Red Palm Weevil, Rhynchophorus ferrugineus （Olivier）： Economic Importance, Biology, Biogeography and Integrated Pest Management

The Red Palm Weevil （RPW）, Rhynchophorus ferrugineus （Olivier）, （Coleoptera, Curculionidae, Rhynchophorinae）, is an invasive species that is originated from Southeast Asia. It has.invaded Middle East and several countries of the Mediterranean Basin during the last three decades where it attacks palm trees. During the last three decades, multiple introductions of RPW to the Middle East, Europe and Caribbean （Island of Curacao, Netherland Antilles）, Lebanon and United States of America （Laguna Beach, Orange County, California） （USA） have occurred and the RPW is now a serious pest of many palm species. Duration of all life parameters varies significantly where the entire life cycle takes about 45 to 298 days. Different artificial diets were developed and were tested for mass rearing of RPW. Control of RPW is difficult due to the concealed nature of the life cycle of the pest. Integrated Pest Management （IPM） strategy has been applied successfully to deal with RPW problem. The IPM strategy consists of various preventive and curative methods; those methods were categorized in nine categories in this review. The main objective of this work was to review the existing knowledge on RPW＇s different aspects, with an ultimate aim of revealing the actual situation of the research on RPW.

Effect of Zinc Sulfate against the Red Palm Weevil Rhynchophorus ferrugineus with Reference to Their Histological Changes on the Larval Midgut and Adult Reproductive System

The red palm weevil Rhynchophorusferrugineus is the most important insect pest for the date palm trees in the Middle East and Gulf states. Zinc sulfate （ZnSOa＇H20） was toxicologically, biologically and physiologically evaluated as insect development disruptors against the RPW. LCs0 of Zinc sulfate against 10 days old larvae was 0.566%, 3% concentration inhibited the larvae from feeding. LCs0 concentration of zinc sulfate solution was capable to disrupting growth, development and reproduction of R. ferrugineus. Growth and development disruptions are resulted from larval feeding on the treated diet that causing percentage of mortality rate, retardation in larval and pupal duration, percentage of pupation, adults emergence, reduction in deposited eggs that laid by the resulting adults and in the egg fertility. The study further reveals that Zinc sulfate effects on histological structure of epithelial cells of the larval midgut including separation and elongation of their cells, rupture in the peritrophic membrane and in some microvilli and some degeneration of the surrounding muscles. Histological changes also was observed on the adults ovary, in this way, disrupt female gamete production through their action on the accumulation of yolk granules （vitellogenesis） and follicular epithelial cells. Disruption of male gamete production was detected by disorganized of testicular cysts and depopulation of these cysts in addition to degeneration in germ cells. Zinc sulfate may be used among other control methods by injection into the tree trunk or as fertilizer around the tree roots which in turn may have an indirect effect for controlling the RPW.

Biodiesel Production from Rhynchophorus ferrugineus Larvae Oil: Physichochemical Properties and Acid Composition of Oil as Affected by Oil Extraction Protocol

Biodiesel, a renewable energy source made from natural oils and fats, can be produced using white raffia larvae as a raw material. These larvae have a high lipid content and a short life cycle, making them suitable for this purpose. One crucial step in biodiesel production is oil extraction, and this study aimed to investigate how the extraction protocol affects the fuel properties of the oil. To study the impact of solvent type, solvent volume, and residence time on oil yield, 200 grams of Rhynchophorus ferrugineus were used in a Soxhlet extractor. The researchers examined the physicochemical properties and fatty acid composition of the crude grease using the European biodiesel standard (EN14214) and gas chromatography methods, respectively. The study found that hexane as a solvent produced the highest oil yield (64.44%) during a four-hour extraction period with a solvent ratio of 300 ml. Furthermore, the hexane-extracted oil had the highest iodine number (3.02 g/100 g) and cetane number (55.69). These values indicate favorable properties for biodiesel production. The Rhynchophorus ferrugineus larvae oil proved to be a rich source of monounsaturated fatty acids (76%), which were found to be significantly affected by the solvent type. Based on quality assessment, Rhynchophorus ferrugineus can be suitable for biodiesel production. In summary, under the given operational conditions, hexane is the most suitable solvent for Rhynchophorus ferrugineus oil extraction for biodiesel production. Further research in optimizing the extraction process can contribute to the efficient utilization of renewable energy sources like white raffia larvae for biodiesel production.

Shoot drying and its cause in Calamus simplicifolius at Nanmeiling, Hainan, China

Many stems are subject to shoot drying in the plantations of Calamus simplicifolius Wei at the Nanmeiling Base of the Forestry Bureau of Baisha County, Hainan Province. As a palm, stems of C simplicifolius stop growing and later die if the shoots are dry. Generally, shoot drying means reduced cane production and reduced profit for a rattan plantation. We aimed to quantify the incidence of shoot drying and determine its reason. We sampled eight 20 m × 20 m plots in the C simplicifolius plantations. In each plot, we counted stems and categorized them as drying shoot or normal shoot, and mother stem or sucker stem. We measured stem length and categorized them as drying shoot and normal shoot for mother stems. We cut open each shoot-drying stem to determine the cause of drying from drying part to fresh part. The frequency of mother stems （259 stem·ha^-1）, was significantly lower than sucker stems （588 stem·ha^-1）. The percentage of shoot drying was 33.8% for mother stems, not significantly higher than that for sucker stems （18,9%）. The mother shoot stems were significantly shorter if they were drying than if normal. 80% of stems with a drying shoot were hollow within the leaf sheath, whereas 10% hosted lively mature larvae （one larvae per shoot） and 10% hosted several lively young larvae. Mature larvae were identified as the Red Palm Weevil, Rhynchophorus ferrugineus Oliver. To confirm the present of the weevil, three pheromone traps for the weevil were set up in the plantations and adult weevils were trapped on the next day and identified as the Red Palm Weevil. We conclude that shoot drying of C. simplicifolius is probably caused by the Red Palm Weevil.

Knoxdaviesia with K.serotectus(Van der Linde&Jol.Roux)Z.W.de Beer&M.J.Wingf.a new world record from the gut of red palm weevils

During surveys of the mycota inhabiting guts of insect species in Assiut area,Egypt,two interesting isolates were obtained from two different gut samples(out of 11 investigated)of the red palm weevil(Rhynchophorus ferrugineus Olivier).These isolates were identified phenotypically as Knoxdaviesia serotectus(≡Gondwanamyces serotectus).The isolates were deposited in the Assiut University Mycological Centre Culture Collection and given AUMC numbers,AUMC 10299 and AUMC 10293.Brief descriptions and photos are presented.This species is recorded here for the first time worldwide from the gut of red palm weevils.

Assessing immunocompetence in red palm weevil adult and immature stages in response to bacterial challenge and entomopathogenic nematode infection

Parasites and pathogens can follow different patterns of infection depending on the host developmental stage or sex.In fact,immune function is energetically costly for hosts and trade-offs exist between immune defenses and life history traits as growth,de-velopment and reproduction and organisms should thus optimize immune defense through their life cycle according to their developmental stage.ldentifying the most susceptible target and the most virulent pathogen is particularly important in the case of insect pests,in order to develop effective control strategies targeting the most vulnerable individuals with the most effective control agent.Here,we carried out laboratory tests to identify the most susceptible target of infection by infecting different stages of the red palm weevil Rhynchophorus ferrugineus(larvae,pupae,male,and female adults)with both a generic pathogen,antibiotic-resistant Gram-negative bacteria Escherichia coli XL1-Blue,and two specific strains of entomopathogenic nematodes(EPNs),Steinernema carpocapsae ItS-CAO1 and Heterorhabditis bacteriophora ItH-LUI.By evaluating bacterial clearance,host mortality and parasite progeny release,we demonstrate that larvae are more resistant than adults to bacterial challenge and they release less EPNs progeny after infection despite a higher mortality compared to adults.Considering the two EPN strains,S.carpocapsae was more virulent than II.bacteriophora both in terms of host mortality and more abundant progeny released by hosts after death.The outcomes attained with unspecific and specific pathogens provide useful information for a more efficient and sustainable management of this invasive pest.