DESERT LOCUST BULLETIN

FAO Emergency Centre for Locust Operations No. 228 (8 September 1997)

General Situation during August 1997 Forecast until mid-October 1997

Significant Desert Locust infestations continued to persist along the Indo-Pakistan border where patchy breeding started in July and continued throughout August. The majority of the infestations were in Pakistan where control was carried out against an increasing number of hopper bands and adults during the month. At the end of the month, mature swarms were reported moving back and forth across the Indo-Pakistan border. As a result of recent rainfall, conditions are expected to remain favourable to allow rapid maturation and a second generation in both countries. In West Africa, widespread rains fell in Mauritania where breeding conditions are improving but so far very few adults have been found during surveys. In East Africa, small scale breeding is in progress in central Sudan. No significant infestations were reported in the Near East or North-West Africa.   Eastern Region Breeding was reported over a limited area of the Tharparkar desert in south-eastern Pakistan which has resulted in a patchy distribution of more than a thousand small hopper bands. In early August, control teams treated about 10,000 ha containing more than 1,600 bands and several spots of high density solitarious adults. New adults started to appear by mid month and some of these rapidly matured and formed swarms. There were dozens of reports of mature swarms copulating along the border in Pakistan and to a lesser extent in India at the end of August. The number of reports of swarms moving back and forth across the common border suggests that there may have been areas of earlier undetected breeding. It is expected to be very difficult to control all infestations and prevent a second generation of breeding which will commence in early September. The number of hopper bands and new swarms produced in both countries will depend on the ability to find enough of the infestations and treat them successfully. Central Region Solitary and transiens hoppers and new adults were reported in the interior of Yemen where conditions are becoming dry which may encourage adults to move to the coastal plains. Breeding on a small scale is in progress in parts of eastern, central and western Sudan where rain was reported in a few places. As conditions continue to be favourable for breeding, locust numbers are expected to increase during the forecast period, but still remain at a low level. A few isolated adults were reported on the Red Sea coastal plains of Eritrea where breeding had occurred in areas of run-off. Greater numbers of adults are likely to be present and breeding in the western lowlands in areas of recent rainfall. Isolated adults were present in northern Somalia and south-eastern Egypt. Western Region Only isolated adults were reported in southern Mauritania. Numbers are expected to increase as a result of widespread rains in late August and subsequent breeding that may occur during September. No reports were received from Mali, Niger or Chad where conditions are thought to be less favourable. Heavy rains fell in southern Algeria where conditions are reported to be favourable for breeding.

Weather & Ecological Conditions during August 1997

light...heavy Figure 1. Cold-cloud image for August 1997 indicating a continued increase in activity over the Sahel of West Africa, especially Mauritania, northern Mali, western Niger and Sudan. An increase is also apparent in western Eritrea and north-western Somalia.

Good rains fell in parts of the Sahel in West Africa and along the Indo-Pakistan border where conditions are favourable for breeding. Elsewhere, no significant rains were reported.   In West Africa, the position of the Inter-Tropical Convergence Zone (ITCZ) was extremely variable during August, fluctuating between 15-26N. Widespread rains fell over parts of the region in association with northern surges of the ITCZ and with a few eastward moving depressions over North-West Africa. In Mauritania, rains continued to fall in the south throughout most of the month but other areas remained relatively dry. During the third dekad, rainfall increased over a large portion of the north (Bir Moghrein: 38 mm, to Akjoujt: 45 mm) extending to central areas (Tidjikja: 67 mm), the west and south-west (Trarza and western Brakna) and parts of the south (Aioun: 171 mm). Consequently, breeding conditions are expected to improve and be favourable over large parts of the country. In Mali, good rains fell in the south-west (Nioro: 119 mm, Nara: 62 mm) and clouds were present over the north but no reports of significant rainfall were received. Conditions are expected to be favourable for breeding near Nara and Nioro and to a lesser extent in parts of the Adrar des Iforas and Tamesna. In Niger, rains were weak over Tamesna and Air (Agadez: 43 mm) and light rains fell in the north-east (Bilma: 13 mm). Breeding conditions are probably similar to that in northern Mali. In Chad, clouds were present over Tibesti and light rain was reported in the east (Abeche: 17 mm). Favourable conditions are expected to be limited to a few wadis and low-lying areas. In North-West Africa, moderate rains fell in a few isolated places of the central Sahara in Algeria (Tamanrasset: 34 mm) and on the southern side of the Atlas Mountains in Morocco (Ouarzazate: 30 mm). Heavier rains fell in the extreme south of Algeria. Breeding conditions are expected to be improving in these areas. In East Africa, clouds were present at times over the summer breeding areas in Sudan and western Eritrea. In Sudan, light to moderate rains were reported in a few parts of Darfur, Kordofan and the Eastern province. Although there were no indications of any unusually heavy rainfall, conditions are said to be favourable for breeding in the most areas. In Eritrea, rains may have fallen over the western lowlands and breeding conditions are expected to be favourable. The Red Sea coastal plains remained dry in both countries except for a few wadis which may have received some limited run-off from rains in the adjacent highlands. In northern Somalia, heavy rains fell in the north-west along the Ethiopian border (Borama: 125 mm, Hargeisa: 85 mm). Green vegetation was present over a large area from Jijiga, Ethiopia to the Dobo Valley. In the Near East, no significant rainfall was reported except on the Red Sea coast of Saudi Arabia where 22 mm fell at Jizan. Consequently, conditions in other areas are expected to be dry and not favourable for breeding. In South-West Asia, light to moderate rains associated with the monsoon fell in Rajasthan, India and the Tharparkar desert in south-eastern Pakistan where conditions were favourable for breeding during August. The heaviest rains reported in Rajasthan were at Jodhpur (221 mm) and Barmer (140 mm) while lighter rains fell at Bikaner (41 mm) and Jaisalmer (26 mm). In Tharparkar, heavy rains continued to fall at Chhore (156 mm). Consequently, breeding conditions are expected to remain favourable in Tharparkar and southern Rajasthan while less favourable conditions are expected in Cholistan, Pakistan. There were periods of south-westerly winds over Tharparkar especially at the end of the month from the 27th onwards. Rainfall reports from national meteorological stations in Mauritania indicate that rains fell over a large part of the country during August. 25-100 mm (white); 100+ mm (red)

Area Treated

India 1,200 ha (28-30 August) Pakistan 16,700 ha (August) Sudan 100 ha (August)

Desert Locust Situation and Forecast

WEST AFRICA Mauritania Situation Isolated maturing and mature solitarious adults persisted throughout August near Kiffa (1638N/1128W) and Nema (1632N/0712W). No locusts were seen during surveys carried out in the south-west. Forecast As a result of the widespread good rains in late August, breeding is expected to occur during September within a large area of the south and south-east (the two Hodhs), extending north into central areas (southern Tagant) and to the south-west (Trarza and western Brakna). Consequently, solitarious locust numbers are expected to increase during the forecast period. Mali Forecast Breeding on a small scale is likely to be in progress in a few places of the Adrar des Iforas, Timetrine and Tamesna. As favourable conditions are expected to be limited to some wadis and depressions, only low numbers of hoppers and adults are likely to be produced during the forecast period. Niger Situation There was an unconfirmed report by travellers of isolated adults in the Air in late July. Forecast Small scale breeding is likely to be in progress in a few areas of Tamesna and Air where recent rains have fallen. As favourable conditions are thought to be limited to some wadis and depressions, only low numbers of hoppers and adults are likely to be produced during the forecast period. Chad Forecast Breeding on a small scale may be in progress in some parts of the north and east, especially in areas of recent rainfall near Abeche and perhaps Tibesti. However favourable conditions are thought to be limited and consequently only low numbers of locusts are likely to be produced during the forecast period. Burkina Faso, Cape Verde, Gambia, Guinea Bissau, Guinea Conakry and Senegal Forecast No significant developments are likely. NORTH-WEST AFRICA Algeria Situation No locusts were seen in July and August. Forecast Scattered adults may be present in a few places of the Hoggar near Tamanrasset and in the extreme south. These may breed in areas of recent rainfall or run-off. Morocco Situation No locusts were seen in July and August. Forecast No significant developments are likely. Tunisia and Libya Forecast No significant developments are likely. EASTERN AFRICA Sudan Situation In the eastern provinces, infestations reported during July along the western side of the Red Sea Hills north of Kassala declined during August. Scattered mature adults were seen in only one area, Wadi Habob (1818N/3535E), at densities of 450 per ha. Isolated breeding occurred at the same location as suggested by the presence of fifth instar hoppers on 14-15 August. In the central provinces, ground control operations treated 100 ha of second and third instar solitarious hoppers near Ed Duiem at Umm Rimta (1451N/3204E). Hatching and first instar hoppers were also reported at the same location. Surveys were in progress in the White Nile area. In the western provinces, no locusts were seen during surveys in the El Geneina area near the Chad border on the 10-12th; no surveys were conducted in Northern Kordofan or elsewhere in Northern Darfur during August. Forecast Breeding on a small scale is expected to be in progress in parts of Northern Darfur, Northern Kordofan and White Nile provinces in areas of recent rainfall. Breeding may also be in progress on a slightly larger scale in the eastern provinces west of the Red Sea Hills where rains have been heavier. As a result, low numbers of adults are likely to be produced and some of these may start moving towards the Red Sea coast at the end of the forecast period. These may be supplemented by additional adults from the western lowlands of Eritrea. Eritrea Situation Low numbers of maturing solitarious adults continued to be present at a few places on the Red Sea coastal plains during August. On the 20th, mature adults were seen in the Shebah area (1542N/3902E) and second to fourth instar hoppers at densities of 5-10 per bush, and fledglings and adults were reported in the Sheib area at Bisses (1553N/3900E). Most of the hoppers were fourth instar. Forecast Low numbers of adults will persist at a few places on the Red Sea coast. These are expected to concentrate in low-lying areas as vegetation continues to dry unless further rainfall occurs. Higher numbers of locusts are likely to be present and may be increasing in the western lowlands where breeding is likely to be in progress in areas of recent rainfall. Somalia Situation Low numbers of immature adults were seen during surveys on the central northern coast near Las Khoreh (1110N/4812E) and in subcoastal areas near Erigavo (1040N/4720E) during the first week of August. No locusts were seen during surveys undertaken on the 14-19th between Hargeisa (0931N/4402E) and Berbera (1028N/4502E). Forecast Low numbers of solitarious adults are likely to persist in the few inland valleys of the north and north-west that remain green. Other adults may appear, mixed with Locusta, in the north-west between Hargeisa and Borama. Djibouti, Ethiopia, Kenya, Tanzania and Uganda Forecast No significant developments are likely. NEAR EAST Saudi Arabia Situation No locusts were reported during August. Forecast Low numbers of locust adults are likely to be present on the southern coastal plains of the Red Sea near Jizan. These may persist and lay in areas of recent rainfall. Yemen Situation Small locust infestations continued to be present in the Shabwah region of the interior as a result of breeding last month. Solitarious and transiens hoppers and fledglings increased in density and have become concentrated in two areas: to the west of Ataq at Erga (1429N/4637E) within an area of 40 sq. km, and to the east at Jebel Hadid (1433N/4636E) in 10 sq. km. Hoppers of all instars were reported on 8-9 August with second instar as the predominant stage at densities of 40-60 per sq. m. Scattered adults were seen in Wadi Jannah (1508N/4555E). Forecast Small groups of immature adults are likely to form in the Shabwah region as vegetation continues to dry. These may move to the coastal plains along the Red Sea and Gulf of Aden if rainfall occurs there. Egypt Situation Isolated solitarious mature adults continued to be reported from a few places in the extreme south-east in the Wadi Diib area (2205N/3555E) near the Sudanese border in late August. Forecast Isolated adults are likely to persist in a few places in the south-east. Bahrain, Iraq, Israel, Jordan, Kuwait, Oman, Qatar, Syria, Turkey and UAE Forecast No significant developments are likely. SOUTH-WEST ASIA Pakistan Situation During the first fortnight of August, control operations continued against hopper bands which were scattered within an estimated area of 15,000 ha in the Tharparkar desert between Chachro (2509N/7018E), Mithi (2443N/6953E) and Chhore (2535N/6948E). Nearly 1,600 first to fourth instar bands were treated by ground teams covering an area of about 8,000 ha. Outside of this area, solitarious hoppers at densities of 3-10 hoppers per bush were present in a few parts of the Khipro and Tharparkar deserts which were treated, covering 2,300 ha. Control operations were also carried out against a high concentration of adults in the Nara desert at Garh (2720N/6915E) on the 13th. Elsewhere, solitarious adults were scattered over a large area near the Indian border, extending from Tharparkar to Cholistan and reported from 26 locations at densities of 1-50 adults per location. During the second fortnight of August, a total of four mature swarms and adult groups were reported and treated in the Nara desert and 14 in the Khipro desert from the 24th onwards. Some were said to have crossed the border from India. The swarms were 200-400 ha in size and most of them were seen copulating. In Tharparkar, control operations continued, treating 40 third and fourth instar hopper bands within an area of 1,200 ha. Low to medium densities of solitary adults were present throughout the period in all of the above area and in Lasbela district. Medium densities of solitary hoppers were present and treated in 8 places of Nara and Tharparkar. Forecast A second generation of breeding is expected to occur in Tharparkar and to a lesser extent in Khipro and Nara deserts in areas of recent rainfall with laying continuing into September. Consequently, small hopper groups and bands are likely to appear which could lead to swarm formation by the end of the forecast period. These could be supplemented by adults as they move back and forth across the border with India. The scale of breeding is estimated to be low to moderate, depending on the success of survey and control operations. Breeding is less likely to continue in Cholistan unless additional rains fall. India Situation During the first fortnight of August, adult densities declined in Rajasthan where scattered mature adults were reported from 48 locations of Bikaner and Barmer districts and, to a lesser extent, Jodhpur and Jaisalmer. A maximum density of 45 adults per location was seen in Jaisalmer at Dhanana (2640N/7027E) on the 11th. Second to fourth instar solitarious hoppers at low densities were seen on the 3rd at Kupauria (2656N/7304E) in Jodhpur district and on the 11th at Surjara (2804N/7249E) in Bikaner. Four small mature swarms were seen coming from the west on 28-30 August and settled west of Jaisalmer near Sam (2652N/7030E). The swarms varied from 100-400 ha in size. Control operations were immediately undertaken. Forecast A second generation of breeding is expected to occur in parts of western Rajasthan where good rains fell in August. Consequently, hoppers could start appearing during September and form bands, possibly leading to swarm formation by the end of the forecast period. The scale of breeding is estimated to be low to moderate, depending on the success of survey and control operations. There is a good possibility of adults moving back and forth across the Pakistan border. Afghanistan and Iran Forecast No significant developments are likely.

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The FAO Desert Locust Bulletin is issued monthly, supplemented by Updates during periods of increased Desert Locust activity, and is distributed by fax, e-mail, FAO pouch and airmail by the Migratory Pests Group, AGP Division, FAO, 00100 Rome, Italy. It is also available on the Internet. Telephone: (39-6) 570-52420 (24 hr, daily) Facsimile: (39-6) 570-55271 Telex: 610181 FAO 1 E-mail: [email protected] Web site: http://www.fao.org (Global Watch - Locust)