Showing papers on "Infestation published in 1987"
TL;DR: Experiments indicated that current infestation levels of Eurosta solidaginis are primarily due to genetic variation in the plant's resistance, not field resistance or susceptibility.
Abstract: Variation in insect infestation levels among plants is a result of both genetic variation in susceptibility and variation in previous insect attack. A plant's history of insect attack can either increase or decrease susceptibility and can also influence the number of potential colonizers. Experiments were conducted to determine whether infestation levels of Eurosta solidaginis, the goldenrod ball gallmaker, on Solidago altissima were a result of genetic variation among plant clones (i.e., resistance) or previous attack levels. Results indicated that current infestation levels are primarily due to genetic variation in the plant's resistance. Plant clones were found to differ in the percentage oframets in which oviposition was attempted by Eurosta, the percentage of ramets galled, and in the percentage of ramets with Eurosta oviposition punctures that were galled. Field resistance or susceptibility was maintained in plant clones grown in a common garden.
74 citations
62 citations
TL;DR: Relating adult size to food consumption indicated that the Yemen strain consumed proportionally more of the seed to attain their adult size, compared with other strains from Nigeria and Brazil.
41 citations
40 citations
TL;DR: Two-way selection for lines of honey bees susceptible and resistant to infestation by tracheal mites demonstrates that genotypic variability exsts within North American populations and that selection for resistance is feasible.
Abstract: Two-way selection for lines of honey bees (Apis mellifera L.) susceptible and resistant to infestation by tracheal mites (Acarapis woodi Rennie) was conducted for two generations. Individuals of the susceptible line were 1.4 and 2.4 times more likely to become infested by female mites after the first and second generations, respectively. These results demonstrate that genotypic variability exsts within North American populations and that selection for resistance is feasible. The mechanisms of resistance are unknown.
37 citations
TL;DR: A high infestation rate of honeybee colonies by Tropilaelaps clareae mites was found in Afghanistan and southern Vietnam and a low rate in northern Vietnam, suggesting that in the colder areas V. jacobsoni mites remain outside sealed brood for a shorter time, resulting in a more rapid population increase there.
Abstract: SummaryA high infestation rate of honeybee (Apis mellifera) colonies by Tropilaelaps clareae mites was found in Afghanistan and southern Vietnam and a low rate in northern Vietnam. The rate of infestation by Varroa jacobsoni was low in both parts of Vietnam. The ratios of brood: worker infestation by T. clareae ranged from 13·5–16·0 in Afghanistan and southern Vietnam and 26·1–36·9 in northern Vietnam. The corresponding ratios for V. jacobsoni were 0·8 in southern Vietnam and 2·9–8·2 in the north. These data suggest that in the colder areas V. jacobsoni mites remain outside sealed brood for a shorter time, resulting in a more rapid population increase there.Some measures of population for T. clareae mites in honeybee colonies with low (26%) and high (72%) rates of infestation were as follows: 1·3 and 2·3 females were found on average per brood cell, 18 and 7·3% of females were infertile, one female produced an average of 1·3 and 1·9 descendants, and the mean overall numbers of mites per brood cell were 2·...
35 citations
TL;DR: Annual canarygrass and oats were found to be free of natural infestations of wheat midge (Sitodiplosis mosella Gehin) in northeastern Saskatchewan.
Abstract: Annual canarygrass and oats were found to be free of natural infestations of wheat midge (Sitodiplosis mosellana Gehin) in northeastern Saskatchewan. Six-row barley cultivars had low infestations and triticale, rye, wheat and durum wheat, high levels of infestation. Differences among susceptible cultivars were frequently due to asynchrony of plant susceptibility and midge oviposition.Key words: Sitodiplosis mosellana Gehin, wheat midge, cereals, cultivars
32 citations
TL;DR: Results suggest that acquired resistance to hypodermosis has a cellular basis with participation of both B- and T-cell components and that the response to antigen continued at 10 months post-infestation.
30 citations
TL;DR: It was demonstrated that stink bugs fed preferentially on seeds in upper halves of plants until high infestation levels forced bugs to feed in lower halves, and feeding by stink bugs at low infestation level effected increases in weights of 100 seeds.
Abstract: Yield, pod filling, weights of 100 seeds, viability, and vigor of seeds from upper and lower halves of soybean, Glycine max (L.) Merrill, plants were examined in response to four levels of natural infestation (population means of 3.8, 3.0, 1.5, and 0.3 bugs per meter of row) by a stink bug complex that included Nezara viridula (L.), Acrosternum hilare (Say), and Euschistus spp. Reductions in yield occurred as stink bug infestation levels increased; these reductions primarily were confined to upper halves of plants. Feeding damage, as evidenced by reductions in pod filling, seed viability, and seed vigor, was restricted to upper halves of plants until infestations reached the highest level (i.e., 3.8 bugs per meter of row). These results demonstrated that stink bugs fed preferentially on seeds in upper halves of plants until high infestation levels forced bugs to feed in lower halves. Results also suggest that feeding by stink bugs at low infestation levels (i.e., 1.5 bugs per meter of row) effected increases in weights of 100 seeds. Damage-free seeds compensated for damaged seeds by exhibiting increases in weights of 100 seeds of as much as 43.8%.
30 citations
TL;DR: Modifications of serum C3 levels during reinfestations influenced C3 contents in the blood meal of fed ticks, which contained more C3 than midguts of ticks of the same engorged weights fed during the first or second infestations.
Abstract: Serum C3 levels of rabbits infested 3 times withIxodes ricinus L. females and C3 in midgut extracts of fed ticks have been measured by a single radial immunodiffusion test. From the first tick attachment, the mean serum C3 level of hosts increased. A peak of C3 occurred 6 days after the beginning of each infestation and was highest during the third infestation (about 8 times more pronounced than the level measured before the first). After the end of all infestations of the rabbits, the serum C3 level decreased and approached normal levels. Modifications of serum C3 levels during reinfestations influenced C3 contents in the blood meal of fed ticks. Midguts of ticks fed during the third infestation contained more C3 than midguts of ticks of the same engorged weights fed during the first or second infestations.
28 citations
TL;DR: Observations on infestations with the tick, Amblyomma triguttatum, in soldiers who were bivouacked in two areas near Perth report that local skin reactions to tick‐bites were frequent; they usually developed 24–48 h after removal of the tick and may indicate delayed hypersensitivity reactions.
Abstract: We report observations on infestations with the lick, Amblyomma triguttatum, in soldiers who were bivou- acked in two areas near Perth; 34% ol 175 persons were infested with varying stages of the ectoparasite. Most persons were infested with only one tick but some troops had multiple infestations. Local skin reactions to tick-bites were frequent; they usually developed 24-48 h atter removal of the tick and may indicate delayed hypersensitivity reactions. A small number of persons developed secondary bacterial infections. Management and prevention of these infestations is reviewed briefly. (Med J Aust 1987; 1$t 238-240) ick-bite is a common problem in eastern Australia, particularly among persons who live in the tropics and subtropics.' In most reported instances, infestation has occurred with the Australian scrub-tick, Ixodes holocyclus, which is distributed from Normanton in the Gulf of Carpentaria, Queensland to Bairnsdale, Victoria.'?'3 This ectoparasite has been reported to cause local allergic reactions, secondary skin infections, anaphylaxis, and neuromuscular paralysis, as well as the trans- mission of organisms such as Rickettsia ouStralis, the aetiological agent of Queensland tick typhus. Ixodes holocyclus is not found in the southern parts of Western Australia, but infestation may occur with other species of ticks. Persons who are particularly at risk are bushwalkers and those who camp in the countryside. This paper reports the incidence of infestation in troops who were encamped at two sites near Perth and describes the clinical manifestations of infestation with the hard-tick, Amblyomma triguttatum, which is commonly known as the "kangaroo-tick".
TL;DR: In this article, the number of phytophagous insects living on Nothofagus was estimated in 125 species and a total of 34 species were reported as pests, and the importance that the infestation to different parts of the plant, would have in tree performance was indicated.
Abstract: Nematodes and insects have been the only zoophytophagous groups that have been reported in the literature living on Nothofagus in Chile. According to the area covered by Nothofagus and the type of plant that it represents, (apparent) the number of phytophagous insects living on this genus was estimated in 125. A total of 34 phytophagous species were reported as pests. The importance that the infestation to different parts of the plant, would have in tree performance is indicated. The close relationship of sap suckers fauna living on Nothofagus in Australia, New Zealand and Chile is reported. Two genero and two species of phytophagous nematodes is indicated.
TL;DR: Resistance to infestation was mainly attributable to the testa of the groundnuts, except in PI274/191, which was found to be the most susceptible variety.
TL;DR: The resistance of 32 melon lines to Tetranychus cinnabarinus (Boisduval) was studied in Israel and the results suggest there is a definite variation amongMelon lines in resistance to mite infestation.
Abstract: The resistance of 32 melon lines to Tetranychus cinnabarinus (Boisduval) was studied in Israel. Average counts ten days after infestation, at the fourth-leaf stage, ranged from 3·5 to 57 mites per four leaf discs 1 cm in diameter; six lines had significantly low counts, ranging from 0·9 to 1·5 mites per four leaf discs. Fourteen of the lines were also tested at the flowering stage. No mites were found on two lines, and on a third line very few mites were observed. All three lines also had had significantly low mite counts at the fourth-leaf stage. The results suggest there is a definite variation among melon lines in resistance to mite infestation.
TL;DR: The nature and extent of damage by these borers warrants adoption of effective prophylactic treatments to timber stored in depots and storage yards.
TL;DR: In tomato, infestation by the natural population of the fruit borer, Heliothis armigera (Hubner), on number basis was positively correlated with infestation on weight basis and infestation was negatively correlated with the number of flowers per inflorescence.
Abstract: In tomato, infestation by the natural population of the fruit borer, Heliothis armigera (Hubner), on number basis was positively correlated with infestation on weight basis. Infestation was negatively correlated with the number of flowers per inflorescence. Surface texture of calyx also affected the susceptibility of the genotype. Reducing sugars in fruits were positively correlated, while zinc and iron content in foliage and ascorbic acid contents in fruits were negatively correlated with degree of infestation. Coefficient of determination revealed that 87% variability in borer infestation was due to zinc, iron, ascorbic acid and reducing sugar content.
TL;DR: The phenology of the emergence of brassica pod midge from overwintering sites previously sown with spring oil-seed rape and its subsequent infestation of spring rape crops was studied over 3 years.
Abstract: The phenology of the emergence of brassica pod midge from overwintering sites previously sown with spring oil-seed rape and its subsequent infestation of spring rape crops was studied over 3 years. Adults emerged from the overwintering sites from mid-May until early July, but infestation of spring rape did not begin until late June. Two generations occurred on spring rape. Mature larvae dropped from the pods almost daily from early to mid-July until mid-August to early September to form cocoons in the soil. A small proportion of these larvae developed into pupae and emerged as a second generation of adults to lay further eggs in the crops. Larvae from these eggs dropped to the soil to diapause within cocoons.
TL;DR: The results show a high head lice infestation, particularly in the early school years, where presumably interpersonal contacts are most frequent, facilitating contagious spread in the rapidly expanding Saudi Arabian city of Jeddah.
Abstract: The prevalence of infestation with the head louse, Pediculus capitis, was assessed among the child population, from birth to 10 years old inclusive, of the rapidly expanding Saudi Arabian city of Jeddah. Over a period of two months, 300 consecutive children attending the general practitioner for any reason were examined specifically to identify those infested with head lice: 37 cases of active infestation were found, which is an overall prevalence of 12%. An interesting distribution, however, was noted in respect of age, ranging from less than 2% in the first year of life, rising rapidly to around 30% in ages six to eight years, thereafter declining steadily to about 16% by age 10 years. The distribution of infestation among males and females was broadly similar. These results show a high head lice infestation, particularly in the early school years, where presumably interpersonal contacts are most frequent, facilitating contagious spread. As the head lice is known to spread several viral and rickettsial diseases, such as relapsing fever and typhus, greater efforts should be made towards patient education in hygiene, and towards identifying and treating the disease when found.
TL;DR: Animals confined in small pastures had higher incidences of lice than animals in totally or partially confined systems, although confinement type did not affect incidence of mites, and infestations of both lice and mites were higher during cooler months.
Abstract: A survey was conducted during 1980 and 1981 to determine seasonal incidence of hog lice, Haematopinus suis (L.), and sarcoptic mange mites, Sarcoptes scabiei (De Geer), in market-weight swine in Indiana. The survey indicated that infestations of both lice and mites were higher during cooler months. Over the course of the survey, hog lice and mange (itch) mites were present on 18.1 and 25.3% of all animals examined, respectively. Animals confined in small pastures had higher incidences of lice than animals in totally or partially confined systems, although confinement type did not affect incidence of mite infestation. Results of a questionnaire sent to Indiana veterinarians concerning these pests are discussed. Responding veterinarians estimated a 51.5% incidence of hog lice and 36.2% incidence of sarcoptic mange mites on farms visited. Veterinarians did not notice correlations between lice or mange and confinement type, animal breed and age, or geographical area. Results of questions asking the veterinarians treatment methods preferred and importance of these parasites are presented.
TL;DR: The host's clinical and immune response markedly affected the fecundity of adult female ticks and the viability and hatchability of the laid eggs in Haemaphysalis punctata and Ixodes ricinus biology.
TL;DR: Seven generations of selection reduced the level of nymphal infestation by 71% and severity of plant damage (hopperburn) by 45%.
Abstract: ASolanum tuberosum L. Gp. Tuberosum population was recurrently selected for resistance to potato leafhopper (PLH) (Empoasca fabae, Harris). Primary selection was for low levels of nymphal infestation under natural infestation in field tests. The selection procedures allowed completion of a selection generation per year. The original population and seven selection-generation populations were tested for PLH resistance for three years at two locations. Averaged over six tests, seven generations of selection reduced the level of nymphal infestation by 71% and severity of plant damage (hopperburn) by 45%. The rate of reduction slowed in later generations.
TL;DR: In this age group delusions of infestation may be less persistent and pernicious than those of the monosymptomatic psychoses that are reported more commonly in younger middle-aged patients, and the presence of some organic impairment should not detract from the treatability of the condition through an appreciation of the mood disorder.
Abstract: SIR: Renvoize et a! (Journal, March 1987, 150, 403—405)provide a useful review of the literature, including the German literature, in reporting their interesting patient whose delusions of infestation occurred during the course of a dementing illness. We have been interested to find that delusions of infes tation are seen quite commonly among the patients referred to our psychiatric services for the elderly and we recently reviewed seven cases that presented between 1983and 1986.There were two men and five women. Their ages ranged from 69 to 76—a little above the boundary of †̃¿ late middle age', the age group from which patients are most frequently reported, but not very old (patients aged 75 and above constitute about three quarters of our referrals). All seven were found to be depressed. None were seriously demented, although in three there was clear evidence of some organic cerebral impairment and in only one could we be sure that there was no such pathology. In two patients the delusions of infes tation developed in the context of guilt at not main taining cleanliness in the home after the death of a spouse. In three, previous neurotic preoccupation with cleanliness or †̃¿ phobia' of †̃¿ creepy-crawlies' had become delusional in the setting of severe depression, and in the last two the delusion was part of a systematic belief that the body was changed and degenerating. In most of our patients the delusions appeared when powerful change of affect occurred with mild organic change. This is a potent combination in the genesis of delusions (Hay et al, 1974). Successful treatment of the mood disorder has led to resolution of the delusions of infestation in the six cases we have known longest. Thus, in this age group delusions of infestation may be less persistent and pernicious than those of the monosymptomatic psychoses that are reported more commonly in younger middle-aged patients. The presence of some organic impairment should not detract from the treatability of the condition through an appreciation of the mood disorder. MICHAEL Moiuus DAVID J. JOLLEY Reference
TL;DR: Results indicate that the tolerance of cotton to mite infestations increases with crop maturity, and timing of initial infestation was shown to affect ultimate yield of cotton.
Abstract: Artificially inoculated spider mite foci increase in size at an exponential rate. Productivity was greatest on plants farthest from the center of each focus. Timing of initial infestation was shown, both experimentally and through simulation, to affect ultimate yield of cotton: the earlier the initiation of infestation, the lower the yield. These results as well as those of other researchers indicate that the tolerance of cotton to mite infestations increases with crop maturity.
Journal Article•
TL;DR: It is concluded that a number of factors each contribute to stress the fish sub-lethally, the cumulative effect eventually resulting in mortality.
Abstract: The phenomenon of mortalities of cichlids during winter was investigated in the Hartbeespoort Dam, Transvaal. Infestation statistics of potential pathogens occurring in or on the mozambique tilapia, Oreochromis mossambicus during the period February to August 1985, were determined. A number of experiments were carried out to establish the effect of temperature variation on ectoparasitic protozoan infestation and saprolegniasis and the effect of ectoparasitic crustaceans on the blood chemistry of their hosts. A broad spectrum of factors which might influence the susceptibility of fish to temperature stress is discussed. It is concluded that a number of factors each contribute to stress the fish sub-lethally, the cumulative effect eventually resulting in mortality.
TL;DR: Honeybee colonies examined in South Vietnam were infested by Varroa jacobsoni and Tropilaelaps clareae and Amitraz was more effective than phenotiazine against both mite species, killing 95·7% of V. jacOBsoni mites and 56·4% of T.Clareae mites.
Abstract: SummaryIn honeybee (Apis mellifera) colonies examined in South Vietnam an average of 4·9% of brood cells were infested by Varroa jacobsoni and 46·2% by Tropilaelaps clareae. Average rates of infestation of adult workers were 6·3 per 100 for V. jacobsoni and 3·4 per 100 for T. clareae. Thus, despite a tenfold higher infestation of brood by T. clareae, infestation of adults by V. jacobsoni was twice as high. Amitraz was more effective than phenotiazine against both mite species, killing 95·7% of V. jacobsoni and 79·2% of T. clareae mites whereas phenotiazine killed only 57·7% of V. jacobsoni mites and 56·4% of T. clareae. Because of the low incidence of V. jacobsoni, mite treatment in Vietnam should be concentrated on T. clareae which can be controlled without medication.
Journal Article•
TL;DR: Augmentation of indigenous ladybird beetles to control sugarcane woolly aphid, Ceratoyacuna lanigera Zehntner, was experimented in Guangxi during 1982-85 and as a result, the aphid infestation rate of Sugarcane plants was reduced by 96.6%, and leaf infested rate reduced by 90%.
Abstract: Augmentation of indigenous ladybird beetles to control sugarcane woolly aphid, Ceratoyacuna lanigera Zehntner, was experimented in Guangxi during 1982-85. Two species of coccinellid beetles, Svnonycha grandis (Thunberg) and Cpelophora biplagiata (Swartz), were collected from the fields in November, and stored in a room of 18-20℃, 75-85% RH for overwintering. After about five months of storage, the surviving rate of S. grandis and C. biplagiata was 62.96-82.92% and 45.71-100%, respectively. At the temperature of 23-26℃, 75-85% RH, the surviving rate of storing the first generation and the overwintering generation of S. grandis during summer was 69.13% and 53.8%, respectively. After the winter or summer storage, the predators were released into sugarcane fields. A total of 44,660 beetles were released during the four years period. As a result, the aphid infestation rate of sugarcane plants was reduced by 96.6%, and leaf infestation rate reduced by 90%.