| Pin nematodes (Paratylenchus
spp.) are the smalles plant parastic nematodes that attack plants. Adult females
found in mint average 0.4 mm (0.016 inch). Pin nematodes are migratory
ectoparasites, which have four juvenile stages. Females lay an average of 2-3 eggs/day
when feeding, but few eggs are laid while females are not feeding. Eggs hatch in 7-8
days, and egg to egg generation time varies from 36-38 days at 28-20 C. Once eggs hatch,
the juveniles migrate towards the growing root tip as it advances through the soil. Pin
nematodes easily detect and move towards plant roots, with the majority found around the
root within 30 minutes. |
Pin nematodes rarely cause damage to
plants unless present in very high numbers. However, mint is one of the best hosts for pin
nematodes, and populations frequently exceed 100,000/quart soil. Effects of feeding by pin
nematodes on the appearance, structure or function of mint roots has not been studied. In
other crop plants, symptoms range from no noticeable pathology at the feeding sites to
shallow localized lesions. Rate of root growth and lateral root development may be reduced
or terminated by the prolonged feeding of many individuals on the same root. This may
reduce the nutrients, and thus energy, which can be stored into the rhizome, potentially
reducing the health and vigor of the plants. |
