Desert Locust Control Research Articles

Farmers’ perceptions of integrated desert locust management: a case study in Isiolo and Meru Counties of Kenya

Abstract The destructive nature of desert locust invasions in terms of reduced food security and loss of agricultural income necessitates effective control strategies. While chemical spraying is effective, it is harmful to the environment, human, and animal health. Therefore, an alternative is the implementation of an integrated desert locust management (IDLM) approach that entails surveillance and early warning systems, rational combination of chemicals, biological measures, and indigenous control methods. Adopting IDLM depends on an understanding of human behavior and perceptions as an avenue for disseminating information for effective control. However, there is limited knowledge of the drivers of farmers’ perceptions of IDLM. This study sought to fill the above knowledge gap by applying the principal component analysis method to develop a composite index that was subsequently used in a regression analysis of data collected from a sample of 391 farmers in Isiolo and Meru counties in Kenya. Descriptive results showed that informal sources and channels were the main sources of desert locust information, and most farmers held positive or neutral perceptions. The regression analysis results highlighted the role of formal and informal sources of information, private land ownership, and previous shocks in influencing farmers’ perceptions of integrated desert locust management. The study recommends targeted messaging of desert locust management approaches through coordinated surveillance and timely response by national and international agencies, empowering community leaders as the key entry point, and building local capacity for accurate observation and timely reporting of invasions as measures towards sustainable desert locust control efforts.

Improving Uptake of Biopesticides for Desert Locust Control

Improving Uptake of Biopesticides for Desert Locust Control

Desert Locust Invasion in Uganda: Effects on Household Food Consumption and Effective Control Interventions

Desert locust invasions are still a danger to the well-being of natural and man-made ecosystems in the tropics. This study examined desert locust invasion duration, survival probability, and control as well as their effects on household food item consumption in the drylands of Uganda. Primary socioeconomic data were collected using various methods (household survey, focus group discussion, and key informant interviews) in May/June 2020 to document the perceptions of households regarding locusts. Our findings reveal that the most significant drivers of desert locust invasions were rainfall, surface temperature, strong winds, soil moisture, soil type, and vegetation type (p ≤ 0.05). The locusts lasted between 3 and 4 weeks. The survival probability of locusts beyond 1 week was 90%. There were significant differences in the day’s food items consumed before and after the locust invasion, except for ground nuts and cashew nuts (p ≤ 0.05). The number of days per month the food items were consumed decreased after the locust invasion. The most effective locust control measure undertaken was the use of ground and aerial pesticide spraying. The major sources of desert locust control information were radio and television. This information is a prerequisite in desert locust invasion preparedness, response, and recovery but can also strengthen sustainable green economy efforts, especially in fragile semi-arid ecosystems.

Effect of desert locust control on non-target edible termites in eastern Uganda

Effects of widescale locust control with insecticides on non-target edible insects have been scarcely assessed. This study was carried out to investigate the effect of spraying desert locust with cypermethrin and chlorpyrifos on: (1) termite mound activity; (2) safety of edible termites from contamination with pesticide residues; and (3) nutritional composition of non-target edible termites. Incidences of inactive termitaria in the sprayed and unsprayed sites were enumerated. Edible soldiers ofMacrotermes spp. from sprayed and unsprayed colonies whose alates swarm around dusk, midnight and dawn were analysed for cypermethrin and chlorpyrifos residues, and proximate, mineral and flavonoid compositions. The pesticide sprays did not influence the incidence of inactive termitaria. No cypermethrin and chlorpyrifos residues were detected in the termites. Chlorpyrifos spraying lowered crude fibre and protein contents in soldiers of dawn and midnight swarming colonies, respectively; whereas cypermethrin spraying lowered ash and crude fat contents in soldiers from dawn and dusk swarming colonies, respectively. Cypermethrin spraying increased moisture content in soldiers from midnight swarming colonies. The level of manganese in soldiers from dawn swarming colonies was lowered by cypermethrin spraying, while contents of aluminium and cobalt from the same type of colony were lowered by chlorpyrifos spraying. However, levels of calcium, potassium, magnesium, phosphorus, zinc, aluminium, manganese and iron were enhanced in soldiers from different termite colonies sprayed with cypermethrin and/or chlorpyrifos. Similarly, soldier termite samples from both insecticide sprayed sites contained higher flavonoid levels than the samples from unsprayed sites. Freedom of the edible soldier termites from the pesticides residues renders them safe for consumption. The results provide insights into the likely effects of wide-scale pesticide sprays against locust on the nutritional profiles of edible termites.

Optimum Flight Height for the Control of Desert Locusts Using Unmanned Aerial Vehicles (UAV)

Desert locust is one of the most destructive migratory pest in the world. Current methods of control rely on conventional chemical insecticides during invasion. Some environmentally friendly biopesticides based on Metarhizium acridum and insect growth regulators have also been deployed in preventive control operations. They have been tested in sprayers mounted on commonly used platforms such as vehicles, aircraft, and human. However, despite being used successfully, these tools present many challenges, hence the need to supplement them with suitable alternatives. The successful use of drones to control pests such as fall armyworm, planthoppers, aphids, among others, makes it an attractive technology that has the potential to improve locust management, especially in inaccessible areas. However, key parameters for the safe and optimal use of drones in desert locust control are not documented. This study established the key parameters for spraying desert locusts with a drone. To test the optimum height for spraying Metarhizium acridum on the locusts, the drone was flown at five different heights: 2.5, 5, 7.5, 10, and 12.5 m. At each height, the drone sprayed the ink mixture on spray cards pinned to the ground to approximate the droplet density and compare it to the standard droplet density recommended for desert locust control. To assess the efficacy of M. acridum and the effectiveness of drones in its application, 50 g of spores were mixed in 1 L of diesel and sprayed on caged live locusts of different stages (3rd and 4th instars, as well as the adults); they were monitored for twenty-one days in a controlled room, and their mortality was determined. Variation in droplet density between the tested heights was significant. A height of 10 m agrees with the recommended standard droplet density within the 45 droplets/cm2 range. Mortality varied among the locusts’ developmental stages within and between heights. Survival probability varied between heights for 3rd instar, 4th instar, and adults. All the developmental stages of the desert locust were susceptible to Novacrid and the recommended target stage is the 3rd instar. Management of desert locusts by the use of drone technology appears promising when the pesticides are applied at an optimum height and standard operating procedures are followed. Further research could explore the gap in the effects of environmental parameters on flight application efficiency.

Disaster management takes to the skies: How new technologies are reconfiguring spatialities of power in desert locust management

This article explores how new technologies – such as drones and satellites – are incorporated into disaster management and questions the implications for power relations between disaster authorities and subjects. This is a critical area of research, as the proliferation of aerial and networked technologies has made their use in disaster management and response more common. Although concerns have been raised about the potential use of aerial and networked technologies in the surveillance and spatial discipline of populations by commercial and government actors, few have considered the implications for disaster management. In response, this article turns to geographical literature on necropower, verticality, and planetary spatialities to analyse technological innovations in responses to desert locust upsurges in Kenya. Drawing from qualitative research carried out between February 2020 and January 2021, we explain how desert locust control operations have shifted from horizontal to vertical to networked and planetary in nature through experimentation with new technologies over the past century. We argue that aerial and networked technologies have led to a volumetric shift in desert locust management and response, giving remote and increasingly automated actors who operate ‘above’ greater power over the life and death of populations ‘below’. In making this argument, we adopt a more-than-human perspective to account for how nonhuman entities and lifeforms shape and are subjected to necropolitical disaster management and responses. We conclude by reflecting on what this analytical approach has to offer the study of vertical and volumetric geographies.

Impact of insecticides used in controlling desert locust (Schistocerca gregaria Forskal) and on crawling arthropods in Shieb, Eritrea

The experiment conducted at Shelshela, sub-region Shieb – Eritrea during November 2015 to February 2016 showed that the use of fenitrothion 96 per cent ULV and chlorpyrifos 45 per cent ULV to control locust led to significant reduction in arthropod population after 48 hrs of post-spray than the control plot. The fenitrothion treated plots generally showed more reduction in population count than chlorpyrifos. Fenitrothion treated plots recorded maximum reduction (89%) of formicids population. Whereas, chlorpyriphos recorded the lowest of carabids (52%). Population count of Gryllidae and Tenebrionidae showed slight improvement after a month of spray than others. Generally, a population reduction of 86.2 per cent in fenitrothion and 81.1 per cent in chlorpyrifos was recorded in first post-spray count of D3 as compared to pre-spray counts of D1 and D2. From the study it is also observed that Formicidae and Gryllidae can be used as bio-indicators during insecticide control of desert locust in the study areas.

Biopesticides - An environmentally friendly approach for desert locust control

Biopesticides - An environmentally friendly approach for desert locust control

Biological control of desert locust ( Schistocerca gregaria Forskål)

Abstract Desert locust ( Schistocerca gregaria Forskål) is one of the most serious agricultural pests in the world due to its voracity, speed of reproduction, and range of flight. We discuss the current state of knowledge on its biological control using microorganisms and botanical extracts. Metarhizium flavoviride was among the first fungus to be recognized as a bio-control agent against desert locust in the laboratory and field conditions. Nevertheless, its oil formulation adversely affected non-target organisms, hence led to further research on other microorganisms. Metarhizium anisopliae var. acridum (syn. Metarhizium acridum ) is an environmentally safer bio-pesticide that has no measurable impact on non-target organisms. However, there are various shortcomings associated with its use in desert locust control as highlighted in this review. Bacterial pathogens studied were from species of Bacillus , Pseudomonas , and Serratia . Botanical extracts of 27 plant species were tested against the locust but showed varied results. Azadirachta indica and Melia volkensii were the most studied plant species, both belonging to family Meliaceae, which is known to have biologically active limonoids. Out of the 20 plant families identified, Apiaceae was the most represented with a frequency of 21%. However, only crude botanical extracts were used and therefore, the active ingredients against desert locust were not identified. Through a comprehensive research, an integrated pest management strategy that incorporates these bio-controls would be a realistic option to control desert locust infestations.

Desert Locust Control: The Effectiveness of Proactive Interventions and the Goal of Outbreak Prevention

Desert Locust Control: The Effectiveness of Proactive Interventions and the Goal of Outbreak Prevention

Soil moisture from remote sensing to forecast desert locust presence

Abstract Preventive control of desert locusts is based on monitoring recession areas to detect outbreaks. Remote sensing has been increasingly used in the preventive control strategy. Soil moisture is a major ecological driver of desert locust populations but is still missing in the current imagery toolkit for preventive management. By means of statistical analyses, combining field observations of locust presence/absence and soil moisture estimates at 1 km resolution from a disaggregation algorithm, we assess the potential of soil moisture to help preventive management of desert locust. We observe that a soil moisture dynamics increase of above 0.09 cm3/cm3 for 20 days followed by a decrease of soil moisture may increase the chance to observe locusts 70 days later. We estimate the gains in early warning timing compared to using imagery from vegetation to be 3 weeks. We demonstrate that forecasting errors may be reduced by the combination of several types of indicators such as soil moisture and vegetation index in a common statistical model forecasting locust presence. Policy implications. Soil moisture estimates at 1 km resolution should be used to plan desert locust surveys in preventive management. When soil moisture increases in a dry area of potential habitat for the desert locust, field surveys should be conducted two months later to evaluate the need of further preventive actions. Remote sensing estimates of soil moisture could also be used for other applications of integrated pest management.

Assessment of nocturnal insects in desert locust habitat after the application of insecticides against Desert Locust in Sub-Zoba Shieb, Eritrea

The study on the impact of insecticide nocturnal insects used to control desert locust was conducted at Shelshela, sub-region Shieb from November 2015 to February 2016. Its aim was to assess the impact of Desert Locust control insecticides spray on non-target arthropods. The experiment was carried out in RCBD using three treatments of fenitrothion 96% ULV, chlorpyrifos 45% ULV and control with three replications. It was replicated three times. Each plot had a size of 1 ha with a buffer zone among plots and blocks were 100 m. Data were recorded two times at pre-sprays and five times at post-sprays. During study period 4 insect families were observed and data were analyzed. These were Calliphoridae, Elateridae, Scarabidae, and Pselaphidae. In pre-spray, data did not show significant difference among treatments used. After 48 hrs of post-spray result showed significant difference among treatments. Both insecticides treated plots showed significantly lower population count than control plot. Between the treatments used fenitrothion treated plots generally showed more reduction in population count than chlorpyrifos. From the study it is observed that Elateridae can be used as bio-indicator during insecticide control of desert locust in the study areas.

Ligand-binding characterization of simulated β-adrenergic-like octopamine receptor in Schistocerca gregaria via progressive structure simulation

It is important to design insecticides having both low drug resistance and less undesirable toxicity for desert locust control. Specific GPCRs of Schistocerca gregaria, especially β-adrenergic-like octopamine receptor (SgOctβR), can be considered as its potential effective insecticide targets. However, either the unavailability of SgOctβR’s structure or the inadequate capability of its sequence lead the development of insecticide for Schistocerca gregaria meets its plateau. To relax this difficulty, this paper develops a promising progressive structure simulation from SgOctβR’s sequence, to its predicted structure of SgOctβR in vacuum, to its conformation as well as its complex with endogenous ligand octopamine in a solvent-membrane system. The combined approach of multiple sequence alignment, static structural characterization, and dynamic process of conformational change during binding octopamine reveal three important aspects. The first one is the characterization of SgOctβR’s active pocket, including the attending secondary structure elements, its hydrophobic residues and nonpolar surface. The second one is the interaction with octopamine, especially the involved hydrogen bonds and an aromatic stacking of pi–pi interactions. The third one is the potential binding sites, including six highly conserved residues and one highly variable residue for locust insecticide design. This work is definitely helpful for the further structure-based drug design for efficient and eco-friendly insecticides, as well as site-directed mutagenesis biochemical research of SgOctβR.

Operational Monitoring of the Desert Locust Habitat with Earth Observation: An Assessment

Desert locust swarms intermittently damage crops and pastures in sixty countries from Africa to western Asia, threatening the food security of 10% of the world’s population. During the 20th century, desert locust control operations began organizing, and nowadays, they are coordinated by the Food and Agriculture Organization (FAO), which promotes a preventative strategy based on early warning and rapid response. This strategy implies a constant monitoring of the populations and of the ecological conditions favorable to their development. Satellite remote sensing can provide a near real-time monitoring of these conditions at the continental scale. Thus, the desert locust control community needs a reliable detection of green vegetation in arid and semi-arid areas as an indicator of potential desert locust habitat. To meet this need, a colorimetric transformation has been developed on both SPOT-VEGETATION and MODIS data to produce dynamic greenness maps. After their integration in the daily locust control activities, this research aimed at assessing those dynamic greenness maps from the producers’ and the users’ points of view. Eight confusion matrices and Pareto boundaries were derived from high resolution reference maps representative of the temporal and spatial diversity of Mauritanian habitats. The dynamic greenness maps were found to be accurate in summer breeding areas (F-score = 0.64–0.87), but accuracy dropped in winter breeding areas (F-score = 0.28–0.40). Accuracy is related to landscape fragmentation (R2 = 0.9): the current spatial resolution remains too coarse to resolve complex fragmented patterns and accounts for a substantial (60%) part of the error. The exploitation of PROBA-V 100-m images at the finest resolution (100-m) would enhance by 20% the vegetation detection in fragmented habitat. A survey revealed that end-users are satisfied with the product and find it fit for monitoring, thanks to an intuitive interpretation, leading to more efficiency.

Locust Control Management: Moving from Traditional to New Technologies – An Empirical Analysis

The desert locust (Schistocerca gregaria Forskal) has caused great losses to agriculture in Africa, the Middle East and South West Asia. Their annual migrations take them downwind where winter, spring and summer rains fall for breeding. During the period 1863 to 1962 there were ten plagues in India and 18 upsurges from 1963 to 2012. Traditional desert locust control methods were used which were not successful. Newer technologies in the form of pesticides, ULV spraying, GPS, GIS tools, Satellite data imagery, RAMSES and elocust2 with the computers have been introduced for quick data management and analysis for planning desert locust control. The impact of newer technologies for locust control management in India for last 50 years has been successful. The South West Asia and the Middle East countries have taken responsibility for monitoring the breeding grounds and applying plague prevention strategy for desert locust control in the outbreak areas and by exchanging desert locust infestation information through FAO. The early prevention strategy for desert locust control has achieved its original objective of preventing damage to major agricultural zones in invasion area and helps protect the crops of small farmers as well as grazing grounds for the livestock.

In vitro impact of five pesticides alone or in combination on human intestinal cell line Caco-2

In Burkina Faso, as in most Sahelian countries, the failure to follow good agricultural practices coupled with poor soil and climate conditions in the locust control context lead to high environmental contaminations with pesticide residues. Thus, consumers being orally exposed to a combination of multiple pesticide residues through food and water intake, the digestive tract is a tissue susceptible to be directly exposed to these food contaminants. The aim of our work was to compare in vitro the impact of five desert locust control pesticides (Deltamethrin DTM, Fenitrothion FNT, Fipronil FPN, Lambda-cyalothrine LCT, and Teflubenzuron TBZ) alone and in combination on the human intestinal Caco-2 cells viability and function. Cells were exposed to 0.1–100 μM pesticides for 10 days alone or in mixture (MIX). Our results showed a cytotoxic effect of DTM, FNT, FPN, LCT, and TBZ alone or in combination in human intestinal Caco-2 cells. The most efficient were shown to be FPN and FNT impacting the cell layer integrity and/or barrier function, ALP activity, antioxidant enzyme activity, lipid peroxidation, Akt activation, and apoptosis. The presence of antioxidant reduced lipid peroxidation level and attenuated the pesticides-induced cell toxicity, suggesting that key mechanism of pesticides cytotoxicity may be linked to their pro-oxidative potential. A comparative analysis with the predicted cytotoxic effect of pesticides mixture using mathematical modeling shown that the combination of these pesticides led to synergistic effects rather than to a simple independent or dose addition effect.

Coupling historical prospection data and a remotely-sensed vegetation index for the preventative control of Desert locusts

Locusts are grasshopper species that exhibit phase polyphenism resulting in the expression of gregarious behaviors that favor the development of large devastating bands and swarms. Desert locust preventative management aims to prevent crop damage by controlling populations before they can reach high densities and form mass migrating swarms. The areas of potential gregarization for Desert locust are large and need to be physically assessed by survey teams for efficient preventative management. An ongoing challenge is to be able to guide where prospection surveys should occur depending on local meteorological and vegetation conditions. In this study, we analyzed the relationship between historical prospection data of Desert locust observations from 2005 to 2009 and spatio-temporal statistics of a vegetation index gathered by remote-sensing with the help of multiple models of logistic regression. The vegetation index was a composite Normalized Difference Vegetation Index (NDVI) given every 16 days and at 250m spatial resolution (MOD13Q1 from MODIS satellite). The statistics extracted from this index were: (1) spatial means at different scales around the prospection point, (2) relative differences of NDVI variation through time before the prospection, and (3) large-scale summary of vegetation quantity. The multi-model framework showed that vegetation development a month and a half before the survey was amongst the best predictors of locust presence. Also, the local vegetation quantity was not enough to predict locust presence. Vegetation quantity on a scale of a few kilometers was a better predictor but varied non-linearly, reflecting specific biotope types that support Desert locust development. Using one of the best logistic regression models and NDVI data, we were able to derive a predictive model of probability of finding locusts in specific areas. This methodology should help in more efficiently focusing survey efforts on specific parts of the gregarization areas based on the predicted probability of locusts being present.

RNA interference of insulin-related peptide and neuroparsins affects vitellogenesis in the desert locust Schistocerca gregaria

The ‘classic’ insect hormones, juvenile hormone and 20-hydroxyecdysone, can stimulate vitellogenesis and/or ovarian development in adult females of several insect species. Accumulating evidence also indicates a crucial role in female reproductive physiology for peptide hormones, such as insulin-related peptides (IRPs) and neuroparsins (NPs). Especially in dipteran species, IRP signaling has been shown to regulate female reproductive events. The first NP was originally identified from the migratory locust ( Locusta migratoria) as an antigonadotropic factor that delayed vitellogenesis. Moreover, NP family members display sequence similarities with the N-terminal domain of vertebrate insulin-like growth factor binding proteins (IGFBPs). In the current study, RNA interference (RNAi) was employed to investigate the possible involvement of IRP and NPs in the control of the female desert locust ( Schistocerca gregaria) reproductive system. The cDNAs encoding an IRP ( Scg-IRP) and four NPs ( Scg-NPs) had previously been cloned from S. gregaria. An RNAi-mediated knock-down of either Scg-NP or Scg-IRP transcript levels was induced in adult female desert locusts and the subsequent effects were analyzed. Knock-down of the Scg-NPs or Scg-IRP affected vitellogenin transcript levels and oocyte growth in a positive and negative way, respectively. The current findings are indicative for a role of Scg-NPs and Scg-IRP in the control of vitellogenin synthesis. A plausible hypothesis is that Scg-IRP may act as a sensor of the nutritional and metabolic status that determines whether vitellogenesis can occur. That the same processes were affected in opposite ways in both RNAi experiments offers an extra argument for antagonizing roles of Scg-NPs and Scg-IRP.

Impact of chlorpyrifos used for desert locust control on non-target organisms in the vicinity of mangrove, an ecologically sensitive area

Ecologically sensitive areas (ESAs) including the mangrove along the Red Sea Coast of Sudan may be subjected to adverse impacts of insecticides for controlling desert locust, Schistocerca gregaria (Acrididae). This study assessed potential impacts of an aerial application of chlorpyrifos (Ultra Low Volume [ULV], 279 g a.i. ha−1) during conditions resembling an operational treatment of desert locust. The surveyed non-target organisms were studied in one treated and one untreated area (88 ha each), during a 13-week pre-spray period and an 8-week post-spray period, from November 2001 to April 2002. Survival of caged prawns (Penaeidae) in the mangrove lagoon were tested in situ, and monitoring of relative abundances of non-target organisms included (i) terrestrial transect counts of hoopoe larks, Alaemon alaudipes (Alaudidae), and of antlion larval pits, Cueta spp. (Myrmeleontidae) and (ii) pitfall sampling of epigeal arthropods in the terrestrial zones from shore to cropland. The survival of Metapenaeus monoceros juvenile prawns fell dramatically between the third and fifth day after the application in the treated area compared to the untreated area, in which mortality was delayed. In the early mornings when control operations often occur, a northern and northwestern wind direction, i.e. from land towards the sea, dominates, thus adverse impact on the prawns is a risk. The abundance of antlion pits was reduced in the treated area following spraying, but not in the untreated. The same was true for observations of hoopoe larks, numbers of Mesostena angustata (Tenebrionidae), and Gryllus bimaculatus (Gryllidae), at species and family levels, and arachnids.

Novel cross-stage solitarising effect of gregarious-phase adult desert locust ( Schistocerca gregaria (Forskål)) pheromone on hoppers

Previous studies had demonstrated stage differentiation in the cohesion (aggregation) pheromone systems of the desert locust, Schistocerca gregaria. In laboratory arena, the nymphal and adult stages responded aggregatively to their own pheromone, but dispersed evenly within the arena in the presence of the other. In the present study, we explored the effects of longer-term contact of field gregarious hopper bands and laboratory crowd-reared nymphs with the major constituent of the adult pheromone. During the first few days, hoppers in treated bands became relatively hyperactive. Over the next few days, their movements became random and they stopped marching as coherent groups, they started to roost for longer periods on vegetations, and they fragmented into smaller and smaller groupings and individuals. When attacked by birds, they demonstrated subdued levels of collective defensive behaviour compared to normal hoppers, and there were clear signs of increased predation and cannibalism at the roosting sites. In cage experiments, crowd-reared nymphs treated with the pheromone component became hyperactive, showed abnormal diel patterns and reduced feeding on plants but increased cannibalism. Our observations show that the major adult pheromone constituent has a solitarising effect on gregarious hoppers. The mechanism underlying this effect and the potential of the agent in desert locust control are discussed.