).

Article Google Scholar

Hall, D. G. & Hentz, M. G. Influence of light on reproductive rates of Asian citrus psyllid (Hemiptera: Liviidae). J. Insect Sci. 19, 9 (2019).

Article PubMed PubMed Central Google Scholar

EFSA Panel on Plant Health (PLH) et al. Pest categorisation of Diaphorina citri. EFSA J. 19(1), e06357 (2021).

Article PubMed Central Google Scholar

Arengo, E. Trioza erytreae (African citrus psyllid) CABI Compendium. CABI Int. https://doi.org/10.1079/cabicompendium (2022).

Article Google Scholar

Catling, H. D. Notes on the biology of the South African citrus psylla, Trioza erytreae (Del Guercio) (Homoptera: Psyllidae). J. Entomol. Soc. South. Afr. 36, 299–306 (1973).

Google Scholar

Insausti, P. E. L., Ploschuk, M., Izaguirre, M. & Podworny, M. The effect of sunlight interception by sooty mold on chlorophyll content and photosynthesis in orange leaves (Citrus sinensis L.). Eur. J. Plant Pathol. 143, 559–565 (2015).

Article CAS Google Scholar

Bové, J. M. Huanglongbing: A destructive, newly-emerging, century-old disease of citrus. J. Plant Pathol. 88, 7–37 (2006).

Google Scholar

Yamamoto, P. T. et al. Detection of Candidatus Liberibacter americanus and asiaticus in Diaphorina citri Kuwayama (Hemiptera: Psillidae). In Proceedings of Huanglongbing-Greening International Workshop, Ribeirão Preto (Vol. 87) (2006).

Ajene, I. J. et al. First report of field population of Trioza erytreae carrying the huanglongbing-associated pathogen, ‘Candidatus Liberibacter asiaticus’, in Ethiopia. Plant Dis. 103, 1766 (2019).

Article Google Scholar

Reynaud, B. et al. The African citrus psyllid Trioza erytreae: An efficient vector of Candidatus Liberibacter asiaticus. Front. Plant Sci. 13, 1–11 (2022).

Article Google Scholar

Antolinez, C. A., Moyneur, T., Martini, X. & Rivera, M. J. High temperatures decrease the flight capacity of Diaphorina citri Kuwayama (Hemiptera: Liviidae). Insects 12, 394 (2021).

Article PubMed PubMed Central Google Scholar

Arakawa, K. & Mivamolo, K. Flight ability of Asiatic citrus psyllid, Diaphorina citri Kuwayama (Homoptera; Psyllidae), measured by a flight mill. Res. Bull. Plant Prot. Serv. Jpn. 43, 23–26 (2007).

Google Scholar

Boina, D. R., Meyer, W. L., Onagbola, E. O. & Stelinski, L. L. Quantifying dispersal of Diaphorina citri (Hemiptera: Psyllidae) by immunomarking and potential impact of unmanaged groves on commercial citrus management. Environ. Entomol. 38, 1250–1258 (2009).

Article PubMed Google Scholar

Cifuentes-Arenas, J. C., de Goes, A., de Miranda, M. P., Beattie, G. A. & Lopes, S. A. Citrus flush shoot ontogeny modulates biotic potential of Diaphorina citri. PLoS One 13, 1 (2018).

Google Scholar

Pluke, R. W., Qureshi, J. A. & Stansly, P. A. Citrus flushing patterns, Diaphorina citri (Hemiptera: Psyllidae) populations and parasitism by Tamarixia radiata (Hymenoptera: Eulophidae) in Puerto Rico. Fla. Entomol. 91, 36–42 (2008).

Article Google Scholar

Samways, M. J. & Manicom, B. Q. Immigration, frequency distributions and dispersion patterns of the psyllid Trioza erytreae (Del Guercio) in a citrus orchard. J. Appl. Ecol. 1, 463–472 (1983).

Article Google Scholar

USAID (U.S. Agency for International Development). Citrus 2005 (USAID, 2005).

Google Scholar

Liu, Y., Heying, E. & Tanumihardjo, S. A. History, global distribution, and nutritional importance of citrus fruits. Compr. Rev. Food Sci. Food Saf. 11, 530–545 (2012).

Article CAS Google Scholar

FAOSTAT. FAO Statistics (Food and Agriculture Organization of the United Nations, 2022). http://faostat.fao.org/ (Accessed 23 Nov 2022).

Brentu, F. C. et al. Crop loss, aetiology, and epidemiology of citrus black spot in Ghana. Eur. J. Plant Pathol. 133, 657–670 (2012).

Article Google Scholar

Yang, C. T. Psyllidae of Taiwan. Taiwan Mus. Spec. Publ. Ser. 3, 37–41 (1984).

Google Scholar

OEPP/EPPO. EPPO Standards PM 7/52(1). Diagnostic protocol for Diaphorina citri. OEPP/EPPO Bull. 35, 331–333 (2005).

Google Scholar

Dellaporta, S. L., Wood, J. & Hicks, J. B. A plant DNA mini preparation: Version II. Plant Mol. Biol. Rep. 1, 19–21 (1983).

Article CAS Google Scholar

Boykin, L. M. et al. Overview of worldwide diversity of Diaphorina citri Kuwayama mitochondrial cytochrome oxidase 1 haplotypes: Two old world lineages and a new world invasion. Bull. Entomol. Res. 102, 573–582 (2012).

Article CAS PubMed PubMed Central Google Scholar

Pérez-Rodríguez, J. et al. Classical biological control of the African citrus psyllid Trioza erytreae, a major threat to the European citrus industry. Sci. Rep. 9, 9440 (2019).

Article ADS PubMed PubMed Central Google Scholar

Hall, T. A. BioEdit: A user-friendly biological sequence alignment editor and analysis program for Windows 95/98/NT. Nucleic Acid Symp. 41, 95–98 (1999).

CAS Google Scholar

Altschul, S. F., Gish, W., Miller, W., Myers, E. W. & Lipman, D. J. Basic local alignment search tool. J. Mol. Biol. 215, 403–410 (1990).

Article CAS PubMed Google Scholar

Kumar, S., Stecher, G. & Tamura, K. MEGA7: Molecular evolutionary genetics analysis version 7.0 for bigger datasets. Mol. Biol. Evol. 33, 1870–1874 (2016).

Article CAS PubMed PubMed Central Google Scholar

Muhire, B. M., Varsani, A. & Martin, D. P. SDT: A virus classification tool based on pairwise sequence alignment and identity calculation. PLoS One 26, e108277 (2014).

Article ADS Google Scholar

Percy, D. M. Making the most of your host: The Metrosideros-feeding psyllids (Hemiptera, Psylloidea) of the Hawaiian Islands. ZooKeys 649, 1 (2017).

Article Google Scholar

Khamis, F. M. et al. DNA barcode reference library for the African citrus triozid, Trioza erytreae (Hemiptera: Triozidae): Vector of African citrus greening. J. Econ. Entomol. 110, 2637–2646 (2017).

Article CAS PubMed Google Scholar

Li, W., Hartung, J. S. & Levy, L. Quantitative real-time PCR for detection and identification of Candidatus Liberibacter species associated with citrus huanglongbing. J. Microbiol. Methods 66, 104–115 (2006).

Article CAS PubMed Google Scholar

Li, W., Duan, Y., Brlansky, R., Twieg, E. & Levy, L. Incidences and population of ‘Candidatus Liberibacter asiaticus’ in Asian citrus psyllid (Diaphorina citri) on citrus plants affected by huanglongbing in Florida. Int. Res. Conf. HLB, Dec. 1–5, 2008, Orlando (2008).

Li, W., Li, D., Twieg, E., Hartung, J. S. & Levy, L. Optimized quantification of unculturable Candidatus Liberibacter spp. in host plants using real-time PCR. Plant Dis. 92, 854–861 (2008).

Article CAS PubMed Google Scholar

Shimwela, M. M. et al. First occurrence of Diaphorina citri in East Africa, characterization of the Ca. Liberibacter species causing huanglongbing (HLB) in Tanzania, and potential further spread of D. citri and HLB in Africa and Europe. Eur. J. Plant Pathol. 146(2), 349–368 (2016).

Article Google Scholar

Mack, R. N. et al. Biotic invasions: Causes, epidemiology, global consequences, and control. Ecol. Appl. 10, 689–710 (2000).

Article Google Scholar

Holford, P. et al. High altitudes limit the incidence of huanglongbing and its vector, Diaphorina citri, in citrus orchards. IOP Conf. Ser. Earth Environ. Sci. 1018(1), 012019 (2022).

Article Google Scholar

Asante, F. A. & Amuakwa-Mensah, F. Climate change and variability in Ghana: Stocktaking. Climate 3, 78–101 (2014).

Article Google Scholar

Liu, Y. H. & Tsai, J. H. Effects of temperature on biology and life table parameters of the Asian citrus psyllid, Diaphorina citri Kuwayama (Homoptera: Psyllidae). Ann. Appl. Biol. 137, 201–206 (2000).

Article Google Scholar

Aidoo, O. F. et al. Temperature-based phenology model of African citrus triozid (Trioza erytreae Del Guercio): Vector of citrus greening disease. J. Appl. Entomol. 146, 88–97 (2022).

Article Google Scholar

González-Tokman, D. et al. Insect responses to heat: Physiological mechanisms, evolution and ecological implications in a warming world. Biol. Rev. 95, 802–821 (2020).

Article PubMed Google Scholar

Ajene, I. J. et al. Genetic diversity of Diaphorina citri (Hemiptera: Liviidae) unravels phylogeographic structure and invasion history of eastern African populations. Ecol. Evol. 12, e9090 (2022).

Article PubMed PubMed Central Google Scholar

Das, A. K., Rao, C. N., George, A. & Chichghare, S. A. Molecular identification and characterization of the Asian citrus psyllid vector, Diaphorina citri (Hemiptera: Psyllidae) and the transmitted Huanglongbing-associated bacterium, Candidatus Liberibacter asiaticus in India. J. Plant Pathol. 104, 1–14 (2022).

Article Google Scholar

Meng, L., Wang, Y., Wei, W. H. & Zhang, H. Population genetic structure of Diaphorina citri Kuwayama (Hemiptera: Liviidae): Host-driven genetic differentiation in China. Sci. Rep. 8(1), 1–15 (2018).

ADS Google Scholar

Gottwald, T. R., Graça, J. V. D. & Bassanezi, R. B. Citrus huanglongbing: The pathogen and its impact. Plant Health Prog. 8(1), 31 (2007).

Article Google Scholar

Alquézar, B. et al. Cultural management of huanglongbing: Current status and ongoing research. Phytopathology 112(1), 11–25 (2022).

Article PubMed Google Scholar

Antolínez, C. A., Martini, X., Stelinski, L. L. & Rivera, M. J. Wind speed and direction drive assisted dispersal of Asian citrus psyllid. Environ. Entomol. 51, 305–312 (2022).

Article PubMed Google Scholar

Tomaseto, A. F., Krugner, R. & Lopes, J. R. S. Effect of plant barriers and citrus leaf age on dispersal of Diaphorina citri (Hemiptera: Liviidae). J. Appl. Entomol. 140, 91–102 (2016).

Article Google Scholar

Merfa, M. V. et al. Probing the application of OmpA-derived peptides to disrupt the acquisition of ‘Candidatus Liberibacter asiaticus’ by Diaphorina citri. Phytopathology 112(1), 163–172 (2022).

Article CAS PubMed Google Scholar

Chow, A. & Sétamou, M. Parasitism of Diaphorina citri (Hemiptera: Liviidae) by Tamarixia radiata (Hymenoptera: Eulophidae) on residential citrus in Texas: Importance of colony size and instar composition. Biol. Control 165, 104796 (2022).

Article Google Scholar

Cui, X. et al. Population diversity of ‘Candidatus Liberibacter asiaticus’ and Diaphorina citri in Sichuan: A case study for Huanglongbing monitoring and interception. Plant Dis. 106, 1632–1638 (2022).

Article CAS PubMed Google Scholar

Padhi, E. M. et al. The impact of Diaphorina citri-vectored ‘Candidatus Liberibacter asiaticus’ on citrus metabolism. Phytopathology 112(1), 197–204 (2022).

Article CAS PubMed Google Scholar

Sawadogo, M. W. et al. Identification of alternative hosts of the tomato leafminer Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae) in West Africa. Afr. Entomol. 30, 1–5 (2022).

Article Google Scholar

Zhou, S., Qin, Y., Wang, X., Zheng, X. & Lu, W. Fitness of the fall armyworm Spodoptera frugiperda to a new host plant, banana (Musa nana Lour.). Chem. Biol. Technol. Agric. 9(1), 1–9 (2022).

Article ADS CAS Google Scholar

Sonter, S., Mishra, S., Dwivedi, M. K. & Singh, P. K. Chemical profiling, in vitro antioxidant, membrane stabilizing and antimicrobial properties of wild growing Murraya paniculata from Amarkantak (MP). Sci. Rep. 11(1), 1–15 (2021).

Article ADS Google Scholar

Manjunath, K. Á., Halbert, S. E., Ramadugu, C. H., Webb, S. U. & Lee, R. F. Detection of ‘Candidatus Liberibacter asiaticus’ in Diaphorina citri and its importance in the management of citrus huanglongbing in Florida. Phytopathology 98, 387–396 (2008).

Article CAS PubMed Google Scholar

Rao, C. N., Shivankar, V. J., Deole, S., David, K. J. & Dhengre, V. N. Insecticide resistance in field populations of Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae). Pestic. Res. J. 26(1), 42–47 (2014).

CAS Google Scholar

Tiwari, S., Mann, R. S., Rogers, M. E. & Stelinski, L. L. Insecticide resistance in field populations of Asian citrus psyllid in Florida. Pest Manag. Sci. 67, 1258–1268 (2011).

Article CAS PubMed Google Scholar

Wenninger, E. J., Stelinski, L. L. & Hall, D. G. Relationships between adult abdominal color and reproductive potential in Diaphorina citri (Hemiptera: Psyllidae). Ann. Entomol. Soc. Am. 102, 476–483 (2009).

Article Google Scholar

Download references

We thank the Texas A&A University Kingsville, Citrus Center, The Texas AgriLife Extension Center, the University of Environment and Sustainable Development (UESD) for access to instruments, Dr. Gertrude L. A. Dali, University of Cape Coast, and Mr. Jonathan Dabo of Forest Research Institute of Ghana for the assisting us with the identification of the host plant species.

Department of Biological Sciences, University of Environment and Sustainable Development, PMB, Somanya, E/R, Ghana

Owusu F. Aidoo, Kodwo D. Ninsin, William K. Heve & Aboagye K. Dofuor

Council for Scientific Industrial Research, Oil Palm Research Institute, Coconut Research Programme, P. O. Box 245, Sekondi, Ghana

Fred K. Ablormeti & Frederick L. Sossah

Cocoa Research Institute of Ghana, New Tafo, E/R, Ghana

Akua K. Antwi-Agyakwa & Clement O. Aryee

Department of Physical and Mathematical Sciences, University of Environment and Sustainable Development, Somanya, Ghana

Jonathan Osei-Owusu & George Edusei

Texas A&M University-Kingsville Citrus Center, Weslaco, 78599, USA

Yovanna L. Soto & Mamoudou Sétamou

Presbyterian University, Ghana, Abetifi-Kwahu, Eastern Region, Ghana

Angelina F. Osabutey

Department of Plant Pathology and Microbiology, Texas A&M AgriLife Research and Extension Center, Weslaco, TX, 78596, USA

Olufemi J. Alabi

You can also search for this author in PubMed Google Scholar

O.F.A. wrote the first draft. O.F.A. and M.S. conceived and designed the study. O.F.A., F.K.A., A.K.A.A., K.D.N., J.O.O., W.K.H., A.K.D., G.E., A.F.O. and F.L.S. collected data. O.J.A., O.F.A., M.S., C.O.A., and Y.L.S. conducted analyses. All authors read the final manuscript.

Correspondence to Owusu F. Aidoo or Mamoudou Sétamou.

The authors declare no competing interests.

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.

Reprints and Permissions

Aidoo, O.F., Ablormeti, F.K., Ninsin, K.D. et al. First report on the presence of huanglongbing vectors (Diaphorina citri and Trioza erytreae) in Ghana. Sci Rep 13, 11366 (2023). https://doi.org/10.1038/s41598-023-37625-9

Download citation

Received: 21 December 2022

Accepted: 24 June 2023

Published: 13 July 2023

DOI: https://doi.org/10.1038/s41598-023-37625-9

Anyone you share the following link with will be able to read this content:

Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.