Coffee nematode decline is a disease caused by Meloidogyne konaensis, a root-knot nematode primarily in the Kona region of the Big Island of Hawaii. Juvenile nematodes penetrate coffee root tips and establish permanent feeding sites near the root vascular system. Once matured, female nematodes can lay roughly 100 eggs within the roots. Once hatched, these juveniles can re-infect the same host plant or move to a neighboring host and begin the process again. The life cycle of M. konaensis is about six weeks. M. konaensis “occurs on about 85% of the acreage in the Kona area. On infested coffee farms, the overall yield loss is estimated at 60%.” (Nelson, Schmitt, & Smith, 2002)
General management practices for nematodes include crop-rotation, isolating contaminated soils, solarization and soil fumigation, and employing resistant cultivars. In Hawaii, coffee-specific management practices primarily focus on methods of reducing soil populations of nematodes to a level of acceptable damage. This can be achieved with a combination of multiple control processes. Field rejuvenation programs should focus on planting resistant cultivars or grafted plants using resistant rootstock, such as robusta root stock. Organic matter should be incorporated into the soil surrounding coffee trees to force microbial competition for the nematodes. Propagation techniques should ensure new plant stock is clean of nematodes to prevent re-introduction of nematodes. This can be done by separating nursery locations from production crop areas, using sterile media for seed germination, maintaining seeds and seedlings on elevated benches above the soil, purchasing only certified, clean plant stock, etc. Plants used for intercropping or as a cover crop should be poor hosts or non-hosts for the nematode. Any plant that is a good host (supports rapid nematode reproduction) should not be planted in or near coffee fields.
Nelson, S. C., Schmitt, D. P., & Smith, V. E. (2002). Managing coffee nematode decline. Cooperative Extension Service, College of Tropical Agriculture and Human Resources, University of Hawaiʻi at Mānoa.
Hurchanik, D., Schmitt, D. P., Hue, N. V., Sipes, B. S., & others. (2003). Relationship of Meloidogyne konaensis population densities to nutritional status of coffee roots and leaves. Nematropica, 33(1), 55–64.