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Coffee Berry Disease

Coffee Berry Disease caused by Colletotrichum coffeanum was detected in Kenya 1922. The fungus lives in the bark of the coffee tree and produces spores which attack the coffee cherries. Spraying has been determined to be the best way to avoid the coffee berry disease.

Symptoms

Although this pathogen is capable of infecting leaves, stem bark, and twigs of the coffee plant, only the strain or species of Colletotrichum that can infect immature or green berries is the causal organism of CBD. Direct losses occur as a result of flower and young fruit infection. CBD on green berries has two forms. Active lesions are initially evident as small dark sunken spots which spread rapidly to involve as much as all of the berry. If infection occurs early and climatic conditions favor disease development, berry development is arrested, resulting in mummified berries on the fruiting branch.

Coffee Berry Disease Infection

Flowers are susceptible at all developmental stages from the pale green unopened spike. Immature fruit or berries are most susceptible during their expansion phase which occurs from 4-14 weeks after flowering. Earlier berry stages or pin head berries and the mature green beans are fairly resistant, becoming susceptible again as the berry begins to ripen. The pathogen sporulates readily and is evidenced by a pale pink crust on the lesion surface. When the berry ripens and anthracnose fully develops, the bean can become infected and seed borne.

Spores germinate to produce germ tubes and appressoria in free water from which infection pegs emerge to penetrate the surface cuticle. Optimum Temperature is form 22°C to 27°C it can take place form 10°C to 30°C. Infection leads to typical black sunken anthracnose lesions of CBD initially appear about 1 week after inoculation and most by 2 weeks for berries.

Coffee Berry Disease Infection

During the afternoon of the second of March we can see that a sporulation of CBD took place in Sabukia, Kenya. This sporulation completed at 22:00 and the model started to calculate the progress of an infection. This infection was completed at 5:00 at the third of March. Whereas at the first of March air temperature has been too low to complete an infection.

Coffee Berry Disease Infection Severity: The Infection severity is evaluated on basis of the rain intensity during the leaf wetness period leading to infection. More than 10 mm of rain => Severity := 5

  • More than 5 mm of rain => Severity := 4
  • More than 2 mm of rain => Severity := 3
  • No rain => Severity := 2
  • No Infection => Severity := 0


Coffee Berry Disease Infection Severity: The infection was completed at 5:00 at the third of March. The severity was rated to be 3. There has been more than 2 mm of rain during the leaf wetness period.

When we look for the daily values we can get an overview over the complete February and the first day of March. Where we can see an increase in disease severity in the last week of February and in the first days of March.