Responses of different genotypes of citrus to huanglongbing (Citrus Greening) under field condition

Abstract

Citrus fruits belonging to the family Rutaceae, occupies a place of considerable importance in the fruit crop due to high economic returns. The citrus greening disease was observed in citrus germplasm orchard of All India Coordinated Research Project on Citrus, Department of Horticulture Mahatma Phule Krishi Vidyapeeth, Rahuri. Therefore attempts were made to study the detection by transmission studies, reaction of citrus varieties against the greening pathogen. In the present study, nineteen species/varieties of citrus were screened for their reaction against the citrus greening disease under field conditions. In field plant symptoms Leaf chlorotic mottling were the most diagnostic type of symptoms and was followed by vein yellowing. Fully matured leaves showed the most reliable symptoms of leaf mottling viz., yellowing along the midrib and leaves veins which spread in the adjacent tissues to produce a mottled effect. Such symptoms were observed in the citrus species of C. grandis, Tangerin ling ming, unidentified hybrid (Rough lemon Chettalli x Cleopatra mandarin) and C. limon. In case of varietal reaction of different citrus varieties or species to citrus greening diseases, significantly highest percent disease incidence (100 %) was observed on leaves of C. sinensis, C. reticulata, tangelo, C. grandis and C. jambhiri. Whereas, the C. paradisi (90 %), C. limonia (86.67 %) and Citrus reshni (63.33 %) showed highly susceptible reaction.