NOTES ON TAXONOMY AND BIOLOGY: This amphimictic lesion nematode is similar to a Pratylenchus, but differs as females have two functional ovaries instead of one. Females have a subcylindrical tail marked by 16-23 annuli. This lesion nematode is migratory endoparasitic pests. Its development and reproduction occurs inside the root tissues of plant host.

GEOGRAPHICAL DISTRIBUTION: Z. guevarai occurs in Bulgaria, Czechoslovackia, France, Former Yougoslavia, Germany, Greece, Hungary, Italy, Malta, Pakistan, Poland, Spain, Tunisia, Turkey, Uzbekistan, South Africa and United Kingdom. This species has also been reported in California (CAB International, 2001; Siddiqi, 1975; Siddiqui et al., 1973).

HOSTS: Zygotylenchus guevarai infects ornamental trees, weeds, alfalfa (Medicago sativa), almond (Prunus dulcis), broad bean (Vicia faba), carrot (Daucus carota), cawpea (Vigna unguiculata), celery (Apium graveolens), chick pea (Cicer arietinum), corn (Zea mays), cotton (Gossypium hirsutum), cypress (Cupressus sempervirens), English violet (Viola odorata), escarole (Lactuca scariola), grapevine (Vitis sp.), grass (Poa sp.), hemp (Cannabis sativa), Inca lily (Astroemeria sp.), kidney bean (Phaseolus vulgaris), lesser pea (Lathyrus cicera), melon (Cucumis melo), oats (Avena sativa), parsley (Petroselinum crispum), pea (Pisum sativum), pepper (Capsicum annuum), potato (Solanum tuberosum), and tomato (Lycopersicon esculentum), vetch (Vicia lens), and wheat (Triticum durum) (CAB International, 2001; Siddiqi, 1975; Vovlas et al.,1976).

CROP LOSSES: Growth suppression has been reported on celery in Italy (Vovals et al., 1976).

MEANS OF MOVEMENT AND DISPERSAL:  Through root material and by poorly sanitized bare root propagative plant material.

RATING: (L) Taking into consideration the known damage caused by this nematode in Italy and its establishment in California, regulatory agencies in vegetable producing states should adopt measures to prevent the spread of this pest from California to other vegetable growing states. Appropriate actions should be evaluated by APHIS in order to minimize the risks of introduction of this nematodes from other countries.

REFERENCES:
    CAB International, 2001. Zygotylenchus guevarai in: Crop protection compendium, global module, 3rd edition. Wallingford, UK: CAB International.
    Siddiqi, 1975. Zygotylenchus guevarai.  CIH description of plant parasitic nematodes Set 5, No. 65. St. Albans, UK: Commonwealth Institute of Helminthology.
    Siddiqui, I. A., S. A. SHER, and A. M. FRENCH. 1973. Distribution of plant parasitic nematodes in California. California Department of Food and Agriculture, Sacramento. California USA.
    Vovlas, N., R. N. Inserra, and F. Lamberti. 1976. Osservazioni syll’epidemiologia e sulla patogencita’ di Zygotylenchus guevarai (Tobar) Broun & Loof. Nematologia Mediterranea 4:183-193.