last final thesis of umer

(Vandermeer, 1989; Letourneau, 1990). Thus, depending on the crop, the attack may affect
resource capture, resource conversion efficiency or harvest index (HI) through attacking of leaves,
flowers, flower buds and fruits hence upsetting the source-sink relationship and phenology (Baker
& Yusaf, 1976; Crawley, 1989). Various integrated pest management (IPM) control strategies such
as the use of cultural, biological and chemical methods are also being used for insect pest control.
Root (1973) stated that pests find it very difficult to find their hosts because of visual disturbance
for their search pattern and tend to stay for shorter times because of disruptive effect of landing on
non-host plants resulting in slow survival. Even the presence of weeds can similarly affect pest
search for their hosts (Altieri, Glaser & Schmidt, 1990).
Breeding of cereal cultivars resistant to diseases has also been used in intercropping to control
airborne diseases of rapidly evolving specialized fungal diseases such as rusts and mildews (Wolfe,
1985). Maize leafhopper (Dalbus maindis) was significantly reduced from different maize
cultivars under intercropping (Power, 1990). This was the same with fungal spores on leaves, root
parasitic nematodes (eelworms) intercepted by roots of hosts and non-hosts (Trudgill, 1991).
Intercropping the cowpea cultivar PAN 311 also reduced stalk borer Chilo partellus (Swinhoe)
infestation significantly in sorghum compared to sole crop (Ayisi & Mposi, 2001). Bean yield was
found to be reduced by intercropping as well as aphid attack (Florentine et al.,2003). Thus, when
yield is reduced due to diseases and pests attack LER is also reduced (Kass, 1978).
The variability of insect pest control and yield improvement in intercropping systems relative to
sole cropping have been inconsistent over habits, component species, varieties, density, row
arrangement, soil fertility and moisture (Ayisi & Mposi, 2001) and individual crops may not
respond the same (Nwanze & Mueller, 1989). Maize stem borer was found to be more severe under
sole cropping than intercropping with lablab [Lablab purpureus (L)] (Maluleke, Addo-Bediako &
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