Coconut Pest Research Articles

Proposal for detecting coconut rhinoceros beetle breeding sites using harmonic radar

Coconut rhinoceros beetle (CRB), a major pest of coconut and oil palms, is causing severe economic and environmental damage following recent invasions of several Pacific islands. Population suppression and eradication of this pest requires location and destruction of active and potential breeding sites where all life stages aggregate. Three search tactics for discovering breeding sites have been used with limited success: visual search by humans, search with assistance from detector dogs and search by tracking CRB adults fitted with radio transmitters. Here, we suggest a fourth search tactic: releasing CRB adults fitted with harmonic radar tags to locate breeding sites. Our idea is to find static end points for tags which accumulate at breeding sites, rather than active tracking of individual beetles. We plan to use commercially available hand-held harmonic radar devices. If we are successful, this technique may be useful for locating other insects which aggregate, such as hornets and other social insects.

Social media posts suggest that coconut rhinoceros beetle has established in the Western hemisphere

AbstractThe coconut rhinoceros beetle (CRB: Oryctes rhinoceros L.) is one of the most damaging pests of coconut and oil palms in the Asia/Pacific region but has not been reported from the Western Hemisphere. Here, we report a possible establishment of CRB in Nayarit, Mexico, based on an analysis of social media reports and photographs indicating the presence of the beetle and the distinctive v‐shaped notches in palm fronds caused by the beetle feeding. CRB populations are destructive once established, therefore, urgent actions are required to contain the pest and prevent damage to coconut and oil palm in the Americas.

Field evaluation of red palm weevil Rhynchophorus ferrugineus Olivier pheromone lures

The red palm weevil Rhynchophorus ferrugineus Olivier (Coleoptera: Curculionidae) is a key pest of coconut. The efficiency of pheromone lures sourced from three countries along with natural (sugarcane) and synthetic (ethyl acetate) co-attractants, was tested in the infested coconut plantation. The results revealed that synergists and co-attractants are essential to sustain trapping efficiency. The best weevil captures were obtained when the pheromone trap had both the natural food bait (sugarcane) and the synthetic co-attractant (ethyl acetate). Pheromone traps with only ethyl acetate as a co-attractant led to lower captures as compared to pheromone traps with only the food bait (sugarcane). In general, the captures were female dominant with an overall male: female ratio of 1:1.35.

Behavioural Response Of Parasitoid <i>Encarsia guadeloupae</i> Viggiani To Infested Host Plants Of Rugose Spiraling Whitefly <i>Aleurodicus rugioperculatus</i> Martin

The rugose spiralling whitefly (RSW) Aleurodicus rugioperculatus Martin is an invasive pest of coconut in India. The behavioural response of its parasitoid Encarsia guadeloupae Viggiani (Hymenoptera: Aphelinidae) on healthy and RSW infested host plants of coconut, banana, sapota and guava has been assessed in this study using a six arm olfactometer. Parasitoids’ attraction was maximum with the infested banana leaves (1.62± 0.28) followed by coconut (1.28± 0.20), guava (1.05± 0.24) and sapota (0.82± 0.24). The results obtained also reveal that E. guadeloupae can be mass reared on banana plants infested with RSW nymphs to enable better mass production of the parasitoid.

Estimating the population size of Steneotarsonemus concavuscutum in coconut fruits using diagrammatic damage scales

Predictive models based on diagrammatic scales of damage have been developed to estimate the population density of Aceria guerreronis, an important coconut pest. Steneotarsonemus concavuscutum colonizes the same habitat as A. guerreronis and causes similar lesions on fruits. The present study aims to evaluate the possibility of using predictive models developed for A. guerreronis to estimate S. concavuscutum populations. Fruits infested by S. concavuscutum were collected and evaluated according to the diagrammatic scales developed by Galvão et al. (2008) and by Sousa et al. (2017). All active forms of S. concavuscutum were accounted for. Graphical and statistical analyzes were performed to evaluate the adequacy of the predictive models. Both the models proved to be inadequate to estimate the population of S. concavuscutum, both statistically and graphically. New predictive models were proposed using the grades of the diagrammatic scales and the mean numbers of S. concavuscutum/fruit. To validate the models, new fruits were collected and evaluated by 10 examiners with both the diagrammatic scales. All active forms of S. concavuscutum were accounted for. The new predictive model based on the grades of Galvão et al. (2008) underestimated the populations of S. concavuscutum, while the model obtained from the grades of Sousa et al. (2017) generated values close to the expected, proving itself to be adequate statistically and graphically, to estimate the populations of S. concavuscutum.

Farmers' Knowledge and Farm-Level Management Practices of Coconut Pests in Ghana: Assessment Based on Gender Differences

Coconut production is significantly constrained by a wide variety of pests. Anecdotal evidence also suggests that management of these pests is influenced by gender differences. Therefore, there was a need to assess farmers' knowledge about coconut pests, farm-level pest management strategies, and institutions offering training to farmers to develop an ecologically sound management strategy. To achieve this research need, we surveyed six coconut-growing districts, three each from the Western and Central Regions of Ghana, using face-to-face interviews, discussions, and direct observations. In addition, a multistage sampling technique was used to sample the coconut farmers. The sample population for each town was determined using a proportional to population size approach. The sample population was randomly drawn from each town/village using a sampling frame based on the agricultural sector records. The results showed that a majority of the farmers mentioned Oryctes monoceros as the most important coconut pest. Significantly more females than males mentioned weaver birds in their plantations ( P = 0.035). The number of women who did not mention any of the pests was significantly higher than that of men ( P = 0.007). There was a significant difference between male and female farmers who used indigenous knowledge (i.e., knowledge accumulated by an indigenous [local] population over generations of living in a certain area) ( P = 0.018) for pest management. However, pest management strategies did not vary in the Central Region. Our results showed a significant difference between male and female farmers who did not use any of the management strategies, suggesting that future studies and training should consider gender in developing sustainable pest management strategies for the pests. [Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

Shoot Borers Beetle Pest of Coconut (Oryctes rhinoceros L.) Investment at Agave spp

Background: Agave is known as one of the natural fiber-producing plants that have many benefits. Agave plants can grow well on dry land, however, many organisms can damage agave crops in the field. One of the agave plant is Shoot Borers Beetle Pest of Coconut (Oryctes rhinoceros L). The purpose of this research is to get information about variation damage of agave germ plasma to Shoot Borers Beetle Pest of Coconut (Oryctes rhinoceros L). Methods: The research was conducted at the Agave balittas collection in the Experimental Garden Balittas Karangploso. Observation of shoot borers beetle pest of coconut (Oryctes rhinoceros L.) was carried out on 6 plants. Observations were made by calculating the number of holes that were found on the leaves. Results: The results showed that the investment of Shoot Borers Beetle Pest of Coconut (Oryctes rhinoceros L) causing damage to agave germplasm varies. The average percentage of damage to Agave angustifolia and Agave cantala in 2017 due to the investment in Shoot Borers Beetle Pest of Coconut (Oryctes rhinoceros L) is range from 66.7 to 100%. The average damage caused by Shoot Borers Beetle Pest of Coconut (Oryctes rhinoceros L) investment in Agave sisalana ranges from 0 to 16.7%. Conclusions: The investment of shoot borers beetle pest of coconut in agave plants has a big impact on decreasing crop production and fiber quality.

Incorporation of essential oil from Vitex gardneriana (Lamiaceae) in microemulsions systems based on mineral and cottonseed oils increased its bioactivity against a coconut pest mite

Coconut (Cocos nucifera L.) is an important cash crop for Asia, Africa and tropical America. The coconut mite, Aceria guerreronis Keifer (Acari: Eriophyidae) is a major coconut pest, inflicting heavy damage to fruits, thereby reducing yields and farmers profitability. Previous research has demonstrated that high contents of sesquiterpenes compounds present in the essential oil of Vitex gardneriana Schauer (Lamiaceae) (EOVG) showed high potential to control A. guerreronis. Systems stabilized by surfactants, such as microemulsions (MEs), are promising to carry essential oils due to their solubilization and protection properties, generally allow for greater spreadability, wettability and have thermodynamic stability and lower viscosity. Here, we compared the acaricidal activity of MEs containing EOVG a based cottonseed oil (CO) and mineral oil (MO) as different oily phases. MEs formulations were obtained through the pseudoternary phase diagram using a 1:1 mixture of polysorbate 80: propylene glycol as surfactant and co-surfactant, respectively, and CO and MO as oily phases and water as aqueous phase. The MEs were characterized by polarized light microscopy, dynamic light scattering as well as by rheological behavior. Results based on concentration-mortality bioassays, showed that the toxicity of ME-CO containing EOVG was higher (LC50 = 195 ppm) in comparison with ME-CO without EOVG (LC50 = 669 ppm). Similarly, adding EOVG to ME-MO increased the toxicity further (LC50 = 120 ppm). Moreover, the LC50 of ME with and without EOVG for A. guerreronis was higher than the LC50 determined for the EOVG alone (LC50 = 888 ppm). The MEs containing EOVG in their LC80 and mainly LC50, repelled the mite. Overall, our results indicate that the MEs hold potential for controlling A. guerreronis, especially when EOVG was added with both oil phases.

Mite damage provides refuges and affects preference and performance of a subsequent herbivorous moth

AbstractDamage by herbivores often modifies plant structure and physiology, which may change the behaviour and performance of future herbivores. Here, we studied such interactions among the major coconut pest, the mite Aceria guerreronis (Acari: Eriophyidae), and two minor pests, the mite Steneotarsonemus concavuscutum (Acari: Tarsonemidae) and the moth Atheloca bondari (Lepidoptera: Pyralidae). All these species develop in the meristematic zone of coconuts, which is difficult to access because of the small opening between the epicarp and perianth. Both mites cause necrosis on the epicarp of the nuts, which may facilitate access to the meristematic zone by caterpillars of the moth. However, the caterpillars co‐occur predominantly with A. guerreronis and not with S. concavuscutum. We show that caterpillars did not colonize nuts without mites and colonized nuts with A. guerreronis most frequently, in agreement with the openings caused by this mite and caterpillar size. When the opening between epicarp and perianth was artificially increased, caterpillars also colonized nuts without mites and nuts with S. concavuscutum. When offered a choice, caterpillars preferred nuts with easy access to the meristematic region, regardless of the presence of mites. Caterpillars performed better on the A. guerreronis‐infested nuts than on other nuts, but moth females did not preferentially oviposit in coconut bunches infested with mites. Hence, caterpillars, not adults, select suitable feeding sites within a bunch of coconuts, and A. guerreronis facilitates the infestation of coconuts by A. bondari. We discuss how damage by mites affects the relevance of A. bondari as a coconut pest.

Model‐based prediction of the potential geographical distribution of the invasive coconut mite, Aceria guerreronis Keifer (Acari: Eriophyidae) based on MaxEnt

Abstract The coconut mite Aceria guerreronis Keifer (Acari: Eriophyidae), is a destructive mite pest of coconut, causing significant economic losses. However, an effective pest management strategy requires a clear understanding of the geographical areas at risk of the target pest. Therefore, we predicted the potential global distribution A. guerreronis using a machine learning algorithm based on maximum entropy. The potential future distribution for A. guerreronis covered the 2040 and 2060 periods under two climate change emission scenarios (SSP1‐2.6 and SSP5‐8.5) in the context of the sixth assessment report (AR6) of the Intergovernmental Panel on Climate Change. The MaxEnt model predicts the habitat suitability for A. guerreronis outside its present distribution, with suitable habitats in Oceania, Asia, Africa, and the Americas. The habitat suitability for the pest will decrease from 2040 to 2060. The areas with the highest risk of A. guerreronis are those with an annual average temperature of around 25°C, mean annual precipitation of about 1459 mm, mean precipitation seasonality close to 64%, an average variation of daytime temperature of about 8.6°C, and mean seasonality of temperature of about 149.7°C. Our findings provide information for quarantine measures and policymaking, especially where A. guerreronis is presently still absent.

Larvicidal Activity of Silver Nanoparticles Synthesized from Azadirachta indica Leaf Extract Against Oryctes rhinoceros (L.) Beetle

The coconut rhinoceros beetle, Oryctes rhinoceros (L), has been one of the major pests of coconut in India and other coconut producing countries causing direct or indirect losses to the crop. It can be controlled by eliminating the places where they breed and by manually destroying adult and immature (larvae). Botanical insecticides are relatively safer, degradable and are readily available source of biopesticides. Biosynthesis of pesticides from plant extracts is most promising approach for pest control. The present investigation aims to find out the possibility of eco-friendly management of the pest Oryctes rhinoceros by incorporating with silver nanoparticle synthesized from neem plant extracts. The silver nanoparticles (AgNPs) were synthesized by using aqueous extracts of Azadirachta indica. Formation of silver nanoparticles was observed by colour change of the solution, UV, FT-IR and SEM analysis. The Larvae is treated against different concentrations of plant extract and silver nanoparticles solution. 100% larval mortality was observed in higher concentration of silver nanoparticle solution. This result concluded that both silver Nanoparticles and leaf extract have larvicidal properties but Silver nanoparticles are more efficient and it serves as an alternative to synthetic insecticides for controlling harmful pest larvae. Hence the synthesized silver nanoparticles from the A.indica can be used as potential biolarvicidal agent against Oryctes rhinoceros.

Degree of damage and infestation of coconut leaf beetle Brontispa longissima (Gestro) on seedlings of selected coconut varieties

The Coconut Leaf Beetle, scientifically known as Brontispa longissima (Gestro), is an introduced species that is becoming an alarming pest of coconuts in the Philippines. The infestation caused by this pest is damaging to all stages of coconut growth. This study was conducted to assess the degree of damage and infestation caused by Brontispa longissima on the seedlings of 10 selected tall and dwarf coconut varieties in the National Coconut Research Center at Visayas State University, Leyte, Philippines. Among the selected varieties, seedlings of Baybay Tall (green and brown) and Albuera Dwarf varieties succumbed to more damage by B. longissima beetles compared with the other varieties observed with 41-80% of the first openned leaf area damaged. Seedlings of Malayan Yellow Dwarf and Malayan Red Dwarf varieties had the least damage with 0-20% of the first openned leaf area damaged. The high damage ratings of Baybay Tall and Albuera Dwarf were expected because these varieties had high infestation rates and harbored the most numbers of B. longissima adults, eggs, and larval stages, which indicated the preference of B. longissima for these varieties. The developmental period of B. longissima in Baybay Tall and Albuera Dwarf of 44 days and 45 days on the average, respectively, was shorter than in other varieties, indicating that these are suitable and preferred hosts. Baybay Tall seemed to be the most preferred variety. The beetles had least preference for Malayan Yellow Dwarf and Malayan Red Dwarf varieties.

The potential of Beauveria bassiana to control Raoiella indica (Acari: Tenuipalpidae) and its compatibility with predatory mites

The red palm mite, Raoiella indica (Acari: Tenuipalpidae), is a serious pest of coconut plantations in tropical countries such as Brazil. Ecologically-sound control strategies have been sought for this pest; however, the potential of entomopathogenic fungi such as Beauveria bassiana (Hypocreales: Cordycipitaceae) in controlling this pest, as well as its compatibility with co-occurring natural enemies, remains poorly investigated. Thus, the present study was conducted to investigate the potential of four B. bassiana strains in controlling R. indica, as well as the compatibility of the most pathogenic fungal strain with the predatory mites Amblyseius largoensis and Typhlodromus ornatus (Acari: Phytoseiidae). Briefly, the pathogenicity of four B. bassiana strains (Bb-032, Bb-053, Bb-057 and Bb-086), isolated from coconut pests, were tested against R. indica. The B. bassiana strain Bb-032 was selected for further bioassays for being the most pathogenic to R. indica. The red palm mite survival and mean survival time drastically decreased when exposed to B. bassiana strain Bb-032 at both LC50 and LC80. In contrast, neither survival nor mean survival time of A. largoensis and T. ornatus were affected by the exposure to LC50 and LC80 of B. bassiana strain Bb-032. The fungal strain showed considerable selectivity to the two predatory mites; however, at its estimated LC80 for R. indica, reduced oviposition, egg viability and the instantaneous rate of increase (ri) were generally observed for both natural enemies. Therefore, B. bassiana holds potential promise for controlling R. indica in addition to being generally selective to non-target predatory mites.

Genome-Wide Identification of the Gustatory Receptor Gene Family of the Invasive Pest, Red Palm Weevil, Rhynchophorus ferrugineus (Olivier, 1790)

Simple SummaryThe red palm weevil (Rhynchophorus ferrugineus) is an invasive pest that causes severe economic loss in palm plant cultivation (e.g., oil palm, date, and coconut) in many regions of the world. The development of efficient approaches to controlling this pest is urgently needed. Previous research focused on the molecular basis of its olfaction, leading to the identification of this species’ aggregation pheromone receptor, which can help develop biosensors and bait traps. To gain more understanding of the chemoreception in this species, we used a bioinformatic approach to identify all the gustatory receptor genes from its genome and transcriptome data. There are 50 gustatory receptor genes encoding 65 functional receptors, including CO2, sugar, and bitter receptors. Our results will help elucidate how this beetle discriminates and evaluates food and egg-laying sites and communicates via gustation.The red palm weevil (Rhynchophorus ferrugineus) is a highly destructive pest of oil palm, date, and coconut in many parts of Asia, Europe, and Africa. The Food and Agriculture Organization of the United Nations has called for international collaboration to develop a multidisciplinary strategy to control this invasive pest. Previous research focused on the molecular basis of chemoreception in this species, particularly olfaction, to develop biosensors for early detection and more effective bait traps for mass trapping. However, the molecular basis of gustation, which plays an essential role in discriminating food and egg-laying sites and chemical communication in this species, is limited because its complete gustatory receptor gene family still has not been characterized. We manually annotated the gene family from the recently available genome and transcriptome data and reported 50 gustatory receptor genes encoding 65 gustatory receptors, including 7 carbon dioxide, 9 sugar, and 49 bitter receptors. This study provides a platform for future functional analysis and comparative chemosensory study. A better understanding of gustation will improve our understanding of this species’ complex chemoreception, which is an important step toward developing more effective control methods.

Pengendalian Hama Kelapa Larva Kumbang Badak (Oryctes rhinoceros, L.) Instar III Dengan Metarhizium anisopliae, Metch. yang Ditumbuhkan Pada Berbagai Macam Dedak Gandum

The research objectives were to observe the growth and spore production of Metarhizium anisopliae grown at wheat-pollard and wheat-brand and to test the M. anisopliae pathogenicity on instar III rhinoceros beetle larva of coconut pest (Oryctes rhinoceros, L.). The research were executed in 3 phases : (1) Regeneration phase of M. anisopliae, the experiment was arranged in single factor CRD with 3 kinds of wheat and 3 replications. The influences of the treatments on biomass, spore number and spore viability were observed then; (2) lethal dosage (LD50) determination phase; and (3) phatogenicity test of M. anisopliae, the experiment was arranged in 3 x 3 factorial CRD, where the first factor was the kinds of wheat (i.e. Pollard, Brand and Pollard Brand) and the second factor was the dosage of biopesticide (i.e. 0,5 LD50 LD50 and 2 LD50). The phatogenicity testing was conducted to evaluate the effects on toxicity, mortality speed, and effication percentage. The result indicated that the wheat-brand was the better medium for M. Anisopliae than the pollard and the pollard-brand ones. The average spore number (1021,67 x 1014 spora/ml), biomass (95,94 g) and the viability (127,00 x 108 spora/ml) were significantly higher than the others. The lethal dosage obtained was 6,70g to gave the mortality percentage (73,33 %) and the effication percentage (73,33 %) significantly higher than the other treatments.

Efficacy of Amblyseius largoensis (Muma) as a biocontrol agent of the red palm mite Raoiella indica (Acari: Tenuipalpidae)

The red palm mite, Raoiella indica Hirst (Acari: Tenuipalpidae), is a severe pest of coconut (Cocos nucifera L.), banana (Musa sp.), and some ornamental palms. The predatory mite Amblyseius largoensis Muma (Acari: Phytoseiidae) has been reported in association with R. indica in several countries. Here, we assessed the interaction effect between prey density and population structure on predation and fecundity of this phytoseiid species. Specifically, we estimated the predation capacity of nymphs and females of A. largoensis based on their functional and numerical responses when fed on eggs, immature stages (deutonymphs or protonymphs), and females of R. indica. Nymphs and females of A. largoensis presented type II functional responses to R. indica, except for nymphs of the predator when consuming immature stages of the pest that exhibited a type III functional response. Nymphs and females of the predator showed a higher attack rate and shorter handling time when feeding on eggs of R. indica than on immatures and females. The highest oviposition rates of A. largoensis were observed when eggs and immatures of the pest were offered as prey. The results indicate that nymphs and females of A. largoensis may be effective in suppressing R. indica populations, mainly at lower prey densities.

The complete mitochondrial genome sequence of Oryctes rhinoceros (Coleoptera: Scarabaeidae) based on long-read nanopore sequencing.

BackgroundThe coconut rhinoceros beetle (CRB, Oryctes rhinoceros) is a severe and invasive pest of coconut and other palms throughout Asia and the Pacific. The biocontrol agent, Oryctes rhinoceros nudivirus (OrNV), has successfully suppressed O. rhinoceros populations for decades but new CRB invasions started appearing after 2007. A single-SNP variant within the mitochondrial cox1 gene is used to distinguish the recently-invading CRB-G lineage from other haplotypes, but the lack of mitogenome sequence for this species hinders further development of a molecular toolset for biosecurity and management programmes against CRB. Here we report the complete circular sequence and annotation for CRB mitogenome, generated to support such efforts.MethodsSequencing data were generated using long-read Nanopore technology from genomic DNA isolated from a CRB-G female. The mitogenome was assembled with Flye v.2.5, using the short-read Illumina sequences to remove homopolymers with Pilon, and annotated with MITOS. Independently-generated transcriptome data were used to assess the O. rhinoceros mitogenome annotation and transcription. The aligned sequences of 13 protein-coding genes (PCGs) (with degenerate third codon position) from O. rhinoceros, 13 other Scarabaeidae taxa and two outgroup taxa were used for the phylogenetic reconstruction with the Maximum likelihood (ML) approach in IQ-TREE and Bayesian (BI) approach in MrBayes.ResultsThe complete circular mitogenome of O. rhinoceros is 20,898 bp in length, with a gene content canonical for insects (13 PCGs, two rRNA genes, and 22 tRNA genes), as well as one structural variation (rearrangement of trnQ and trnI) and a long control region (6,204 bp). Transcription was detected across all 37 genes, and interestingly, within three domains in the control region. ML and BI phylogenies had the same topology, correctly grouping O. rhinoceros with one other Dynastinae taxon, and recovering the previously reported relationship among lineages in the Scarabaeidae. In silico PCR-RFLP analysis recovered the correct fragment set that is diagnostic for the CRB-G haplogroup. These results validate the high-quality of the O. rhinoceros mitogenome sequence and annotation.

A Bioclimate-Based Maximum Entropy Model for Comperiella calauanica Barrion, Almarinez and Amalin (Hymenoptera: Encyrtidae) in the Philippines.

Simple SummaryThe discovery of Comperiella calauanica a parasitoid confirmed to be the major natural enemy of the invasive diaspidid, Aspidiotus rigidus, has led to the promise of biological control in sustainable pest management of this devastating coconut pest. In this study, we employed Maximum Entropy (Maxent) to develop a bioclimate-based species distribution model (SDM) for the parasitoid from presence-only data recorded from field surveys conducted in select points the Philippines. Results of assessment of the generated model point to its excellent power in predicting either suitability of habitat, or potential occurrence or distribution of C. calauanica. Since the parasitoid is highly host-specific, the model may also apply to A. rigidus. Field surveys in select areas in the Philippines confirmed the occurrence of the invasive coconut scale in areas predicted by the model as having considerable probability of occurrence, or habitat suitability. Our findings strongly suggest the potential utility of Maxent SDMs as tools for pest invasion forecasting and GIS-aided surveillance for integrated pest management (IPM).Comperiella calauanica is a host-specific endoparasitoid and effective biological control agent of the diaspidid Aspidiotus rigidus, whose outbreak from 2010 to 2015 severely threatened the coconut industry in the Philippines. Using the maximum entropy (Maxent) algorithm, we developed a species distribution model (SDM) for C. calauanica based on 19 bioclimatic variables, using occurrence data obtained mostly from field surveys conducted in A. rigidus-infested areas in Luzon Island from 2014 to 2016. The calculated the area under the ROC curve (AUC) values for the model were very high (0.966, standard deviation = 0.005), indicating the model’s high predictive power. Precipitation seasonality was found to have the highest relative contribution to model development. Response curves produced by Maxent suggested the positive influence of mean temperature of the driest quarter, and negative influence of precipitation of the driest and coldest quarters on habitat suitability. Given that C. calauanica has been found to always occur with A. rigidus in Luzon Island due to high host-specificity, the SDM for the parasitoid may also be considered and used as a predictive model for its host. This was confirmed through field surveys conducted between late 2016 and early 2018, which found and confirmed the occurrence of A. rigidus in three areas predicted by the SDM to have moderate to high habitat suitability or probability of occurrence of C. calauanica: Zamboanga City in Mindanao; Isabela City in Basilan Island; and Tablas Island in Romblon. This validation in the field demonstrated the utility of the bioclimate-based SDM for C. calauanica in predicting habitat suitability or probability of occurrence of A. rigidus in the Philippines.

Development of a new modular software tool for agroecological food web model development: Tiko'n

Abstract Agroecological food web modelling, which models trophic relationships between the species present in agricultural fields, has significant potential uses in the fields of theoretical and practical agroecology, specifically regarding the planning and evaluation of integrated pest management and biocontrol strategies. However, the practical use of such models with field data has been hindered by their complexity and difficulty in calibration, as well as the lack of software tools to streamline and standardise their development and evaluation. In this research we present a new modular software tool, Tiko’n, which allows users to rapidly (within a few lines of Python code) develop, calibrate and validate agroecological food web population dynamics models based on observed field population data. We then demonstrate its use in developing a food web model of a coconut pest in Sri Lanka and apply the model to assessing the potential impact of alternative biocontrol strategies. The software allowed for very rapid model development and adjustment and showed that smaller parasitoid releases may be more efficient than a single, larger application. It is the authors’ hope that this tool will contribute to a more widespread use of agroecological food web modelling in research and agronomic practice.

Field distribution patterns of pests are asymmetrically affected by the presence of other herbivores

Because plant phenotypes can change in response to attacks by herbivores in highly variable ways, the distribution of herbivores depends on the occurrence of other herbivore species on the same plant. We carried out a field study to evaluate the co-occurrence of three coconut pests, the mites Aceria guerreronis (Acari: Eriophyidae), Steneotarsonemus concavuscutum (Acari: Tarsonemidae) and the moth Atheloca bondari (Lepidoptera: Pyralidae). The eriophyid mite Ac. guerreronis is the most important coconut pest around the world, whereas S. concavuscutum and At. bondari are economically important only in some areas along the Brazilian coast. A previous study suggested that the necrosis caused by Ac. guerreronis facilitates the infestation of At. bondari larvae. Because all three species infest the area under the perianths on coconuts and S. concavuscutum also causes necrosis that could facilitate At. bondari, we evaluated the co-occurrence of all three species. We found that the occurrence of At. bondari was positively associated with Ac. guerreronis, but negatively associated with S. concavuscutum. In addition, the two mite species showed negative co-occurrence. Atheloca bondari was found on nuts of all ages, but more on nuts that had fallen than on those on the trees, suggesting that nuts infested by At. bondari tend to fall more frequently. We discuss the status of At. bondari as a pest and discuss experiments to test the causes of these co-occurrence patterns.