Tropical Rotation Crops Influence Nematode Densities and Vegetable Yields

The effects of eight summer rotation crops on nematode densities and yields of subsequent spring vegetable crops were determined in field studies conducted in north Florida from 1991 to 1993. The crop sequence was as follows: (i) rotation crops during summer 1991; (ii) cover crop of rye (Secale cereale) during winter 1991-92; (iii) ''Lemondrop L'' squash (Cucurbita pepo) during spring 1992; (iv) rotation crops during summer 1992; (v) rye during winter 1992-93; (vi) ''Classic'' eggplant (Solanum melongena) during spring 1993. The eight summer crop rotation treatments were as follows: ''Hale'' castor (Ricinus communis), velvetbean (Mucuna deeringiana), sesame (Sesamum indicum), American jointvetch (Aeschynomene americana), weed fallow, ''SX- 17'' sorghum-sudangrass (Sorghum bicolor x S. sudanense), ''Kirby'' soybean (Glycine max), and ''Clemson Spineless'' okra (Hibiscus esculentus) as a control. Rotations with castor, velvetbean, American jointvetch, and sorghum-sudangrass were most effective in maintaining the lowest population densities of Meloidogyne spp. (a mixture of M. incognita race 1 and M. arenaria race 1), but Paratrichodorus minor built up in the sorghum-sudangrass rotation. Yield of squash was lower (P ≤ 0.05) following sorghum-sudangrass than after any of the other treatments except fallow. Yield of eggplant was greater (P ≤ 0.05) following castor, sesame, or American jointvetch than following okra or fallow. Several of the rotation crops evaluated here may be useful for managing nematodes in the field and for improving yields of subsequent vegetable crops.     

Egg parasitoids (Hymenoptera: Mymaridae and Trichogrammatidae) of okra leafhopper,Amrasca biguttula (Ishida) (Hemiptera: Cicadellidae), in southern Japan

The okra leafhopper, Amrasca (Sundapteryx) biguttula (Ishida) (Hemiptera: Cicadellidae), is an economically important pest of okra, Abelmoschus esculentus (L.) Moench (Malvaceae), in Japan. During 2019 and 2022 surveys for its egg parasitoids (Hymenoptera) were conducted on Kyushu and Ryukyu islands in southern Japan. Five species of Mymaridae, Anagrus (Anagrus)?atomus (L.), A. (A.) japonicus Sahad, A. (A.) turpanicus Triapitsyn and Hu, Arescon enocki (Subba Rao and Kaur), and Stethynium empoascae Subba Rao, as well as one of Trichogrammatidae, Pseudoligosita nephotetticum (Mani), were recorded from eggs of A. biguttula on okra in Japan. Of these, A. (A.) turpanicus, identified using a combination of molecular and morphological methods, is newly recorded from Japan; A. (A.)?atomus, A. (A.) turpanicus and P. nephotetticum are for the first time reported from eggs of okra leafhopper.     

Effects of Tropical Rotation Crops on Meloidogyne arenaria Population Densities and Vegetable Yields in Microplots

The effects of 12 summer crop rotation treatments on population densities of Meloidogyne arenaria race 1 and on yields of subsequent spring vegetable crops were determined in microplots. The crop sequence was: (i) rotation crops during summer 1991 ; (ii) cover crop of rye (Secale cereale) during winter 1991-92; (iii) squash (Cucurbita pepo) during spring 1992; (iv) rotation crops during summer 1992; (v) rye during winter 1992-93; (vi) eggplant (Solanum melongena) during spring 1993. The 12 rotation treatments were castor (Ricinus communis), cotton (Gossypium hirsutum), velvetbean (Mucuna deeringiana), crotalaria (Crotalaria spectabilis), fallow, hairy indigo (Indigofera hirsuta), American jointvetch (Aeschynomene americana), sorghum-sudangrass (Sorghum bicolor x S. sudanense), soybean (Glycine max), horsebean (Canavalia ensiformis), sesame (Sesamum indicum), and peanut (Arachis hypogaea). Compared to peanut, the first eight rotation treatments resulted in lower (P ≤ 0.05) numbers of M. arenaria juveniles on most sampling dates. Soybean, horsebean, and sesame rotations were less effective in suppressing nematodes. Yield of squash was greater (P ≤ 0.05) following castor, cotton, velvetbean, and crotalaria than following peanut. Compared to the peanut rotation, yield of eggplant was enhanced (P ≤ 0.10) following castor, crotalaria, hairy indigo, American jointvetch, and sorghum-sudangrass. Several of these rotation crops may provide a means for depressing M. arenaria population densities on a short-term basis to enhance yields in a subsequent susceptible vegetable crop.     

Egg parasitoids (Hymenoptera: Mymaridae) of Amrasca biguttula (Ishida) (Hemiptera: Cicadellidae) on Okinawa Island,a pest of okra in Japan

The fairyfly Anagrus (Anagrus) japonicus Sahad (Hymenoptera: Mymaridae) is identified for the first time as an egg parasitoid of the okra leafhopper Amrasca (Sundapteryx) biguttula (Ishida) (Hemiptera: Cicadellidae) on Okinawa Island, Japan. Amrasca biguttula is a serious pest of okra, Abelmoschus esculentus (L.) Moench (Malvaceae), both in Okinawa and Bonin Islands. Female of A. japonicus is redescribed, and its previously unknown male is described, based on the reared specimens from Okinawa. Prior to this study, host associations of A. japonicus were unknown. Another species of Mymaridae, Arescon enocki (Subba Rao and Kaur), also emerged from eggs of A. biguttula on okra in Okinawa, albeit in much smaller numbers.     

Presence of two host races of Aphis gossypii Glover (Hemiptera: Aphididae) collected in Turkey

The aphid, Aphis gossypii, is a primary pest of citrus, cotton, cucurbits and greenhouse‐grown vegetables in Turkey and throughout Europe. There is some previous empirical data suggesting that host‐adapted genotypes of this aphid exist which may in fact be host‐races. To determine if host races of A. gossypii are indeed present in the eastern Mediterranean region of Turkey, reciprocal host transfer experiments and life table analyses were performed with multiple asexual lineages (= clones) of the aphid collected from different hosts. The collection hosts included citrus, cucumber, eggplant, okra, sweet pepper and cotton. Aphid developmental times on the host from which the aphid was originally collected (= collection or natal host) were shorter (5.2–6.0 days) and had a higher intrinsic rate of population growth (r_m = 0.25–0.44) than the 6.6–7.3 days required when the aphid was reared on a non‐original collection host (= non‐collection host or non‐natal host) and had r_m = 0.03–0.30. Total immature mortality of the cotton clone, especially in the first nymphal stage, was high (51–100%) with low r_m (0–0.03) on cucumber, citrus and sweet pepper. Aphid populations transferred from citrus, eggplant and okra to cotton (r_m = 0.29–0.30) did not differ significantly in their performance from that of the cotton population on cotton (r_m = 0.34), whereas that from sweet pepper and cucumber populations (r_m = 0.22–0.24) were significantly lower. These data have allowed us to separate A. gossypii into two distinct biological groups: (a) a ‘generalist’ population obtained from cucumber, sweet pepper, citrus, eggplant and okra which exhibited statistically better development on cotton; versus (b) a population from cotton which, by comparison on reciprocal hosts, developed poorly on non‐natal hosts except on eggplant. Development of the cotton clone on cucumber and okra was not improved after four successive generations on the non‐natal host. The good development of A. gossypii from eggplant and cotton on these reciprocal hosts suggests that these particular clones were similar, if not identical, host races.     

Aspects of the ecology and energetics of the egg sac parasites of the wolf spider Pardosa lugubris (Walckenaer)

Summary The egg sacs of the wolf spider Pardosa lugubris are parasitised by two ichneumonid wasps, namely Gelis micrurus and Hidryta sordidus. The parasites are bivoltine, the first generation parasitising the summer egg sac of P. lugubris and the second generation parasitising, and overwintering in, the autumn egg sac. Parasitised egg sacs have a characteristic appearance.The degree of egg sac parasitism was 9.8% and 6.9% for the two egg sac batches in 1965 and 2.9% and 34.8% for those of 1966. The degree of parasitism varies from area to area as does the percentage parasitism attributable to the two species.The gross growth efficiency for Hidryta from the first egg sac is 31.2% and from the second 16.2%. 3.0% in 1965 and 4.3% in 1966, of the annual yield from P. lugubris to predators and parasites, goes to the egg sac parasites. This represents reductions in recruitment of 9.1% in 1965 and 10.9% in 1966.     

GENERAL BIOLOGY OF SPECIES

Enderson , J. H. 1965. A breeding and migration survey of the Peregrine Falcon. Hudson , R. 1966. Adult survival estimates for two Antarctic petrels. Kobriger , G. D. 1965. Status, movements, habitats, and foods of Prairie Grouse on a sandhills refuge. Lindhe , U. 1966, (The choice of prey of Tengmalm's Owl (Aegolius funereus) in Lysksele Parker , S. A. 1963. A note on the habits of Mayrornis schistaceus Mayr (Muscicapide) of the Southwest Pacific. Parker , S. A. 1963. Nidification of the genus Melanocharis Sclater (Dicaeidae). Pitman , C. R. S. 1962. Notes on the African Finfoot Podica senegalensis (Vieillot) with particular reference to Uganda. Percy , (the late) Lord William 1963. Further notes on the African Finfoot, Podica senegalensis (Vieillot). Pitman , C. R. S. 1963. The breeding of the Great Spotted Cuckoo Clamator glandarius L. in Iraq and a note on the Iraq eggs of the Kashmir Magpie Pica pica bactriana Bp. Pitman , C. R. S. 1963. The nesting of the Black-bellied Seed-cracker, Pirenestes ostrinus in Uganda, and notes on its habitat and classification. Reid , B. 1965. The Adelie Penguin (Pygoscelis adeliae) egg. Skutch , A. F. 1966. Life history notes on three tropical American cuckoos. Stonehouse , B. 1966. Emperor Penguin colony at Beaufort Island, Ross Sea, Antarctica. Sulkava , P. 1964. (On the behaviour and food habits of the Sparrowhawk (Accipiter nisus) during the nesting season). Sulkava , S. 1964. (The Goshawk (Accipiter gentilis) and its feeding habits in south and central Finland.) Taylor , R. H. 1964. Adelie Penguin rookeries in the Ross Dependency. Walkinshaw , L. H. 1966. Summer biology of Traill's Flycatcher. Westerkov , K. 1965. Utilization of grit by Pheasants in New Zealand.     

Identification of Top-Down Forces Regulating Cotton Aphid Population Growth in Transgenic Bt Cotton in Central China

The cotton aphid Aphis gossypii Glover is the main aphid pest in cotton fields in the Yangtze River Valley Cotton-planting Zone (YRZ) in central China. Various natural enemies may attack the cotton aphid in Bt cotton fields but no studies have identified potential specific top-down forces that could help manage this pest in the YRZ in China. In order to identify possibilities for managing the cotton aphid, we monitored cotton aphid population dynamics and identified the effect of natural enemies on cotton aphid population growth using various exclusion cages in transgenic Cry1Ac (Bt)+CpTI (Cowpea trypsin inhibitor) cotton field in 2011. The aphid population growth in the open field (control) was significantly lower than those protected or restricted from exposure to natural enemies in the various exclusion cage types tested. The ladybird predator Propylaea japonica Thunberg represented 65% of Coccinellidae predators, and other predators consisted mainly of syrphids (2.1%) and spiders (1.5%). The aphid parasitoids Aphidiines represented 76.7% of the total count of the natural enemy guild (mainly Lysiphlebia japonica Ashmead and Binodoxys indicus Subba Rao & Sharma). Our results showed that P. japonica can effectively delay the establishment and subsequent population growth of aphids during the cotton growing season. Aphidiines could also reduce aphid density although their impact may be shadowed by the presence of coccinellids in the open field (likely both owing to resource competition and intraguild predation). The implications of these results are discussed in a framework of the compatibility of transgenic crops and top-down forces exerted by natural enemy guild.     

Influence of selected host plants on biology of castor whitefly,Trialeurodes ricini (Hemiptera: Aleyrodidae)

The development time, immature survivorship, immature size, tertiary sex ratio, pre-oviposition period, fecundity, and preferences of the castor whitefly, Trialeurodes ricini on four host plant species (castor, eggplant, cotton and green bean) were evaluated under laboratory conditions. Development time from egg to adult emergence was the longest on cotton (33.3 days), the shortest on green bean (25.4 days), and intermediate on eggplant (28.5 days) and castor (28.3 days). The survival rate was the highest on castor (92.5%), followed by those on green bean (80.2%) and eggplant (73.8%), and the lowest on cotton (42.6%). The sex ratio was the highest on cotton (♀:♂ = 2.45:1.00), the lowest on eggplant (♀:♂ = 0.75:1.00), and intermediate on castor and green bean (♀:♂ = 1.04:1.00). T. ricini immatures and adults were generally larger when reared on castor and eggplant than on other plants. The net reproduction rate (R₀) was 57.656 females per female per generation, the generation time (T) was 35.9 days, the intrinsic rate of increase (r_m) was 0.1128 eggs per female per day, the gross reproduction rate (GRR) was 108.04 eggs per female per generation, the finite rate of increase (λ) was 1.1194 females per female per day, and the doubling time (DT) was 6.1149 days. In both no-choice and two-choice tests, T. ricini adults preferred castor for feeding and oviposition.     

Potential of pigeon pea as a trap crop for control of fruit worm infestation and damage to okra

相似文献   

Recombination Among Begomoviruses on Malvaceous Plants Leads to the Evolution of Okra Enation Leaf Curl Virus in Pakistan

Whitefly transmitted begomoviruses (family Geminiviridae) are the major reason for significant yield losses of dicotyledonous crops in tropics and subtropics. Okra (Abelmoschus esculentus) is one of the important vegetable crops, and leaf curl disease caused by geminiviruses is the most important limiting factor for its production in Pakistan. Here, we report a new species of okra‐infecting begomovirus in south‐eastern region of Pakistan and the name Okra enation leaf curl virus (OELCuV) complex is proposed. This okra enation leaf curl disease complex (OELCuD) in Pakistan is found to be associated with Ageratum conyzoides symptomless alphasatellite (AConSLA). All efforts to clone the betasatellite were unsuccessful. Comprehensive sequence analyses suggest that intermalvaceous recombination between okra and cotton‐infecting begomoviruses resulted in the evolution of the new species. Surprisingly, Bhendi yellow vein mosaic virus (BYVMV) which has not been reported previously from Pakistan is the major parent while Cotton leaf curl Multan virus (CLCuMV) acts as a distant parent of the virus. Comparative recombination analysis also reveals that okra‐infecting begomoviruses from south and north‐western India is causing OELCuD in the Pakistan by recombining with CLCuMV at the Rep (1964–1513 nts). Recombination is common among geminiviruses and recombining of BYVMV and CLCuMV resulted in a new species: OELCuV. To the best of our knowledge, this evolution of a new species of okra‐infecting begomovirus is the first report of intermalvaceous recombination where Rep acts as the target region.     

Parasitism of aphid embryos by Aphidius smithi: some effects of extremely small host size

Embryos of the pea aphid, Acyrthosiphon pisum (Harris), were successfully parasitized by Aphidius smithi Sharma & Subba Rao while still inside their mother. Parasites from embryos were much smaller, laid fewer eggs, but survived as long as their counterparts that had developed in adult viviparous aphids. Lifetime fecundity was positively correlated with wasp size, as measured by dry weight at the time of death. A. smithi females produced the same offspring sex ratio at eclosion on both host classes, although emergence was significantly lower from mummified adult aphids than from embryos. The data are discussed with regard to progeny and sex allocation decisions by solitary hymenopterous parasites. It is suggested that, in A. smithi, the decision to lay a fertilized or unfertilized egg is influenced by the host's overall size, rather than by the size and quality of a smaller target area inside the host, such as embryos.     

TAXONOMIC, FAUNISTIC AND MISCELLANEOUS

Al -Dabagh , M. A. 1964. The incidence of blood parasites in wild and domestic birds of Columbus, Ohio. Amadon , D. 1966. The super:pecies concept. Bergstrand , J. L. & Klimstra , W. D. 1964. Ectoparasites of the Bobwhite Quail in Southern Illinois. Bernis , F. 1963. La invernada y migración de nuestros Ansares. Brinck , P., Svedmyr , A. & Zeipel , G. von . 1965. Migrating birds at Ottenby, Sweden, as carriers of ticks and possible transmitters of tick-borne encephalitis virus. Carrick , R. & Ingham , S. E. 1967. Antarctic sea-birds as subjects for ecological research. Carriker , M. A. 1966. New species and records of Mallophaga (Insectnt) from Neotropical owls (Strigiformes). Davis , P. 1963. Recent developments at Fair Isle. Diamond , A. W., Douthwaite , R. J. & Indge , W. J. E. 1965. Notes on the birds of Berneray, Mingulay and Pabbay. Dott , H. E. M. 1967. Numbers of Great Skuas and other seabirds of Hermaness, Unst. Evans , P. R. & Flower , W. U. 1967. The birds of the Small Isles. Grierson , J. 1962. A check-list of the birds of Tentsmuir, Fife. Gysels , H. 1964. Bijdrage tot de Systematiek van de Vogels, aan de hand van de elektroforese in agar van de oplosbare lens- en spierproteinen. Harris , M. P. 1964. Ring loss and wear of rings on marked Manx Shearwaters. Hytönen , 0. 1965. Fruhjahrsbeobachtungen uber die Vogelwelt der siidlichen Toskana. Jackson , E. E. 1966. The birds of Foula. Johnsgard , P. A. 1967. Sympatry changes and hybridisation incidence in Mallards and Black Ducks. Johnson , N. K. 1966. Bill size and the question of competition in allopatric and sympatric populations of Dusky and Gray Flycatchers. MOEPCKE, M. 1965. Zur Kenntnis einiger Furnariiden (Aves) der Küste und des westlichen Andenabhanges Perus. Lanyon , W. E. 1966. Hybridization in Meadowlarks. Maynard Smith , J. 1966. Sympatric speciation. Mayr , E. 1965. What is a fauna? Mc Clure , H. E. 1966. An Asian bird-bander's manual. Medway , Lord . 1966. Field characters as a guide to the specific relations of Swiftlets. Novobytov , A. 1968. [Bird strikes on aircraft in the Soviet Union.] Yuni Tekhnik [The Young Technician] Packard , G. C. 1967. House Sparrows: Evolution of populations from the Great Plains and Colorado Rockies. Pearson , J. M. & Scott , P. 1965. “Save the Flamingo”: was it a good idea? Pennie , I. D. 1962. A century of bird-watching in Sutherland. Pennie , I. D. 1966. Ornithology in Scotland: a historical review. Penny , R. L. & Sladen , W. J. L. 1966. The use of Teflon for banding Penguins. Prigogine , A. 1967. La faune ornithologique de l'ile Idjwi. Sandeman , P. W. 1965. Attempted reintroduction of White-tailed Eagle to Scotland. Sessions , P. H. B. 1966. Notes on the birds of Lengetia Farm, Mau Narok. Short , L. L. 1965. Variation in West Indian Flickers (Aves, Cokzptes). Sick , H. 1963. Hybridisation in certain Brazilian Fringillidae (Sporophila and Oryzoborus). Siaden , W. J. L. & Friedmann , H. 1961. Antarctic Ornithology. Sladen , W. J. L. 1965. Ornithological research in Antarctica. Slater , R. L. 1967. Helminths of the robin, Turdus nzigratorius Ridgway, from Northern Colorado. Smith , V. W. 1966. Birds seen on a trans-Saharan overland crossing in spring 1966. Strange , I. J. 1965. Beauchene Island. Voous , K. H. 1967. Man and predators. Vos , A. De . 1964. Range changes of birds in the Great Lakes region. Waters , W. E. 1962. The birds of St. Kilda—winter 1961–62. Weins , J. A. 1966. On group selection and Wynne-Edwards' hypothesis.     

GENERAL BIOLOGY OF SPECIES

Balfour , E., Anderson , A. & Dunnet , G. M. 1967. Orkney Cormorants—their breeding distribution and dispersal. Bernis , F. 1966. El Buitre Negro Aegypius monachus en Iberia. Boase , H. 1965. Movements of the Mute Swan in East Scotland. Boylan , P. J. 1967. Western Atlantic Fulmars on the East Yorkshire coast. Bray , R. P. 1966. Progress report on the Pheasant Study, 1965. Brown , L. H. 1965. Redwinged starlings of Kenya. Brown , L. H. 1965. Observations on Verreaux's Eagle Owl Bubo lacteus (Temminck) in Kenya. Caldwell , L. D. 1964. Dove production and nest-site selection in southern Michigan. Campbell , B. 1965. The Crested Tit. Forestry Commission leaflet No. 41. Dowsett , R. J. 1967. Breeding biology of Lamprotornis mevesii (Wahlberg). Evans , P. R. 1966. Some results from the ringing of Rock Pipits on Skokholm, 1952–65. Harris , S. W., Morse , M. A. & Longley , W. H. 1963. Nesting and production of the Mourning Dove Zenaidura macroura in Minnesota. Hewson , R. 1967. The Rock Dove in Scotland in 1965. Hilden , O. 1965. Zur Brutbiologie des Temminckstrandlaüfers Calidris temininckii (Leisl.). Lind , E. A. 1964. Nistzeitliche Geselligkeit der Mehlschwalbe Delichon u. urbica Macdonald , D. 1965. Notes on the Corn Bunting in Sutherland. Macmillan , A. T. 1965. The Collared Dove in Scotland. Nelson , J. B. 1964. Some aspects of breeding biology and behaviour of the North Atlantic Gannet on the Bass Rock. Newton , I. 1964. The breeding biology of the Chaffinch. Nickell , W. P. 1965. Habitats, nesting, and territory of the Catbird. Nyholm , E. S. 1965. Ecological observations on the geese of Spitzbergen. Pinder , R. 1966. The Cape Pigeon Duption capensis Linnaeus at Signy Island, South Orkney Iskands. Richdale , L. E. 1965. Biology of the birds of Whero Island, New Zealand, with special reference to the Diving Petrel and the White-faced Storm Petrel. Rogers , J. P. & Korschgen , L. J. 1966. Foods of Lesser Scaups on breeding, migration and wintering areas. RYDER, J. P. 1967. The breeding biology of Ross' Goose in the Perry River region, Northwest Territories. Sandeman , G. L. 1963. Roseate and Sandwich Tern colonies in the Forth and neighbouring areas. Siegfried , W. R. 1967. The distribution and status of the Black Stork in southern Africa. Soikkeli , M. 1964. The distribution of the Southern Dunlin Calidris alpina schinzii in Finland. Speidel , G. 1966. Adelie Penguins in the Milwaukee County Zoo. Suetens , W. & Groenendael , P. Van . 1966. Ecología y conducta reproductora del Buitre Negro Aegypius monachus. Taylor , W. K. 1966. Additional records of Black-tailed Gnatcatchers Polioptila melanura parasitized by the dwarf-headed cowbird Molothrus ater Valverde , J. A. 1966. Sobre Buitres Negros en Andalucia. Waters , W. E. 1963. Observations on the Fulmar at St. Kilda. Waters . W. E. 1964. Observations on small petrels at St. Kilda. 1961–62. Scott.     

ECOLOGY AND POPULATIONS

Bagge , P., Lehtovouri , M. & Lindqvist , O. 1963. [Quantitative investigations of the bird fauna of Inari and Enontekiö in northern Lappland.] Bailey , R. S. 1967. An index of bird population changes on farmland. Brenner , F. J. 1966. The influence of drought on reproduction in a breeding population of Redwinged Blackbirds Agelaius phoeniceus. Davis , B. N. K. 1967. Bird feeding preferences among different crops in an area near Huntingdon. Dick , J. A. & Rising , J. D. 1965. A comparison of foods eaten by Eastern Kingbirds and Western Kingbirds in Kansas. Evans , F. C. 1964. The food of Vesper, Field, and Chipping Sparrows nesting in an abandoned field in Southeastern Michigan. Haapanen , A. 1965. Bird fauna of the Finnish forests in relation to forest succession. Hildén , O. 1964. Ecology of duck populations in the island group of Valassaaret, Gulf of Bothnia. Jenkins , D., Watson , A. & Miller , G. R. 1964. Current research on Red Grouse in Scotland. Kear , J. 1962. Feeding habits of the Grey Lag Goose Anser anser on the Island of Bute. Kear , J. 1965. Recent changes in Scottish barley acreages and the possible effect on wild geese. KEAR, J. 1967. Feeding habits of the Greylag Goose Anser unser in Iceland, with reference to its interaction with agriculture. Kikkawa , J. 1966. Population distribution of land birds in temperate rainforest of southern New Zealand. Kulczycki , A. 1966. [The birds of the Lańcut Park.] Murton , R. K. 1965. Natural and artificial population control in the Wood-Pigeon. Murton , R. K. c. 1966. A statistical evaluation of the effect of Wood-Pigeon shooting as evidenced by the recoveries of ringed birds. Nelson , J. B. 1966. Population dynamics of the Gannet (Sula bassana) at the Bass Rock, with comparative information for other Sulidae. Paynter , R. A. 1966. A new attempt to construct life tables for Kent Island Herring Gulls. Pulliainen , E. 1963. On the history, ecology, and ethology of the Mallards (Anas platyrhynchos L.) overwintering in Finland. Ratcliffe , D. A. 1967. The Peregrine situation in Great Britain 1965–66. Schemnitz , S. D. 1964. Comparative ecology of Bobwhite and Scaled Quail in the Oklahoma Panhandle. Skead , C. J. 1967. Ecology of birds if the Eastern Cape Province. Sladen , W. J. L., Wood , R. C. & Emison , W. B. 1966. Antarctic avian population studies, 1965–66. Snow , D. W. & Snow , B. K. 1961. Breeding seasons and annual cycles of Trinidad land-birds. Snow , D. W. 1966. Population dynamics of the Blackbird. Soikkeli , M. 1965. On the structure of the bird fauna of some coastal meadows in western Finland. Watson , A. 1965. Research on Scottish Ptarmigan. Watson , A. 1966. Hill birds of the Cairngorms. Westerskov , K. 1965. Winter ecology of the Partridge Perdix perdix in the Canadian Prairie. Williamson , K. 1964. Bird Census work in Woodland. Williamsonj , K. 1967. The bird community of farmland. Willson , M. F. 1966. Breeding ecology of the Yellow-headed Blackbird.     

Oviposition preference of cotton leafhopper in relation to leaf-vein morphology

Abstract:  The oviposition preference of the cotton leafhopper, Amrasca biguttula biguttula (Ishida) was investigated in relation to leaf-vein characteristics of 12 plant species, namely okra, cotton, castor, pigeonpea, cowpea, cluster bean, green gram, egg plant, sesame, country mallow, portia tree and shoe flower. Observations on the oviposition of the leafhopper under no-choice conditions were recorded on three occasions during the peak period of leafhopper incidence in the field. On all three occasions the leafhopper rejected green gram, shoe flower and portia tree for egg-laying, thereby indicating non-acceptance of these plants for oviposition. For the remaining plants, the number of eggs per leaf differed significantly. Okra received the maximum number of eggs. The lateral veins of castor, cotton, cowpea, egg plant and country mallow leaves received more eggs in comparison with the main vein and subveins whereas in okra the subveins received the highest number of eggs followed by lateral and main veins. The leaves of cluster bean, pigeonpea and sesame were devoid of subveins. In cluster bean and sesame the lateral veins received more eggs than the main vein but in pigeonpea the main vein received more eggs than the lateral veins. Correlations of trichome density and length with the number of eggs laid in different veins were non-significant. All types of veins in okra leaves were thicker than the rest of the test plants, which might have stimulated more egg laying in okra. The thickness of each category of vein, namely main vein ( r =0.60), lateral veins ( r =0.65) and subveins ( r =0.56) was found to be positively correlated with the number of eggs laid. The length of the main and lateral veins were also found to be positively and significantly related to the number of eggs laid. It can be concluded from the present investigations that leaf-vein thickness and length are crucial factors in influencing the oviposition behaviour of the cotton leafhopper.     

Prevalence of the major pests in transgenic and non-transgenic cotton genotype in response to climatic factors and their impact on yield

Abstract

The incidence of insect pests in cotton crop, such as Bemisia tabaci, Amrasca devastans and Pectinophora gossypiella (PBW) is dependent on climatic factors, such as maximum and minimum temperature, relative humidity and rainfall. Besides, cotton leaf curl disease (CLCuD) is also a major yield-limiting factor in the cotton crop. The results indicated that non-transgenic genotypes were heavily infested by whitefly, whereas jassid infested all genotypes with little difference. The population of whitefly and jassid acquired peak level in the month of July and August on all the genotypes. The correlation studies indicated the negative correlation of jassid, pink bollworm and CLCuD on yield component, whereas whitefly infestation was found positively correlated with CLCuD. Moreover, multivariate regression analysis (MRA) indicated the maximum and minimum temperature impacted the infestation of whitefly and jassid more than other factors, whereas maximum temperature greatly impacted the infestation of PBW in transgenic genotypes.     

Spider predators of lepidopteran eggs in south Texas field crops

Observations were made of spiders attacking lepidopteran eggs in south Texas field crops (cotton, corn, and soybean) from 2001 to 2004. Twelve species of spider from seven families were observed feeding on the eggs during the 4 years. These spiders were primarily cursorial hunting spiders, and they were observed feeding on eggs most frequently in cotton, representing 26.6% of all observations in cotton over the 4 years. Spider predation on eggs was proportionally less frequent in corn and soybean with 6.3% and 15.4% of observed predation in those crops, respectively. Four species of spider were responsible for 86.1% of the predation by spiders. The anyphaenid Hibana futilis (Banks) was the spider most frequently observed feeding on lepidopteran eggs during the 4 years of this study, constituting 45.1% of all spiders observed. Grammonota texana Banks (Linyphiidae), Hibana arunda Platnick (Anyphaenidae), and Cheiracanthium inclusum (Hentz) (Miturgidae) were the 2nd, 3rd, and 4th most frequently observed spiders constituting 15.6%, 12.8%, and 11.7% of all spiders observed, respectively. Most spiders represented taxa that are known to forage without a web. However, G. texana was observed feeding on eggs independent of a web, which is uncharacteristic of linyphiids. Other cursorial hunting spiders feeding on eggs included members of the Clubionidae, Corrinnidae, and Salticidae. Ninety-eight percent of all observations of egg predation by spiders were nocturnal; only the Salticidae were diurnal. It is likely that previous studies of predation in crops have vastly underestimated the importance of spiders as predators of lepidopteran eggs due to inadequate evaluation of nocturnal predation.     

Host-range Characterization of Two Pratylenchus coffeae Isolates from Brazil

Two isolates of Pratylenchus coffeae were collected from coffee roots (in Marília, São Paulo State, Brazil) and Aglaonema (in Rio de Janeiro City, Rio de Janeiro State, Brazil) and maintained in the laboratory on alfalfa callus. Twenty-four plants were tested in the greenhouse to characterize the host preference of these isolates. The host ranges of the isolates differed from each other and, interestingly, coffee, banana, and citrus were not among the better hosts of either isolate. Rather, sorghum, maize, rice, millet, okra, melon, eggplant, and lettuce were the best hosts of the Marília isolate. Poor hosts included French marigold, Rangpur lime, banana, sesame, peanut, sunflower, cotton, French bean, onion, and small onion. The best hosts of the Rio de Janeiro isolate were sesame, soybean, sorghum, castor oil plant, watermelon, squash, eggplant, and melon; the poorest hosts were French marigold, coffee, Rangpur lime, banana, sunflower, peanut, maize, millet, French bean, cotton, onion, sweet pepper, lettuce, okra, and small onion. These isolates have important molecular and morphological differences, suggesting host preference is linked to these characteristics.     

Foraging behaviour of the parasitoid Lysiphlebus testaceipes (Hymenoptera: Braconidae) in response to plant volatiles,with reference to biocontrol of aphids in peri-urban vegetable production systems

Foraging behaviour of Lysiphlebus testaceipes was studied in a Y-tube olfactometer. Naïve females responded to the Aphis gossypii/eggplant complex on which they had been reared, but did not show a preference for this aphid/plant complex over an uninfested eggplant, an eggplant that had been damaged by the aphid or an A. gossypii/okra complex. Females that had been allowed to forage on the A. gossypii/eggplant complex before being tested in the olfactometer showed a strong preference for an uninfested eggplant over an uninfested okra plant and for the A. gossypii/eggplant complex over an A. gossypii/okra complex, indicating that they had learned to associate eggplant-derived volatiles with host availability. When females that had been reared on the A. gossypii/eggplant complex were tested after foraging experience on the A. gossypii/okra complex, they did not show a preference for either complex, suggesting that they still retained a memory of the cues associated with the complex on which they had been reared. The efficiency of L. testaceipes as a biological control agent in peri-urban vegetable production, such as the Cuban organoponics system, potentially could be improved by producing and releasing females behaviourally primed to prefer specific host/plant complexes.