Alexandre V. Latchininsky

Moroccan locust Dociostaurus maroccanus (Thunberg, 1815): a faunistic rarity or an important economic pest?

The Moroccan locust, Dociostaurus maroccanus (Thunberg), was traditionally considered as one of the most dangerous agricultural pests in the Mediterranean (s.l.) zone. Its broad polyphagy, extreme voracity, enormous fecundity and capability to migrate in swarms made it a major enemy of agriculturists from the Canary Islands to Afghanistan. However, outbreaks of the Moroccan locust seem to have been more frequent in the past and, in many regions, the species has become rare. Climatic factors, in particular the amount of spring rainfall, are critical for the developmental cycle of D. maroccanus. However, anthropogenic factors appear to have the most powerful effect on the locusts population dynamics. On the one hand, deforestation and overgrazing create the necessary prerequisites for colonization by the Moroccan locust. On the other hand, converting grasslands into croplands makes the habitat totally unsuitable for the insect because females can lay eggs into undisturbed soil. These two conflicting tendencies appear to govern the current evolution of Moroccan locust populations, their manifestations being different according to the geographical zone. Although in some regions (e.g. in many European countries) D. maroccanus has lost its formerly high economic importance, in others (North African and central Asian countries) the species continues to flourish and may even increase its pest status.

Locusts and remote sensing: a review

Abstract A dozen species of locusts (Orthoptera: Acrididae) are a major threat to food security worldwide. Their outbreaks occur on every continent except Antarctica, threatening the livelihood of 10% of the world’s population. The locusts are infamous for their voracity, polyphagy, and capacity for long-distance migrations. Decades of research revealed very complex bio-ecology of locusts. They exist in two, inter-convertible and density-dependent states, or “phases.” Despite the evident progress in understanding locust behavior, our ability to predict and manage locust outbreaks remains insufficient, as evidenced by locust plagues still occurring during the 21st century. One of the main reasons is that locusts typically inhabit remote and scarcely populated areas, and their distribution ranges often spread across continents. This creates tremendous obstacles for locust population monitoring and control. Traditional ground locust surveys are inadequate to address the enormous spatial scale of the locust problem in a limited window of time dictated by the pest’s development. Remote sensing (satellite information) appears a promising tool in locust monitoring. Satellite data are increasingly used for monitoring and forecasting two locust species, the desert and the Australian plague locust. However, applications of this geospatial technology to other locust species remain rare.

A Spatial, Markovian Model of Rangeland Grasshopper (Orthoptera: Acrididae) Population Dynamics: Do Long-Term Benefits Justify Suppression of Infestations?

Abstract Using 49 yr of rangeland grasshopper (Orthoptera: Acrididae) survey data for Wyoming digitized into a spatially explicit format, we constructed a two-state (infested or uninfested) Markov chain model to evaluate the probabilities of population changes between states at the scale of 1 km2. Our analyses revealed that only very limited areas of Wyoming are likely to support multiyear infestations of rangeland grasshoppers. Across the state, 91% of the land has a >50% probability of a transition from infested to uninfested conditions from one year to the next. Considering only the land that has ever been infested by grasshoppers, 55% of this area was found to have a >90% probability of becoming uninfested in the year after an infestation. The life expectancy of a grasshopper infestation in Wyoming is generally <2 yr, and large portions of the state can expect infestations to persist for <1 yr. Although rangeland grasshopper infestations are unlikely to persist for >1–2 yr, uninfested conditions are also unlikely to last. Of the land that has ever been infested, uninfested conditions are expected to persist for ≤10 yr on 36% of the area. Thus, rangeland grasshopper outbreaks are highly erratic events, with either infested or uninfested conditions lasting for short periods. Contrary to previous analyses at much coarser spatial scales, the probability of rangeland grasshopper infestations persisting for multiple years appears to be quite low. As such, for most of Wyoming there is little basis for prorating the benefits of control beyond the year of treatment.

Can we make locust and grasshopper management sustainable

Abstract Scale is the fundamental conceptual problem in assessing the sustainability or value of controlling grasshoppers or locusts. Using case studies from North America (United States: Wyoming), Africa (Eritrea), and Asia (Russia: Irkutsk), we analyzed the viability of control programs. There are at least four dimensions to acridid pest management. At the geopolitical scale, all three cases reveal that although the greatest cost/risk of acridid outbreaks accrues locally, distant governments play a primary role despite recent, undirected trends toward decentralization. Examination of the social scale reveals that in all three cases, the individual farm/ranch is the fundamental unit of concern, but these units place high value on preventing acridid infestations from spreading to neighboring lands. None of the systems appear to be driven by the agrochemical industry; rather, the motive force is food security (Eritrea), food quality (Wyoming), or both (Irkutsk). With respect to the interest scale, in all three systems agriculturalists have nothing to gain and much to lose from acridid outbreaks, as compared to the general public (no gains, modest losses), agrochemical industries (low gains, no losses), and governments (low gains, modest losses). In terms of the temporal scale, extremely rapid (and localized) losses and short-term (annual) productivity define the situation for farmers/ranchers, while governments exhibit far slower and longer-term responses and perspectives. From these findings, the keys and obstacles to sustainable acridid pest management are discussed.

Can early season Landsat images improve locust habitat monitoring in the Amudarya River Delta of Uzbekistan

Abstract Reed (Phragmites australis) stands of the Amudarya River delta south of the Aral Sea in Uzbekistan serve as permanent breeding areas of the Asian migratory locust (Locusta migratoria migratoria). Locust swarms threaten agricultural fields adjacent to the delta. Every year, specialists from the Uzbekistan Plant Protection Service attempt to survey this vast delta to assess growth of reed which provides a habitat for locust nymphal infestations. Inferences regarding locust distribution are drawn and recommendations for chemical treatments made, based on very limited samples. This often results in blanketing wetland areas with broad-spectrum insecticides, thus harming nontarget fauna. In this study, early season Landsat data, coinciding with the locust survey planning stage, were used to generate a map of potential locust habitat. Using iterative image classification and reference data, a reed distribution map was generated with an overall accuracy of 74% (kappa agreement = 0.686). Landsat data were able to correctly identify 87% of the reed beds, but had some difficulty separating other vegetation when it was mixed with reeds. Minimizing these errors would improve the overall accuracy; however, this does not diminish the utility of this tool for locust habitat monitoring. Incorporation of remotely sensed data into current survey practices could provide precise information about the spatial distribution of reeds. Plant protection specialists could then use this to optimize planning and execution of antilocust treatments, reducing the negative environmental impact of these.

Locusts and grasshoppers: Behavior, ecology, and biogeography

1Department of Renewable Resources, University of Wyoming, 1000 E. University Avenue, Laramie, WY 82071, USA 2School of Biological Sciences, University of Sydney, Sydney, NSW 2006, Australia 3Department of Entomology, Faculty of Ecology and Evolutionary Biology, Heep Building, Texas A&M University, College Station, TX 77842-2475, USA 4Department of General Biology and Ecology, Novosibirsk State University, 2 Pirogova Street, Novosibirsk 630090, Russia 5Laboratory of Insect Ecology, Institute of Systematics and Ecology of Animals, Siberian Branch, Russian Academy of Sciences, 11 Frunze Street, Novosibirsk 630091, Russia 6Division Entomologia, Museo de La Plata, Universidad Nacional de la Plata, Paseo del Bosque S/N,1900 La Plata, Argentina 7CIRAD Bioagresseurs, TA A-106/D, Campus International de Baillarguet, 34398 Montpellier cedex 5, France

Locust Habitat Monitoring and Risk Assessment Using Remote Sensing and GIS Technologies

Locust outbreaks occur on all continents except Antarctica and can affect the livelihoods of one in 10 people on Earth. To prevent economic and environmental losses, locust breeding areas should be periodically monitored, and an early detection-early response strategy should be in place. Traditional, ground survey methods are inefficient to adequately address the large spatial scale of the locust problem. Remote Sensing and the associated geospatial technologies can provide timely data to assess the risk of impending locust outbreaks. This information could be used for targeted preventive management actions in the locust breeding areas. Remotely sensed data are used for monitoring habitats of certain species such as the Desert, Migratory and Australian Plague locusts. However, the vast potential of this technology remains untapped for other locusts. This chapter provides a review of remote sensing and GIS concepts, types of data collected by various remote sensing satellites, and applications of geospatial tools for locust habitat monitoring and risk assessment.

Can late summer Landsat data be used for locating Asian migratory locust, Locusta migratoria migratoria , oviposition sites in the Amudarya River delta, Uzbekistan?

Existing survey methods for assessing the Asian migratory locust, Locusta migratoria migratoria L. (Orthoptera: Acrididae), infestation risk in the Amudarya River delta, Uzbekistan, are largely constrained by economic resources and site accessibility. The surveys are restricted to a few easily accessible areas, which leads to a misinterpretation of the threat of locust infestation. This often results in indiscriminate blanket treatments of vast areas of wetlands with broad‐spectrum insecticides, which may adversely impact non‐target fauna and flora. In order to minimize the bias during surveys, one approach would be to allocate the sampling locations based on the distribution of the primary food and shelter plant of the locusts, the common reed, Phragmites australis (Cav.) Trin. ex Steud (Poaceae). In this study, we evaluated the utility of satellite‐based remotely sensed data (Landsat TM) acquired in August 2006 to characterize reed distribution in the delta and identify potential locust oviposition sites. The overall accuracy of the Landsat data to map land cover classes in the delta was 84%. The Landsat TM data identified 90% of the reeds, but it was less useful in identifying areas where other vegetations (shrubs and grasses) were mixed with reeds. During the following summer field survey in June 2007, we identified 37 sites that were infested with early‐instar locusts. The low migration capacity of young nymphs in dense reed vegetation allowed us to presume that these sites were used for oviposition in the previous summer. Twenty‐eight (74%) of these 37 sites had reeds in the previous year. Results from these studies demonstrate that reed distribution maps derived from satellite data could be used for targeting locust egg‐pod survey locations, in order to minimize sampling bias while predicting locust infestation risks for the following season.

Grasshopper Control in Siberia: strategies and perspectives

Summary The area of potential grasshopper damage in Siberia covers a wide zone of meadow-steppe localised between 50° and 55°N, 68° and 132°E. Among some 40 grasshopper species inflicting damage to grasslands and crops, about half a dozen arc regular pests. The strategy for their control is essentially curative: large-scale insecticide spraying in breeding areas soon after mass hatching of hoppers. The average surface of annual treatments is about 200,000 ha, exceeding 500,000 ha in the years of heavy outbreaks (e.g. 1994) The list of conventional insecticides registered for grasshopper control includes a dozen formulations, among which malathion (2–3 l/ha) and deltamethrin (0.4–0.5 l/ha) are most commonly utilised. Alternative strategies of grasshopper control involve the use of prospective natural enemies (e.g. fungus Beauveria tenella, nematode Steinernema carpocapsae and others). With the use of such biopesticides, we hope to shift the existing strategy of grasshopper control towards methods less hazardous to the environment.

Changes in non-target arthropod populations following application of liquid bait formulations of insecticides for control of rangeland grasshoppers

Abstract This study was undertaken to determine the non-target impacts of rangeland grasshopper control using liquid bait formulations of insecticides (canola and corn oil as carriers of carbaryl, diflubenzuron, and malathion). The research was conducted on native rangeland in Wyoming under drought conditions. Three collection methods (pitfall traps, yellow sticky cards, and sweep nets) were used to estimate non-target arthropod densities. The formulated insecticides were applied according to the protocol of reduced agent-area treatments, an application method designed to reduce economic and environmental costs by applying insecticides at low rates with incomplete coverage via alternating treated and untreated swaths). Canola and corn oils are vegetable oils high in linolenic and linoleic acids which function as attractants and phagostimulants for many species of grasshoppers. Crop oil is a biologically inert paraffin-based petroleum product that served as a control. Although all treatments markedly reduced grasshopper population densities, non-target populations were nominally affected. There were no consistent, significant differences in the responses of non-target populations to treatments with the liquid baits (canola and corn oil carriers) relative to those observed with the standard carrier (crop oil). Only one taxonomic group (Formicidae) showed a significant negative response to treatment relative to untreated controls. Logistical and ecological factors associated with grasshopper control methods may account for the nominal effects on non-target taxa. Sweep net and sticky trap sampling were more sensitive to treatment effects and time-by-treatment interactions. Temporal changes in population densities may have made treatment effects difficult to distinguish in several taxonomic groups.