Uniformity of early growth is critical to uniform forcing and harvest. Incipient butt-rot infections may severely affect early plant-growth uniformity (Plate 25). Depending on initial populations of root pathogens at planting and the soil environment, nematodes, symphylids and root-rot pathogens may begin to attack the newly developing root system by the end of the first 3 months of growth. Seed material infested with mealybugs and/or scale at planting provides a source of pests that only requires ants to begin to establish damaging mealybug populations throughout the field and the potential for development of mealybug wilt. Additionally, during early growth, plants are especially susceptible to the fungal and bacterial heart rots.
Above-ground symptoms of potential root health problems will not generally be evident during early plant growth. However, nematode populations will begin to increase. Ants, if uncontrolled, will begin to move into the field from adjacent areas or from in-field colonies that were not destroyed by fallowing practices and will begin to expand. With increases in ant infestation, mealybugs will increase and, if uncontrolled, will have the potential to cause mealybug wilt.
The above-ground symptoms of root rot are similar to any symptom resulting from loss of a functional root system (e.g. mealybug wilt, nematodes, symphylids, root rot and water stress). Infected plants are stunted, show signs of stress and may or may not be easily pulled out of the soil. Thus, symptoms must be associated with evidence of poor soil drainage for fungal root rot, nematode galls for the root-knot nematode, and ants and mealybugs for mealybug wilt. Soil and root sampling for nematodes should be done to confirm their presence during this period.
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