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Production and Protcction Division of FAO with the collaboration of 5 working groups, one of which consists of nematologists. The nematology group had che assiscance of nemaroJogist correspondents from 18 diflferent couniries. An introduction by L. Chiarappa, F. J. Moore and A. H. Strickland sets out che aims of che manuał, defines the basie concepts and explains che lay-out. The primary aim is co guide plant protcction workers in planning and canying out field experiments to measure crop losses. The 2nd secrion gives generał guidance on the prinriples involved in the cołłection of data on crop losses with a chapter on field ezperiments by E. L. Le Clerg and one on the place of sample survey in crop loss esdmation by B. M. Church. The major part of the manuał is in aection 3 with 3 sub-sections on techniques and apparatus, generał methods and special methods. For the chapter on escimating nematode densities in soil and roots by A. L. Taylor see No. 926 above. The 3rd section gives special methods for assessment of losses in 84 crop/disease situations of which 4 are due to nematodes, namely Heterodera rostochiensis on potato (by E. B. Brown, UK), H. avenae on cereals (by G. M. Dixon, UK), Meloidogyne hopla on luceme (by D. C. Norton, USA) and Belonolaimus longicaudatus on groundnut (by J. N. Sasser, USA). Each host-parasite combination is on a separace loosc-lcaf shcct with information under thc headings: “method dcvclopcd in^{1 2} (country), "field symptoms”,

0 688-USA, 1970. "83rd Annual Report, Fiscal Year ending June 30, 1970, Mississippi Agricul-rural and Forestry Experiment Station." Mississippi Agricultural and Forestry Experiment Station: 126 pp. [Plant nematology pp. 39, 50-51, 74, 98.J (En)

Mention is madę of thc devc!opment of root-knot resistant varicties of tomaco, pepper, red clover, cotton and soybean. Resistance is combined with tolerance to fungał diseases in cotton and soybean and to tobacco mosaic virus in pepper. Resistance to cyst nematode also is incorporated in soybean. Experiments with a rangę of nematicides for usc against root-knot nematodes on okra, bcan, cucur-bits and sweet potato are briefly reported.

0 5 9 0 —SIDDIQI, M. R., 1972. “On the genui Helicotylenchus Steiner, 1945 (Nematoda: Tylen-chida), with descriptions of nine new spedes.” Nematologica, 18 (1), 74-91. (En, dej Common-wealth Inst. of Helminthology, St. Albans, UK.

The genus Hehcotylenchus is discussed and a key to its spedes given. 9 new spedes are described: H. dihysteroides n.sp. from tomato soil in Portugal, Habunaamai n.sp. from soil around roots of Citrus paradisi, Psidium guajava_t Vitis ińmfera and Gossypium hirsutum in Sudan; H.conicephalus n.sp. from soil around roots of Aeolanthus mynan-thus in Malawi and Citrus paradisi and Vitis yinifera in Sudan; H. densibullatus n.sp. and H. talonus from soil around roots of A. myrianthus in Malawi; H. paraplatyurus n.sp. from culdvated soil in Portugal; H. australis n.sp. from soil around roots of Nicotiana tabacum in Western Australia; H. orthosomaticus n.sp. from luceme soil in Tanzania and H, toillmottae n.sp. from potato soil in India. H, microlobus is considered a valid spedes. Heh~ cotylenchus annobonensis (Gadea, 1960) n.comb. it proposed for Tylenchorhynchus africanus v. annobonensis of Gadea, 1960.

0 5 9 1 -CAVENESS, F. E., 1972. “Changes in plant parasitic nematode populations on newly cleared land.” (AbstractJ Nematropica, 2 (1), 1-2, 15-16. (En, EsJ International Inst. of Tropi-cal Agriculture, Ibadan, Nigeria.

On land previously farmed traditionally, abandoned, or covered with thicket or secondary forest in Nigeria, 19 plots werc cleared and croppcd succes-sively with maize, cowpea (Vigna unguiculata) and maize. Nematodes were counted in soil samples tak en monthly during the 19 montbs of the investi-gation. Within 2 momhs of clearing, nematode numbers decreased by 85%, chen inereased under the crops and decreased betwcen crops. The princi-pal spedes to inerease under crops werc Pratylenchus coffeae, Meloidogyne incognito and Helicotylenchus pseudorobustus, the first being rare before cropping but accounting for 96% of thc total at the cnd. H. pseudorobustus was dominant before clearing and second dominant under cultivation. M. incognito was uncommon before clearing and inereased under cultiyation. Spedes that disappeared under culti-vation were Scutellonema brodys, Xiphinema ameri-canum, X. ebriense, Xiphinema sp. and Criconemoides sp. It is concluded that plant-parasitic nematodes can survive in smali numbers under shifting cultivation and modem farming practices favour the inerease of some species at the expense of others.

0 69 2 -OVERMAN, A. J.; BRYAN, H. A.; HARKNESS, R. W., 1972. “Effect of weed eon troi on nematodes and potato (Solanum iuberosum L.) yields in marł type soils.” [Abstract] Nematropica, 2 (1), 8-9, 22. [En, Es] Agricultural Research and Educarion Center, 5007-60th Street E., Bradenton, Florida 33505, USA.

Populations of Criconemoides onoensis and Tylenchorhynchus martim in marł type soils in Florida, USA, were affected by weed eon troi in summer preceding the potato crop. Plots sown with Sorghum tndgare during the summer gave the highest counts of the nematodes in the following potato crop. The nematode populations were decreased morę by 4 ploughings at intenrals of 3 to 5 weeks than by 2 applicarions of the herbidde Dalapon and one ploughing. Pb taro yields were greater from the weed-free plots with smali er nematode populations than from the plots where sorghum had grown and nematode populations 170 inereased.

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o 5 8 9 -GOLDEN, A. M.; BIRCHFIELD, W., 1972. “Heterodera graminophila n.sp. (Nematoda: Heteroderidae) from grass with a kcy to closely related species.” Journal of Nematology, 4 (2), 147-154. (En] Agricultural Research Servicc USDA, BeltsviUe, Md. 20705, USA.

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Heterodera graminophila n.sp., found on Echinochloa colomem in USA, belongs to the H. goettingiana group. It is closest to H. cyperi and H. graminis but differs in having 3 incisures on the lateral field of małe and larva and in che mean length of the larval stylet and hyaline taił tip being 22-7 and 32 p respecdvely. Males and larvae have 5 head annules. The cysts are abullate, ambifenestrate, with a strongly devcloped underbridgc--the bifurcated ends of which look at first sight like builae.. The anu$ is 20% of the cyst length from the terminal cone, compared with 10% in H. cyperi and H. graminis, and there is no circum-anai cyst wali panem as in those species. The vulval slit is 45p. compared with 30 and 38 p long respcctively in the other species. A key to the 10 species in the goettingiana group is given, based on cyst and tarval charactcrs.. Biology of the new species was given in papers abstracted in Helminthological Abstraets, Series B, 40, No. 150 and Senes B, 41, No. 164.