Occurrence Of Pests Research Articles

Infestation index of Drosophila suzukii (Diptera: Drosophilidae) in small fruit in southern Brazil

ABSTRACT: The spotted-wing drosophila, Drosophila suzukii Matsumura, is considered the main insect pest of small fruit in the world. Identifying susceptible hosts is essential to develop management strategies. The aim of this study was to verify the level of D. suzukii infestation in blackberry, blueberry, strawberry, cattley guava and Surinam cherry fruits cultivated in the southern region in Brazil, and to determine the infestation index (II) per fruit. The studies were carried out during two harvests (2015/16 and 2016/17) in three areas with organic cultivation of small fruit. The highest level of D. suzukii natural infestation was observed in blackberry (40 to 65% infestation), and strawberry (approximately 30% infestation) fruits. In contrast, blueberries were less preferred (< 7% infestation). For native fruit of the region (cattley guava and Surinam cherry), it was also verified infestation of the fly, demonstrating they are hosts for multiplication in the off-season periods of the other crops. In relation to II, blackberry and Surinam cherry provided a higher average number of insects per gram of fruit (≈ 1.6 adults of D. suzukii). In contrast, blueberries and cattley guava had the lowest insect ratio per gram of fruit (≈ 0.7 adults per gram). The period between late spring to mid-autumn was considered ideal for the pest occurrence in the field. The knowledge of natural infestation levels is essential for understanding the behavior of the pest in the field, which will assist in the design of management strategies.

Sucking pest and their management in mulberry (<em>Morus alba</em>): A review

Mulberry (Morus spp.) is regarded as a native of Himalayas and is cultivated in more than 32 countries in tropical, subtropical and temperate regions of the world. Mulberry being the sole food plant of mulberry silkworms, the quality, productivity and profitability in commercial sericulture depends on the yield of mulberry. Mulberry crop is considered as only food for the silkworm, Bombyx mori L. which is commercially exploited. It is a perennial, evergreen, luxuriant crop cultivated in all types of soils, both under rainfed and irrigated conditions. The crop is prone to depredation of diverse organisms, because of its fast growth and green foliage throughout the year, in varying proportions either for space, food or both. So far, over 300 insect and non-insect species of pests are known to infest mulberry in varying intensities during different stages of the crop and seasons. The maximum leaf yield potential of mulberry is yet to be trapped under irrigated conditions which are low for various reasons. Of these, improper nutrient management practice, decline in soil fertility status and delayed irrigation (due to failure of rains or canal water) and imbalanced nutrition and non-adaptability of prime production practices and insect pest are major constraints for low leaf productivity. Among the production constraints, sucking pest occurrence has become major problem in mulberry garden cultivation. The pests which are infesting mulberry are categorized into sap suckers, defoliators and root feeders. The sucking pest includes mealy bug, trips, spiralling whitefly, leaf hoppers, jassids and scale insects which cause damage to mulberry crop. Most of the sap sucking insects, such as adult leaf hoppers, aphids or thrips causes minimal direct tissue destruction. These insects use a specialized mouth part, the style, to locate, penetrate and drain sap from the phloem sieve elements of the plants vascular tissue. Majority of the sericulture farmers throughout the country have opined that mulberry (Morus spp.) is very much prone to sucking pest. Now a day’s majority of the mulberry cultivars and sericulture farmers have been approaching scientists and extension agencies for efficient control measures of sucking pest of mulberry especially thrips under such condition management of thrips through the eco-friendly approach and giving the crop condition in the parcel basis to the farmers is necessary to increase the mulberry leaf yield. Hence, the review.

침엽수 채종원에서 구과해충의 발생소장과 수종별 구과 피해 및 화학적 방제

침엽수 채종원에서 구과해충의 발생소장과 수종별 구과 피해 및 화학적 방제

SEPARABILITY OF TRANSPLANTED AND DIRECT SEEDED RICE USING MULTI-TEMPORAL SENTINEL-1A DATA

Abstract. Occurrence of pests and diseases are influenced by several factors including weather, landscape and field-level factors such as crop management practices including crop establishment method. In this paper, we adopted and applied a method using Sentinel-1A (S-1A) Synthetic Aperture Radar (SAR) intensity to discriminate between rice fields that are transplanted and direct seeded to come up with a robust method for automated classification of crop establishment method. Multi-temporal S-1A C-band dual polarization images at 20m resolution covering the wet cropping season over four provinces in the Philippines were acquired from March to November 2018. Field measurements, observations and interviews were conducted on 186 sample fields and mean backscatter values for each of the sampled fields were generated from S-1A data acquired during the season. The reported dates of land preparation and estimated dates of crop growth stages were matched with the corresponding SAR acquisition dates. We used the Mann-Whitney U test to identify growth stages for which there are significant differences in backscatter values between transplanted and direct seeded rice. The results are generally consistent with the findings of a previous study conducted in one province in the Philippines in the dry season of 2017. We found, however, some inconsistencies in terms of the polarization where the significant differences were observed. These findings demonstrate the possibility of discriminating transplanted from direct seeded rice using SAR temporal data but suggests further fine tuning in the methodology is needed for different locations and seasons.

Climate Change Impacts on Forest Management: A Case of Korean Oak Wilt

Climate change is expected to affect the occurrence of forest pests. This study depicts a method to measure the impact of damage inflicted by a forest pest like oak wilt as a result of climate change. We determine the damage function considering the factors related to the pest damage and forecast the future damage rate under future climate change. We estimated the damage rate by using the quasi-maximum likelihood estimation (QMLE) and predicted the future damage rate by using representative concentration pathways (RCP) 8.5 data. We assessed the impact of pests on the management income and the rotation age by using a dynamic optimization model. The results show that the damage rate and the affected area from oak wilt would increase under the climate change. In addition, the economic evaluation indicates that altered climate would reduce the management returns and increase uncertainty. However, these outcomes could be alleviated by carrying out the control and prevention measures after the infection occurs.

Occurrence prediction of pests and diseases in cotton on the basis of weather factors by long short term memory network

BackgroundThe occurrence of cotton pests and diseases has always been an important factor affecting the total cotton production. Cotton has a great dependence on environmental factors during its growth, especially climate change. In recent years, machine learning and especially deep learning methods have been widely used in many fields and have achieved good results.MethodsFirst, this papaer used the common Aprioro algorithm to find the association rules between weather factors and the occurrence of cotton pests. Then, in this paper, the problem of predicting the occurrence of pests and diseases is formulated as time series prediction, and an LSTM-based method was developed to solve the problem.ResultsThe association analysis reveals that moderate temperature, humid air, low wind spreed and rain fall in autumn and winter are more likely to occur cotton pests and diseases. The discovery was then used to predict the occurrence of pests and diseases. Experimental results showed that LSTM performs well on the prediction of occurrence of pests and diseases in cotton fields, and yields the Area Under the Curve (AUC) of 0.97.ConclusionSuitable temperature, humidity, low rainfall, low wind speed, suitable sunshine time and low evaporation are more likely to cause cotton pests and diseases. Based on these associations as well as historical weather and pest records, LSTM network is a good predictor for future pest and disease occurrences. Moreover, compared to the traditional machine learning models (i.e., SVM and Random Forest), the LSTM network performs the best.

Automated Fall Armyworm (Spodoptera frugiperda, J.E. Smith) Pheromone Trap Based on Machine Learning

Maize is the main food crop that meets the nutritional needs of both humans and livestock in the sub-Saharan African region. Maize crop has in the recent past been threatened by the fall armyworm (Spodoptera frugiperda, J.E Smith) which has caused considerable maize yield losses in the region. Controlling this pest requires knowledge on the time, location and extent of infestation. In addition, the insect pest’s abundance and environmental conditions should be predicted as early as possible for integrated pest management to be effective. Consequently, a fall armyworm pheromone trap was deployed as a monitoring tool in the present study. The trap inspection is currently carried out manually every week. The purpose of this paper is to bring automation to the trap. We modify the trap and integrate Internet of Things technologies which include a Raspberry Pi 3 Model B+ micro-computer, Atmel 8-bit AVR microcontroller, 3G cellular modem and various sensors powered with an off-grid solar photovoltaic system to capture real-time fall armyworm moth images, environmental conditions and provide real-time indications of the pest occurrences. The environmental conditions include Geographical Positioning System coordinates, temperature, humidity, wind speed and direction. The captured images together with environmental conditions are uploaded to the cloud server where the image is classified instantly using Google’s pre-trained InceptionV3 Machine Learning model. Intended users view captured data including prediction accuracy via a web application. Once this smart technology is adopted, the labour-intensive task of monitoring will reduce while stakeholders shall be provided with a near real-time insight into the FAW situation in the field therefore enabling pro-activeness in their management of such a devastating pest.

Effects of the Morphological Diversity of Leaf Surface and Phytochemicals Composition on Preference Behavior of Leafhopper and Planthoppers on some Solanaceous Crops

The present experiments were conducted to study the effect of different solanaceous host plants on the population density of the leafhoppers and planthoppers according to the morphological diversity of host surface and phytochemical composition on the preference behaviour of the insect pests during the two successive seasons 2017 and 2018 in Gharbia governorate. The leafhoppers, Empoasca decipiens and Empoasca decedens preferred eggplant as a host plant followed by tomato and pepper by using the three methods (leaf sample, yellow sticky traps, sweep net) during the two seasons. Meanwhile, Cicadulina chinai preferred tomato followed by eggplant and pepper by using the different methods. While, Balcutha hortensis preferred pepper followed by eggplant and tomato. On the other hand, the planthoppers, Sogatella futcifera preferred eggplant followed by pepper and tomato. Statistical analysis revealed that highly significant differences were recorded between the three host plants during the two seasons according to the average number of different leafhoppers and planthoppers by using the three sampling methods. Depending on the percentage of insect pest occurrence, sweep net recorded the highest percentage followed by yellow sticky traps and the lowest percentage of occurrence was recorded by leaf sample method. The insect population varied among leaf surface morphological characters. The Scanning Electron Microscope pictures revealed that, the trichome type was non-glandular in eggplant and tomato, while in pepper was hairiness. Population density exhibited significantly of trichome length on eggplant, whereas had less significantly on tomato leaves with higher hair density. Peppers, with no trichome had the lowest population of insect. Depending on the analysis of phytochemical composition of plant leaves, a highly positive correlated leafhopper and plant hoppers with higher ratios was found for the total protein, total nitrogen, α-esterase, β- esterase and Glutathione S-transferase (GST). However, the population density affected by the total ratio of carbohydrate of eggplant. While, there was a negative correlated between insect infestation and the contents of phenols, potassium, phosphorus and the plant soap acidity (pH), thus the population was high with low content of these components in eggplant followed by tomato then pepper. This study showed that the development of the host plant resistant to the insect pests is an important strategy of integrated pest management programs and the recognition of morphological and phytochemical characteristics may lead to develop resistance character in acceptable plant genotypes.

Effects of Different Water Regimes and Spacing on Insect Pest Infestation and Efficacy of Control Measures in Cucumber (Cucumis sativus)

Aim: Information on the influence of water availability during different seasons of rainfed or irrigated agriculture as it relates to insect pest population build-up in crops could assist in the development of integrated pest management. A study was therefore conducted to investigate effects of spacing, pest infestation and control on cucumber under rainfed and irrigated conditions.
 Place and Duration of Study: At the Teaching and Research Farm, Ekiti State University, Ado Ekiti, Nigeria during the 2016/2017 rainy and dry seasons.
 Methodology: The experiment was laid out using randomized complete block design (RCBD) in a split-plot arrangement in five replications, with spacing (60 x 60 cm, 60 x 90 cm and 60 x 120 cm) as the main plot treatments and the sub-plot treatments were different pest control strategies. The pest control strategies include synthetic insecticide (Lambda-cyhalothrin), botanical insecticide (Anogeissus leiocarpus) and control. Growth parameters and yield attributes were recorded. Insect pest occurrence, their build-up and percentage infestation on cucumber and the efficacy of the management strategies were monitored.
 Results: The results showed that yield was enhanced in irrigated system with the widest spacing of 60 x 120 cm botanical treatment interaction. Bemisia tabaci was the most prominent insect pest attacking cucumber under irrigated system.
 Conclusion: Other cultural control practices such as the use of trap crops with little or no financial implication should also be added to botanical pesticides as an integrated pest management tactic for effective management and control of the pest.

Susceptibility of eucalypt taxa to a natural infestation by Leptocybe invasa

Recently, pest occurrence in forest plantations has been increasing influenced by genotypes and environmental conditions such as climate change, thus impacting production negatively. In 2008, the exotic pest Leptocybe invasa (Hym: Eulophidae), known as the blue gum chalcid, was introduced in Brazil causing damage to eucalypt plantations in many regions of the country. To this end, this study evaluated the susceptibility of Eucalyptus camaldulensis (one seedlot), E. grandis (four seedlots), E. urophylla (four seedlots), and the “E. urograndis” hybrid (E. urophylla × E. grandis) (three seedlots) exposed to a natural infestation by L. invasa in two seasons (winter and summer). The attack on seedlings was classified in terms of severity as healthy (no pest attack), oviposition (only oviposition signs) and gall formation. The results show a significant higher pest incidence in summer compared to winter. Further, Eucalyptus urophylla was the least attacked and 90% of the seedlings were healthy whereas E. grandis showed the highest number of seedlings with galls. The E. urograndis hybrid showed intermediate results between the two species. Differences in susceptibility were observed between seedlots within species. Eucalyptus camaldulensis, which was expected to have the highest incidence of galls, had a high oviposition incidence (60%) and low gall incidence (< 10%), probably due to its provenance. The susceptibility of the different eucalypt families varied significantly with respect to L. invasa infestation, and family heritability ranged from 0.27 to 0.68. The genetic control of L. invasa is possible through the selection of tolerant and resistant material, considering the species, provenance, and family.

Monitoring, Assessment and Management of Forest Insect Pests and Diseases

Forest pests are one of the most important factors disturbing forest ecosystems, by impacting forestry economy, ecosystem services, biodiversity, and sustainable ecosystem management. Monitoring the occurrence of forest pests offers clues to understand their impacts on the forest ecosystem and develop a sustainable ecosystem management strategy. This special issue is designed to create a better understanding of the changes and impacts of forest pests according to forest changes, caused by natural or anthropogenic causes. There are 13 papers published in this special issue, covering several issues concerning forest pests. Two of the papers reviewed the changes in forest pests in Korea or Poland. The remaining twelve papers covered issues concerning the monitoring, assessment, and management of forest pests. Through this special issue, we expect to contribute towards the improvement of our knowledge of the structures and processes in forest ecosystems relating to forest pests and fundamental information for the effective management of forest pests.

Extraction of distribution information of Angelicae sinensis plants in Weiyuan county based on remote sensing technology

Due to the large amount of nutrients required during the cultivation of Angelica sinensis and in order to prevent the occurrence of pests and diseases,and the annual reduction of the planting area of Angelica and the balance of supply and demand of A. sinensis,the A. sinensis plantation adopts the rotation mode. This paper takes Wuyuan county of Gansu province as the research scope and use GF-1 Satellite data as the data source,using remote sensing technology combined with field survey results,to explore the effective method of visual interpretation for the extraction of A. sinensis planting area. A sample was selected to generate a spectrum according to different feature types. The different characteristics of A. sinensis and other features were analyzed and distinguished in remote sensing images,so that the A. sinensis planting plots were extracted and verified in remote sensing images. The results showed that the accuracy verification value of the visual interpretation method was 95. 85%. It is determined that the visual interpretation method can effectively extract the A. sinensis planting plots within the research scope and realize the comprehensive grasp of the spatial distribution information of A. sinensis.

First Record of Ectomyelois muriscis (Dyar, 1914) (Lepidoptera: Pyralidae) on Jatoba Hymenaea stigonocarpa (Fabaceae) Fruits in Brazil

The jatoba, Hymenaea stigonocarpa Mart. Ex Hayne (Fabaceae), is a tree species native to the Brazilian Cerrado and is recommended for recovering degraded areas. The fruit of this species is used for food and traditional medicine purposes, and its propagation occurs occurs through seeds. This study aimed to record, for the first time in Brazil, the occurrence of an insect pest on jatoba fruits. We sampled 58 H. stigonocarpa fruits from September to October 2017, on a typical Brazilian Savanna area in the municipality of Monte Carmelo, Minas Gerais (18&amp;deg;50&amp;prime;26&amp;Prime; S and 47&amp;deg;19&amp;prime;04&amp;Prime; W). The emergence of nine adults belonging to the Ectomyelois muriscis (Dyar, 1914) (Lepidoptera: Pyralidae) species was recorded on four jatoba fruits (6.9%). The insect only occurred on injuried fruits. The larva was fed from the pulp of the fruit until reaching the pupa stage, but not consuming the seeds. This is the first record of E. muriscis on jatoba fruits in Brazil.

Impact of Plant Clinics on Farmers‘ Knowledge, Attitude and Practice With Plant Health Issues

Plant clinics in Nepal has been started in 2008 and has coverage in more than 40 districts of Nepal. A study has been conducted in Chitwan district of Nepal to assess the changes on farmer‘s knowledge attitude and practice due to implementation of plant clinics. Total of 175 clinic attendants and 175 non-attendants were selected by simple random sampling method and interviewed by using semi-structured questionnaire. By and large, this study found wider positive changes among clinic attendants than non-attendants especially on their knowledge and skills to identity pests and diseases with their causes and practice appropriate remedial measures against those problems. The study revealed positive impact to by increasing knowledge and skillset among attending farmers to assess the season of disease and pest occurrence, estimate economic threshold level as well as preventive and curative measures against the plant health problems. Plant clinic has made impressive positive changes on adoption of recommended dose of pesticides and organic control methods among attendants than non-attendants. The level of awareness and adoption of waiting period after pesticide use was found higher among attendants than non-attendants.

Visual analysis of impact factors of forest pests and diseases

In the field of forest pest and disease research, researchers have combined the experience and data accumulated over many years and conducted long-term and systematic observations of the research object; they have used regression analysis to determine the factors that affect the occurrence of pests and diseases. This traditional approach is time-consuming and highly dependent on expert experience. In this paper, we propose a multicombination multivariable linear regression model to quantitatively describe the multiple linear combinations of relationship between multiple independent variables and a single dependent variable. Based on this model and a data flow model combined with statistical principles and visualization techniques, we propose a multicombination multivariable linear regression visual analysis method to assist researchers in quickly assessing the correlations between the disease indexes of forest diseases and pests and the factors that may affect the pest and disease occurrences. Based on this approach, a multicombination multivariable linear regression visual analysis system was designed and implemented, and the cases of a given forest pest and disease data set were analyzed. It is shown that the multicombination multivariable linear regression visual analysis method can effectively assist researchers in quickly understanding pest and disease data, determining impact factors, and finding relevant laws.

Timing of releases of the parasitoid Habrobracon hebetor and numbers needed in augmentative biological control against the millet head miner Heliocheilus albipunctella

Heliocheilus albipunctella de Joannis (Lepidoptera: Noctuidae) is one of the major insect pests of pearl millet in the Sahel. The native parasitoid, Habrobracon hebetor Say (Hymenoptera: Braconidae), is currently being promoted for augmentative biological control of the pest in the Sahel. The current study was carried out to identify the right time for releases of the parasitoid using either pearl millet growing stage, or pest occurrence as reference, and to determine the optimal number of parasitoids needed to cover a given area. Our results indicate that release of parasitoids at the panicle emergence stage or six weeks after first sight of eggs of H. albipunctella lead to highest parasitism of H. albipunctella larvae by H. hebetor. The dose of 800 parasitoids for a distance of 3 km radius was enough for controlling H. albipunctella. The implications of the results are discussed toward cost effective and practical recommendation adapted to the Sahelian conditions.

PRELIMINARY SURVEY ON OCCURRENCE OF APHIDS, THRIPS LEAF MINER IN TOMATO GROWING AREAS IN MOROGORO REGION TANZANIA

Tomato (Lycopersicum esculentum L.) is one of the important crop in East Africa as a source of food, income and export. Occurrence of different pest including indigenous and alien in tomato fields are considered as a major threat pests to tomato growers. Worldwide pest problems in horticultural investment need to be considered carefully as their presence increase cost of production. Despite of this information in Tanzania there has been little research to update pest list infesting our tomatoes. The study was conducted in Morogoro region in Kauzeni and Bigwa wards whereby farmers grow different varieties of tomatoes. Farmers spray different fungicides and pesticides twice per week to manage different pests. The selected fields were located at S 04˚47ʹ41.7ʹʹ, E 038˚13ʹ11.8ʹʹ and S 06˚53ʹ38.3ʹʹ, E 037˚36ʹ07.4ʹʹ Random sampling using “W” Pattern was used to get representation of the fields. Occurrence of pest population was estimated from ten plants during 2018/19, searching from young, middle and older leaves. Insect specimens were collected using fine forceps, aspirators, and preserved in ethanol 70% for laboratory identification.&#x0D; The results showed no aphids were detected from frequent sprayed tomato fields, other pests observed include the white flies with mean (57) individuals per plant, followed by leaf miner (70) and the highest number was thrips representing (107) Mean population comparison showed a significant differences P&lt; 0.005. Understanding occurrence of different pests in tomato growing areas could assist in planning sustainable Integrated Pest Management programme in tomato growing areas.

Effect of plant protection on assemblages of carabid beetles (Coleoptera, Carabidae) in beetroot crops in four-year rotation

Ground beetles (Col., Carabidae) are common predators in agrocenoses. A number of plant pests occurring on arable fields become their feed. Therefore, they contribute to a natural reduction of the occurrence of pests. In addition, they are well-known bioindicators used, among others to determine the state of the habitats and the impact of human activity on entomofauna. In the fields, the use of chemical plant protection products is a very controversial activity. The aim of the study was to investigate assemblages of ground beetles occupying conventional and organic sugar beetroot crops. Therefore, to determine the impact of the application of pesticides on the assemblages of these useful beetles was made. The study was conducted at the Agricultural Experimental Station in Winna Góra near Środa Wielkopolska in Poland from May till September of 2004, 2008, 2012 and 2016. The experiment was carried out in the field with organic crop of sugar beet, and in the crop, for which an integrated plant protection programme was planned. The area of each field was 0.5 ha. Modified Barber traps were used to catch insects. On each of the selected fields 10 pitfalls were set up, which were emptied every 14 days. Within 4 years of the study a total of 11865 specimens belonging to 52 ground beetle species were recorded. 5582 specimens belonging to 50 species and 6283 specimens belonging to 46 species were caught in the fields under chemical protection and organic, respectively. On a multiannual scale, there were no statistically significant differences in the number of individuals and species of Carabidae on conventional and organic fields. Fluctuation in ground beetles abundance and species richness were observed dependent on the year of study but not of the treatment. Harpalus rufipes was the most represented species in all fields. The main conclusion is that using chemical plant protection on a multiannual scale does not adversely affect the number and species richness of ground beetles.

First Experience with Ozone Used in Fruit Tree Storage

In the present study we investigated the possibility to use air ozone in fruit tree storage. The variables were: rate of ozonization, length of exposure to ozonized air and storage temperature. We assessed the impact of ozone on the vitality of the trees or bench grafted rootstocks, any changes appearing after storage and the feasibility of this technique under real conditions. Supplementary research was done to test the impact of ozonization on the potential occurrence of microorganisms and pests on trees. Results showed that trees can withstand relatively high rates of ozonization except for peach which is the most sensitive fruit; all the ozonization treatments impaired peach vitality. Other species withstand three months of storage in 1 °C and one hour of exposure to ozone in fortnight intervals without a significant impact on their vitality. A higher (5 °C) storage temperature with or without ozonization decreased the vitality of trees. Although it has been proved that ozonization can suppress damage‑causing microorganisms (bacteria and fungi) on trees, the fortnight frequency of ozonization did not prevent mould to develop. Results also indicated the potential effect of ozonization on the disinfestation of plant material from overwintering pests. The main operation restrictions of ozone exposure is the ability of ozone to decompose some materials and that it is harmful to human health.

Many unreported crop pests and pathogens are probably already present

Invasive species threaten global biodiversity, food security and ecosystem function. Such incursions present challenges to agriculture where invasive species cause significant crop damage and require major economic investment to control production losses. Pest risk analysis (PRA) is key to prioritize agricultural biosecurity efforts, but is hampered by incomplete knowledge of current crop pest and pathogen distributions. Here, we develop predictive models of current pest distributions and test these models using new observations at subnational resolution. We apply generalized linear models (GLM) to estimate presence probabilities for 1,739 crop pests in the CABI pest distribution database. We test model predictions for 100 unobserved pest occurrences in the People's Republic of China (PRC), against observations of these pests abstracted from the Chinese literature. This resource has hitherto been omitted from databases on global pest distributions. Finally, we predict occurrences of all unobserved pests globally. Presence probability increases with host presence, presence in neighbouring regions, per capita GDP and global prevalence. Presence probability decreases with mean distance from coast and known host number per pest. The models are good predictors of pest presence in provinces of the PRC, with area under the ROC curve (AUC) values of 0.75-0.76. Large numbers of currently unobserved, but probably present pests (defined here as unreported pests with a predicted presence probability >0.75), are predicted in China, India, southern Brazil and some countries of the former USSR. We show that GLMs can predict presences of pseudoabsent pests at subnational resolution. The Chinese literature has been largely inaccessible to Western academia but contains important information that can support PRA. Prior studies have often assumed that unreported pests in a global distribution database represent a true absence. Our analysis provides a method for quantifying pseudoabsences to enable improved PRA and species distribution modelling.