English

Abstract

Cotton is an important cash crop of Pakistan and is severely affected with wilt in cotton-growing areas of Punjab province. Research was carried out on two major pathogens of cotton Fusarium oxysporum f. sp. vasinfectum and Meloidogyne incognita and their possible role in wilt disease complex. During 2017-19, a survey of cotton growing areas of Punjab (Jhang, Multan, Vehari, Mianwali, Rahim Yar Khan, Bahawalpur, Kabir Wala, Dakota, Basti Dharik, Tibba Sultan Pur, Rajan Pur, Chak 27 (Layyah), Chak 99B (Layyah), Lodhran, Fateh Pur and Dagar Rohtass) was conducted to collect a sample on symptomology basis of yellowing of leaves, discoloured bark of lower part of the stem, blackened xylem vessel and wilting. Data were recorded on wilt disease incidence, prevalence, associated pathogens and root-knot nematodes. Prevalence of cotton wilt was recorded the maximum 85% in areas of Vehari, Kabir Wala and Rajan Pur while the maximum incidence in both Multan and Tibba Sultan Pur was 15%. Percentage association of wilting fungi was recorded from the soil, roots, stem and leaves on placing them in artificial media and soil dilution techniques were used to determine fungi in rhizosphere such as Fusarium oxysporum, Verticillium spp., Penicillium spp., Aspergillus spp., Rhizoctonia spp., Colletotrichum spp., Rhizopus spp., Mucor and Pythium. Root associated fungi were isolated by Hyphal tip method and isolated F. oxysporum, Rhizoctonia spp. and Pythium spp. From stem and leaf sample, F. oxysporum, Verticillium spp., Colletotrichum spp., Alternaria spp. and Botryodiplodia spp. were recorded. Relative density nematode was recorded from different locations and highest occurrence was observed in Bahawalpur (85%) by using different extraction methods. Eggs masses of root knot nematodes were staining by using Phloxin B and nematodes inside root system was done by using acid fuchsin. Nematode reproduction parameters like No. of J2/roots system, J2 in 100ml of soils, eggs masses/root system, females/ roots system, galls/ root system were recorded. Cotton wilt caused by the interaction of Fusarium and Root knot nematode is threat to cotton industry in Pakistan and it should be treated to avoid economic losses.