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STUBBY-ROOT NEMATODE LIFE CYCLE |
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CONTENTS
[Return to Nematode Identification] |
Stubby-root nematodes (Paratrichodorus spp.) are migratory ectoparasites which occur in mint occasionally, but their impact on mint production is unknown. They have a wide host range, however, and cause considerable damage to beets, celery, sweet corn, onions, etc. and are the vector for tobacco rattle virus which causes the devastating corky ringspot disease in potato. Stubby-root nematodes generally do best in sandy soils and are capable of considerable vertical migration between the surface and depths greater than three feet. Paratrichodorus allius appears to be the most common species recovered from mint.Life Cycle The life cycle of stubby-root nematodes is completed in as short as 2 1/2 weeks at 30 C and in three weeks at 22 C but at cooler temperatures may take as long as six weeks. Males appear to be important in some species but not in others. Feeding BehaviorIn contrast to other plant parasites, the stylet of stubby-root nematodes is solid. These nematodes form a feeding tube into the plant cell with salivary secretions that rapidly solidify. Cell contents are then pumped through this feeding tube into the mouth (Sijmons et al., 1994). Symptoms and Effects on Plant GrowthFeeding by stubby-root nematodes causes the root tip to stop growing, stunting root growth. Lateral roots often emerge from behind the root tips which are also fed upon. These become stunted and produce lateral roots of their own. Swelling of roots is also common, producing a prolific system of many short, branched, "stubby" appearing roots which do not explore sufficient soil volume to take up adequate water and nutrients for the plant. Thus, plant tops show water and nutrient stress, such as stunting, wilting easily, and appearing unthrifty. Stubby-root nematodes can be very damaging to potato and onion and must be controlled before rotating into these crops. |
