The date-palm fruit is also known as heavenly fruit because of its mention in religious scriptures. It contains rich carbohydrate vitamins Band D potassium, calcium, iron and other tonic ingredients. Its exact native place is unknown but date-palm probably originated somewhere in the north America and perhaps also in south west Asia (Muhammed and Mal 2005).
Pakistan is ranked among the 5th leading producers of dates after Iraq, Egypt, Saudi Arabia and Iran.
The date-palm trees are infested by number of pathogens including nematodes which eventually reduce its yield.
During the study period from July 2001 to June 2005 a total of six nematode species namely Helicotylenchus indicus Sher, 1963; H. multicinctus (Co bb, 1893), Sher, 1961; Tylenchorhynchus brassicae Siddiqi, 1961; Meloidogyne incognita (Kofoid & White, 1919), Chitwood, 1949; Pratylenchus thomei Sher & Allen, 1953 and P. penetrans (Cobb, 1917), Filipjev & Schuumaus Stekhoven, 1941 were recorded from Lasbela district, Balochistan, Pakistan.
The similarity between localities based on the qualitative (presence/absence) nematode data was calculated on the basis of Jaccard's coefficient of similarity and has been studied in detail.
Group structure inherent in the data sets relevant to Lasbela district localities were exposed using average linkage clustering strategy.
Poultry manure was evaluated for its nematicidal potential in a date-palm field at two dosages (300 and 600 kg/ha) , while Carbofuran was used for the purpose of comparison. It was observed that Carbofuran and poultry manure at 600 kg/ha effectively controlled the populations of Meloidogyne incognita, Helicotylenchus indicus and Tylenchorhynchus brassicae over the controls. The practical implications of organic amendments in the management of nematode populations are discussed.
When different nematode management materials such as neem oil-cake, castor oil-cake and mustard oil-cake were applied in an experiment at Fatoo farm, Lasbela district, it was found that nematode populations declined significantly as a result of oil-cake, treatments compared to controls. In general, mustard oil-cake was the most effective in controlling nematode populations.
In the second experiment conducted at Awaran Chowk region, Lasbela district castor and mustard oil-cakes were used to control nematodes. Carbofuran was used for comparison purpose. Of the two amendments, mustard oil-cake was more effective in the control of Helicotylenchus multicinctus at 3,6 and 12 months and castor oil at 3 and 12 months and mustard oil-cake at 6 months reduced the Pratylenchus penetrans populations. However, the yield remained uninfluenced by the treatments.
The effect of single and repeated applications of organic amendments including castor, mustard and neem-oil-cakes and poultry manure on the stylet bearing nematode populations associated with the rhizosphere of date-palm was examined. Carbofuran was used for the purpose of comparison. Meloidogyne incognita population was more effectively controlled by the multiple dosage of the organic amendments but the populations of Helicotylenchus multicinctus and Pratylenchus thomei did not respond to the mode of application. In general, M. javanica and H. multicinctus populations were best controlled by poultry manure when given as single or repeated dosage. On the other hand, P. thomei population was most effectively managed by neem cake among the organic amendments.
Single dosages of organic amendments did not alter the yield of date but repeated dosages of poultry manure gave increased yield over the control.
Besides, histological studies were conducted on roots infected with Pratylenchus penetrans. Roots lesions showed puncture of epidermal cells, disarrangement of cortical cells with large empty, abnormal cavities, thin cell walls that were wavy and collapsing as the supporting material was destroyed by nematode infection.
Histological changes in the young date-palm roots infected with the root-knot nematode, Meloidogyne incognita, collected from Balochistan during August 2002, revealed that the nematode larvae penetrated the roots of date-palm by puncturing action of stylet and finally migrated into the cortex and endodermis layers where the cells were damaged. Hypertrophy, resulting in the formation of giant cells in the cortical and stellar regions of the roots, was recorded. Presence of gelatinous egg masses, hyperplasia of cells, with cells having relatively thick walls and shrunken basophilic cytoplasm were found in the infected roots.
Histological studies were included as additional work to examine the extent of damage caused by the nematodes.