SCIENTISTS WAR ON THE LOCUST

Press, Volume CI, Issue 29844, 9 June 1962, Page 8

SCIENTISTS WAR ON THE LOCUST

London Research Unit

t Specialty written for “Tne Press” by AVERIL DREW] 'piROS 4, the United States weather satellite, has been pressed into service in the battle being waged against one of mankilffl’s most persistent and destructive enemies, the locust. ’K*

A large part of this world-scale battle is going on within the sober walls of offices and laboratories in the heart of London, at the Anti-Locust Research Centre. Here coded information from Tiros and other sources is analysed to build up charts on the climatic conditions of the many countries in the Northern Hemisphere still plagued by locusts.

The new director of the centre. Dr. P. T. Haskell, told, me that by regularly plotting weather conditions in places as far apart as West Africa and North India, it is hoped to gain fuller information on the swarming habits of the pest. Despite “amazing progress" recorded since the Second World War, locusts still create havoc in many under - developed countries which can ill afford crop losses.

To be caught in the path of a locust swarm can be one of the most terrifying experiences. In isolation, one of these creatures is repulsive enough. Between three and four inches long in its fullygrown state, and built like a giant grasshopper, it regularly discards its tough protective skin as it steadily grows larger. In a swarm, locusts can darken the sky and create a deafening noise with their beating wings. Anyone caught in a “locust storm” might emerge with hands and face lacerated and with clothes cut to ribbons. Swooping down out of the sky with little warning, they descend on crops and steadily eat their way through them till either the food gives out or the swarm is driven off by chemicals. When a swarm comes down, as many as 70 locusts per square yard have been known to settle on the ground. Apart from their inroads into crops and vegetation, these pests are potent carriers of epidemic disease, outbreaks of which in Africa, the Middle East, Asia and Latin America have been traced to this source.

Many Species A medium-sized swarm—about l’i million—can eat roughly 3000 tons of crops in a day. And the many species now being bred under laboratory conditions in the AntiLocust Research Centre in Kensington live up to their reputation. Kept in glass cages with small sand buckets in which to lay their eggs, the creatures I saw were relentlessly chewing their way through greenery constantly fed to them. The locust has another peculiarity: persistent contact with them by a human being can result in locustallergy. so that scientists working with them at the London centre are forced to wear heavy rubber masks. Broadly, the battle against this ruthless pest is being fought on two distinct fronts. In Africa, where the migratory locust and the red locust were till recently a constant threat to vegetation, attacks are being made at the breeding source with highly concentrated insecticides. Because both of these species breed in comparatively small areas in Northwest Africa and Central Africa, it has been possible to kee'p the breeding grounds under constant survey. According to Dr. Haskell, his team of about 40 research workers has had great success in efforts to control the two species. Desert Locust Work is now beginning to focus more sharply on a third species, the desert locust. This creature, though comparatively small, still has scientists baffled. One entire wing of Dr. Haskell’s unit is hard at work gathering all possible information about its erratic and appallingly destructive breeding and swarming habits. Ln all, 60 countries are liable to attack from the desert locust The big problem—from the scientists' point of view—is that it will breed nearly anywhere. In one season there may be an outbreak in Persia, in another season reports of infestation may come from as far to the east as Andhra Pradesh, in India. For long periods it may neglect a country, only to descend on it again at a time when control measures have been relaxed. India, for example, for several years was untouched by the desert locust. Today her Government is forced to rely heavily on alerts about impending attacks, many of the alerts coming direct from London, where the necessary information is constantly being collated. It has been estimated that well over £6 million is spent annually on control measures alone against this species. One attack in Morocco in 1954 caused damage estimated at

£3j million Another in Ethiopia resulted in a loss of £3 million. In the last few years the incidence of the Desert Locust seems in fact to have been increasing. Because of the widespread breeding habits of the desert locust, it is much more difficult to control at source. One of Dr. Haskell’s major preoccupations at present is building up precise long-term data about outbreaks, with the hope of discovering definite seasonal patterns and thus being able to forecast possible attacks.

Maps are kept of locust plagues as far back as the 1920'5. Each month new charts are compiled showing the time and place of attacks, climatic conditions in the region, the varieties of vegetation attacked, the incidence of breeding in the area. In a period of three months it is possible to plot the course of locust swarms over a -distance of 1000 miles. Research of a fundamental type is still going on, too, into the actual flight behaviour of locusts. What makes them

swarm? Why do swarms keep together? Why do some swarms fly blanket-like over the ground, while others progress in high, narrow columns? Answers to such questions are still tentative, but a new theory at present being developed and backed with money from a special United Nations fund promises great advances in the next year or two. This theory is based on a view that scientists have held for some years—that a definite relationship exists between climatic conditions and the movement of swarms. Meteorological studies have revealed the existence of an “inter-tropical front” passing horizontally through Central Africa and extending into the Middle Eastern countries. This is an area into which wind blows .from both sides, causing upward currents and fairly constant rainfall. Control Measures If swarms get into this front they are trapped. Scientists have formed the tentative conclusion that it would be better to concentrate existing anti-locust control measures in this region. This, Dr. Haskell hopes, will help narrow the front of the present battle. Dr. Haskell believes that progress in such fields as the development of insecticides is satisfactory. In Kenya in 1945, for example, a gallon of insecticide was found to kill about 9000 locusts. Today it is possible to wipe out as many as 3,000000 flying locusts with a gallon of niocern spray from an aircraft. There has beeh an increase in the use of spray as well. In Morocco alone, during a four-month period in 1959-60, 25 aircraft were used to apply 3400 tons of spray. One problem in such massive use of insecticide is that damage may be done to animals and harmless insects. Work is therefore progress-

mg on “specific” chemicals, to be known as locusticides, which will leave other creatures unharmed. Research Work Dr. Haskell believes that the funds now coming forward for anti-locust research my possibly be adequate to get the pest under control if more steps were taken toward better co-ordination of programmes on an international scale. Examples ’’f this kind of co-operation are becoming more numerous. In India and Pakistan a special air unit backed, by United Nations funds has been formed to test the possibilities of international control over a six-year period. A special locust division of the Food and Agriculture Organisation is helping io direct this type of work. The World Meteorological Organisation, too. is assisting with background information for study of the “inter-tropical front” theory described above. One of Dr. Haskell’s latest worries is a prospect that the red locust and the migratory locust of Africa may once more get out of control. Here politics enters the scene as a factor in the anti-locust battle. One of the principal breeding grounds of the migratory locust is in the former French Sudan, now the independent territory of Mali. Fears are being expressed in scientific circles that newly-independent countries such aS Mali will not in future be able to find the funds to maintain close scrutiny of breeding grounds. A similar problem may arise in Central Africa should more new States arise there. One of the main preoccupations of the F.A.O. locust division, and the London Anti-Locust Research Centre, is that these new countries ought to be impressed withthe need for constant vigilance against this plague and helped to provide the means for containing it in future.