Palm Crowns Research Articles

Spectral–Spatial transformer-based semantic segmentation for large-scale mapping of individual date palm trees using very high-resolution satellite data

Date palm plantations in the United Arab Emirates (UAE) are under threat from soil salinity, drought, and date palm weevils. Accordingly, monitoring and conserving date palms are crucial to preserving a vital component of the country’s agricultural heritage, economy, food security, and ecological balance. Previous studies have effectively identified date palm trees using RGB-based aerial and UAV imagery utilizing diverse deep learning methods. However, the utilization of very high-resolution satellite data for delineating individual date palm crowns remains unexplored due to the limited spatial resolution capabilities of existing satellite systems. This study primarily aimed to achieve precise and comprehensive mapping of date palm trees using WorldView-3 (WV-3) satellite data by leveraging the high representational power of the state-of-the-art vision transformers (ViT) in capturing global information from the input data. First, an in-depth analysis assessment of the various transformer-based semantic segmentation architectures, including UperNet with vision transformer and Swin transformer, SegFormer, Mask2Former, and UniFormer, was conducted. Second, the integration of spectral data on the performance of ViTs was evaluated. Moreover, the models’ generalizability and complexity effect on the segmentation effectiveness were assessed. Accordingly, a postprocessing strategy was developed to aid in delineating and counting date palm trees from semantic segmentation outputs. Results demonstrated that integration of WV-3 spectral data into the analysis resulted in a marked improvement in segmentation quality. The UniFormer, UperNet-Swin, and Mask2Former models demonstrated considerable improvements in multispectral data analysis, with increases in mean intersection over union (mIoU) of 2.17% (77.88% mIoU, 86.01% mean F-score [mF-score]), 2% (78.10% mIoU, 86.18% mF-score), and 1.15% (77.36% mIoU, 85.59% mF-score), respectively, compared with their RGB-based results. Evaluations of model transferability also indicated that Mask2Former, UniFormer, and UperNet-Swin transformers efficiently adapted to multispectral data in the Dibba region. These models achieved mIoU scores of 84.36%, 84.25%, and 83.17% and mF-scores of 90.95%, 90.87%, and 90.13%, highlighting their effectiveness and potential for broader regional application. This research highlights the efficacy and feasibility of using ViTs with WV-3 multispectral data for accurate and comprehensive surveying of date palm plantations, enabling the development of palm tree inventories and continuously updating geospatial databases.

Red Palm Weevil Detection in Date Palm Using Temporal UAV Imagery

Red palm weevil (RPW) is widely considered a key pest of palms, creating extensive damages to the date palm trunk that inevitably leads to palm death if no pest eradication is done. This study evaluates the potential of a remote sensing approach for the timely and reliable detection of RPW infestation on the palm canopy. For two consecutive years, an experimental field with infested and control palms was regularly monitored by an Unmanned Aerial Vehicle (UAV) carrying RGB, multispectral, and thermal sensors. Simultaneously, detailed visual observations of the RPW effects on the palms were made to assess the evolution of infestation from the initial stage until palm death. A UAV-based image processing chain for nondestructive RPW detection was built based on segmentation and vegetation index analysis techniques. These algorithms reveal the potential of thermal data to detect RPW infestation. Maximum temperature values and standard deviations within the palm crown revealed a significant (α = 0.05) difference between infested and non-infested palms at a severe infestation stage but before any visual canopy symptoms were noticed. Furthermore, this proof-of-concept study showed that the temporal monitoring of spectral vegetation index values could contribute to the detection of infested palms before canopy symptoms are visible. The seasonal significant (α = 0.05) increase of greenness index values, as observed in non-infested trees, could not be observed in infested palms. These findings are of added value for steering management practices and future related studies, but further validation of the results is needed. The workflow and resulting maps are accessible through the Mapeo® visualization platform.

Food web structure and microenvironment affect Chagas disease vector infection and abundance in a rural landscape

AbstractVector‐borne pathogen transmission is shaped by multiple abiotic and biotic factors. Understanding the relative importance of these factors on vector abundance and infection is important for developing vector‐borne disease control strategies. The crown of the Attalea butyracea palm provides a natural arboreal mesocosm suitable for studying how food web relations and microclimate affect Chagas disease vectors of the genus Rhodnius, which feed on vertebrate blood and interact with many vertebrate and invertebrate species, vegetation, and detritus within the palm crown. We performed a cross‐sectional, observational study of A. butyracea crowns using a community ecology network approach to evaluate abiotic and biotic conditions associated with Rhodnius pallescens abundance and infection with Trypanosoma cruzi, the Chagas disease etiologic agent. We collected 1098 R. pallescens from 105 A. butyracea crowns in rural landscapes of Panama. In a palm subset (N = 49), we recorded microclimate and habitat conditions and counted vertebrate and invertebrate species in order to characterize palm crown food webs. We used food web metrics, namely Generality (average number of prey per predator) and Vulnerability (average number of predators per prey) to evaluate associations between palm community trophic structure, vector predators, vector blood meal species composition, vector abundance, and vector T. cruzi infection. Field data analyzed with generalized linear models showed that vector abundance and infection in a given palm crown were influenced by a combination of geographic location, land‐use type, palm crown animal community composition, and microhabitat conditions. Vector abundance was negatively associated with increased overall palm crown community diversity. However, vector abundance was positively associated with the invertebrate predator and mammal community. R. pallescens Vulnerability score, which measures predation pressure on the vector within the palm crown, was positively associated with vector abundance. Vector infection with T. cruzi was positively associated with mammal presence; vectors in palms with mammals were about 25 times more likely to be infected with T. cruzi compared with vectors in palms without mammals. Our findings suggest that a holistic study of food webs and environmental variables at the local scale can provide useful information for vector‐borne disease management across a wide habitat range.

Development of an Ergonomic, Portable, Climber-Propelled Date Tree Climbing Device

ABSTRACT In the most of main date fruit producer regions, including Iran, date palm crown access operation is still performed traditionally. The date plantation workers need to climb date trees. This may cause an unsafe condition, which increases the risk of fall from height. It is also associated with ergonomic and health problems. The present study aimed to develop a date tree climber device (DTCD) covering all aspects of safety, ergonomics and efficiency. A primary model of the DTCD was structured and modified based on a review of existing devices, a field investigation and an unstructured interview with 20 farmworkers. Participants rated their comfort, perceived pain and discomfort as well as exertion levels when using the DTCD compared to a traditional device (Parband). In total, eight key elements were suggested for the desired device. More than 60% of the participants reported that the DTCD was comfortable/very comfortable compared to Parband. Additionally, DTCD could significantly reduce the pain and discomfort of the back (p < .001), knees (p = .001) and Ankles/feet (p = .01). However, no significant difference was found between devices when the physical exertion was compared through Borg’s RPE scale and heart rate analysis. The results of regression analysis showed that the DTCD users perceived lower exertion as the body weight increased (β = −0.18, p = .013). The signs of musculoskeletal disorders, pain and discomfort were strongly reduced among DTCD users and safety aspects improved, generally by reducing discomfort and physical exertion.

Geostatistical modeling of “lethal coconut palm crown atrophy”, a new disease in the State of Pará

’Lethal Coconut Palm Crown Atrophy’ (LCCA) is a rapidly spreading disease in Brazil, capable of quickly killing coconut trees and threatening the commercial exploration of this plant. The objective of this work was to characterize the spatial and temporal distribution pattern of LCCA in green dwarf coconut commercial plantation areas, located the municipality of Santa Izabel, mesoregion of Northeastern Pará, Brazil. Surveys were carried out at monthly intervals between January 2014 and December 2018, checking for plants with LCCA-characteristic symptoms. Geostatistics was applied to perform spatial-temporal disease estimates based on semivariogram modeling and preparation of ordinary kriging maps. These spatial estimates are conducted through interpolations that characterize data variability in the area. The spherical model yielded the best fit to the spatial distribution of the disease, as it presented the best coefficient of determination (R²), with the range varying between 14m and 45m. The Spatial Dependence Index (SDI) was moderate in the evaluations carried out between 2014 and 2017 (in the 0.26-0.64 range), but not in 2018, when it was strong (0.23). The values of the clustering intensity of LCCA-symptomatic plants were estimated in non-sampled points. The spherical fit model of the data indicates an aggregated distribution pattern, shown by aggregation patches in the plantation, graded by values of dissemination intensity. The kriging maps allowed the observation that the disease expands between plants in the same line, suggesting the possibility of the presence of a short-range vector.

Relationship of Oil Palm Crown Features Extracted Using Terrestrial Laser Scanning for Basal Stem Rot Disease Classification

The oil palm is the largest plantation industry in Malaysia. It has been one of the major contributors to the country’s economy and the main pillar of the commodity sectors. For over 40 years, the oil palm industry has faced a lethal and incurable disease, Basal Stem Rot (BSR), which is caused by a type of bracket fungus, Ganoderma boninense. The oil palm physical symptoms infected by BSR disease are appearance of many unopened spears, flattening of crown and smaller crown size. Terrestrial Laser Scanning (TLS, also known as ground-based LiDAR) can be used to provide accurate and precise information on tree morphology with high resolution. This study proposed an image processing technique using the ground input data taken from a TLS. Five parameters were used in the study are number of laser hits in strata 200 cm and 850 cm from the top, namely as C200 and C850, respectively, crown area, frond number and frond angle. The objectives of this study are to analyse the relationship between the parameters and to study the relationship of the parameters with the levels of BSR disease. Results have shown that all parameters were significant in all levels of healthiness with p-values less than 5%. Frond number and frond angle showed the highest correlation value, which is equal to -0.94. Frond angle is increasing, while frond number and crown area are decreasing concurrently with the severity levels of BSR infection.

Dynamis borassi (Coleoptera: Curculionidae), a New Potential Pest to the Palms (Arecaceae): An Early Warning for the Palm Producers

Emergent and potentially invasive weevils are a permanent threat to the survival of palm plantations. Hence, understanding the role of emergent pests may be key for preventing future phytosanitary emergencies. In the present study, the role of Rhynchophorus palmarum L. and Dynamis borassi F. (both Coleoptera: Curculionidae) as main causative agents of the peach palm (Bactris gasipaes Kunth; Arecaceae) crown toppling problem were investigated, and the damage was described in 36 farms in the principal production areas of Colombia. A management strategy with the use of 2 pheromones (Rhynchophorol and Ferrolure) in 2 production areas also was evaluated. In total, 4,098 palms were examined from Nov 2017 to Feb 2019. Visible damage oscillated between 0 to 70% of palms affected and was highest on the Pacific coast. Larvae of D. borassi were found exclusively in the inflorescences suggesting that it initiates the damage. Meanwhile, adults of D. borassi and all stages of R. palmarum were recovered from stem damages. Also, new reports of damage were confirmed at the southern Pacific coast, the Andes, and the Amazon region. A total of 8,239 D. borassi and 2,886 R. palmarum were captured in pheromone traps for 14 mo on the Pacific coast. The traps baited with Ferrolure + Rhynchophorol captured a greater number of D. borassi specimens. The data strongly confirm the central role of D. borassi in peach palm damage. Therefore, it is recommended strongly that pheromones be used to prevent further spread of this pest in other countries of this region and to protect palm industries.

Distilling Professional Opinion to Gauge Vulnerability of Guam Avifauna to Brown Treesnake Predation

The avifauna of Guam was devastated by the introduction of the Brown Treesnake, and the restoration of native birds would need to address the problem with eradication or suppression of BTS. With eradication of the snake unlikely in the near term, and suppression capabilities limited to specific finite areas, key information for reintroductions is how low BTS abundance will likely need to be for each bird species to be re-established based on their vulnerability to BTS predation. Here, we estimate vulnerability, which can no longer be measured directly, so biologists who are familiar with one or more of seven Guam birds were surveyed to obtain their knowledge and produce quantitative vulnerability estimates. As is typical of birds adapted to islands devoid of predators, respondents judged that our focal species exhibit few predator avoidance and tolerance traits, leaving body size as the prime determinant of vulnerability. Respondent opinion also holds that any behavior that reduces the likelihood of an encounter by BTS, e.g., roosting/nesting in palm crowns, cavity nesting, and in particular urban dwelling, substantially reduces vulnerability. Our results can help inform species-specific decisions about when it may be safe to consider the release of birds on Guam depending on the relative vulnerability of each species to predation by BTS.

Rhodnius spp. infestation in palm trees and natural infection by Trypanosoma cruzi and Trypanosoma rangeli in periurban and rural areas of state of the Rondônia, in the Brazilian Amazon

The state of Rondônia in the Brazilian Amazon is prone to diseases transmitted by insect vectors because of the environmental and population changes resulting from large hydroelectric projects and the expansion of agricultural and livestock industries. The first case of Chagas disease by vectorial transmission was recorded in 2019 in a rural area in Rondônia, reinforcing the need for entomological surveillance. Hence, our goal was to estimate the abundance of Rhodnius spp. in palm trees located in rural and periurban areas and in Brazil-Bolivia border regions, perform domiciliary searches, and check for possible associations between triatomines and the presence/absence of palm-inhabiting fauna and outdoor farming, domestic animals, and buildings. The sampling took place in five municipalities of Rondônia in 2014 (June to August) and 2015 (April to June). Triatomines were collected by active searches during the selective pruning of palm tree crowns. Domiciliary inspections lasted from 30 to 60 min. A set of captured triatomines was analyzed for Trypanosoma cruzi and T. rangeli infection by PCR. Overall, 496 insects were captured during sampling of 150 palms in rural areas and 150 in periurban areas. No triatomine was found during active searches of 59 dwelling either indoors or outdoors. The majority of triatomines caught in the palm trees were identified as Rhodnius robustus (98.6%), and seven specimens were R. pictipes. Triatomine infestation was observed in only 20% of the sampled palms (61/300) in the vicinity of 26/59 households. Nearly half of the infested palm trees had only one or two triatomines, and few palms presented more than 15 triatomines. The municipality of Buritis had the highest triatomine abundance and percentage of infested palms; however, the highest triatomine density per infested palm was observed in Alvorada D'Oeste, where a quarter of the palms were infested. Ants, arachnids, termites, reptiles, and rodents were frequently found in palm trees. Dogs were the predominant domestic animals in households, whereas hens and cattle were the main farming animals. Model estimates showed that the number of triatomines was affected by the presence of henhouses and varied strongly between localities. No relationships were detected between the average number of triatomines and palm fauna and/or palm height. Overall, approximately half of the triatomines were infected with T. cruzi (51.4%) and/or T. rangeli (47.2%), reinforcing the need for continuous entomological surveillance and implementation of community-based approaches because the Brazilian state of Rondônia borders areas experiencing reinfestation by domiciled species and potential colonization of animal shelters by triatomines.

Occupational safety and health in traditional date palm works.

Date palm is mostly cultivated in Western Asia and North Africa and is the main wealth for the people of these regions. Traditional date palm crown access via manual climbing, as the main activity in date fruit production, suffers from occupational hazards. Mitigation of these problems through interventions or new designs initially needs to complete knowledge of safety and health aspects and relationships between them and characters of date palm climbers. This study provided detailed information about this concern. A questionnaire consisting of personal, operational, safety, satisfaction, financial and ergonomic demographics was used for data collection. 117 climbers participated in the study. Nonparametric correlations using Spearman's coefficient and logistic regressions investigated the linkage between characters obtained by the questionnaire. The annual mortality rate of falls from height was calculated by 3.4 per one thousand men. Fall was a major challenge in traditional date palm crown access and its rate was highly greater in comparison with the estimation of International Labor Office (ILO) about fatal agricultural injuries. Safety and health condition was the main contributing factor in the status of date palm climbing and was significantly linked to job satisfaction. Safety risk-taking and non-awareness of technology had a significant linkage with together (r = - 0.195, p = 0.035). Safety risk-taking, also, had significant correlations with discomfort in back (r = - 0.201, p = 0.030). Regressions showed heavier climbers (> 75kg) were expected about 4.3 (1/0.230) times than more lightweight ones to have an upper leg discomfort with high severity relative to low severity (p = 0.018). Obesity, senescence, and awareness of technology as three personal characteristics of climbers need to be addressed. Future strategies are required to improve the safety condition of climbing and manage the workforces as well as governmental decision making to address the financial aspects of climbers for sustainable date production and reduction in reasons causing unemployment. Considering current status and modification of the present tool and equipment is recommended.

Remote Sensing for Detection of Ganoderma Disease and Bagworm Infestation in Oil Palm

Two major disease and pest in oil palm are Ganoderma disease and bagworm infestation. Ganoderma disease caused by Ganoderma boninense and bagworm infestation caused by Metisa Plana has caused significant loss to oil palm industry. Therefore, early detection and control are important to reduce the losses. This paper reviewed the existing approaches, challenges and future trend of aerial remote sensing technology for Ganoderma disease and bagworm infestation in oil palm. The aerial remote sensing technology comprises of multispectral, hyperspectral camera and radar which have different platform such as satellite, aircraft and Unmanned Aerial Vehicle (UAV). The aerial multispectral and hyperspectral remote sensing analysed spectral signatures from visible and near infrared spectrum range for detection of the disease and pest attacks. Studies showed that satellite-based multispectral remote sensing only provide moderate accuracy (&lt;70%) compared to UAV-based multispectral remote sensing (&gt;80%) for detection of disease and pest infestation. Meanwhile, our study using UAV showed 90% of accuracy for moderate and severe Ganoderma disease detection in oil palm. Meanwhile, application of aerial hyperspectral remote sensing for Ganoderma disease showed potential for early detection of Ganoderma disease in oil palm and also can be used to detect early pest infestation in oil palm based on field spectroscopy results. Other than that, radar remote sensing has also able to differentiate healthy and Ganoderma-infected oil palm and also pest infestation by analysis of radar backscatter image of the foliar, frond and crown of oil palm. The challenges for the implementation of aerial remote sensing technology for disease and pest detection in oil palm is in tackling problems from shadows, mixed-class from single canopy and false-positive classification and also producing equipment at a lower and affordable price and also a user-friendly data analysis system that can be used by the plantations for a fast disease and pest detection works. The introduction of Artificial Intelligence (AI), Machine Deep Learning (MDL), low-cost remote sensing camera and light-weight UAV has opened the opportunity to tackle the challenges. As a conclusion, aerial remote sensing provides better and faster disease and pest infestation detection system compared to ground-based inspection. The advancement of the aerial remote sensing technology can provide more economic and efficient disease and pest infestation detection system for large oil palm plantation areas.

Analysis of Oil Palm Tree Recognition using Drone-Based Remote Sensing Images

The oil palm tree, or scientifically called as Elaeis guineensis is native to West Africa, where it grows in the wild, transformed into a crop that later was introduced to Malaysian industry. The cultivation of oil palm improved rapidly under the agricultural sector causes degradation, particularly when the oil palm plantation goes uncontrolled. Tree plantation identification is very important for plantation management, environmental management, biodiversity monitoring and many other applications. Accurate inventories and monitoring oil palm estates can be a challenge and critical towards the plantation management and plant area expansion. Managing oil palm estate manually can almost be impossible, so do the tree counting. Manual field-based tree counting is time-consuming and high cost. Conventional method for tree counting can be carried out by manually marked on images or carry out field surveying using GPS to collect the positions of oil palm trees and display their position on image. Developing easier, simpler and cheaper method for tree counting is needed. The aim of this study is to analyse oil palm trees using drone-based remote sensing images. The algorithms used in this research study including Gray-Level Co-occurrence Matrix (GLCM), wavelet transform and template matching. The database of oil palm tree been developed with a total of 131 oil palm trees and 161 of non-oil palm trees have been collected. The window size of oil palm tree been analysed where 250 x 250 pixels which GLCM showed the best overall accuracy of 73.10% for both oil palm and non-oil palm. In this specific window, the oil palm crown can be covered and the result given is more accurate compared to other window sizes. The resulting analysis shows that wavelet transform algorithm gives the highest overall accuracy value which is 82.07%. The other eight statistic parameters can also used to modify the GLCM in order to observe the accuracy and identify which give the best classification accuracy. The availability and ubiquity of drone technologies with high resolution images and regular basis monitoring, new techniques in image and pattern recognition using drone-based remote sensing images let the idea of high accuracy oil palm tree detection become a reality.

Study of the oil palm crown characteristics associated with Basal Stem Rot (BSR) disease using stratification method of point cloud data

Basal Stem Rot (BSR) disease caused by the Ganoderma boninense fungus is the most serious issue affecting the oil palm industry. Terrestrial laser scanning (TLS) technology is a precise, contact-free, and active remote sensing method which is widely used for determining tree morphology using the crown strata. However, its capability in BSR detection using crown strata solely has not been explored. Therefore, this study used TLS data to study the effect of crown profile due to BSR and develop a BSR detection model using crown strata. Ninety-two palms were selected at random consists of 36 healthy oil palm trees and 56 unhealthy oil palm trees infected by Ganoderma boninense. The palms were each scanned at four different positions around them, and crown strata (named as Cn; where n is the crown length in cm) were generated using crown stratification method. The numbers of laser hits in the strata were used to generate crown profiles comparing healthy and unhealthy oil palm trees, to develop prediction models and to examine the patterns of crown density in different parts. The study has accounted for the occlusion problem by carrying out a systematic multi-scan approach. Moreover, the short traveling distance (less than 12 m) needed for the laser to reach the maximum crown tips ensures greater point density. The profiles of crown strata revealed that the healthy trees have higher crown densities than unhealthy trees starting from 250 cm from the top (strata no. 5) to the bottom. Prediction models using the strata parameters C650, C700, C800, and C850 were 92.5% accurate in the classification of healthy-unhealthy trees.

Assessing the Influence of UAV Altitude on Extracted Biophysical Parameters of Young Oil Palm

The information on biophysical parameters—such as height, crown area, and vegetation indices such as the normalized difference vegetation index (NDVI) and normalized difference red edge index (NDRE)—are useful to monitor health conditions and the growth of oil palm trees in precision agriculture practices. The use of multispectral sensors mounted on unmanned aerial vehicles (UAV) provides high spatio-temporal resolution data to study plant health. However, the influence of UAV altitude when extracting biophysical parameters of oil palm from a multispectral sensor has not yet been well explored. Therefore, this study utilized the MicaSense RedEdge sensor mounted on a DJI Phantom–4 UAV platform for aerial photogrammetry. Three different close-range multispectral aerial images were acquired at a flight altitude of 20 m, 60 m, and 80 m above ground level (AGL) over the young oil palm plantation area in Malaysia. The images were processed using the structure from motion (SfM) technique in Pix4DMapper software and produced multispectral orthomosaic aerial images, digital surface model (DSM), and point clouds. Meanwhile, canopy height models (CHM) were generated by subtracting DSM and digital elevation models (DEM). Oil palm tree heights and crown projected area (CPA) were extracted from CHM and the orthomosaic. NDVI and NDRE were calculated using the red, red-edge, and near-infrared spectral bands of orthomosaic data. The accuracy of the extracted height and CPA were evaluated by assessing accuracy from a different altitude of UAV data with ground measured CPA and height. Correlations, root mean square deviation (RMSD), and central tendency were used to compare UAV extracted biophysical parameters with ground data. Based on our results, flying at an altitude of 60 m is the best and optimal flight altitude for estimating biophysical parameters followed by 80 m altitude. The 20 m UAV altitude showed a tendency of overestimation in biophysical parameters of young oil palm and is less consistent when extracting parameters among the others. The methodology and results are a step toward precision agriculture in the oil palm plantation area.

Tracking Red Palm Mite Damage in the Western Hemisphere Invasion with Landsat Remote Sensing Data.

Simple SummaryThe red palm mite is a destructive pest for palm trees, impacting their productivity. Detection of their presence is important for management and the prevention of spread. Remote sensing may provide an opportunity to monitor and detect red palm mite presence using readily available land surface remote sensing, such as the Landsat satellite constellation. A study was conducted to determine if Landsat products are able to detect infestations at select sites in the Caribbean, Central, and South America. After a time series analysis, we determined that there are several impediments to detecting red palm mite damage at palm plantations.Red palm mites (Raoiella indica Hirst, Acari: Tenuipalpidae) were first observed in the western hemisphere on the islands and countries surrounding the Caribbean Sea, infesting the coconut palm (Cocos nucifera L.). Detection of invasive pests usually relies upon changes in vegetation properties as result of the pest activity. These changes may be visible in time series of satellite data records, such as Landsat satellites, which have been available with a 16-day repeat cycle at a spatial resolution of 30 m since 1982. Typical red palm mite infestations result in the yellowing of the lower leaves of the palm crown; remote sensing model simulations have indicated that this feature may be better detected using the green normalized difference vegetation index (GNDVI). Using the Google Earth Engine programming environment, a time series of Landsat 5 Thematic Mapper, Landsat 7 Enhanced Thematic Mapper Plus and Landsat 8 Operational Land Imager data was generated for plantations in northern and northeast Brazil, El Salvador, and Trinidad-Tobago. Considering the available studied plantations, there were little or no differences of GNDVI before and after the dates when red palm mites were first revealed at each location. A discussion of possible alternative approaches are discussed related to the limitations of the current satellite platforms.

How microclimatic variables and blood meal sources influence Rhodnius prolixus abundance and Trypanosoma cruzi infection in Attalea butyracea and Elaeis guineensis palms?

Chagas disease is a zoonosis that affects several million people and is caused by the parasite Trypanosoma cruzi, which is mainly transmitted through the feces of triatomine bugs. Within triatomines, several Rhodnius species have been found inhabiting palms, and certain factors such as palm species and location have been related to the abundance and T. cruzi infection of those insects in palms. In this study, the main goal was to determine if R. prolixus abundances and infection rates in Attalea butyracea and Elaeis guineensis palms are related to ecological factors such as palm species, crown microclimate, and available blood meal sources. Triatomine sampling was performed in two municipalities of Casanare, Colombia, specifically in the intersection of riparian forests and oil palm plantations. For R. prolixus abundance per palm, the predictors showing more relationship were palm species and blood meal species identified in the palm, and for T. cruzi infection per triatomine, they were palm species and nymphal stage. Palm microclimate was very similar in both palm species and did not show a relationship with triatomine abundance. Comparing palm species, A. butyracea showed more blood meal species, including more refractory host species, than E. guineensis, but lower T. cruzi infection rate and parasitaemia. Interestingly, non-arboreal blood meal species were frequently found in the analyzed nymphs, indicating that the blood source for R. prolixus in palms corresponded to all the fauna located in the surrounded landscape and not only in the palm. These results could expose a new ecological scenario to interpret the T. cruzi transmission in sylvatic environments.

Co-occurrence or dependence? Using spatial analyses to explore the interaction between palms and Rhodnius triatomines

BackgroundTriatomine bugs are responsible for the vectorial transmission of the parasite Trypanosoma cruzi, the etiological agent of Chagas disease, a zoonosis affecting 10 million people and with 25 million at risk of infection. Triatomines are associated with particular habitats that offer shelter and food. Several triatomine species of the genus Rhodnius have a close association with palm crowns, where bugs can obtain microclimatic stability and blood from the associated fauna. The Rhodnius-palm interaction has been reported in several places of Central and South America. However, the association in the distributions of Rhodnius species and palms has not been explicitly determined.MethodsNiches of Rhodnius and palm species with reports of Rhodnius spp. infestation were estimated by minimum volume ellipsoids and compared in the environmental and the geographical space to identify niche similarity. Rhodnius spp. niche models were run with the palm distributions as environmental variables to determine if palm presence could be considered a predictor of Rhodnius spp. distributions, improving model performance.ResultsNiche similarity was found between all the studied Rhodnius and palm species showing variation in niche overlap among the involved species. Most of the areas with suitable conditions for Rhodnius species were also suitable to palm species, being favorable for more than one palm species in the majority of locations. Performance was similar in Rhodnius niche models with and without palm distributions. However, when palm distributions were included, their contribution to the model was high, being the most important variable in some Rhodnius spp.ConclusionsTo our knowledge, this is the first time that the distributions of Rhodnius and palm species were compared on a large scale and their spatial association explicitly studied. We found spatial association between Rhodnius and palm species can be explained because both organisms shared environmental requirements, and most of the areas with suitable conditions for Rhodnius species were also suitable to several palm species. Rhodnius presence would not be restricted to palm presence but the zones with palm presence could be more suitable for Rhodnius spp. presence.

Deltamethrin resistance in Chagas disease vectors colonizing oil palm plantations: implications for vector control strategies in a public health-agriculture interface

BackgroundTriatomine bugs are responsible for the vectorial transmission of the parasite Trypanosoma cruzi, etiological agent of Chagas disease, a zoonosis affecting 10 million people and with 25 million at risk of infection. Several triatomine species of the genus Rhodnius have been found inhabiting palm crowns where insects can find shelter in leaves axils and blood from palm-associated vertebrates. Rhodnius prolixus insects have been collected in oil palms in Colombia, and high T. cruzi infection rates were found. Since pest control is carried out in oil palm plantations, continuous exposure to insecticides could be occurring in these triatomines. Some insecticides suggested for pest control in oil palm plantations are also recommended for triatomine control in human dwellings. In this study, our objective was to assess if triatomines inhabiting oil palms exhibit resistance to deltamethrin, an insecticide used for vector control.MethodsRhodnius prolixus nymphs were sampled in oil palms located in Tauramena, Colombia. To determine deltamethrin resistance, biological and biochemical assays were carried out on fifth-instar nymphs from the F1 generation. For biological assays, pure and commercial deltamethrin were used, and in biochemical assays, activities of detoxifying enzymes related to pyrethroid resistance, such as oxidases, esterases and transferases, were quantified.ResultsDeltamethrin lethal dosage 50 and 90 in R. prolixus from oil palms was significantly higher than in those from a susceptible colony suggesting possible deltamethrin resistance. Moreover, mortality with commercial deltamethrin was very low in insects from oil palms. In biochemical assays, the activity of evaluated detoxifying enzymes was significantly higher in R. prolixus from oil palms than in those from the susceptible colony.ConclusionsPossible deltamethrin resistance found in R. prolixus insects from oil palms could threaten traditional vector control strategies in urban settings if insecticide-resistant triatomines can migrate from oil palms plantations. In palm oil producer countries such as Colombia, the oil palm plantations are growing constantly during the last years. We suggest that pest control strategies in oil palm crops should include triatomine surveillance and toxicological monitoring, especially in zones with several Chagas disease cases.

Identifying and Quantifying the Abundance of Economically Important Palms in Tropical Moist Forest Using UAV Imagery

Sustainable management of non-timber forest products such as palm fruits is crucial for the long-term conservation of intact forest. A major limitation to expanding sustainable management of palms has been the need for precise information about the resources at scales of tens to hundreds of hectares, while typical ground-based surveys only sample small areas. In recent years, small unmanned aerial vehicles (UAVs) have become an important tool for mapping forest areas as they are cheap and easy to transport, and they provide high spatial resolution imagery of remote areas. We developed an object-based classification workflow for RGB UAV imagery which aims to identify and delineate palm tree crowns in the tropical rainforest by combining image processing and GIS functionalities using color and textural information in an integrative way to show one of the potential uses of UAVs in tropical forests. Ten permanent forest plots with 1170 reference palm trees were assessed from October to December 2017. The results indicate that palm tree crowns could be clearly identified and, in some cases, quantified following the workflow. The best results were obtained using the random forest classifier with an 85% overall accuracy and 0.82 kappa index.

PENGARUH VARIASI KERAPATAN SPORA Beauveria bassiana DAN KONSENTRASI LCPKS TERHADAP MORTALITAS LARVA Oryctes rhinoceros

Oryctes rhinoceros beetle is one of the pests that attacksimmature oil palm plants.This pest attacks oil palm plants in larvae or imago phase. This pest is usually damaging the respiratory roots, trunk bark, dry petiole,or periphery crown of oil palm leaves which can interferes the leaf growth and finally reduce the production even collapse the tree. Chemically pest control have the positive impact with faster pest death beside the negative impacts such as resistance, resurgence, disturbing human health and also environmental and ecosystem pollution. Biological control is one alternative pest control that is safe for the environment and can reduce chemical residues in agricultural products and environment. This study was conducted in Medan Denai district on July – Agustus 2019. This study aimed to determine the effect of the use of Beauveria bassiana and palm oil mill effluent to control Oryctes rhinoceros larvae. The method used in this study is a two factorial randomized block design (RBD), with 2 replications. The results of this study showed that the best density of Beauveria bassiana spores in controlling Oryctes rhinoceros larvae was 109 spores / ml and 50ml LCPKS (I2Q2) with death time of 40 hours, daily mortality 60%, total mortality 100%.