A detailed analysis of a
Desert Locust Upsurge in Saudi Arabia
(Nov 1996 - May 1997)
Locust
infestations pdf
version
(441kb) MARCH-APRIL.
High density hatching commenced about
mid March and increased over the next few weeks in
all areas. This led to large numbers of hoppers
and, in some cases, grouping and small band
formation during April. By the end of April,
hoppers were fledging and new adults started to
appear. Another period of laying occurred in early April
which was primarily concentrated on the northern
coast near Yanbu, Umm Lajj and Al-Wajh as well as
further south near Khulais. This was probably
associated with late maturing adults of the
incoming swarms combined with adults produced
locally earlier in the year. Those in the north
were not reported by locals who collect them for
selling. Densities of laying adult groups were
probably higher in northern areas than near Khulais
and estimated to be about 5-20/m2. Hatching
occurred in late April and new adults started to
appear by late May. Fourth and fifth instar
gregarious hopper groups were present near Al-Wajh
on 28 May at densities up to 50 per m2. MAY. By
early May, vegetation was rapidly becoming dry on
the coastal plains. As a result, immature adults
were concentrating in the few remaining green areas
along the base of the foothills. Some adults had
moved up the valleys of the foothills east of
Khulais and Al-Wajh. JUNE. As a
result of the control operations of the previous
months, only small adult infestations were present.
In response to the dry conditions and high
temperatures, these migrated off the coastal plains
west towards the interior of Sudan. A few of these
also moved east towards the interior of Arabia.
