Spiralling whitefly and its management practices in the South Pacific. A review

A few species of whiteflies are considered a serious insect pest of vegetation and ornamental plants across many countries. The Spiralling whiteflies, Aleurodicus dispersus Russell has been recorded on many different plant species across countries. These whiteflies feed exclusively on leaves and have the ability to spread plant diseases. A great deal of research has been done on whiteflies in relation to which control methods would be most effective in pest management. The management of Spiralling whitefly in the South Pacific is heavily reliant on biological control (using the parasitic wasps, predators, and entomopathogenic fungi). Other control methods include physical, botanical, and chemical to keep the whitefly population at lower levels. In this paper, an overview of Spiralling whiteflies and its management practices in the South Pacific will be reviewed

Change detection of a coastal woodland mangrove forest in Fiji by integration of remote sensing with spatial mapping

Mangroves play key ecological role in structuring the availability of coastal resources. The current study was focused on change detection in a large mangrove patch located in Votua area of the Ba province in Fiji. Globally, the mangrove population continues to decline with the changes in climatic conditions and anthropo-genic activities. Baseline information through wetland maps and time series change are essential references for the development of effective mangrove management plans. These maps reveal the status of the resource over a period of time and the impacts from anthropogenic activities. Remote sensing techniques were integrated with geographic information system tools for mapping and detecting temporal change over a period of 20 years. Remotely sensed imagery data from Landsat satellite was sourced from the year 1999 to 2018 for this investigation. The mapping analysis of temporal changes in mangrove forests was carried using the versatile ArcGIS and ENVI software. The pilot change detection analysis revealed a small but important change in the mangrove patch over these years. Landward creep of mangroves was also detected. The outcomes of this study serve as baseline and conservation information for the development and implementation of effective management plans for one of Fiji’s largest mangrove patches

In Vitro Hepatic Assessment of Cineole and Its Derivatives in Common Brushtail Possums (Trichosurus vulpecula) and Rodents

Folivore marsupials, such as brushtail possum (Trichosurus Vulpecula) and koala (Phascolarctos cinereus), can metabolise higher levels of dietary terpenes, such as cineole, that are toxic to eutherian mammals. While the highly efficient drug metabolising enzymes, cytochrome P450 3A (CYP3A) and phase II conjugating enzymes (UDP-glucuronosyltransferase, UGT), are involved in the metabolism of high levels of dietary terpenes, evidence for inhibitory actions on these enzymes by these terpenes is scant. Thus, this study investigated the effect of cineole and its derivatives on catalytic activities of hepatic CYP3A and UGT in mice, rats, and possums. Results showed that cineole (up to 50 µM) and its derivatives (up to 25 µM) did not significantly inhibit CYP3A and UGT activities in mice, rats, and possums (both in silico and in vitro). Interestingly, basal hepatic CYP3A catalytic activity in the possums was ~20% lower than that in rats and mice. In contrast, possums had ~2-fold higher UGT catalytic activity when compared to mice and rats. Thus, these basal enzymatic differences may be further exploited in future pest management strategies

Bioactivity of selected essential oils from medicinal plants found in Fiji against the Spiralling whiteflies (Aleurodicus dispersus Russell)

The concentration of essential oil solutions [0.25%, 0.5% and 5% (v/v)] of five medicinal plants found in the South Pacific (Fiji) were subjected to the whitefly (Aleurodicus dispersus Russell) in order to assess eventual control activities, by both fumigant and repellent tests. The essential oil of Ocimum tenuiflorum L. exhibited the strongest fumigant activity against the Spiralling whiteflies with an LC50 value of 0.003% followed by the essential oil of Cymbopogon citratus (DC.) Stapf. (LC50 = 0.004%), Cananga odorata (Lam.) Hook F. and Thoms (LC50 = 0.050%), Murraya koenigii (L.) Spreng. (LC50 = 0.113%), and Euodia hortensis forma hortensis (LC50 = 0.114%). The essential oil of M. koenigii (RI=52%) and C. citratus (RI=52%) at 5% (v/v) concentration were found to have a higher repellent toxicity against the Spiralling whiteflies. The chemical composition of the selected essential oils was also determined using GC-MS. The trend in the chemical constituent of essential oils revealed that the phenolic and alcoholic compounds were the major groups of contributors to the tested activities. Thus, these data suggested that essential oils from the selected medicinal plants found in the South Pacific (Fiji) have the potential to be employed in the pesticidal activities

Spiralling whitefly and its management practices in the South Pacific. A review

A few species of whiteflies are considered a serious insect pest of vegetation and ornamental plants across many countries. The Spiralling whiteflies, Aleurodicus dispersus Russell has been recorded on many different plant species across countries. These whiteflies feed exclusively on leaves and have the ability to spread plant diseases. A great deal of research has been done on whiteflies in relation to which control methods would be most effective in pest management. The management of Spiralling whitefly in the South Pacific is heavily reliant on biological control (using the parasitic wasps, predators, and entomopathogenic fungi). Other control methods include physical, botanical, and chemical to keep the whitefly population at lower levels. In this paper, an overview of Spiralling whiteflies and its management practices in the South Pacific will be reviewed

Egg deposition by Spiralling whiteflies (Aleurodicus dispersus) strongly influences the stomatal conductance of Manihot esculenta

Whiteflies are considered a most damaging pest in all cassava-producing regions, as they are responsible for transmitting plant viruses and directly damaging plants via heavy infestation. Aleurodicus dispersus Russell (Hemiptera: Aleyrodidae) commonly known as Spiralling whitefly, a native to the Caribbean region and Central America. Over 300 plant species from approximately 77 families have been recorded as hosts of Aleurodicus dispersus Russell, worldwide, and the species is known to have widely spread over North America, South America, Asia, Africa, Australia and in several Pacific Island Countries (PIC). In the South Pacific it is known from Majuro (1986) (Marshall Is), Cook Islands (1984), Fiji (1985), Nauru (1987), Papua New Guinea (1987), Kiribati (June 1988), Tokelau (late 1988) and Tonga (November 1988

A mini-review of essential oils in the South Pacific and their insecticidal properties

Studies on traditional medicinal plants (TMPs) found in the South Pacific that holds potential for the insect controls have been reviewed. Few TMPs are known to have insecticidal properties, however many of those are still unknown in the South Pacific. The information on plants were collected using online databases such as Science Direct, PubMed, Google Scholar, Scopus and Springer Open in order to confirm the studies that support the insecticidal properties of plants present in the South Pacific. The following study confirmed that there is a potential for the selected TMPs suggesting enough evidence for their usage in the insecticidal activities. These plants would represent an alter- native in crop protection due to its novel, safe and eco-friendly substitutes for its effective insecticidal properties

In Vitro Hepatic Assessment of Cineole and Its Derivatives in Common Brushtail Possums (<em>Trichosurus vulpecula</em>) and Rodents

Folivore marsupials, such as brushtail possum (Trichosurus Vulpecula) and koala (Phascolarctos cinereus), can metabolise higher levels of dietary terpenes, such as cineole, that are toxic to eutherian mammals. While the highly efficient drug metabolising enzymes, cytochrome P450 3A (CYP3A) and phase II conjugating enzymes (UDP-glucuronosyltransferase, UGT), are involved in the metabolism of high levels of dietary terpenes, evidence for inhibitory actions on these enzymes by these terpenes is scant. Thus, this study investigated the effect of cineole and its derivatives on catalytic activities of hepatic CYP3A and UGT in mice, rats, and possums. Results showed that cineole (up to 50 µM) and its derivatives (up to 25 µM) did not significantly inhibit CYP3A and UGT activities in mice, rats, and possums (both in silico and in vitro). Interestingly, basal hepatic CYP3A catalytic activity in the possums was ~20% lower than that in rats and mice. In contrast, possums had ~2-fold higher UGT catalytic activity when compared to mice and rats. Thus, these basal enzymatic differences may be further exploited in future pest management strategies

Antibacterial and Antifungal Activities of Essential Oils from Medicinal Plants Found in the South Pacific

Natural products such as essential oils have been studied since ancient times to understand their biological properties. Essential oils are noted for their antimicrobial activity. Thus, the focus of this study was to evaluate the antimicrobial effect of five essential oils (EOs) from selected medicinal plants found in the South Pacific, on selected human pathogenic bacteria and fungi affecting agricultural industries. The disc diffusion method was carried out and the diameter of inhibition zones (mm) (DZI) using 0.25, 0.5, 5, 25, 50 and 100% (v/v) of essential oil concentrations were reported. The activity of Cananga odorata essential oils against Thermus thermophiles and Pseudomonas aeruginosa were among the selected bacteria that only showed the susceptibility at the lowest concentration (0.25% v/v). The diameter inhibition zones were 1.60 mm and 4.20 mm, respectively. The inhibitory effect of Ocimum tenuiflorum L essential oils at the highest concentration (100%) showed DZI ranging above 14 mm for all the selected bacteria and above 25 mm for the all selected fungi. The inhibitory effect of selected bacteria and fungi increased with stronger concentrations of essential oils. Hence, the essential oils from medicinal plants found in the South Pacific hold great potential for the antibacterial and antifungal properties