Agricultural Research Corporation (ARC) - Sudan
Proceedings of the Meetings of the National Crop Husbandry Committee - NCHC
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Investigation on Agrilus
nubeculosus (Fairm) with Special Reference to its Association with
Gummosis in Acacia Senegal
Sayeda Ali Ahmed Khalil
Abstract:
This study was carried out in El Heimayra forest (Northern Kordofan
State) to investigate farmer’s believe that there is a positive
correlation between the abundance of A. nubeculosus and the yield of gum
arabic from A. senegal. Trees from three age classes namely; 5-9, 10-14
and 15-20 years old were selected randomly. Twenty trees were covered
with wire mesh and sprayed with 57% malathion and labeled as control
trees (C) and 20 other trees were left for natural infestation by the
insect and labeled as infested trees (O). These experiments were
replicated during three tapping periods: early, mid and late. Yield from
infested trees increased by 97% in all age classes and tapping periods.
Yield from infested trees was highest in early period in all age
classes. Yield from infested trees varied considerably in its physical
properties (colour, shape, optical rotation, moisture content and size)
as well as chemical properties (nitrogen, ferrous, calcium and manganese
contents) as compared to gum from control trees. The life cycle of A.
nubeculosus was investigated. Micro-organisms in the hindgut of A.
nubeculosus were isolated and identified as Aspergillus spp.and
Staphyllococus spp. Trees which were inoculated with fungus produced
higher amounts of gum than those which were inoculated with fungus and
bacterium simultaneously, with bacterium alone, and higher than trees
which were naturally infested with A. nubeculosus and control trees. It
is apparent that A. nubeculosus transmits both Aspergillus spp.and
Staphylococcus spp.which might have presented a stress that resulted in
more gum production confirming earlier hypothesis that gummosis is a
pathological reaction and/or a modification of some physiological
processes of A. senegal as a result of microbial infection.
Proceedings of the Meetings of the National Crop Husbandry Committee 39th (2005) pp. 96-104
Proceedings of the Meetings of the National Crop Husbandry Committee - Sudan
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