Desert Locust swarms building in Northern Africa
Nevertheless, the Sahel Desert Locust is one of the most feared locusts in the world. An outbreak in 1988-9 spread throughout Northern Africa, throughout the Middle East and Asia, eventually impacting one fifth of the land mass of the Earth. Given the huge areas these locusts can infest, chemical control is extremely difficult, and there are concerns about the persistance in the environment of the powerful chemical agents used to kill them.
The FAO has issued a desert locust alert.This years outbreak seems to have the potential to become one of these enormous swarm events, and the Food and Agriculture Organization states that the situation is swiftly evolving and that "The number of locusts is increasing rapidly. They are beginning to concentrate themselves into groups characteristic of an outbreak." According to the FAO a full scale locust plague could threaten the good harvest over Northern Africa, and by spreading througout the Middle East and Asia, could eventually devestate the livelihoods of up to one tenth of the world's population.
Currently the FAO's locust group is attempting to stop the plague from developing by spraying chemicals, but given the size of the area, and the handful of teams they have on the ground it seems questionable whether this tactic will be able to forstall the swarm.
In a PDF paper discussing locust control in Africa the authors address the question, "Chemical controls : do they work?" and note that to the present, chemical control has never been known to end a desert locust plague.
"Older organochlorine pesticides used to spray on locusts werehazardous to the environment. Newer pesticides can be hazardousto humans and wildlife. The FAO’s Pesticide Referee Panel providesinformation about recognised locust control chemicals. There islittle evidence that chemical controls—as opposed to winds, rain orlack of food—have wiped out plagues."They also comment on the FAO strategy of 'pre-emptive spraying' currently underway in Northern Africa by commenting,
"The preventative approach seeks to monitorlocust breeding areas and spray as gregarisingpopulations of locusts are identified. This isdifficult in practice, as many of the principalbreeding zones are difficult to reach.The costand effort of infrastructure and communicationsrequired is very considerable. In many areas—Mali, Niger, Chad, Ethiopia and Sudan—there isor has been until recently civil strife."Describing the varieties of chemical control agents available, they note that,
"Dieldrin and otherorganochlorine insecticides were eventuallybanned because of persistence, environmentaleffects, and bioconcentration in fatty tissues.Replacement insecticides included theorganophosphate products fenitrothion,malathion and diazinon, and the carbamatescarbaryl and propoxur. These were less hazardousto the environment but more hazardous tohuman and animal health. They were followed bychemicals of the pyrethroid family such ascypermethrin and lambda-cyhalothrin, and thenew phenyl pyrazole fipronil. All these broadspectrum ‘knock-down’ chemicals are hazardousto non-target species."Locusts differ from grasshoppers in that they can swarm. Normally locusts are solitary insects, but under the right circumstances of rain, combined with population density, and consequent shrinking of food resources, they develope swarming behavior. Locusts lay 'egg pods' which each contain about 100 eggs. Upon hatching, in two to three weeks from the time the egg pod was laid, the flightless locusts can form hopper swarms with a density as great as 5,000 per square meter. As they reach adulthood, they develope wings, and under the right conditions, begin to swarm and can cover vast distances. These swarms can be many square kilometers in size, and the insects are able to completely devastate entire fields in only a matter of minutes. This swarming behavior is a survival strategy, since it is typically the case that locusts breed in drier regions, and swarming over vast distances ensures the survival of the species (which is dependent on rainfall, which might be erratic in these drier regions).
Up to four locust generations are born each year, and it typically takes good rains, and at least four generations for the locusts to reach swarming density, as under these favorable conditions population growth is quite rapid.
A low pressure system has been bringing rains to the North Western Sahara recently, and cloud top Satellite images over recent weeks have shown heavy rains over the Sahel persisting into the month of October.
This pattern of increasing rains has been building in tempo since the late 90s, with record breaking harvests occuring several times over the last couple of years, although the amount of rain falling was nowhere near the record breaking torrential downfalls that occured this year.
Vegetation 2003, 2002
Scale : blue =healthiest vegetation, dark to light green = fair
Vegetation health maps show extremely healthy vegetation over the Sahelian region, and some patches appearing over the Sahara, although the map shows more response over the Sahara desert at this time last year than is currently visible on the map for the corresponding period this year. This is indicative of the strange oscillations in the weather patterns taking place over the Sahara region in recent years. The abundant rains and abundant vegetation have created the perfect conditions for another great Desert Locust swarming event (after a record heat wave and drought, then flooding, and now a plague of locusts...one thing leading right to the other).
It would seem that human beings are pretty much at the mercy of nature when it comes to dealing with the dreaded Desert Locust of Northern Africa, and as the research paper above has noted, there is no evidence that chemical spraying has ever been able to control these insects or bring down the swarm, and it is typically the case that nature runs it course, and that it is nature which eventually brings the swarm to a halt.
Nevertheless, given the threat that such insects pose to human agriculture, research continues on finding the means to control these outbreaks. A paper from the Sustainable Development Organization investigates Organic methods for controlling Desert Locust Swarms.
D D T, Fipronil, Chlorpyrifros, Malathion, are all commonnames in the war against locusts, borers and otherdestructive insects. According to the FAO EmergencyCenter for Locust Operations, “the primary method ofc o n t rolling Desert Locust swarms and hopper bands iswith mainly organophosphate chemicals applied insmall-concentrated doses … by vehicle-mounted and aerialsprayers and to a lesser extent by knapsack and handheldsprayers.If you read the rest of the article, they explain that this organic pesticide works by stabbing the insect full of tiny holes made by sharp particles of silicate earth when they are sprayed, which causes the insect to lose body moisture and die. Because the pesticide is 'mechanical' (involving stabbing the bugs to death with tiny particles of suspended silicates) there is never any chance of the insect developing immunity. Its a novel sounding idea, but would require a change in thinking (it is not possible to 'spray it and leave it' but rather the insects must be engaged in order for the method to work.)
Yes, these pesticides will kill the insects, but theyalso cause damage to the environment and to thepeople whose crops and lands are being sprayed; as wellas to those who ingest such contaminated food. In mostp a rts of sub-Saharan Africa, the harvesting of maize(the staple food crop), and other cereals is done by hand.Most of the pesticides currently being sprayed int h i rd-world countries have been banned in the UnitedStates and the EU.
For the farmer, insect control is of paramountimportance. Recognising this, Organic Solutions continuallyresearches for ways to provide the farmer withcost - effective insect control, providing maximumresults with low to no risk for humans, livestock andthe environment ... All tests (in the labratory) have confirmed the efficiency of Org a n i cSolutions on locusts and stemborers’.
Organic SolutionsInsecticides act just after simple contact by tearing offthe insect cuticle, exposing it to pro g ressive desiccationup to the critical water point and eventuallydeath (which means that it takes longer to have an effect than typical insecticides ... but with typical insecticides the researchers found that the insect either died right away, or lived, thus developing resistance).
Whether this years heavy rains, after causing flooding and a heat wave in Europe, will now result in another globe spanning locust plague, will become clear in the coming weeks as eggs continue to hatch, and hoppers mature and develope wings (which takes about four weeks).
Other Climate related news
In other climate news, the drought in the Western unhealthy forests of the United States continues to deepen in severity, and has also spread a little further west. The bright red areas indicate 'extreme drought' and the dark brown areas indicate 'severe drought' while the blackish spots indicate 'exceptional drought'. Light brown indicates 'drought' and yellow indicates 'usually dry'. According to the Weather Channel, heat records have been broken daily over the Western United States over the past week, and as they state on their website, with temperatures forecast to go up into the 80s in some areas this week, more record temperatures will be falling in the Western United States this week. (According to their online forecast for Tuesday, October 21, 2003, "record-shattering warmth will again bake the Interior West." Their top video story of the day is titled Record heat continues in the West.
Also peculiar is the development of 'swamp like' conditions in the American East, with dark green being extremely moist, medium green being very moist, and light green being 'unusually moist' soil. I have found this pattern to be eerie since it agrees with what certain climate computers have predicted as the future of the United States (a big desert in the west, with a swamp along the coast).
