Showing papers on "Infestation published in 1992"
TL;DR: The objective of this research was to define the relationship between endophyte infestation level of tall fescue seed lots and a seedling disease caused by Rhizoctonia zeae and to determine percentage of loss for Forager (a low-endophyte cultivar).
Abstract: The objective of this research was to define the relationship between endophyte (Acremonium coenophialum) infestation level of tall fescue (Festuca arundinacea) seed lots and a seedling disease caused by Rhizoctonia zeae. Seeds were planted in soilless medium or medium amended with R. zeae cultures, and number of seedlings per three 5.0-cm cores was determined. In a preliminary experiment, percentage of loss (61%) was greater for Forager (a low-endophyte cultivar) than for a Kentucky 31 seed lot with an 85% endophyte infestation level (32%) (.)
163 citations
TL;DR: A series of experiments involving artificial infestation of coffee trees with coffee berry borer in Chiapas, Mexico found that two peaks of egg production occurred at about 10 and 50 days post-infestation, with the second peak probably the work of one or more daughters of the founding female.
Abstract: 1. A series of experiments involving artificial infestation of coffee trees with coffee berry borer were carried out in Chiapas, Mexico. Attacked berries were marked to identify time of infestation. 2. Berry samples were taken every 3-4 days for periods of up to 91 days and number of developmental stages present recorded. Two peaks of egg production occurred at about 10 and 50 days post-infestation. The second peak is probably the work of one or more daughters of the founding female. 3. Berries removed and placed on the ground 4 days after infestation, developed significantly (P<0.0001) larger numbers of eggs than berries remaining on the tree
86 citations
TL;DR: The cessation of growth of wheat during infestation by the Russian wheat aphid and ability of the host to recover rapidly when the aphid was removed indicate that the duration of infestation, rather than the level of infesting, may be more important to the host.
Abstract: The effect of feeding by the Russian wheat aphid, Diuraphis noxia (Mordvilko), on growth of seedling ‘TAM W-lOl’ winter wheat ( Triticum aestivum L.) was investigated. A primary response of the wheat plant to aphid feeding involves water imbalances expressed as a loss of turgor and reduced growth. Russian wheat aphids caused substantial reductions in biomass of all plant components measured. When aphids were removed, absolute growth rates quickly recovered as relative growth rates increased. Compared with undamaged controls, recovering plants were more efficient in terms of carbon assimilation, which resulted in higher relative growth rates and compensated for lowered leaf area ratios. Reduction in leaf area ratios results from decreases in specific leaf areas (i.e., a combination of leaf stunting and the inhibition of new-leaf unfolding). As plants recovered, stem weight ratios were substantially reduced, indicating that carbon partitioning to the stem was decreased to compensate for leaf and root growth. The cessation of growth of wheat during infestation by the Russian wheat aphid and ability of the host to recover rapidly when the aphid was removed indicate that the duration of infestation, rather than the level of infestation, may be more important to the host.
79 citations
TL;DR: Infestation intensity and tissue damage together with field observations strongly indicate that infestation by C. cerastodermae I was responsible for the mass mortality of C. edule during the summer of 1991.
Abstract: The trematode Cercaria cerastadermae I, a parasite of the cockle Cerastaderma edule, is recorded for the first time in Scandinavian waters. More than 20% of the investigated population of C. edule was infested by C. cerastodermae I, and most individuals showed severe tissue damage. Infestation intensity and tissue damage together with field observations strongly indicate that infestation by C. cerastodermae I was responsible for the mass mortality of C. edule during the summer of 1991. Patterns of infestation intensity, damage to the bivalve foot and an experiment on burrowing behaviour suggest that infestation by C. cerastadermae I impairs burrowing ability. The resulting large numbers of C. edule lying on the sediment surface may be misinterpreted as being caused by other factors e.g. oxygen deficiency.
64 citations
TL;DR: The purpose of the present study was to determine the host status of rock elephant shrews and Namaqua rock mice for these ticks and to investigate the seasonal abundances of the ticks and the effects of landscape topography and sex of the host on infestation levels.
Abstract: Several tick species of medical and veterinary importance occur in the southern Orange Free State. The purpose of the present study was to determine the host status of rock elephant shrews ( Elephantulus myurus) and Namaqua rock mice ( Aethomys namaquensis) for these ticks. Infestation levels were used as a criterion. The seasonal abundances of the ticks as well as the effects of landscape topography and sex of the host on infestation levels were also investigated. Incidental observations were made on the pouched mouse (Saccostomys campestris). No adult ticks were recovered from any of these small mammals. Seven tick species were found on the elephant shrews of which only Ixodes rubicundus and Rhipicephalus punctatus occurred in high numbers on a large proportion of the animals. Both these ticks cause paralysis in domestic stock. The Namaqua rock mice harboured eight tick species. Only Haemaphysalis leachi/spinulosa and R. punctatus had a relative abundance exceeding 15%. Three of the 10 pouched mice exam...
59 citations
TL;DR: The intensity and timing of infestation events of caligid copepods in wild or cultured fish populations may be predicted from previous local production of nauplius I of the parasite, but this relationship is not well established and the role of host reactions to the invading copepodid is unknown.
Abstract: Summary The intensity and timing of infestation events of caligid copepods in wild or cultured fish populations may be predicted from previous local production of nauplius I of the parasite. However, this relationship is not well established, the spatial scales over which it operates are unclear, and the role of host reactions to the invading copepodid is unknown. Rate of development (and population structure), generation time and rate and actual reproductive output are temperature-dependent. In Ireland between five and seven generations of Lepeophtheirus salmonis (Kroyer) can develop annually and generation time varies from over 120 days in winter to 23 days in summer. Host reactions may affect the rate of development of the parasite but are less important than temperature. Host reactions may also cause parasite mortality, but this effect is specific for individual host parasite associations. The distribution of L. salmonis in cultured host populations is typically normal but is very over-dispersed in wi...
46 citations
TL;DR: Results support the hypothesis that hypersensitivity is the phenotypic basis of resistance in the Hessian fly-wheat interaction and involves “recognition” of an avirulence gene product or process.
Abstract: Cytological analysis of wheat infested by the Hessian fly, Mayetiola destructor (Say), indicated that on susceptible plants, virulent larvae (biotype L, virulent to resistance genes H3,5,6,7/8) caused a generalized increase in cuticular-membrane permeability of cells in the lower leaf sheath. On resistant plants, feeding by avirulent larvae (biotype GP, no genes for virulence) resulted in localized responses. This suggests that plant responses limited the ability of avirulent larvae to elicit generalized changes in cell permeability. Analyses of plant protein patterns by polyacrylamide gel electrophoresis and immunoblots indicated that separate changes in protein metabolism occurred in susceptible versus resistant wheat in association with Hessian fly infestation. In susceptible wheat, ribulose-l,5-bisphosphate carboxylase (Rubisco) increased in the lower leaf sheath in association with infestation. In resistant wheat (cv. Caldwell, H6 gene for resistance), proteins of low molecular weight appeared in the lower leaf sheath in association with infestation by avirulent larvae. Protein changes associated with infestation were not elicited by physical wounding of plants. Protein changes detected in resistant wheat infested by avirulent larvae (biotype GP) did not appear when the plants were infested with virulent larvae (biotype L). Results support the hypothesis that hypersensitivity is the phenotypic basis of resistance in the Hessian fly-wheat interaction and involves “recognition” of an avirulence gene product or process.
43 citations
TL;DR: Ectoparasite pressure on the host population changed seasonally and was greatest when host density was the highest, suggesting both that host PC was not affected by ectoparsite burden and that exsanguination leading to anaemia was the main effect of the ectopar asites.
Abstract: To assess ectoparasite impact on individuals and populations of Gerbillus andersoni allenbyi under natural conditions, I addressed the following questions. Do ectoparasites affect their host fitness and, if so, how? Do ectoparasites affect host population level? Does this parasite–host interaction support the traditional concept of parasite evolution towards avirulence? For this purpose, host infestation, infection, survival, haematological indices, and physical condition were recorded. A field experiment which included manipulating host infestation while recording host survival was conducted to determine the causal relations between these variables. G. a. allenbyi was infested by 2 fleas (Synosternus cleopatrae and Stenoponia tripectinata), 5 mesostigmatid mites (Androlaelaps centrocarpus, A. hirsti, A. insculptus, A. marshalli and Hirstionyssus carticulatus), 1 tick (Rhipicephalus sanguineus), and 1 louse (Polyplax gerbilli). Ectoparasite burden significantly reduced host survival and red blood cell indices (red cell concentration, haemoglobin concentration and haematocrit). Ectoparasite burden did not significantly affect white blood cell concentration. Gerbils were not infected by haemoparasites or gut helminths which potentially could cause anaemia. The causal relationship between S. cleopatrae burden and host survival was established by manipulation of host infestation. Both ectoparasite removal and initial level of infestation significantly affected host survival. Ectoparasites that caused anaemia were not associated with host physical condition (PC), measured as weight/length3. None of the red blood cell indices was correlated with host PC. These results suggest both that host PC was not affected by ectoparasite burden and that exsanguination leading to anaemia was the main effect of the ectoparasites. Ectoparasite pressure on the host population (based on the ectoparasite effects as estimated by statistical models, combined with dispersion of the infestation within the host population) changed seasonally and was greatest when host density was the highest. A large segment of the gerbil population was affected by ectoparasites during the entire year. An explanation for the evolution of parasite virulence, contrasting parasites that evolve towards increased virulence with parasites that evolve towards avirulence is presented. This classification is primarily based on whether parasite impact is equated with a higher efficiency of host exploitation, or whether it is a ‘side effect’ of parasite biology.
39 citations
TL;DR: A marked increase in the γ-fraction of scrum proteins, reduced lymphocyte numbers and increased granulocyte numbers are indicative of a humoral and cellular immune response in a European eel population naturally infested by the sanguivorous nematode Anguillicola crassus.
Abstract: . Haematological variations were studied in a European eel population, Anguilla anguilla L., naturally infested by the sanguivorous nematode Anguillicola crassus. This occurred off the Swedish Baltic coast in an area receiving heated cooling water from a nuclear power station. The erythrocyte count, haematocrit, leucocrit, haemoglobin concentration, mean corpuscular volume, mean corpuscular haemoglobin and mean corpuscular haemoglobin concentrations, the various cell types in peripheral blood, serum iron concentration, the amount of total serum protein, and scrum protein fractions α1, β1, α2, β2 and γ were all measured. Each variable was correlated to: (1) the intensity of infestation, i.e. number of parasites per host; and (2) a parasitization index, i.e. the weight of parasites per somatic weight of the host. Most variables showed no or only minor reactions to the infestation. However, a marked increase in the γ-fraction of scrum proteins, reduced lymphocyte numbers and increased granulocyte numbers are indicative of a humoral and cellular immune response.
38 citations
TL;DR: Records of domestic animals brought to the Veterinary Entomology Laboratory for diagnosis of suspected lice and mite infestation over a 10 year period were analysed and from a total of 794 suspected cases, 137 (17·3%) and 247 (31·1%) were positive for lICE and mange mites respectively.
Abstract: Records of domestic animals brought to the Veterinary Entomology Laboratory for diagnosis of suspected lice and mite infestation over a 10 year period were analysed. From a total of 794 suspected cases, 137 (17·3%) and 247 (31·1%) were positive for lice and mange mites respectively. The most common lice species recorded wereLinognathus vituli (66·7%) on cattle,L. ovillus (83·3%) on sheep,Haematopinus suis (100%) on pigs andMenacanthus stramineus (54·5%) on poultry. Other lice species recorded includedHaematopinus bovis andSolenopotes capillatus on cattle,Damalinia ovis on sheep,Linognathus stenopsis andMenacanthus stramineus on goats,Goniocotes sp. on a horse,Linognathus setosus andMenacanthus stramineus on dogs,Goniodes gigas, Lipeurus caponis, Menopon gallinae andChelopistes meleagrides on poultry.
32 citations
TL;DR: Compared with menthol, vegetable oil gave equivalent mite control on all sampling dates, and infestation was lowest in the oil + menthol treatment from 3 April through 9 May.
Abstract: The efficacy of vegetable oil and menthol was tested in controlling tracheal mites ( Acarapis woodi [Rennie)) in honey bees ( Apis mellifera L.). Each of 40 bee colonies was given one of four treatments: (1) vegetable oil, (2) menthol, (3) vegetable oil and menthol, or (4) no treatment (control). Colonies were sampled for percentage bees infested and severity of infestation per infested bee on nine dates from 14 February to 7 August 1991. Treatments were applied on 27 February and removed on 18 April. On 3 April, mite infestation was reduced in the oil + menthol treatment. On every sampling date after 3 April, infestation was reduced by all oil or menthol treatments. Compared with menthol, vegetable oil gave equivalent mite control on all sampling dates. From 3 April through 9 May, infestation was lowest in the oil + menthol treatment. Except for one sampling date, severity of infestation per infested bee was unaffected by treatments.
Journal Article•
TL;DR: There were substantial losses in thiamine, riboflavin and niacin contents of wheat, maize and sorghum grains at three infestation levels (25, 50 and 75%) caused by releasing two insect species viz., Trigoderma granarium and Rhizopertha dominica separately and mixed population.
TL;DR: A system was designed for projecting the growth of uneven-aged stands of interior Douglas fir of the Kamloops Region of British Columbia after defoliation by the western spruce budworm, and losses resulting from infestations lasting 1–9 years are reported.
TL;DR: Population dynamics of Phytophthora capsici were monitored in artificially infested plots in fields planted with bell peppers and pathogen population densities increased and then decreased over time in each field.
Abstract: Population dynamics of Phytophthora capsici were monitored in artificially infested plots in fields planted with bell peppers (Capsicum annuum). Plots were drip-irrigated on either a more frequent (three times per week) or a less frequent (one or two times after infestation) schedule and were infested with one of three levels of inoculum or left uninfested. Pathogen population densities increased and then decreased over time in each field. In a field with moderate rainfall, plots had population densities of 0, 5, 18, and 41 cfu/g of dry soil at the time of infestation (.)
TL;DR: The guinea pig, Cavia porcellus, is the only species to show antibodies or to express and maintain an acquired resistance to tick feeding throughout five infestations.
Abstract: The house mouse (laboratory strain), Mus musculus (L.), the cotton mouse, Peromyscus gossypinus (LeConte), the broad-headed skink, Eumeces laticeps (Schneider), and the guinea pig, Cavia porcellus (L.), were successively infested five times with larvae of the blacklegged tick, Ixodes scapularis Say. Tick feeding success, engorgement weight, and subsequent molting success were measured after each infestation. A greater percentage of ticks (P less than 0.05) fed on M. musculus and E. laticeps than on P. gossypinus or C. porcellus. P. gossypinus expressed a transitory partial resistance, measured in percentage of ticks feeding, during the third infestation but showed increased tolerance during the fourth and fifth infestations. Ticks fed on E. laticeps were heavier than those fed on any other host (P less than 0.05). Those fed on M. musculus were heavier than those fed on P. gossypinus, but the difference was not statistically significant. On C. porcellus, only 1.6% of larvae from the third infestation and none thereafter engorged; weights of larvae from first and second infestations were higher (P less than 0.05) than those fed on M. musculus and P. gossypinus and lower (P less than 0.05) than those fed on E. laticeps. A greater percentage of larvae from E. latticeps and M. musculus (P less than 0.05) molted to nymphs compared with those from P. gossypinus and C. porcellus. Molting success was the same for ticks fed on P. gossypinus and on C. porcellus during the first and second infestations. M. musculus, P. gossypinus, and E. laticeps expressed no resistance (measured as percentage feeding, engorgement weight, and molting) to feeding by I. scapularis larvae after five infestations. Host serum was tested using an ELISA for detection of antibodies against I. scapularis salivary gland antigens before and after each infestation. Antibodies were detected after the second infestation and thereafter in C. porcellus, the only species to show antibodies or to express and maintain an acquired resistance to tick feeding throughout five infestations.
TL;DR: Field application of granulosis virus in spray form to surface soil is recommended as a method of reducing PTM infestation at harvest in areas with Mediterranean climate conditions and has the added benefit of reducing the evolution of PTM in stored potatoes.
TL;DR: The aim of this study was to quantify the infestation densities of Karoo and brown paralysis ticks on sheep and goats and explain it in terms of the etho-ecology of these ticks and their domestic hosts.
Abstract: The aim of this study was to quantify the infestation densities of Karoo and brown paralysis ticks on sheep and goats and explain it in terms of the etho-ecology of these ticks and their domestic hosts. The Karoo paralysis tick usually quests from a vantage point on the vegetation whereas the brown paralysis tick displays an appetence response from the ground and mainly engages hosts that are prostrate. Both tick species are confined chiefly to hilly areas. Temporal differences in the infestation densities of the hosts within and between tick species were evident. These differences were related to disparities in the spatial distribution of the hosts, their activity patterns and the specific appetence responses of the two tick species. Differential climatological conditions affected the quality of forage in areas with a varied topography and the feeding preferences of hosts influenced tick-host sympatry and hence infestation densities.
Journal Article•
TL;DR: The infestation was light, therefore, impetigo was minimal and overcrowding at home is the main factor facilitating the transmission of the infestation from one head to another among these children.
Abstract: A survey of five primary schools in the Njala area, Sierra Leone showed that Pediculus humanus capitis infestation is wide-spread. The overall prevalence was 6.8% among 1007 school children examined. Infestation rates varied between schools from 1.4% to 14.6% and the prevalence of infestation increased with age, from 3.1% among class I children to 10.2% among class IV and decreased to 4.9% among class VI children. Females had a higher infestation rate (8.3%) than their male counterparts (5.4%). The infestation rate was higher' in children whose fathers were Farmers (9.4%) followed by Traders (7.8%), Artisans (6.5%) and Professionals who had the lowest infestation rate of (5.8%). Sharing of beds, beddings and combs had a significant effect (P < 0.01) on the rate of infestation. The infestation was light, therefore, impetigo was minimal. Overcrowding at home is the main factor facilitating the transmission of the infestation from one head to another among these children.
TL;DR: Echinochloa glabrescens f.
Abstract: Echinochloa glabrescens Munro ex Hook. f., a common weed in flooded fields, was highly competitive with rice (Oryza sativa L.) when its seedlings were transplanted with rice seedlings. Age of the transplanted E. glabrescens seedlings had little effect on its weight at harvest and rice grain yield at different infestation levels. Average rice yield reductions from transplanted E. glabrescens ranged from 6% at the 5% infestation level to 73% at the 40% infestation level. Transplanting shock delayed vegetative growth of rice and E. glabrescens at early stages and influenced growth patterns until maturity. When all rice hills were infested, competition resulted in 11.9 and 12.8% reduction in height; 60.5 and 62.5% reduction in tiller number; 59.1 and 51.5% reduction in maximum leaf area index (LAI); 77 and 81% reduction in total dry weight; and 90 and 94% yield reduction of rice under transplanted and dibbled conditions, respectively. Panicle length and 100‐grain weight were not affected by competiti...
TL;DR: Protein quality of sorghum grains having 25, 50 and 75% infestation caused by mixed population of Trrogoderma granarium Everts and Rhizopertha dominica Fabricius was biologically evaluated by rat growth and nitrogen balance studies and showed negative association with insect infestation levels.
Abstract: Protein quality of sorghum grains having 25, 50 and 75% infestation caused by mixed population ofTrogoderma granarium Everts andRhizopertha dominica Fabricius was biologically evaluated by rat growth and nitrogen balance studies. Feeding of diet containing insect infested sorghum grains (50 and 75%) resulted in marked decrease in food intake, protein intake, gain in body weight, food efficiency ratio, protein efficiency ratio, nitrogen consumption, nitrogen absorption, biological value, net protein utilization, dry matter digestibility, net protein retention and protein retention efficiency. These parameters showed negative association with insect infestation levels. However, 25% level of grain infestation did not affect these parameters significantly.
TL;DR: A systems approach consisting of insecticide application before harvest and use of an insecticidal dip after harvest provided quarantine security that eliminated all insect pests of red ginger and ensured pest-free ginger flowers that met quarantine security requirements.
Abstract: A systems approach consisting of insecticide application before harvest and use of an insecticidal dip after harvest provided quarantine security that eliminated all insect pests of red ginger, Alpinia purpurata (Vieill.) K. Schum., including the banana aphid, Penta Ionia nigronervosa Coquerel; cotton aphid, Aphis gossypii Glover; citrus mealybug, Plano coccus citri (Risso); obscure mealybug, Pseudococcus affinis (Maskell); longtailed mealybug, Pseudococcus longispinus (Targioni-Tozzetti); cardamom thrips, Sciothrips cardamomi (Ramakr); black earwig, Chelisoches Mario (F.); and an ant, Technomynnex albipes (F. Smith). Insecticide application consisted of chlorpyrifos 50 dry flowable (DF) applied to the foliage at 2-wk intervals, or chlorpyrifos 20 microencapsulated (MEC) applied as an insecticide barrier treatment. A 5-min dip with a combination of fluvalinate 2.0 flowable (F) and insecticidal soap (potassium salts of fatty acids) with agitation after harvest killed any remaining survivors as long as field populations had <6% mealybug infestation, <33% banana aphid infestation, and <70% cotton aphid infestation. These procedures plus a final inspection of flowers for live insects ensured pest-free ginger flowers that met quarantine security requirements.
TL;DR: Based on population levels of fourth instar Colorado potato beetles, multiple releases of P. bioculatus and P. maculiventris were not significantly more effective than a single release based on population comparisons of beetles, however, three releases (three predators per plant each release) of both species of predators provided greater potato foliage protection than asingle release.
Abstract: Delaying infestation of potatoes by overwintering Colorado potato beetles Leptinotarsa decemlineata (Say) by either 10 or 20 d following plant emergence increased damage to the potatoes. The egg deposition period was reduced from 5 to 3 wk; both increased rates of egg deposition and feeding occurred over a shorter period of time. Potatoes infested at plant emergence by Colorado potato beetle had fourth instars feeding during a 4-wk period of time while infestation 20 d after plant emergence reduced this feeding period to 2 wk and resulted in significantly greater defoliation than those infested at plant emergence. Delayed infestation by either 10 or 20 d had a negative effect on predation by Perillus bioculatus (Fabr.). Potato plants infested by Colorado potato beetles at plant emergence with releases of P. bioculatus 4 d later had the greatest percentage reduction in fourth instars and provided significantly greater foliage protection than plants infested at 10 or 20 d after plant emergence. Based on population levels of fourth instar Colorado potato beetles, multiple releases of P. bioculatus and P. maculiventris were not significantly more effective than a single release based on population comparisons of beetles. However, three releases (three predators per plant each release) of both species of predators provided greater potato foliage protection than a single release (three predators per plant).
TL;DR: Long term follow-up after Sumithrin powder application for head louse control in a primary school showed that the infestation rate dropped from 33.1% before treatment to 5.4% by seven months after treatment, giving a 83.
Abstract: A mass treatment of head louse infestation with Sumithrin powder (0.4% phenothrin) in primary school children was implemented during the period of September 1991-May 1992. The infestation rate of total 2,515 children was 38.6% in average (21.2% in boys and 57.2% in girls). The reduction rate of head louse infestation was 93.4% with a single treatment and 94.8% with double consecutive treatments with about 10 days interval, which indicated that a single treatment would be recommended for the mass treatment in the community. Long term follow-up after Sumithrin powder application for head louse control in a primary school showed that the infestation rate dropped from 33.1% before treatment to 5.4% by seven months after treatment, giving a 83.4% reduction rate.
TL;DR: The interaction of Retithrips syriacus with the hosts is governed essentially by the biochemical profiles of its hosts, which tend to be altered subsequent to infestation, thus manifesting induced resistance through enhanced production of phenolics.
Abstract: The onset of biotic stress in the host plants as a result of increased insect population size leads to enhanced levels of secondary metabolites and associated phenolic enzyme activity· Of the three host plants examined, viz. Ricinus communis (castor), Eucalyptus globulus (eucalyptus) and Manihot utilissima (tapioca), castor was the host most preferred by Retithrips syriacus· Despite the fact that tapioca had the highest levels of secondary compounds, thrips infestation persisted· However, fecundity and growth were reduced because of the relatively high levels of primary metabolites. Gallic acid was found to be the most toxic of the phenolic acids, followed by pyrogallol, resorcinol, phloroglucinol and vanillic acid· The less toxic phenolic acids and flavanoids were detected in leaves that harboured thrips, while the preponderance of gallic acid was found in uninfested hosts. Thus the interaction of Retithrips syriacus with the hosts is governed essentially by the biochemical profiles of its hosts, which tend to be altered subsequent to infestation, thus manifesting induced resistance through enhanced production of phenolics
TL;DR: An early recommended control measure for cocoa pod borer in Sabah was frequent thorough harvesting to a low standard of ripeness, here called regular complete harvesting (RCH), which reduces the opportunity for CPB to complete its development.
Abstract: An early recommended control measure for cocoa pod borer (CBP) in Sabah was frequent thorough harvesting to a low standard of ripeness, here called regular complete harvesting (RCH). This reduces the opportunity for CPB to complete its development. Chemical sprays were also recommended, commonly five applications of BHC or a synthetic pyrethroid at 10 day intervals, during the period of trough crop, or recently, spraying in response to infestation levels. This paper reports a trial that demonstrated the effect of RCH. Economic control is achieved if 50% or fewer pods are infested and this can easily be achieved by RCH. A late commercial‐scale trial confirmed that it could bring infestation to much lower levels, whilst spraying made little difference. The trials assessed spraying in response to CPB thresholds. Initially spray was in response to moth capture in pheromone traps (January‐June 1986), later to pod infestation level. The field was split into two, with a low infestation threshold in one ...
TL;DR: Protein quality of wheat grains having 25%, 50% and 75% infestation caused by mixed populations of Trogoderma granarium Everts and Rhizopertha dominica Fabricius was biologically evaluated by rat growth and nitrogen balance studies and showed negative association with infestation levels.
01 Jan 1992
TL;DR: Full scale trials in commercial salmon farming indicate that the utilization of cleaner-fish is a realistic alternative to chemical control of lice infestation in sea cage culture of Atlantic salmon.
Abstract: Different wrasse species (Labridae) from Norwegian waters were identified as facultative cleaners of farmed Atlantic salmon (Salmo salar) infested with sea lice (Lepeophtheirus salmonis). In sea cage experiments, goldsinny (Ctenolabrus rupestris) and rock cook (Centrolabrus exoletus) were the most effective cleaners, while female cuckoo wrasse (Labrus ossifagus) showed a more moderate cleaning behavior. The corkwing wrasse (Crenilabrus melops) also performed cleaning, but this species had high mortality. Full scale trials in commercial salmon farming indicate that the utilization of cleaner-fish is a realistic alternative to chemical control of lice infestation in sea cage culture of Atlantic salmon.