586 Journal of Nematology, Volume 18, No. 4, October 1986 cots in the family Commeliaceae. The basic 5. Linford, M. B. 1941. of the root- morphology of these plants appears to fa- knot in leaves and stems. Phytopathology 31:634-648. vor root-knot nematode development in 6. MacGowan,J. B., P. S. Lehman, and K. R. Lang- aboveground plant parts. Leaves of both don. 1979. Root-knot infecting the leaves and inflo- plants develop in the crown near the soil; rescences ofPalisota barteri. Nematology Circular 52, they are large, 20-30 cm long, and densely Florida Department of Agriculture and Consumer Services, Division of Plant Industry, Gainesville. arranged so that on younger 7. Miller, H. N., and A. A. DiEdwardo. 1962. Leaf leaves are protected from direct solar ir- galls on Siderasis fuscata caused by root-knot nema- radiation. The dense pubescent foliage, es- tode, Meloidogyne incognita incognita. Phytopathology pecially the convoluted young leaves, aid 52:1070-1073. in retaining surface moisture, thus provid- 8. Riggs, R. D., and N. N. Winstead. 1959. Studies on resistance in tomato to root-knot nematodes and ing a favorable humid environment for the occurrence of pathogenic biotypes. Phytopa- nematode activity. thology 49:716-724. 9. Taylor, A. L., and J. N. Sasser. Biology, iden- LITERATURE CITED tification and control of root-knot nematodes (Meloi- dog3me species). Cooperative publication of North Car- 1. Esser, R. P., V. G. Perry, and A. L. Taylor. olina State University (Department of Plant Pathology) 1976. A diagnostic compendium of the genus Meloi- and U.S. Agency for International Development. Ra- dog),ne (Nematoda: Heteroderidae). Proceedings of the leigh: North Carolina State University Graphics. Helminthological Society of Washington 43:138-150. 10. Taylor, D. P. 1976. Histopathology of Meloi- 2. Fassuliotis, G., and J. R. Deakin. 1973. Stem dogyne-induced galls on stems of roselle, Hibiscus sab- galls on root-knot nematode resistant snap beans. dariffa. Nematologica 22:218-221. Journal of the American Society for Horticultural 11. Steiner, G. 1940. The root-knot nematode at- Science 98:425-427. tacking stems and leaves of plants. Phytopathology 3. Lehman, P. S. 1985. Galls on above-ground 30:710 (Abstr.). plant parts caused by root-knot nematodes. Nema- 12. Tyler, J. 1938. Proceedings of the root-knot tology Circular 125, Florida Department of Agricul- conference held at Atlanta, Georgia. Plant Disease ture and Consumer Services, Division of Plant In- Reporter Supplement 109:134-150. dustry, Gainesville. 13. Wong, C. L., and H. J. Willetts. 1969. Gall 4. Lehman, P. S., andJ. B. MacGowan. 1983. In- formation in aerial parts of plants inoculated with fection of inflorescences and leaves of Palisota barteri Meloidogynejavanica. Nematologica 15:425-428. by Meloidogyne javanica. Journal of Nematology 15: 482 (Abstr.).

Journal of Nematology 18(4):586-588. 1986. © The Society of Nematologists 1986. Distribution of dipsaci in Daffodil

W. A. WINDRICH 1

Key words: nematode distribution, Ditylenchus dip- after HWT of daffodils is not always from saci, daffodil. inefficient treatment; timing of HWT and the temperature at which bulbs are stored are also important (7). During storage of Complete elimination of the stem nema- the bulbs stem nematodes may desiccate tode (Kfihn, Filipjev) in Ditylenchus dipsaci and are therefore less sensitive to HWT. bulbs in the Netherlands is the aim of the Temperature and humidity during Plant Protection Service. Elimination of storage may influence the efficacy of HWT stem nematode in daffodil bulbs is achieved (2,7). The number of infecting stem nema- by hot-water treatment (HWT). This pro- todes per bulb may also affect efficiency of cedure, however, did not always result in HWT (7), and nematode densities may vary adequate nematode control (5). Slootweg greatly among bulbs (1). My objective was (6) states that survival of stem nematodes to investigate the variation in nematode population densities in bulbs from several Received for publication 20 December 1985. Research Institute for Plant Protection, Wageningen, the lots. Netherlands. Nematodes were isolated by leaving bulbs Research Note: Windrich 587

TABLE 1. Percentages of bulbs of eight lots of daffodil bulbs I-VIII classified according to the numbers of Ditylenchus dipsaci found in the bulbs.

Class I II III IV V VI VII VIII

1 2 3 0.9 4 0.6 5 1,5 0.9 1.1 6 1.5 0.6 1.1 7 1.0 4.0 0.5 0.6 2.0 1,1 8 0.5 0.5 3.1 0.9 2.0 0.6 9 1.5 1.5 0,9 1.8 0.9 5.0 1.1 10 2.5 4.0 1.4 3.1 0.5 2.8 4.0 0.6 11 6.1 3.5 1.9 8.0 1.8 2.8 3,5 1.1 12 7.1 3.0 3,8 6.1 2.7 8.3 6.1 5.0 13 14.2 6.5 9.5 4.9 10.0 7,4 6.6 3.4 14 17,3 10.1 11.4 7.4 7.2 10.3 3.5 6.1 15 24.4 8.0 13.3 13.5 20.8 10.3 7.6 12.3 16 17.8 9.6 23.7 12,3 33.0 19.4 9.1 13.9 17 6.6 19.1 7.6 3.7 17.2 15.7 8.6 21,8 18 1,0 14.6 10.4 18.4 5,0 13.9 16.7 17,9 19 12.1 10.9 9.8 1.8 4.6 16.2 8.9 20 1,5 3.8 4.9 0.9 6.6 3.4 21 0.9 1.2 2,5 22 0.6 23

in a mistifier for 2 days (3), and the nema- Table 1 are composed of numbers of fre- todes extracted were then counted. Eight quencies of bulbs on classes of nematode lots of daffodil bulbs with characteristic population densities on a logarithmic scale symptoms of stem nematode infection were with base 2. Consequently, 0-1, 1-2, 2-4, examined. Infected bulbs are recognized 4-8, 8-16, etc., are indicated in the tables by light to dark brown longitudinal bulb by 0, 1, 2, 3, 4, etc., respectively. In Table cuts of tissue on some scales. Infected scales 2 the data of bulb examination, the num- are also soft and deteriorate during bulb ber of bulbs per distribution, and the char- storage. Bottoms of heavily infected bulbs acterizations of the distributions I-VIII are become partly detached (4). Eight fre- mentioned. quency distributions, indicated by I-VIII Distributions I and II on one side and in Tables 1 and 2, were determined in July- III and IV on the other side are samples October of 1975-79 with 197, 199, 211, from the same lots. Obviously the nema- 163, 221, 108, 198, and 179 Carlton daf- todes reproduced during the time lapse be- fodil bulbs. The distributions presented in tween August and October as can be ab-

TABLE 2. Date of bulb examination, number of bulbs per distribution, and characteristics of the distri- butions I-VIII.

Std. Std, Std, dev,/ Mean Min. Max, Modus err. dev. mean Kurtosis Skewness

I 08-08-1975 197 13,076 5,000 17.000 14.000 0.149 2.095 0.16 5,20 -6.20 II 17-10-1975 199 14.176 4.000 19.000 16.000 0.243 3.434 0.24 1.22 -6.01 III 10-08-1976 211 12.725 4.000 18.000 13.000 0,171 2.480 0.12 0.76 -2.24 IV 28-10-1976 163 14.245 5.000 21.000 17.000 0.264 3,376 0.24 -1.16 -2.64 V 22-07-1977 221 9.448 4,000 13.000 10.000 0.110 1,639 0.17 1.56 -3.94 VI 17-09-1979 108 15.083 3.000 20.000 16,000 0.280 2.907 0.19 6.05 -5.65 VII 10-08-1975 198 10.591 2.000 16.000 13,000 0.259 3,648 0,34 -1.80 -3.88 VIII 02-10-1978 179 15.816 4.000 20.000 17.000 0.228 3.055 0.19 8.98 -9.14 588 Journal of Nematology, Volume 18, No. 4, October 1986 stracted from the shifts of the mean (Table Zeitschrift f/Jr Pflanzenkrankheiten (Pflanzenpa- 2) to classes of higher nematode numbers, thologie) und Pflanzenschutz 76. Jahrgang, Heft 69: 193-208. and it is noteworthy that skewnesses are 3. Seinhorst, J. W. 1950. De betekenis van de toe- more or less the same: -6.20, -6.01 and stand van de grond voor het optreden van aantasting -2.24, -2.64. Skewnesses of the four door het stengelaaltje (Ditylenchusdipsaci (K/ihn) Fi- mentioned distributions and the other four lipjev). Tijdschrift voor Plantenziekten 56:291-348. (Table 2) are all negative and significant (In Dutch.) 4. Slogteren, E. van. 1919. De herkenning van her (> 1.96). Apparently the distribution of aaltjes-ziek der Narcissen en de bestrijding van de Ditylenchus dipsaci in daffodil is pseudo-nor- ziekte in de partij, zolang deze te velde staat. Labora- mal and skews toward the lower classes of torium voor Bloembollenonderzoek, Lisse. Publicatie nematode numbers. no. 2:1-12. (In Dutch.) 5. Slogteren, E. van. 1930. Warm-waterbehan- LITERATURE CITED deling van narcissen. Laboratorium voor Bloembol- lenonderzoek, Lisse. Mededeling no. 37:1-15. (In 1. Hesling, J. j. 1967. The distribution of eel- Dutch.) worm in a naturally-infested stock of . Plant 6. Slootweg, A. F. G. 1963. Hot water treatment Pathology 16:6-10. of daffodils. Laboratorium voor Bloembollenonder- 2. Klingler, J., and V. Langweiler-Rey. 1969. Die zoek, Lisse. Mededeling no. 158:1-6. W~irmeempfindlichkeit yon aktiven und trockenstar- 7. Webster, J. M. 1964. The effect of storage con- ren Ditylenchus myceliophagus, D. dipsaci und Anguina ditions on the infectivity of narcissus eelworm. Plant tritici bei verschiedenen Feuchtigkeitsbedingungen. Pathology 13:151-154.

Acknowledgment

During my tenure as Editor-in-Chief of the Journal ofNematology I have utilized ad hoc reviewers extensively to critique manuscripts. Ad hoc reviewers provide a most valuable service to the Journal--they remove some of the load from the ASsociate Editors, they provide different points of view, and they expand the pool of expertise in reviewing manuscripts. Both the Society of Nematologists and I owe them a very large amount of gratitude. Persons providing ad hoc reviews during the past three years include: G. S. Abawi, S. C. Anand, C. H. Baldwin, K. R. Barker, G. B. Bergeson, E. C. Bernard, G. W. Bird, R. I. Bolla, D. J. Chitwood, C. A. Clark, J. Curran, D. W. Dickson, C. P. DiSanzo, P. A. Donald, V. H. Dropkin, L. W. Duncan, R. A. Dunn, B. A:Ebsary,J. D. Eisenback, B. Y. Endo, R. P. Esser, G. Fassuliotis, L. R. Faulkner, J. Feldmesser, H. Ferris, J. M. Ferris, V. R. Ferris, J. M. S. Forrest, J. A. Fox, D. W. Freckman, R. R. Gaughler, R. Giblin-Davis, A. M. Golden, P. Goldstein, R. Gordon, G. D. Griffin, A. L. Harman, M. B. Harrison, H. Hirschmann, D. W. Hope, R. N. Huettel, R. S. Hussey, R. N. Inserra, B. A. Jaffee, S. B. Jepson, A. W. Johnson, D. T. Kaplan, H. K. Kaya, B. Kerry, R. A. Kinloch, J. B. Kotcon, J. A. LaMondia, J. A. Lewis, A. E. MacGuidwin, A. R. Maggenti, W. F. Mai, R. B. Malek, M. A. McClure, E. C. McGawley, N. A. Minton, R. F. Myers, W. R. Nickle, J. P. Noe, G. R. Noel, E. M. Noffsinger, D. C. Norton, A. P. Nyczepir, T. H. A. Olthof, C. C. Orr, J. j. Petersen, E. G. Platzer, G. O. Poinar, Jr., N. T. Powell, T. O. Powers, J. D. Radewald, D.J. Raski, D. Rawsthorne, R. V. Rebois, R. M. Riedel, R. D. Riggs, R. T. Robbins, A. F. Robinson, R. Rodriguez-Kabana, R. A. Rohde, M. R. Samoiloff, G. S. Santo, R. M. Sayre, N. C. Schenck, D. P. Schmitt, G. . Shannon, R. A. Sikora, G. C. Smart, Jr., H. W. Spurr, Jr., A. E. Steele, A. C. Tarjan, C. E. Taylor, I. J. Thomason, S. D. Van Gundy, J. A. Veech, D. R. Viglierchio, A. K. Watson, J. M. Webster, L. V. White, J. A. Wrather, K. A. Wright, L. D. Young, L. R. Zavaleta, and B. M. Zuckerman. I apologize if I have omitted anyone from this list ofad hoc reviewers.--L. R. KRUSBERG, Editor- in-Chief.