The red locust, Nomadacris septemfasciata Serville, is one of the most important pests in Southern Africa. Red locust plagues are known to originate from a few small outbreak areas where, during recession periods between plagues, they occur as sparse populations of individuals in solitarious phase.

The Wembere plains, Malagarasi River valley and the Lake Rukwa plains in Rukwa region are among the known outbreak areas in Tanzania. Other recognized outbreak areas of the red locust in Southern Africa include Kafue flats, Mweru-we-Ntipa plain and Lukanga in Zambia and Buzi-Gorongosa and Dimba plains in Mozambique.

Upsurges of red locust populations in southern Africa can be sporadic. The last widespread plague occurred from 1930-1944, when almost all of southern, central and eastern Africa, including Tanganyika and Kenya, were invaded.

Despite frequent locust swarm control operations in Tanzania, there is generally inadequate knowledge and awareness about the threat of red locust to food security in Tanzania. Furthermore, most people are also unaware about the potential hazards posed by the current control methods that involve spraying large areas with large quantities of chemical pesticides.

This certainly poses potential hazards to the environment including wildlife as the breeding sites of the red locusts occur in a protected wildlife area, namely Katavi National Park.

These breeding areas occur in important wetlands in western Tanzania, where important development projects involve conservation of the Malagarasi-Muyovozi ecosystem and improvement of the livelihoods of communities living within and around the wetland areas.

Red locust must be suppressed in these breeding areas during their early stages of development in order to avoid the formation of highly mobile swarms that can invade agricultural and grazing areas.

The red locust’s scientific name is Nomadacris septemafasciata.

Plagues of this locust can be a major threat to agricultural and livestock production in Eastern and Southern Africa. Populations of locusts must Red locust must be suppressed in their breeding areas during their early stages of development in order to avoid the formation of highly mobile swarms that can invade agricultural and grazing areas.

The red locust, Nomadacris septemfasciata Serville, is one of the most important pests in Southern Africa. Red locust plagues are known to originate from a few small outbreak areas where, during recession periods between plagues, they occur as sparse populations of individuals in solitarious phase.

The Wembere plains, Malagarasi River valley and the Lake Rukwa plains in Rukwa region are among the known outbreak areas in Tanzania. Other recognized outbreak areas of the red locust in Southern Africa include the Buzi plains in Mozambique

Upsurges of red locust populations in southern Africa can be sporadic. Major plagues occurred in Tanzania during the period 1929 – 1944. They caused significant economic losses. In 1966 alone swarms are believed to have migrated from Zambia

There are ten known breeding areas in Eastern and southern Africa:

lTanzania – Wembere plains, Malagarasi River Basin, North and South Rukwa Valleys,Ikuu-Katavi plains and Bahi Valley

lMalawi – Lake Chirwa Plains

lMozambique – Buzi-Gorongosa and Dimba plains

lZambia – Kafue flats, Mweru-we –Ntipa plain and Lukanga swamp

lBotswana – Chobe plains.

Tanzania harbours 50% of the known major outbreak areas. Furthermore there have been frequent widespread swarms in these areas in recent years that required large scale control operations. In this regard, it has been reported by the Ministry of Agriculture that between 1945 and 2010, 23 locust swarms of varying sizes were recorded in the Lake Rukwa valley and Malagarasi River ecosystems. Accordingly the Rukwa valley remains one of the most important outbreak areas for the red locust.

The reason why plagues of red locust have become almost rare incidences is because in 1949 countries of eastern and sourthern Africa came together to establish The International Red Locust Control Organisation for Central and Southern Africa (IRLCO-CSA) has existed since 1949 (when it was known as the International Red Locust Control Service, IRLCS) after its establishment by an international convention. The formation of IRLCO-CSA was partly a result of nearly 15 years’ work to identify sources of Red Locust

The principal mandate is, as for its predecessor, the prevention of Red Locust plagues, with the additional responsibility of monitoring and forecasting other migratory pests, such as the African Armyworm, Spodoptera exempta and Red-billed Quelea birds, Quelea quelea.

The major red locust plague that lasted nearly 15, started in 1929 and lasted until 1944 affected the whole of Africa south of the equator and some areas further north including Kenya, Tanzania and Uganda.

There recognized outbreak areas of the Red Locust in the eastern and southern African region (Table 1), are believed to have been the sources of this major plague. Scientists believed at the time that swarms which originated from Mweru wa Ntipa in Zambia and the Rukwa Valley in Tanzania probably initiated the plague. At that time outbreak areas were not yet known and, therefore, their contribution to the plague was not documented.
 

It is worth noting that in Mpanda District, which constitutes much of the Rukwa, Ikuu-Katavi and Malagarasi valleys, there have been two important ecological changes occurring since the 1950’s: the establishment of the Katavi National Park, occupying an area of about 650 square kilometers, and the conversion of the natural miombo woodland habitat into subsistence farmland (shambas) and grazing land for the large herds of Wasukuma from the Lake Victoria regions. The effect of this increased increase in human settlement resulting in ecological conversion of the area to farmland, together with the effects of climate change and rainfall variability on red locust populations in the outbreak areas is not known.

Currently red locust is not regarded as a priority by the Government. This is also true in the other member countries of Zambia, Mozambique, Uganda, and Kenya where locust is also recognized as a problem during upsurges when emergency action is swiftly taken, i.e. emergence resources are made available at short notice for swarm control.

This is done partly in response to vocal outcry of communities in affected areas. Such a strategy is not sustainable, as it is soon forgotten by all concerned, not least government officials, during recession periods.

From the above table it appears that Tanzania has a continuing threat of red locust’s plagues. The Rukwa Valley and Katavi in Mpanda District are the areas where swarm formation occurs most frequently.

In fact these two areas, together with the neighboring Malagarasi River Basin in Kigoma, Kaliua and Urambo districts probably harbor about 50% of the known major outbreak areas eastern and southern Africa. The threat from these areas has become more significant in view of the increased human settlements and improvement in agricultural production in Mpanda and Rukwa regions.

Elsewhere in southern Africa, the Mweru-wa-Ntipa breeding area in Zambia, which is believed to have been the source of the prolonged 1930- 44 plague is equally important site. It is worth noting that there have been numerous locust swarms escaping from the Katavi-Malagarasi-Rukwa breeding areas. For example, in 2007 escapes from Malagarasi river basin invaded Uganda and Burundi. According to a report of the Ministry of Agriculture and Food Security, three years later the escapes from Katavi National Park during April and May 2010 invaded farmlands in Mpanda District, threatening more than 132,000 ha of cereal crops

Although this outbreak was reported widely on radio and television Government has been criticized for being slow to react and take appropriate control action. The likelihood of large population build-up in all the breeding sites except Bahi was reported to the Ministry of Agriculture, Food and Cooperative and to the IRLCO-CSA in December 2009.

However, resource mobilization for control operations did not take place until after escapes were reported by villagers and the Park Warden of Katavi National Park in April 2010.

This confirmed the long held view that Red Locust is largely still a political pest because it is only recognized during upsurges.

During such periods fire brigade action is swiftly taken, emergence resources being made available at short notice for swarm controls, to avoid wide outcry of the communities in the affected areas. The whole incidence is quickly forgotten during recession periods needless such a strategy is not sustainable

The author is an entomologist in the Department of Zoology and Wildlife Conservation College of Natural and Applied Sciences of the University of Dar es Salaam