(Ritzema Bos, 1891)
Various common names include Strawberry crimp nematode,
Strawberry spring dwarf nematode, Foliar nematode
Aphelenchoides fragariae is 0.45-0.8mm long.
Reported median body size for this species (Length mm; width micrometers; weight micrograms) - Click:
Temperate and tropical regions, moist conditions. Widespread in the United
States, Europe and Asia as a pest of many plants and seems well adapted to
tropical and temperate climates (Scheck, 2021).
Endoparasite in leaves, but also feeds ectoparasitically on leaf and
flower buds in strawberry, for example.
Nematode enters leaves through stomata or directly.
Aphelenchoides fragariae can swim rapidly; may be negatively
Swiss scientist, J. Klingler studied entry of stomata by Aphelenchoides
fragariae. The nematodes aggregated around slits in plastic film even
when there were no gases emerging, suggesting recognition of a tactile
stimulus. They had negative or indifferent reaction to oxygen, but strong
positive reaction to carbon dioxide emerging from the slits.
That situation would occur at night - no photosynthesis, so CO2
from respiration would emerge from stomata. Also at night, dew would
provide a moisture film and facilitate nematode movement on the leaf
surface. Note, incidentally, that a positive attraction to CO2 is
common in soil nematodes.
More than 250 hosts, in 47 families, including fern, begonia, and strawberry.
The following are listed as hosts in various literature sources:
Nematode feeding causes blotches and necrotic lesions between veins on fern
leaves which start as water-soaked spots and then turn brown.
Disease symptoms on strawberry are called spring dwarf, spring crimp and red
Endoparasitic activity of A. fragariae causes shoot
malformations including twisting and puckering of leaves, discolored areas
with a hard and rough surface, undersized leaves with crinkled edges,
reddening of petioles, tight aggregation of crowns, shortening of internodes
on runners, reduced flower trusses with only one or two flowers or flowers
aborted, and death of the crown bud (Maas, 1998; Ploeg and Westerdahl,
Ectoparasitic feeding on folded crown and runner buds causes small dry,
brown areas that are seen on expanded leaves usually near the mid-rib.
Occasionally the nematodes are found in strawberry fruit pulp (Tacconi,
On flowering ornamentals such as violets, anemone and begonia, the
feeding areas of foliar nematode appear as irregular, water-soaked patches
later turning brown, violet, or black. The affected areas are limited by the
The nematode causes die-back disease of lilies; leaves, flower buds and
fruits turn brown and die (Daughtrey et al., 1995). Ferns develop
water-soaked, often chevron-like stripes on fronds as movement of the
nematodes seems to be delimited by vein. The stripes turn brown in summer
when the fern is the driest (Sandeno and Jensen, 1962).
The nematode is easily spread to new hosts when in the anhydrobiotic
condition, or by movement of infected but asymptomatic planting stock.
Roguing plants, burning infested material, starting/replacing with
healthy stock, general sanitation.
Nematode-free planting stock may be based on inspection by regulatory agencies.
For example, foundation, registered, and certified nursery stock may
be inspected and tested for viral, fungal, and bacterial pathogens, nematodes,
and varietal purity.
Hot water dips can
be used on strawberry plants (15 min. at 47 C.), but cultivars and requirements
change - current experiments are being conducted by Westerdahl.
Plants must not be damaged, and yield must not be affected
Hot water treatment may be used for other crops, also.
Chemical control can be used; e.g., Parathion as a foliar spray.
Host Plant Resistance, Non-hosts and Crop Rotation alternatives:
Bohmer B, 1981. The harmful effect of Aphelenchoides fragariae and A.
ritzemabosi on Fragaria ananassa. Gesunde Pflanzen, 33(5):113-117
CABI Crop Production Compendium 2021. Apehelenchoides fragariae.
https://www.cabi.org/cpc/datasheet/6381 Accessed 9/29/21
Chitambar, J. J., Westerdahl, B. B., and Subbotin, S. A. 2018. Plant
Parasitic Nematodes in California Agriculture. In Subbotin, S., Chitambar
J., (eds) Plant Parasitic Nematodes in Sustainable Agriculture of North
America. Sustainability in Plant and Crop Protection. Springer, Cham.
Daughtrey, M. L., Wick, R. L., and Peterson, J. L. 1995. Compendium of
flowering potted plant diseases. American Phytopathological society, St.
EPPO Global Database. 2021. Aphelenchoides fragariae
https://gd.eppo.int/taxon/APLOFR. Accessed 9/29/2021/21
Goodey, J. B., M. T. Franklin, and D. J. Hooper. 1965. T. Goodey's: The
Nematode Parasites of Plants Catalogued Under Their Hosts. Commonwealth
Agricultural Bureaux, Farnham Royal, Bucks, England. Third Edition
Ibrahim, S. K., R. N. Perry and D. J. Hooper. 1994. Use of esterase and
protein patterns to differentiate two new species of Aphelenchoides on rice
from other species of Aphelenchoides and from
Kohl, L. M. 2011. Foliar nematodes: A summary of biology and control with
a compilation of host range. Online. Plant Health Progress
Maas, J.L., Ed. 1998. Compendium of Strawberry diseases 2nd Edition. APS
Press. Nemaplex UC Davis Nemabase 2010. Aphelencoides fragariae. Accessed
Maeseneer, J. D. 1964. Leaf-browning of Ficus spp., new host plants of
Aphelenchoides fragariae (Ritzema Bos). Nematologica 10:403-408.
Mor, M., and Y. Spiegel. 1993.
Ruscus hypophyllum: a new host for Aphelenchoides fragariae. Journal of
Ploeg, A. and Westerdahl, B. B. 2018. UC IPM pest Management Guidelines:
Strawberry Nematodes. UC ANR Publication 3468
Riedel, R. M. and P. O. Larsen. 1974. Interrelationship of
Aphelenchoides fragariae and Xanthomonas begoniae on Rieger begonia.
Journal of Nematology 6:215-216.
Sandeno, J.L., and Jensen, H. J., 1962. A foliar nematode disease of
western sword-fern, Polystichum munitum. Plant Disease Reporter,
Scheck, H.J. 2021. California Pest Rating Proposal for Aphelenchoides
fragariae (Ritzema - Bos, 1891) Christie, 1932 Strawberry crimp nematode,
Strawberry spring dwarf nematode, Foliar nematode CDFA, Sacramento.
Siddiqui, I. A., S. A. Sher and A. M. French. 1973. Distribution of
Plant Parasitic Nematodes in California. State of California Department
of Food and Agriculture, Division of Plant Industry. 324p.
Tacconi R, 1972. Infestations of Aphelenchoides fragariae, Aphelenchoides
ritzemabosi and Ditylenchus dipsaci on strawberry in some Italian provinces.
USDA Phytosanitary Certificate Issuance and Tracking System,
Phytosanitary Export Database (PExD) Harmful Organisms Database Report.
Aphelenchoides fragariae. Accessed 9/29/2021