The goal fundamental of this work consist in studying the state phytosanitary of orange tree in Ruzizi plain (DR Congo). So seven illnesses have been signaled like constraints to the culture of orange in Ruzizi plain, DR Congo. The greening was signaled in Ruzizi plain with an incidence of 71.01% and severity of 2.8. The higher incidence was recorded in Kamanyola grouping with 78.9% and lower incidence in Sange area with 62%. The sigatoka was signaled in Ruzizi plain with an incidence of 57.05% and severity of 2.89. The higher incidence was found in Kiliba grouping with 70.5% and lower incidence in Sange area with 48.5%. The gall was signaled in Ruzizi plain with an incidence of 53.35% and severity of 2.98. The higher incidence was found in Sange area with 60% and lower incidence in Bwegera area with 47%. The tristeza was signaled in Ruzizi plain with an incidence of 56.17% and severity of 2.98. The higher incidence was recorded in Bwegera area with 62.8% and lower incidence in Kamanyola with 45%. The aphids were signaled in Ruzizi plain with an incidence of 72.3% and severity of 2.83%. The caterpillar was signaled in Ruzizi plain with an incidence of 79.85% and severity of 3.12. The higher incidence of caterpillar was recorded in Sange area with 86.4% and lower incidence in Kamanyola with 73%. The mite was signaled in Ruzizi plain with an incidence of 57.65% and severity of 2.92.

The goal fundamental of this work, consist in studying the state phytosanitary of cassava in the rural area on the west coastline of Lake Kivu in South Kivu Province (DR Congo). So five illnesses have been signaled like constraints to the culture of cassava in the rural area of the South Kivu. The higher incidence of Cassava Mosaic Virus (CMV) has been recorded in Mudaka grouping with 77.6%. The severity in that area was 3.25. The lower incidence was found in Irhambi-Katana area with 67.3%. The overall average of CMV incidence in the rural area was 69.49%. The overall average CMV severity was 3.14. The Cassava Green Mite (CGM) was signaled in the rural area with an incidence of 27.38% and severity of 2.49. The highest incidence was found in Miti area with 52.17%. The severity in that area was 3.08. The anthracnose was signaled in rural area of South Kivu province with an incidence of 8.59% and severity of 2.39. The higher incidence was recorded in Mudaka area with 15.68% and lower incidence in Miti area with 5.46%. The Cassava leaf disease task was signaled in the rural area with an incidence of 49.3% and severity of 2.36. The highest incidence was recorded in Miti area with 65.44% and lower incidence in Irhambi-Katana area with 40.29%. The Mealy Bug (MB) has been signaled in the rural area with an incidence of 12.11% and severity of 2.3.