ROOT KNOT NEMATODE INFESTATION 55 



Pomegranate, see Punica. 



Poncirus trifoliata (Citrus trifoliata), hardy orange. (C) 



Neal 1889 (176) : Seems resistant, but the trial has been brief. Florida. 

 Poppy, California-, see Eschscholtzia; pricklepoppy, see Argemone. 

 Portulaca spp., portulaca. (S) 



Goff 1936 (96) : Infestation to light in 1 planting where the infestation 

 on other plants also was relatively light (50 plants) ; infestation very 

 light to heavy in a second test (25 plants); average rating "lightly 

 infested." Florida. 



Watkins 1929 (248) : Rated as "resistant." Florida. 



Of the two commonly cultivated annual species, P. grandiflora and P. oleracea, 

 Bessey (16) wrote "nematodes abundant, but injury apparently not great"; the 

 latter is given as a wild host by Watson and Goff (258) and by others, whereas 

 Neal (176) reported it "badly affected." 



Potato, see Solanum; sweetpotato, see Ipomoea. 



Pot-marigold, see Calendula. 



Pricklepoppy, see Argemone. 



Pricklypear, see Opuntia. 



Primrose, evening-, see Oenothera. 



Privet, see Ligustrum. 



Prosopis chilensis (P. juliflora) , algaroba, kiabe, mesquite. (C) 



Godfrey 1935: 6 Infestation commonly observed to be light. Hawaii. 

 Prunus angustifolia, chickasaw plum. 



Hutchins, L. M. (Division of Fruit and Vegetable Crops and Diseases, 

 Bureau of Plant Industry. 1939) : No infestation observed in Georgia. 



Prunus armeniaca, apricot. 6 



Brown 1924: 7 Six trees killed near Tucson, Ariz. [Question: On what 

 root? Cf. report of George, below.] 



California Nematode Committee 1925: 8 Apricot resistant "on some types 

 of root." 



Fikry 1939 (64): No infestation found on native apricot (47 roots tested 

 2 to 5 years) ; seedlings in nursery always healthy. Egypt. 



Gardner 1926 (75) : Observed to be a host. California. 



George 1924: 9 Practically all apricot trees in the Salt River Valley, Ariz., 

 are budded on peach roots; no known case of nematodes attacking 

 apricots on their own roots; recent plantings on apricot roots uninjured 

 (the majority of these, however, in soil only lightly infested). 



Hutchins 1937 (114)'- Seedlings of Var. Blenheim (seed from California) 

 were completely resistant in all tests. Georgia. 



Milbrath 1923 (162): Certain varieties of apricot roots have been found 

 free in infested soil; no conclusive evidence for pronouncing resistance. 



1924: 10 Apricot rootstock has been found resistant. California. 



Neal 1889 (176): "Badly affected." Florida. 



Sandground 1922 (207): Parasitized more or less severely in South Africa. 



Taubenhaus and Ezekiel 1933 (226): Losses rarely serious. Texas. 



Tufts 1930 (233): "The apricot root has generally been accepted as im- 

 mune"; H. R. Keller, of Fresno, Calif., has recently reported an in- 

 festation. 



and Day 1934 (234): Apricot root has long been reputed uninjured, 



though sometimes lightly infested. Seedlings of 48 varieties (including 

 P. armeniaca, P. dasycarpa, and P. mume) have stood in the Delhi 

 nursery for 2 to 3 years without infestation. California. 



5 See footnote 10, p. 11. 



6 All available citations on apricot are given. 



7 Orton, C. R., and Wood, Jessie I. diseases of fruit and nut crops in the united states in 1923. 

 (J. S. Bur. Plant Indus., Plant Dis. Rptr. Sup. 33, pp. 35-147, illus. 1924. [Mimeographed.] See report 

 of J. G. Brown, p. 112. 



8 See footnote 6, p. 8. 



8 See report of D. C. George on pp. 112-113 of reference given in footnote 7, above. 

 10 See reports by Milbrath on pp. 104 and 113 of reference given in footnote 7, above. 



