The cocoa pathogens cause a decline in harvest to every cacao plantation. The pathogens or the disease producing agents on cocoa productions are the black pod, witches broom, frosty pod rot, swollen shoot, and the vascular streak dieback. The witches’ broom that affected the cacao plantations in Brazil has affected their harvest. The impact of the fungus results to a drop in the usual harvest from 400,000 metric tons to 100,000 tons. The reduction of harvest even spread to other cacao producing countries such as Venezuela, Colombia, Peru, Ecuador, and Panama.
One of the diseases that has a damaging effect on a cacao tree is the frosty pod rot. The pathogen that causes the disease is known as Moniliopthora roreri. This devastating disease will start an infection at the surface of cocoa pods which can penetrate through the pods during its first ninety days of development and growth. The symptoms can be seen as swelling and followed by a cream colored formation of discoloration outside the pods.
After two weeks of infections the result is a frosty pod with spores that can spread rapidly. It is estimated to obtain 44 million spores per square centimeters that rapidly spread through winds and water droplets during rainy season. The intervention of this fungal disease includes removal of the affected pods, reduction of a cacao tree’s height, biological control, and planting another variety that are resistant to the fungus.
The black pod is another serious fungal disease with its pathogen known as Phytophthora megakarya. The infection starts at any surface of an immature pod while most of the infection can be seen at the tip of a cocoa pod. The fungus that produces infections turns the surface of a cocoa pod into a firm and chocolate brown lesion. The seeds inside each of the pod are not contaminated after initial infection but the harvest can result to yield loss. In other cases of black pod infections the result is a black and mummifies cocoa pods. It also causes blight to the young stem and leaves of cacao seedling in the nurseries. The pathogen that causes black pod comes from the soil, spores from infected pods, and infected stem, leaves, and roots.
The witches broom is another disease that affects cocoa pods and its pathogen is called Crinipellis perniososa. The disease was first reported in the Caribbean Islands and South America. A cocoa tree can be affected by the witch broom basidiospores which are released by the basidiocarps. The spores come from a pinkish mushroom that is spread through winds and rain. During infection, hormonal and physiological changes occur that results to swelling with formations of succulent branches known as witch brooms. The witch brooms are clearly seen after 5 weeks of fungal infection.
The pathogens will cause a decline of cocoa harvest and farmers needed a modern way of cultivating. The cacao tree is one of the benefits of nature given to humankind that needs compelling protection from the complex tropical diversities.