Sarbjeet KaurDhakad, Umesh Kumar2016-09-302016-09-302014http://krishikosh.egranth.ac.in/handle/1/79628Foot rot/gummosis of Kinnow mandarin caused by Phytophthora nicotianae var. parasitica causes considerable damage in nursery as well as in established orchards under Punjab conditions. Soil sampling studies revealed that pathogen propagules were present throughout the year in orchards. Among the three locations sampled viz. Fazilka, Hoshiarpur and Ludhiana, the maximum number of propagules were present in July (366 propagules/cc of soil) and minimum number of propagules were found in June (8 propagules/cc of soil). Population reached maximum in July and afterwards decreased linearly up to June and reached minimum. Maximum population were found in Hoshiarpur followed by Ludhiana and Fazilka. The pathogen population and feeder root rot were significantly higher in 10 year old Kinnow mandarin plants compared to 5 year old plants. Cultivar viz. Kinnow mandarin and Sweet orange had no significant difference on pathogen population and feeder root rot. Irrigation methods had significant effect on pathogen population. Flood irrigated Kinnow orchards have higher propagules counts as well as higher root rot followed by basin and drip irrigation. Among rootstocks tested against pathogen Citrumelo, Pectinifera and X639 showed tolerant reaction while Cleopatra and Rough lemon found to be most susceptible. Various fungicides were evaluated under in vitro conditions against pathogen. Ridomil Gold MZ exhibited 100 per cent growth inhibition at 10 μg/ml concentration. Melody Duo, Mandipropamid, Fluopicolide and Curzate M8 showed 100 per cent growth inhibition at 50 μg/ml concentrationenPhytophthoraThesis