questions: telling that he has 8 numbers of lemon trees. now, 4 numbers out of those 8 are suffering from canker. so, asking the control measure for the same. 
 answers: replied that the canker lesions appear as minute water soaked round spots which enlarge slightly and turn brownish which he may have observed and this bacterial disease can be controlled by spraying streptocyclin 100 ppm with blitox @ 3 gram per litre of water during new flushes.