(a) Rainfall

The 1995 growing season was mostly favourable for crop development. Normal to above-normal cumulative rainfall was registered throughout the Sahel, except in south-east and north of Senegal, and The Gambia where small deficits were reported. Precipitation remained generally widespread in the CILSS countries throughout the growing season.

The rainy season started somewhat early in Burkina Faso, in the south of Chad and Mali where first rains were registered in April and early May. Rains started in May in Guinea-Bissau and central Chad. The rainy season started in early June in the south of Senegal, in mid-June in Gambia and Niger, in late June in Mauritania and in early July in Cape Verde.

Precipitation became abundant in July and August over the main producing zones but remained weak in July and early August in northern Senegal and Burkina Faso, northern and centre-western Mali where crops suffered from water stress. Plantings were delayed in some of these areas. Rains resumed in mid-August in these zones and allowed a good recovery of the crops. They began to decrease in September, notably in northern Senegal, Mali, Burkina Faso and western Mauritania, while precipitation moved southward, but remained widespread over all the countries.

The rains stopped in late September/early October in northern and central Senegal, Mauritania, central Mali, Niger and Cape Verde. Precipitation stopped in mid-October in Burkina Faso and central Chad but remained quite abundant in the south of Chad in early October.

(b) Area Planted and Seed Availability

Only a few Sahelian countries conduct national surveys of area planted. Preliminary indications are that, following favourable rainfall, the aggregate area planted to cereals did not decrease significantly from 1994 levels. As in 1994, some marginal areas were cropped as good rainfall permitted sowing on normally uncultivated lands. Substantial rice producing areas which had been flooded in Niger in 1994 could be cultivated this year. By contrast, flooding in some areas of Chad prevented cultivation, particularly of rice and sorghum, in some low-lying or irrigated areas.

Overall seed availability was adequate following last year's above-average harvests in most countries. Because of the regularity of post-sowing rainfall, the young plants were generally not affected by water stress and there was no or only very limited need for replanting, except in Burkina Faso which registered reduced rains or dry spells in July.

(c) Pest Situation

- Desert Locust
In West Africa, Desert Locust infestations were present primarily in Mauritania throughout 1995.

As a result of a gradual build-up of infestations in western Mauritania and subsequent migration northwards during the last months of 1994, swarms appeared and laid in northern Mauritania in Inchiri, Adrar and Tiris Zemmour regions during January 1995. Infestations were present in the extremely remote El Hank area near the Algerian and Malian border where breeding conditions were unusually favourable during the winter. Swarm laying in the El Hank resulted in numerous hopper bands from late February onwards. A similar situation may have occurred in the adjacent areas of north-western Mali. Despite extensive control operations new adults migrated further north, reaching the southern side of the Atlas Mountains in Algeria and Morocco in March. Ground and aerial control operations were undertaken over a total of more than 132 000 hectares in northern Mauritania from January to mid-April 1995.

A group of adults locusts was first reported in south-eastern Mauritania near Oualata during April 1995, but the southern migration of adults from the spring breeding areas of Morocco and Algeria became more evident during May when a few small swarms appeared in Adrar and Inchiri of northern Mauritania. Several swarms also reached the Nema area. Many adults seem to have dispersed further south in the adjacent areas of western Mali although breeding conditions were already favourable in most of the summer breeding areas of Mauritania south of roughly 16030 N. from earlier than usual rainfall. No significant developments occurred in these areas, nor in the two Hodhs of Mauritania during the summer.

However, the locusts that remained in Mauritania concentrated in the south-west and laid during May and June. A significant build-up of infestations occurred in the Lake R'Kiz and Mederdra areas during July-August, and more than 35 000 hectares of numerous dense hopper bands were treated. Some infestations were also present in the Senegal River Valley where a few groups of adults and hoppers were treated over 1 600 hectares in late July and August. In late September, escapees started to form swarms which began moving towards the winter breeding areas of northern Mauritania. Control operations were undertaken against laying swarms and new hopper bands between Nouakchott and Tidjikja in early October, and hopper infestations appeared south of Atar at the end of the month. During November, nomads reported swarms and hopper bands in Tiris Zemmour. As a result of unusually heavy rains in late September, further breeding is expected to occur this winter in northern Mauritania and perhaps in adjacent areas of Morocco and Algeria if temperatures remain warm.

In northern Niger, mature gregarious adults locusts were present and laid in early February, which resulted in localized hopper infestations. Some 11 300 hectares were treated from late January to late April. Limited control operations were also undertaken in northern Mali during the same period. In early June, a few swarms and a few hopper bands appeared in the north of both countries; Niger treated again 600 hectares. However, most of the adults dispersed in southern regions where some persisted throughout the summer and no further developments occurred. Several swarms appeared in north-eastern Niger by mid-June from North-West Africa. These moved further east, arriving in eastern Chad at the end of June and continued to Sudan. No laying occurred in eastern Chad where only scattered adults remained at a few places from August onwards. - Grasshoppers Several countries experienced localized grasshopper infestations notably in Burkina Faso, Cape Verde, Chad, Mali, Mauritania and Niger. Substantial treatments were undertaken in Niger. Elsewhere, with plentiful natural vegetation from the good rainfall, the grasshoppers did not concentrate on crops.

- Other Pests
Various insect attacks were reported, particularly of cantharides in Burkina Faso, Chad and Senegal. Grain-eating birds were also reported in Chad, the Gambia, Mali, Mauritania and Niger.

(ii) Weather Performance and Monitoring of Crop Development in 1995

In addition to its conventional information sources, the GIEWS uses rainfall data received from meteorological stations as well as information derived from two types of satellite for its crop monitoring and agricultural production forecasting activities in the region.

Through the ARTEMIS System at its Environmental Information Management Service, FAO produces satellite imagery for the whole of Africa indicating 10-day and monthly Cold Cloud Duration (CCD), Estimated Rainfall and Normalised Difference Vegetation Index (NDVI). The CCD information, which indicates hours of coverage of rain-bearing clouds, is produced from data received in real-time from the METEOSAT geo-stationary satellite, operated by EUMETSAT.

GIEWS has access to both the real-time ARTEMIS imagery, as well as to the historic archive. With the historic data, and in combination with ground based observations, the present situation can be compared with previous years, and a spatially more complete and quicker analysis can be made from information derived only from the ground.

Figure 1 gives the occurrence of rain-bearing clouds (Cold Clouds Duration, CCD) for the months of May to September. It shows that CCD, and thus received rainfall, has been the highest during July and August. Compared to 1994, rains were more abundant in August over western Mali and south-eastern Mauritania and less abundant over northern Burkina Faso. They became particularly abundant in Guinea-Bissau, southern Senegal, southern Mali and southern Chad in July and August.

Figure 2 gives the evaluation of the 1995 cropping season, based on a classification of the monthly 1995 CCD occurrence compared to the 1989-94 average. The CILSS area has been divided into five classes. Each class indicates a typical behaviour of the 1995 season as compared to the average and the class profiles are given below the colour image. In grey (class 1), areas are indicated where the 1995 season did not differ much from the average. The yellow and red colours (classes 2 and 3) indicate areas where the rainy season started worse than average, but later experienced much better conditions. In particular, in the red areas the CCD occurrence and rains in July and August were rather high and here also some flooding occurred. Classes 4 and 5 (blue and green) indicate areas that had overall a good rainy season, with class 4 (blue) having somewhat late start, indicated by somewhat lower CCD values in May, and lass 5 (green) having rather high CCD values during July and August.

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