Showing papers on "Infestation published in 1974"

A case of hookworm infestation in a precolumbian American

Abstract: A case of hookworm infestation in a Tiahuanaco mummy dating from around 900 A.D. is presented. The worms found in the small intestine were identified as Ancylostoma duodenale. This is the first recorded case of hookworm infestation in the Americas prior to the coming of Europeans.

Metabolic changes in the rice plant during infestation by the brown planthopper, Nilaparvata lugens stal (Hemiptera: Delphacidae)

Abstract: The brown planthopper IViloparuata tugens is a serious pest in Asia. It darnages the rice plant by sucking the plant sap and by transmitting the grassy stunt virus disease. Apparently the heavy tlllering and shortstatured rice varieties grown with high rates of nitrogen fertilizer favor the population build-up of this species. Censequently its relative importance has increased during the past few years. In a greenhouse experiment at the International Rice Research Institute (IRRI), IR9-60 rice plants infested at 25 and at 50 days after transplanting with 400 newly hatched brown planthopper nymphs wilted and completely dried up in 3 and in 15 days, respectively(PATHAK, 1969). Such damage te the plants is termed \"hopperburn\". Lower insect populations caused reduced tillering, reduced crop vigor, fewer panicles, and higher percentage of unfiIIed grains (BALE and PATHAK, 1970). Basic infbrmation as te how the brown planthopper causes the browning and wilting of the rice plant, the typical characteristics of hopperburn, is still speculative, However, SoGAwA (I971) fbund a progressive decrcase in total protein and an increase in free amino acids, particularly arginine, asparagine, and glutamine in leaf blacles from feeding rice plants to the brown planthopper, Some possible causes ofhopperburn produced by ether species of sucking insects on their host plants have been reported, however. Studies in potato, for instance, showed that mechanical plugging of the xylem and phloem vessels of the host plants by tissues pushed into these vessels during the exploratory feeding of the potato leafhopper, Empeasca fabae, restricted the movement of sugars and starches in the leaves and in the meristematic tissue (DE LoNG,

Ligula infestation of bleak Alburnus alburnus (L.) in the tidal Thames

Abstract: Heavy infestations of the cestode Ligula are reported in bleak Alburnus alburnus (L.) from the tidal Thames. This parasite has not apparently been recorded previously from this host in the British Isles. The life cycle of the parasite is briefly summarized. Data on this infestation suggest an increase in the incidence of infestation up to a maximum in young bleak, followed by a decrease in older fish. There also appears to be a decrease from summer to autumn. The positive relationship between the weight of the parasite and the length of the host is discussed. Observations are made on the effect of Ligula on its host; it is suggested that many of the young bleak die during the autumn and winter, following their infestation.

Vegetation Response Following Spraying a Light Infestation of Honey Mesquite

Abstract: improved vigor of Nuttall saltbush and the introduction of crested wheatgrass. Additional waterholding capacity by furrows was the primary stimulus for improved production. By 1972, when the most recent data were obtained the furrows had been sufficiently filled to reduce the waterholding capacity by 25-300/o their original capabity. Nevertheless, forage production of crested wheatgrass was still over 300 lb/acre. Although Nuttall saltbush production was lowest on the contour-furrowed and seeded site, total herbage production was still maintained at a level significantly greater than on the nontreated native rangeland. The rate at which the furrows continue to fill is expected to decrease in the future. There is a high probability that production on the treated site will remain higher for at least another 20 years.

The population dynamics and host utilization of Geomydoecus oregonus, a parasite of Thomomys bottae.

Abstract: Summary. This study treats the population dynamics and host utilization of Geomydoecus oregonus Price and Emerson, a mallophagan parasite of the pocket gopher, Thomomys bottae (Eydous and Gervais). Over 135000 lice were collected from 393 gophers over a period of 20 months. Average infestation on all gophers was 357 lice. Bimonthly mean densities showed an increase in June-July of both years, and these data were statistically different from the rest. Population age structure remained relatively constant in time with 9.3% females, 7.2% males, 47.4% nymphs and 36.1% eggs. Sex-age class separation of the gophers showed juveniles of both sexes to average 86 lice; subadult males averaged 210 lice; adult males averaged 544 lice; subadult and adult females averaged 255 and 296 lice, respectively. Lice were not randomly distributed on the gopher, but were most numerous on the head and anterior dorsal body. Lice eggs were restricted to hairs around the ears and eyes of the host. Over 80% of the animals sampled had eggs restricted to that region. Embryonic development and eelosion of G. oregonus proceeded over a wide range of environmental parameters. Over 80% of the ova tested survived and hatched in conditions between 33 ~ and 37~ and 22 % and 84 % relative humidity. The greatest survival was 98% at 35~ 75% R. H. and in a 3% COs atmosphere. The generation time of G. oregonus was 40 days. Duration of embryogenesis and nymphal stadia approximated 10 days for each. Adult lice lived 30-t- days on gophers. Age frequency mortalities were calculated as 0.02 for eggs, 0.18, 0.24, and 0.06 for nymphal instars and 0.50 for adult lice. This indicates a Type II survivorship curve. There was a direct linear relationship between the number of female lice on a gopher and the number of lice eggs. The average number of eggs per female was four. Using the pivotal frequency for reproduetives, it was possible to calculate R o for the louse at 1.272. Thus, r was equal to 0.24 per generation or 0.006 per day, and the population doubles in 2.8 generations. Speculations regarding population regulation are also included.

Field assessment of several insecticides against the potato tuber moth (Phthorimaea operculella Zell. Lepidoptera, Gelechiidae) at Pukekohe

Abstract: Field trials at Pukekohe of insecticides against potato tuber moth (Phthorimaea operculella Zell.) showed that little direct control of tuber infestation was achieved. Foliage infestation, however, was effectively controlled; and this indirectly effected a reduction in tuber infestation, as long as nearby areas were also clean. Although both recommended insecticides, azinphos ethyl and endosulfan, were effective against foliage mining under low to moderate population pressure, only azinphos ethyl was consistently effective under high to extreme pressure. Four additional candidate insecticides (ENT 27041, acephate. methamidophos, and chlorpyrifos) were compared with azinphos ethyl, but none proved as good, although acephate showed some promise. The standard aphicide oxydemeton methyl was found to have a small but significant effect on the foliage-mining population. It was found that 4.8% of infested tubers escaped detection at harvest grading because young mines and eggs are not easily seen. As a ...

Collapse of the Elm Spanworm Outbreak in Connecticut: Role of Ooencyrtus sp.

Abstract: The collapse of the elm spanworm outbreak in Connecticut was caused primarily by an Ooencyrtus sp. previously determined as O. clisiocampae (Ashmead), but now thought to be an undescribed species. This parasitoid decimated the egg population in southwestern Connecticut in 1971 and in central and eastern Connecticut in 1972. In 1972 weekly collections of elm spanworm eggs from the infested area showed an increase in the amount of parasitism as summer progressed. At the western edge of the infestation, virtually all eggs were parasitized by July 25. Near the center of the infestation almost all eggs were parasitized by Sept. 5 and at the eastern edge of the infestation by Sept. 19. We attribute this eastward increase in part to the movevement of adult parasitoids into areas where they had previously been absent or rare. Superparasitism of elm spanworm eggs was common in dense populations of the parasitoid. At sites where parasitism was high and superparasitism prevalent, many host eggs were dead and were supporting growth of fungi.

A Review of Changes in the Pattern of Infestation in International Trade

Abstract: Changes in the degree and kind of infestation by storage insects and mites in imports into Great Britain since the EPPO Conference in Lisbon, 1967, are reviewed. There has been an overall fall in the percentage of infested cargoes from 33 % in 1967 to 23 % in 1973, and a corresponding fall in the incidence of occurrence of many species. The various changes in different classes of commodities, cereals, oilseeds, cocoa beans, etc., according to country of origin, are discussed in detail. The effects of containerisation and greater use of road transport, the growing problem of insecticide resistance in storage insects and mites and the significance of infestation in imports are discussed in relation to future developments in international trade.

Effects of Metopolophium dirhodum on Spring Wheat in the Glasshouse

Abstract: SUMMARY Pot-grown plants of spring wheat, cultivar Maris Dove, Were subjected, commencing at ear emergence, to different, constant levelsof infestation hy Metopolophium dirhodum (Wlk.) in a glasshouse. Infestation with six aphids per stem over 11 days had no significant effect on yield. Infestations with either six or 50 adult aphids or their equivalents, when maintained until ripening, resulted in lower yields of both grain and straw dry matter. Loss of grain was due to reduction in both 1,000 grain weight and the average number of grains per fiertile spikelet. Harvested dry matter content of leaf blades was unaffected by infestation, but the dry matter, content of stems was reduced in infested plants. In breeding aphid-resistant cereals for Britain, resistance characters restricting aphid multiplication are most likely to reduce yield losses due to aphid attack.

Relations between two rice borers in Surinam, Rupela albinella (Cr.) and Diatraea saccharalis (F.), and their hymenopterous larval parasites

Abstract: In many tropical countries, lepidopterous stem borers are major pests of the rice crop. Study of the rice borers in Surinam, Rupela albinella and Diatraea saccharalis, was made in the Paramaribo area, at the experimental station 'CELOS' during 1971, 1972 and 1973, since data on the ecology and economic importance of these borers were incomplete and almost lacking for the small holders rice areas. Special attention was paid to the role of the parasites of these borers. I. R. albinella This 'white rice borer' deposits its scale-covered egg masses on the leaves. Newly hatched larvae disperse in a very active way both on plants and on the water surface and they may also use the flow of water. They bore into the stem cavity within 24 hours after hatching. Development to maturity takes place inside one internode. There are five larval instars and only the last two can not be separated by head capsule width. The full-grown larva cuts an exit opening in the stem wall for escape of the adult. The duration of the different developmental stages was determined. Normally the percentage of larvae which entered diapause proved to be very low. It was not clear which factor was reponsible for diapause induction. A correlation with a slightly higher temperature (about 2°C) was detected but the data are still too limited to accept the temperature as a basic factor. Moths are active during darkness and are attracted by ordinary incandescent light, but are seldom captured during the period of full moon. Since Rupela requires an adequate stem cavity for its development, rice plants become vulnerable to attack only 60 days after sowing when a proper internodal space may be present. Rice varieties having a total growth period of only 105 days automatically possess an 'escape resistance', because the larval and pupal development takes about 50 days. Generally R. albinella is well adapted to the rice plant. Crop losses are very small since the stem tissue is only attacked superficially. Four parasites of R. albinella were found, viz.: 1. Telenomus sp., an egg parasite with a short life cycle. This insect was not further studied. 2. Venturia ovivenans, an egg-larval parasite with a high reproduction capacity, parasitizes the eggs. The growth of the parasite larva is moderate until the host is full-grown. Rapid growth follows and the larva leaves its host and pupates inside the stem. Development of host and parasite are well sychronized, both in nondiapause and diapause situations. The average time of emergence of the wasp is two days earlier than of the moth. The species is very common throughout Surinam. 3. Strabotes rupelae, a larval and pupal parasite, deposits its eggs near the fullgrown host larva or pupa. The wasp even crawls into the water in search for hosts. The ectoparasitic larva grows very rapidly and sucks out its host. The duration of the life cycle is one third that of the host. The adult life span may be as long as two months. The parasite was quite common at the 'CELOS' research centre with its continuous rice cultivation program. 4. Heterospilus sp., a gregarious and ectoparasitic wasp, lays its eggs in the stem cavity near a full-grown host larva. Larval growth is very rapid and the total life cycle is one third of that of its host. The parasite was common at the 'CELOS' research centre. The interactions between R. albinella and its parasites are schematically given in Figure 15. The greatest mortality occurs in the L 1 during dispersal and penetration of the host plant. Later on, the effect of parasites as well as pupal mortality are important. The succession of the generations of the borer and its parasites under the 'CELOS' continuous rice cultivation system is given in Figure 18. Over a period of slightly more than two years, borer infestation slowly increased whereas parasitization of the borer slowly decreased. The percentage composition of the parasitic complex remained stable in these two years. II. D. saccharalis An existing aseptical diet for the 'brown borer' was improved and made it possible to rear large numbers of borers. The following good rearing results were obtained: total developmental time (35-38 days), pupal weights (males 75 mg, females 125 mg) and egg production (400 eggs/female). A clear correlation was found between pupal weight and egg production. It was not possible to accurately separate the 6 larval instars by means of head capsule width. The behaviour of the larvae was followed. Moths emerged before midnight and sometimes copulated the same night. A male copulates once a night and at most, three successive nights. Copulation always occurs late in the night. The first eggs are laid the night after mating. Larval and pupal mortality was very high under field circumstances. Agathis stigmaterus was the only important parasite. It was reared in large quantities in host larvae feeding on the diet mentioned above. The wasp deposits its eggs in 6-14 day-old hosts. An average of 100 hosts were parasitized per wasp. The parasite first grows slowly; it then leaves the nearly full-grown host and sucks it out within a few hours. There is a good synchronization between the host and the parasite. Only 2 % of the wasps were males. Ant nests were present in about 15 % of the rice hills. These ants, Paratrechina sp., feed on the young borer larvae. Although D.saccharalis incidentally may cause some local losses, the overall damage is negligible.

On some features of the infestation of the mouth-breeding fish Tilapia melanotheron Rüppel, 1852 by the parasitic copepod Paeonodes lagunaris van Banning, 1974

Abstract: The paper reports on a habitat study of the Sakumo-Lagoon, Ghana, West-Africa, in which a new parasitic copepod species, Paeonodes lacunaris van Banning, 1974, was found in the buccal cavity of the host Tilapia melanotheron Ruppel, 1852 Data are given of the infestation rate and intensity of P lagunaris, together with their relationship with the salinity of the area and the age of the host

Sampling Pecan Weevil Nut Infestations: Effects of Tree, Height and Sector

Abstract: Studies were conducted in 1967 and 1972 to determine the effects of tree, height, and sector on Curculio caryae (Horn) infestations of pecan nuts. In the 1967 study, nuts were collected from 3 height levels on “Stuart” and native pecan trees and checked for pecan weevil damage. No significant variation in infestation occurred among the height levels on the trees. There was significant difference (P < 0.01) in the degree of infestation among individual trees. In 1972, nuts were examined for weevils from 3 height levels and 4 sectors on trees of the “Nugget” variety. Again, variation in infestation was apparent among trees; however, no significant differences in infestation occurred among height levels or sectors.

Infestation of stored food in temperate countries with special reference to Great Britain

Abstract: The author discusses the various insects and mites attacking stored grain, flour and malt in Great Britain, and the damage they cause, together with the principal pests of food and feeding-stuffs in stores, processing factories and domestic premises. Methods of prevention and control are outlined, including the use of contact and fumigant chemicals, and non-chemical techniques such as cooling and hermetic storage; these must be coupled with effective inspection of imports.

Trichogramma semblidis [Chalcidoidea: Trichogrammatidae] as a parasite of the bark beetle eggs [Coleoptera: Scolytidae]

Abstract: It has been found thatTrichogramma semblidis (Aurv) parasitizes the eggs ofleperisinus fraxini (Panz),L orni (Fuchs) andHylesinus crenatus (Fabr) in typical variant ofCircaeo-Alnetum Oberdorfer 1953 in the Laski Experimental Forestry near Kepno Thorough studies were conducted on exposed European ash logs and split wood in 3 methodical variants The analysis of the galleries ofLeperisinus fraxini has showed that the average egg infestation amounted to 141%, 130% and 111% respectively The egg infestation of individual gallery systems in the exposed control logs and split wood ranged between 27–512%, 12–441% and 17–692%, respectively, in different variants and the average effectiveness of the parasite amounted to 127% of the host egg mortality in 1970 Earlier observations and analyses of the gallery systems made on the ash trunks and branches in 1967 and 1968 showed 800% and 980% infestation of the eggs ofL fraxini and 100% and 15% infestation of the eggs ofL orni Separate developmental stages of the parasite, the behaviour of the latter and penetration of the gallery systems were observed too The most important data on the host species ofT semblidis have been compared

Effect of citrus brown mite,Eutetranychus orientalis (Acarina: Tetranychidae), infestation on the N, P, K and pigments of sour orange leaves

Abstract: Es wurde der Einfluss einer Infestation mitEutetranychus orientalis (Klein) auf die chemische Zusammensetzung von Sauerapfelsinen-Blattern untersucht, wobei eine negative Korrelation zwischen Spinnmilbenzahl und den Konzentrationen von N, P, K und Chlorophyll gefunden wurde.

A study of the ectoparasites of alcids in Newfoundland

Abstract: Three groups of ectoparasites, namely, Mallophaga, ticks and feathermites, were recovered from two hundred and sixty-seven alcids of six specie's (Alca torda, Uria aalge, Uria lomvia, Plautus alle, Cepphus grylle, Fratercula arctica) examined. Mallophaga of the genera Saemundssonia, Quadraceps (Ischnocera) and Austromenopon (Amblycera) were recovered from five alcids; only Saemundssonia and Quadraceps from C. grylle. One species of ixodid tick, Ixodes (Ceratitodes) uriae, was recovered from all but P. alle and C. grylle, the majority of which were examined in the winter. Only A. torda and F. arctica harboured feathermites belonging to the genus Alloptes. Four new geographical records and one new host record are reported. -- No significant difference (P > 0.05) was found in the mallophagan infestation of hosts and in the tick infestation of U. aalge from year to year. The tick infestation of F. arctica differed in 1972 and 1973, probably due to few immature Larus argentatus being present in the colony during the latter year. No significant difference was noted for the mallophagan and tick infestation of hosts with regard to sex of the hosts. A correlation was noted only between the weight and mallophagan infestation of U. lomvia. -- Data on the degree of infestation of both adults and chicks with each parasite species are presented. The infestation of adult hosts was related to the host habitat. Chicks were always more heavily infested with Mallophaga than adults. Fluctuations, related to tho host biology, occurred in the mallophagan population on F. arctica. Details on the transfer of Mallophaga from adults-to-chicks are given. -- The distribution of each parasite species on the hosts was determined; the same mallophagan genus generally occupying the same habitat on the different host species. The tick distribution on hosts varied with the host species. -- The population dynamics of each mallophagan species on each alcid was examined. Due to increased reproductive activity, nymphs were more common on adults during the winter and were always dominant on chicks. The sex ratio of each species varied with the host, females being generally more common in winter and on chicks. Correlations were determined for the stages and sexes of each species population on hosts. -- An ischnoceran and an amblyceran occupied virtually the same habitat on the hosts with correlations always existing between them. No interspecific competition existed between the genera on each host. All stages and sexes of the total mallophagan population on hosts were correlated. -- Ixodes ariae preferred U. aalge as hosts. Their distribution in the colony was affected by the density of the hosts and the substrate. The seasonal activity of the tick in the hesting areas and on the hosts were similar. The engorgement time for each stage on various hosts was determined and their percentage increases in weight recorded. The pathological reaction bf the host's skin to tick attachment is described. Observations were made on reproduction and measurements made of a spermatophore. The oviposition rate and the development of each stage under different temperatures and humidity regimes was determined. The life-cycle, based on field and laboratory data, is presented.

Susceptibilities of Carrot Cultivars to Carrot Fly (Psila rosae (F.)

Abstract: SUMMARY In 1972 a trial on susceptibility to carrot fly infestation was conducted on peat soil in East Anglia using 17 carrot cultivars sown on two dates one month apart. The only insecticide applied to the carrots was an aphicidal spray. The early-sown carrots were damaged by the first generation of larvae, but, by the second sampling date in October, there were no infestation differences between the two sowings. At harvest in December, significant differences in infestation levels occurred; these ranged from 82 per cent damaged roots for Amster-dammer Bak, 87 and 88 for two stocks of Royal Chantenay, to 97 per cent for Danvers 126. It is not yet clear whether the differences can be profitably exploited as an adjunct to other methods for controlling this pest.