Abstract

Decline is a serious threat to citrus industry of Pakistan. During 2016–17, a survey was conducted in twelve major citrus growing areas of Punjab, Pakistan including Bhalwal, Sillanwali, Kot-Momin, Sargodha, Shahpur, Khushab, Faisalabad, Toba, Gojra, Mianwali, Multan and Jhang to measure the incidence of citrus decline. Five orchards were selected randomly at each location. The maximum disease incidence (90%) was observed in Khushab and the minimum in Sillanwali (47%). For the isolation of nematodes, four subsamples were collected and mixed to form a composite sample from each tree. Fusarium solani, F. oxysporum and F. semitectum were found to be associated with declining citrus plants. F. solani incidence was the highest in Shahpur (73%) while the lowest (38%) from Gojra. The highest frequency of F. oxysporum (42%) and F. semitectum (66%) was recorded in Khushab and Mianwali, respectively. The maximum number of females nematodes per gram of roots were calculated from Jhang (648) followed by Shahpur (617). The highest population of second stage juveniles from per gram roots was recorded from Jhang (6483) while it was 1541 100 g-1 of soil in Shahpur. The varying frequency of fungal and nematode populations is helpful to determine the association of these pathogens with declining citrus trees in Punjab Province, Pakistan and the correct knowledge and identification of associated pathogens will help to formulate effective management strategy for citrus decline.