Rev 01/30/2023
Synonyms:
Anguina pacificae was synonymized with A. agropyri by Chizhov and Subbotin (1990) based on the identification af a nematode parasitizing Poa in Russia as A. agropyri (the documented host range of A. agropyri is in the grass genus Agropyron while that of A. pacificae is in the grass genus Poa). However, the A. pacificae is still being used in some recent literature, e.g. McClure et al., 2008.
Recent molecular analyses of A. pacificae from California and A. agropyri from Europe indicate differences in the ITS region and suggest that A. pacificae is distributed in California and perhaps Russia while and A. agropyri is in Europe only (Sergei Subbotin, pers. comm.).. Note that A. pacificae has also been indentified in Ireland (Fleming, 2015).
1.44-2.58 mm long. C-shaped when dead. Four lines in lateral field. Tail conical to a sharp point.
Stylet short (8.9-12.4 µm), esophageal glands do not appear to overlap intestine.
Vulva at 82-89%. Monovarial, prodelphic ovary may have one or two flexures and extends to base of esophagus. Post-uterine sac present.
Males
1.22-1.84 mm long.
Caudal alae and gubernaculum present.
Anguina pacificae J2
Anguina pacificae male
Anguina pacificae: male tail, caudal alae, spicules
Photograph: I. Cid del Prado
Reported median body size for this species (Length mm; width micrometers; weight micrograms) - Click:
Anguina pacificae was found on grasses by Larry Costello (UC farm advisor) on Poa annua in 1978. It was described by Cid del Prado Vera and Maggenti in 1984.
It is reported from central coast golf courses in San Francisco, San Mateo and Monterey Counties.
As of 2001, golf course superintendents report that individual golf courses severely affected include Pebble Beach, Cypress Point, the Olympic Club, San Francisco Golf Club, and many other prominent courses.
In 2015, Anguina pacificae was reported and confirmed infesting annual bluegrass (Poa annua) in County Dublin, Ireland (Fleming et al., 2015).
C-rated pest in California, USA.
Damaging on golf courses, considered a serious problem by greens managers. Golf is a major recreational and sporting activity in California and many parts of the world. It supports hundreds of thousands of jobs and contributes billions annually to the economy. In Northern California, McClure et al. (2008) estimated there were over 1 million golfers who play on 400+ courses on which Poa annua accounts for more than 75% of the turf grass maintained on putting greens.
Anguina pacificae is a major threat to greens in cool, coastal golfing areas.
Endoparasite in stem galls
Poa annua L., annual bluegrass.
Several grass and cereal cultivars were tested for susceptibility to the A. pacificae, Dublin population. Of all the cultivars examined, only the P. annua and Velvet bentgrass (A. canina) had observable stem galls containing viable eggs. The other cultivars examined showed no galling; P. pratensis cv. Creon, Highland browntop bent (A. tenuis), F. rubra cv. Lucinda, Triticum aestivum var. Einstein, Triticum aestivum var. Alchemy, Hordeum vulgare var. Suzuka, and Hordeum vulgare var. Saffron. (Fleming et al., 2015).
Ecophysiological Parameters:
The nematode induces green galls at stem bases. Galls may contain several adults and hundreds of juveniles and eggs. It does not attack the inflorescence (and presumably does not form seed galls, which might limit its spread).
Mature galls may be filled with bacteria, which appears as a white cream. That is reminiscent of the association between Anguina spp. and Clavibacter spp. in wheat and ryegrass.
Stem and leaf distortion, stem galls. On annual bluegrass, A. pacificae induces galls at the crown of the plant. The galls sequentially contain developing juveniles, adults, eggs and second-generation J2. Initial symptoms on turf consist of small yellow patches, 25 to 75mm in diameter, which enlarge and may coalesce as the nematodes spread. Young, infected plants may die and, when the infestation is severe, a rough, uneven putting surface results (McClure et al., 2008).
The nematode can be spread by any method that moves infected plant material or soil, or with irrigation water. It is not known to be seed borne (Schenck, 2022).
Chemical Control:
A single application of the nematicide fluopyram, applied at 0.22 lb/acre ,reduced the number of new shoot-galls and improved annual bluegrass appearance for several months. The efficacy was greater at increased rates and application frequency. Although the quality and appearance of the treated turf was improved, and there were fewer new shoot galls, there was little apparent effect on individuals of A. pacficae in the soil, or on other plant-parasitic nematodes. Researchers concluded that fluopyram did not move therough the thatch layer and into the soil although it clearly reduced the ability of pacific shoot-gall nematode juveniles to induce new shoot galls. Two applications of fluopyram provided season-long protection. A formulation of abamectin was similarly effective but required more frequent treatments to achieve the same result (Orlinski et al., 2021; Petelewicz et al, 2020).
Although one might speculate that reduction in numbers of shoot galls, feeding and reproduction sites for A, pacificae, would eventually lead to fewer nematodes, the researchers in the fluopyram study point out that the frequent use of pesticides can result in buildup of biodegrading microorganisms. The reliance on only one active ingredient against a pest like pacific shoot-gall nematode significantly increases the likelihood of developing resistance to the pesticide (Petelewicz et al, 2020).
Host Plant Resistance, Non-hosts and Crop Rotation alternatives:
Cid del Prado Vera, I. and A.R. Maggenti. 1984. A new gall-forming species of Anguina Scopoli, 1777 (Nemata Anguinidae) on bluegrass, Poa annua L., from the coast of California. J. Nematol. 16:386-392.
Chizhov, V.N. & Subbotin, S.A. 1990. [Phytoparasitic nematodes of subfamily Anguininae (Nematoda, Tylenchida). Morphology, trophic specialization, taxonomic]. Zoologichesky Zhurnal 69, 4: 15-26 (in Russian)
Fleming, T.R., A.G. Maule, T. Martin, M. Hainon-McDowell, K. Entwistle, M.A. McClure, C.C. Fleming. 2015. A First Report of Anguina pacificae in Ireland. Journal of Nematology 47:97-105.