COTTON DISEASE MANAGEMENT STRATEGIES
Root and boll rot diseases are most destructive severe
By M. Mithal Jiskani and Khadim H. Wagan
Sindh Agriculture University, Tandojam.
Mar 12 - 25, 2001
Cotton is one of the most important fibre and cash crops of Pakistan, which earns foreign exchange for the country. The crop has maximum area in Punjab followed by Sindh and very negligible in NWFP. The yield per hectare of seed cotton in Punjab is also more to that of Sindh province. On a whole, cotton is a major crop in parts of African tropics, Australia, China, Egypt, India, Mexico, Pakistan, the Soviet Union, Sudan, United States, and warmer regions of cntral and South America.
Archeologists and historians believe that cotton existed 5000 years ago. Mohan-jo-Daro was nature place of cotton, where the people were knowing the arts of spinning and weaving. Cotton Lint was separated from seed on charkha (a kind of hand cranked roller gin) and the fibres processed into fabrics with drop spindles and primitive looms. The quality of the textiles produced had been excellent (Bhatti and Soomro, 1996 and Khoso, 1992). The history of Cotton Crisis" is also as old as its cultivation. Following poem of Shah Abdul Latif, a saint poet of Sindh can be quoted as first example (During 1689-1752 A.D).
In the midst of the trees no cotton plants are: So here are no spinners. The empty baazzar has ensalted my heart; Foolish girl, in your brain.
The second example regarding cotton disease was quoted in Texas Agricultural Experiment Station Bulletin No.4 (1888). Palmel studied and wrote about root rot of cottony (Anonymous, 1981). Up to till date, the struggle against cotton diseases continued and it had been revealed that this crop was subjected to more than 60 diseases (Anonymous, 1981), which reduced the yield and brought about heavy losses. The work carried out so far in Pakistan shows that seedling rot or wilt, root rot, boll rot, anthracnose, different types of leaf spot diseases, premature opening of bolls (Tirak), stunting or reduction in size of leaves, some nematode species, bacterial blights (angular leaf spot and boll rot), caused by a bacterium, Xanthomonos malvacearum, leaf curl and stenosis of cotton, found causing damage to the crop (Kamal and Moghal, 1968, Hafiz, 1986 and Jiskani, 1992). Such diseases are injurious in some areas, in some years and on some plant parts. The magnitude of disease damage depends up on environment and cultivar.
The crop record revealed that root and boll rot diseases of cotton were considered as most severe and destructive, but since last decade, cotton leaf curl virus (CLCV) found to be the most important disease of cotton. This disease was first time reported in 1967 at Multan on cotton plants. In Sindh, this disease was first reported during 1996 at Ubaura, District, Ghotki Now, it is reached upto New Saeedabad, District, Hyderabad during last years (1999-2000). It was considered a minor disease until 1987, but in 1991-92 it infested 35,000 acres and 294,000 acres during 1992-93 causing a huge production and monetary loss to the nation (PARC, 1993).
The cotton diseases management strategies have been evolved, which are being summarized here and based on the recommendations by Bhatti and Jiskani (1995 and 1986), Hafiz (1986) Jagirdar and Jagirdar (1980) Jiskani (1992) Kamal and Moghal (1968) and PARC (1993), for the benefit of cotton growers.
i) Cultivation of disease resistant varieties is only safe measure for control of all different diseases.
ii) Eradication including collection and burning of plant debris may help to control seedling, root, and boll rots, as well as bacterial blight, because disease inoculum may also survive through plant debris.
iii) Deep ploughing with short duration, atleast two months before sowing, help to connntrol seedling and root rot.
iv) Proper land leveling is a preventive measure against seedling and root rot.
v) Use of healthy seed, acid delinting and chemical seed treatment minimize the incidence of seedling, root and boll rot and bacterial blight.
vi) Crop rotation with non-hosts eg. sowing of sorghum for 3-4 years. is useful for control of seedling and root rot.
vii) Mixed cropping with kidney bean or fodder and leguminous crops save the cotton crop from root rot.
viii) Proper use of irrigation and chemical fertilizers improve the disease resistant power in cotton plants.
ix) Early sowing of crop is preventive measure for boll rot.
x) Whitefly transmit cotton leaf curl virus from diseased plant to healthy one, whereas, different cotton boll worms may play a role to transmit the boll rot diseases, hence whitefly and boll worms must be controlled.
xi) Lady's finger (okra), Sun Kukra, China rose, Thorn apple (Dhatura), Mint (Podina), Karund, Cucurbits (especially water melon), beans, tomato, tobacco, chillies, soybean, sunflower, cow peas, egg plant (brinjal), holly hock (gul-e-khera), zinnia, sesame, AK (Calotropis), shesham, citrus species etc are recorded as alternate host plants of cotton leaf curl virus as well as whitefly; and also some of them are alternate hosts of boll worms. Therefore, they all must be eradicated before and during cotton cropping season. Cotton growing zones may play a better role for this purpose.
Meanwhile use of proper cotton production technology as per recommendation of agricultural experts/ researchers is economical and most effective for cotton disease management. It is out look and responsibility of the cotton growers to adopt the modern cotton prodcution technology and play a role for the development and prosperity of the country.