The occurrence of white tip nematode, Aphelenctioîdes besseyi was found to
reflect a lengthy association with natural vegetation or climatic variations within
different regions ¡n Egypt that are diverse enough to influence the pattern of nematode
distribution and/or occurrenœ. Three methods of nematode extraction, ie. Baermann
funnel, plate and sieving were used for nematocie extracting. Three nernatode
inoculum levels. i.e. 250, 500, 1000 individuals/plant) were used, 5 days after rice
transplants to study nematode symptoms throughout growth stages. Under field
conditions, twenty-seven rice growing areas were selected according to easy access
or nematode infected expectations, cho?cing 3-4 fields for each selected area
throughout Nile Delta and surveyed randomly to record both healthy and diseased
plants. In the meantime, at booting stage, samples of 200 grams of fresh rice panicles
were cut to smati pieces, soaked in water for 48 hours to collect and record the
extracted nematodes. Results emprasized that the damage, infection and plant
symptoms were positively corr&ated with nematode inoculums level. Nematode
extracts or isolation and separation methods indicated that Baermann funnel
technique gave the best nematode counts and was considered to be the most
efficient extraction method. Dynamic interactions of rice-nematode symptoms were
found to influence numerous complex biotogical processes. The spatial model was
chosen, and was considered to be the appropriate to iepresent the spatial nature of
rice epidemics. It was found out that the resulting model can implement as a computer
programme proving to be one of the useful investigative tools. Results indicated that
Biala region (Kafr El-Sheikh) was highly epidemic, whereas Dakahlia and Sharkia
Governorates were moderately epidemic. On the other hand, El-Senbiawain area
(Dakahlia Governorate) was considered to be non-epidemic for A.besseyi infestation.
The breeding program indicated that elmer local cultivars, Giza 178, Giza 176 and
Giza 181 or different tested lines were more resis(ant varieties to nematode
infectons, however symptoms were notced. Among 53 cultivars or lines, only 20 were
found to be highly resistant, while Giza 171 was considered to be highly susceptible
cultiva r.