Brazil’s Fund for Defense of Citrus (Fundecitrus) has launched a chemical control program to check citrus canker and citrus black spot, by optimizing sprays of copper, an agrochemical used to combat both the diseases.
Fundecitrus’ researchers believe that the joint management program will maximize the effect of application of copper and will be compatible with spraying intervals.
“The applications of copper, essential for the control of canker, will contribute towards reducing the symptoms of citrus black spot also where it occurs and retard its appearance in new orchards,” affirmed researcher Franklin Behlau.
In plants younger than three years, the focus will be to protect these against citrus canker. In contaminated areas, the application of copper is essential during budding period. In groves with plants over three years, where both diseases are noticed and which have had only main flowering, the copper application for the canker control should be every 21 days through the fall of petals, till the fruits are 50 millimeters in diameter (after nearly four months).
Once the fruits attain this size, these become more resistant and copper applications can be undertaken only when there is budding.
At the same time, the applications of strobilurin, used against the citrus black spot, should be started in November and repeated interleaved with copper spraying every 42 days.
In general, these applications should be undertaken until April/May when the rainy period ends. In groves with more than one flowering, the copper application for canker should be done every 21 days through fall of petals until April/May, when the climate conditions are less favorable to the disease.
“Normally, orchards with less than six years old plants, citrus black spot does not occur in sufficient intensity to lead to fruit fall, and therefore, there is no need to spray strobilurin when the crop is meant for juice. If fresh fruit is meant for the market, then application of fungicide is necessary after the appearance of the first symptoms of the disease in the grove,” said researcher Geraldo J. Silva Jr.