Search Results (6)

Mass vaccination against peste des petits ruminants (PPR) in two southern states of India, namely Andhra Pradesh and Karnataka, has reduced disease outbreaks significantly. The sporadic outbreaks reported now can be attributed in part to the recurring movement of sheep and goats between these contiguous states. This study assessed the present level of economic burden and impact of vaccination on the local system (one state), considering the exposure from the external system (neighboring state) using a system dynamic (SD) model. The SD model relies on interdependence, interaction, information feedback, and circular causality and captures potential feedback between disease control interventions and their impact on various epidemiological and economic outcomes. The data for parameterization of the model were collected through surveys, expert elicitation, and literature review. The sporadic outbreaks reported in recent years (<10 outbreaks/year during 2022) were due to continuous “mass vaccination” for more than a decade. During 2021–2022, the PPR incidence was less in both the states, with an estimated loss of USD 26.30 and USD 22.86 million in Andhra Pradesh and Karnataka, respectively. The SD model results showed a systemic increase in flock size and offtakes and a decline in the number of infected and death cases under high vaccination coverage (75% and 100% coverage) compared to the low-coverage scenario. Hence, the coordinated inter-state vaccination efforts offer better prospects, as efforts in one state have positive externalities in terms of fewer outbreaks in a neighboring state. Full article

Durrantia arcanella is a recurring pest insect of oil palm in Colombia. Because the biology and ecology of D. arcanella are unknown, it was proposed to determine the life cycle and foliar consumption under laboratory conditions. Furthermore, through sequential sampling for two and a half years, its population fluctuation and natural enemies were determined in Agustín Codazzi and El Copey (Cesar, Colombia). Also, temperature, precipitation, and relative humidity were registered. The life cycle of D. arcanella lasted 48.0 ± 10.1 days, the egg 8.0 ± 0.7 days, larva 24.2 ± 6.2 days, pre-pupa 1.5 ± 0.5 days, pupa 7.1 ± 0.9 days, and adult 7.2 ± 2.0 days. The larvae consumed 8.2 ± 5.3 cm² of leaflets. Correlations were found between the population fluctuation in D. arcanella and the temperature in El Copey (ρ = −0.45; p < 0.0043), relative humidity in Codazzi (ρ = 0.33; p < 0.034), and with the natural control in both locations ((ρ = 0, 61; p < 0.000044) and (ρ = 0.42; p < 0.006)). These results suggest monitoring the pest populations in the second semester of the year and show the importance of promoting native natural enemies. Full article

Charonia tritonis (Charoniidae), one of the largest marine gastropods and an echinoderm specialist, preys on Crown-of-Thorns starfish (CoTS), a recurring pest that continues to be a leading cause of coral mortality on Indo-Pacific reefs. Widespread historical exploitation has impacted their numbers, with standing populations considered rare throughout their habitat. Their life-stage attributes, i.e., teleplanic larvae, planktotrophic phase spanning years permitting transoceanic dispersal, and recruitment to coral reefs through oceanic influx with intense larval mortality, have likely hindered their recovery. Decline in numbers is hypothesised to account partially for periodic CoTS outbreaks, yet predator-prey dynamics between these two species that might influence this are poorly understood. The C. tritonis excretory secretome elicits a proximity deterrence effect on CoTS, the nature of which is under investigation as a possible tool in CoTS biocontrol scenarios. However, specificity and zone of impact in situ are unknown, and whether the mere presence of C. tritonis and/or predation pressure has any regulatory influence over CoTS populations remains to be established. The fundamental taxonomy and distinctive characteristics, biology and ecology of C. tritonis is summarized, and knowledge gaps relevant to understanding their role within coral reefs identified. Information is provided regarding exploitation of C. tritonis across its habitat, and prospects for conservation interventions, including captive rearing and stock enhancement to repopulate local regions, are discussed. Its predator-prey ecology is also examined and potential to mitigate CoTS considered. Recommendations to direct future research into this predator and for its inclusion in a CoTS integrated pest management strategy to improve coral reef health are offered. Full article

Due to the narrow row spacing of corn, the lack of light in the field caused by the blocking of branches, leaves and weeds in the middle and late stages of corn growth, it is generally difficult for machinery to move between rows and also impossible to observe the corn growth in real time. To solve the problem, a robot for corn interlines information collection thus is designed. First, the mathematical model of the robot is established using the designed control system. Second, an improved convolutional neural network model is proposed for training and learning, and the driving path is fitted by detecting and identifying corn rhizomes. Next, a multi-body dynamics simulation software, RecurDyn/track, is used to establish a dynamic model of the robot movement in soft soil conditions, and a control system is developed in MATLAB/SIMULINK for joint simulation experiments. Simulation results show that the method for controlling a sliding-mode variable structure can achieve better control results. Finally, experiments on the ground and in a simulated field environment show that the robot for field information collection based on the method developed runs stably and shows little deviation. The robot can be well applied for field plant protection, the control of corn diseases and insect pests, and the realization of human–machine separation. Full article

The guava fruit fly, Bactrocera correcta, is one of the major pests affecting mango (Mangifera indica) and guava (Psidium guajava) production in China. The compound β-caryophyllene was identified from the rectal gland extracts of wild B. correcta males and was demonstrated to be a more specific and potent male lure than methyl eugenol (ME) for B. correcta. In order to find potential additional pheromone attractants for the monitoring and mass-trapping of this fruit fly, a series of chemical and behavioral assays were conducted in this study. Ten compounds were identified from the rectal glands of virgin B. correcta females. These compounds consisted of five major compounds (i.e., ethyl dodecanoate, ethyl tetradecanoate, ethyl (E)-9-hexadecenoate, ethyl hexadecanoate, and ethyl (Z)-9-octadecenoate) in high quantities, and other compounds (i.e., octanal, N-(3-methylbutyl) acetamide, (Z)-9-tricosene, ethyl octadecanoate, and ethyl eicosanoate) in trace amounts, while virtually no compounds were found in male rectal glands. The bioassays indicate that female rectal gland extracts are attractive to virgin females and males. Furthermore, a cyclical production of the five major compounds was found, recurring at roughly 10-d intervals with peaks in 10–13-, 25-, and 35-d-old females. Collectively, these results will contribute to the understanding of pheromone communication in B. correcta and may provide important information for improving existing monitoring and control methods for this pest. Full article

First detected in Switzerland in 2011, the invasive Drosophila suzukii, spotted wing drosophila, has caused recurring costs for growers of berries and fruit. Recommended management approaches rely on a set of methods, tailored to suit crop requirements under the prevailing local conditions. Control of D. suzukii represents a substantial economic burden for growers, in terms of material, equipment, new infrastructure and extra labour. However, those growers who invest wisely to deliver unblemished produce are rewarded with high payoffs. We present insights from a growers’ survey conducted in 2015 and 2016 to gauge the impact of the introduction and establishment of D. suzukii on Swiss sweet cherry production. The surveyed growers (111 in 2015 and 298 in 2016) observed the recommended surveillance, sanitation and control measures. The use of insecticides (78% and 79% of respondents in 2015 and 2016, respectively) and the harvest of all fruits (93% and 59% of respondents in 2015 and 2016, respectively) were the most widespread methods used to reduce damage. Nearly one-third of the respondents set up enclosure nets. Our economic evaluation of different scenarios provides a quantitative indication of the potentially incurred costs. We argue for enhanced stakeholder involvement to raise the acceptance of integrated pest management practices, and to inform research and outreach by providing insights into the motivations and barriers to adoption. Full article