As we all know after grapes, Citrus is extremely popular and it’s the second most vital fruit in worldwide according area and its production. Pakistan holding the 13th position in top producer countries and its area of cultivation is approximately 197,910 hectors in Pakistan with yield of two million tons of fruits per year.
According to doctor’s citrus fruit prevent us from liver, lungs, skin cancer, and heart diseases. it is the source of vitamin C, sugar, amino acids and other nutrients which is essential for humans.
The production of citrus is threatened by insect pest and diseases. Canker is the one of the major diseases of citrus crop.
Citrus canker disease threat to the citrus tree and it leave a bad impact on citrus growth, and it also drops the fruits of tree, and many varieties of citrus is moderately to highly susceptible to the disease.
It is caused by the bacterium Xanthomonas axonopodis and it attacks on Leaves, stems, and fruit of citrus trees.
Symptoms of Canker Disease:
Citrus canker symptoms show brown spot on leaves, and with that oily and water-soaked appearance will show on citrus, and that spot also called lesions which you can observe in below picture where it surrounded by yellow circles.
It can be seen on both side upper and lower side of leaf. And it attacks when condition is favorable for that infection, and it cause defoliation, shoot dieback, and fruit drop.
The bacteria of disease can be entered through natural opening or wound, then it multiplies in the intercellular space of cortical region. Favorable condition for infection is humid weather and mild temperature, and the bacteria of this disease cannot survive in dead plant and soil and it can also spread by through rainfall. Some insect also helps bacteria to spread the disease.
Exclusion: Canker disease of citrus fruit still not exist in some countries where favorable environment for pathogen, because of restriction on importing of propagation materials from areas with canker. So, to prevent from canker disease, exclusion is necessary to get rid of from that disease.
Sanitation: Citrus canker disease, and other type of new infections in fruit also linked to human, you may be known that human can carry bacteria on their skins, clothing, hand tools, ladders, gloves, etc. Whereas machineries such as tractors, implements, sprayers, etc. can be contaminate, and it transport plants then that plant can be affected of that problem, and to prevent from that problem, machinery should spray with bactericidal compounds.
Eradication: The elimination of inoculum by removal of infected trees, it is the form of eradication. There is a law in Florida, to must remove infected trees of citrus in residential as well as for commercial at the distance of 579 m (1900 ft).
There is lot of cultural practices to reduce risk of canker disease which includes windbreaks, sanitation, and pruning. Whereas use of windbreaks reduces wind speed, and reduction of wind speed lower the probability of direct penetration of stomates by bacteria.
Chemical Control: Chemical spray used to control citrus canker disease include spray of copper-based bactericide like copper oxychloride. And also used fungicide of Bordeaux mixture and lime Sulphur is also effective against infection of citrus canker. The spray of copper based depends on the factors of susceptibility of the citrus cultivar and environmental conditions.