Showing papers on "Infestation published in 1988"
TL;DR: Longevity, duration of hive-bound period, and foraging period, of worker bees, infested or not infested during their pupal development, were investigated during the whole year; shortening of lifespan depended on the extent of infestation and on season.
Abstract: SummaryLongevity, duration of hive-bound period, and foraging period, of worker bees, infested or not infested during their pupal development, were investigated during the whole year. Shortening of lifespan depended on the extent of infestation and on season. Influence of infestation on lifespan could be shown during hive-bound and foraging periods; no influence could be shown on flight activity. Drastic differences occurred during winter; in 4 observation hives, only 4–18% of the infested bees that had emerged in September, survived until the following March.
87 citations
TL;DR: The production of this compound appears to be a physiological response of the plant to attack induced by physical disruption of its tissues.
Abstract: SUMMARY
Two maize (Zea mays) inbred lines, A-619, (high DIMBOA content) and W-117 (low DIMBOA content) were artificially infested, at similar physiological stages, with 10 first-instar larvae of Sesamia nonagrioides. The DIMBOA concentration in stem and leaf tissues of damaged and undamaged plants was measured quantitatively in response to larval attack. After 60 h of infestation, both inbred lines were found to respond to insect attack by increasing significantly (P< 0·01) the DIMBOA content in leaf tissues compared with uninfested controls. Similar results were observed 5 days after infestation. No significant differences were found between the stem tissues of the two cultivars during this period. After 9 days infestation, significant increases (P <0·01) could still be found in the stem tissues of the two lines, these showing signs of wounding due to direct insect damage. Thereafter, until day 25 following infestation (the last day of measurement) no significant increased level of DIMBOA was recorded in stem and leaves of the infested lines in any sampling. The production of this compound appears to be a physiological response of the plant to attack induced by physical disruption of its tissues.
43 citations
TL;DR: The effect of period and level of infestation by the fall armyworm, Spodoptera frugiperda, on irrigated maize, Zea mays L., yield was determined and the economic injury level (EIL) was calculated as 2% of the plants infested.
Abstract: The effect of period and level of infestation by the fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), on irrigated maize, Zea mays L., yield was determined. Two applications of the insecticide chlorpyriphos (336 g[ai]/ha) applied directly to the whorl produced yields equivalent to treatments with three applications. FAW infestation of 100% caused 45% yield reduction. A linear regression model (yield[g/plant] = 87.84 - 0.384 (% plants infested by FAW)) explained 46% of the yield variation. The economic injury level (EIL) was calculated as 2% of the plants infested. This low EIL is due to currently high subsidies provided pesticides in Nicaragua. The impact of pesticide subsidies on EIL's is discussed.
40 citations
TL;DR: Collections of wild and cultivated tropical fruits were examined for infestation by Anastrepha spp.
Abstract: Collections of wild and cultivated tropical fruits were examined for infestation by Anastrepha spp. and Ceratitis capitata (Wiedemann) (Diptera: Tephritidae). Of 440 collections (with at least 4 fruits in each) from 201 sites throughout Costa Rica, Central America, 95% of the fruit flies (n = 4126) belonged to the genera Anastrepha (A. obliqua, A. striata, A. serpentina, A. manihoti, A. pickeli, A. distincta, A. chiclayae, and A. fraterculus), while 4.7% were C. capitata. Anastrepha spp. had a strong preference for host plants within the same family. A. obliqua infested 92% of the attacked Mangifera indica (mango), 87.5% of the Spondias mombin (jobo), and 100% of the S. dulcis (June plum/golden plum) and S. purpurea (Spanish plum) collections, all Anacardiaceae. A. striata was recovered from 97.8% of the infested Psidium guajava (common guava), 97% of the P. friedrichsthalianum (Costa Rican sour guava) and 100% of the P. savanarum (guisaro) collections; these three host species belong to the Myrtaceae. A. serpentina was the dominant species in Sapotaceae host plants, and it was recovered from 100% of all infested Manilkara achras (zapote), and Pouteria cainito (yellow caimito), and 98% of Chrysophyllum cainito (caimito morado). A. manihoti and A. pickeli were associated with Manihot esculenta (cassava) (45.8% and 54.2% infestation, respectively). A. chiclayae infested 100% of the Passiflora quadrangularis (granada) collections. A. distincta infested species of Inga (Fabaceae) exclusively. C. capitata was the only species of fruit fly recovered from Prunus persica (cling peach). The infestation rates for C. capitata were low (<7%). Annual phenology of the above listed host plants is presented with additional observations on interactions between fruit flies and their host plants.
36 citations
Journal Article•
TL;DR: Maize plants were artificially infested with egg batches of Busseola fusca at different times after crop emergence to derive regression equations of yield loss on percentage plants with eggs varied over different seasons, which was attributed to hybrid differences and climate.
Abstract: Maize plants were artificially infested with egg batches of Busseola fusca at different times after crop emergence. Regression equations of yield loss on percentage plants with eggs varied over different seasons, which was attributed to hybrid differences and variation in climate.
23 citations
Journal Article•
TL;DR: The degree of infestation was higher in girls than in boys and decreased linearly with age in both sexes, and Pediculosis was directly related to hair length, and the rate of decrease with age was uniform in the three hair length categories compared.
Abstract: An epidemiological survey of head lice infestation among school children at Peshawar (Pakistan) was conducted from April to December 1986. Lice were detected by visual inspection and combing of the head. A total sample of 2287 students (1499 girls, 788 boys) aged 8-16 years from six schools revealed an overall prevalence of 46%, with girls showing a higher infestation rate (49%) than the boys (40%). The infestation in girls was more common in one of the three girls' schools surveyed, while in boys it did not differ significantly among different schools. The prevalence decreased as a linear function of age in both sexes. Pediculosis was directly related to hair length, and the rate of decrease with age was uniform in the three hair length categories compared. The infestation was directly related to crowding at home, and was negatively associated with dandruff. Like prevalence, the degree of infestation was higher in girls than in boys and decreased linearly with age in both sexes.
22 citations
TL;DR: There was no significant difference in infestation in younger and older children of either sex, but the lack of health education of family members may play a crucial role in transference and louse infestation.
Abstract: A school survey of pediculosis capitis in Benghazi, Libya, revealed an alarmingly high prevelence of 78.6%. The percentage of infestation was 67.2% for boys and 88.1 % for girls. It was more frequent in schools located in rural areas (85.55%) as compared with those in urban areas (44.28%). There was no significant difference in infestation in younger and older children of either sex. Besides other factors for such a high prevalence, the lack of health education of family members may play a crucial role in transference and louse infestation.
22 citations
TL;DR: Five species of citrus, including 52 cultivars, were sampled, and field infestations by Anastrepha spp.
Abstract: Five species of citrus, including 52 cultivars, were sampled, and field infestations by Anastrepha spp. and Ceratitis capitata (Wiedemann) were ranked. Fruit factors including sugar content, pH, thickness and mechanical resistance of the peel, and oil-gland density and volume were measured and compared with infestation levels. A. ludens made up 98%, other Anastrepha spp. 1%, and C. capitata , which infested only seven cultivars, 1% of the total infestation. Grapefruits were infested primarily by Anastrepha spp., and tangerines primarily by C. capitata . Significantly more fruit flies emerged from mature than green or half-green fruits. Mechanical resistance, thickness, and estimated oil volume of the peel together were negatively correlated with infestation. For mature fruits, no correlation with infestation, was found between the thickness of the rind or the mechanical resistance of the peel. However, when the data from green and half-ripe fruit also were pooled, there was an inverse correlation between these parameters and infestation levels. The oil volume of the flavedo was inversely correlated with the infestation.
22 citations
TL;DR: Greenbug inhibition may be caused by aphids that remove metabolites (including plant hormones) rather than by chlorotic damage on leaf feeding sites, however, inhibitory substances could have been increased by the aphids' presence.
21 citations
Journal Article•
TL;DR: There was a positive and significant correlation between the incidence and prevailing temperatures during respective weeks and months under observations and Relative humidity was found to be negatively correlated with the incidence, where as rainfall did not show any correlation.
Abstract: Studies on the seasonal incidence of Earias vittella (Fab.) revealed that the infestation on okra shoots and fruits started in the second and sixth week after germination respectively. All the monthly sown crops recorded infestation on shoots from 3rd to 5tQ week during both the years of study. The infestation level on fruits varied from 8.4 to 53.8 and 9.2 to 73.2% in different weeks during 1983 - 84 and 1984 - 85 respectively. The pooled data showed the infestation level of the pest varying from 12.6 to 32.6 and 13.6 to 46.7% under different monthly sown crops in both the years respectively. The 10th week of 1983 - 84 and 11th week of 1984 - 85 sowings suffered heavily. The infestation was more severe in warmer months sowings as compared to rainy or cooler months sowings. There was a positive and significant correlation between the incidence and prevailing temperatures during respective weeks and months under observations. Relative humidity was found to be negatively correlated with the incidence, where as rainfall did not show any correlation.
21 citations
TL;DR: The results indicate that the practice of mixed cropping beans with cowpeas confers no advantage to either crop with respect to attack by M. sjostedti, and the inclusion of a non-host plant (maize) in the mixture, significantly reduces infestation.
Abstract: The effect of growing cowpeas mixed with either beans or maize on population densities of Megalurothrips sjostedti (Trybom) was investigated. Also investigated was the effect of varying the cropping densities of the host plants on the pest populations.There was a significantly lower population of M. sjostedti in cowpea/maize, bean/maize, and cowpea/bean/maize mixed stands as compared with that in either cowpea/bean stands or monoculture stands of cowpeas and beans. Increasing the cropping densities of the host crops increased the abundance of the pest in non-maize based mixed stands, but this effect was not observed in the maize-based mixed stands.The results indicate that with regard to infestation by M. sjostedti, the practice of mixed cropping beans with cowpeas confers no advantage to either crop with respect to attack by M. sjostedti. On the contrary, combining the two crops attracted infestation levels similar to those attracted by either crop grown in monoculture. But the inclusion of a non-host plant (maize) in the mixture, significantly reduces infestation.
TL;DR: The energy demand by the mites on a heavily parasitized host was insignificant relative to the metabolic rate of the host and Parasite energy demand was not responsible for the weight loss or reduced weight gains exhibited by the parasitized hosts.
Abstract: This study examines the energy relationship between the host and the ectoparasitic mite Sarcoptes scabiei var. canis. Parasitized rabbits during the first 14-wk, post-initial infestation gained weight at approximately the same rate, but they consumed more food and water than uninfested control rabbits. During weeks 17–42 after the initial infestation, infestation levels increased until 10–30% of the body area was heavily parasitized. During this time, infested rabbits steadily lost weight even though there was no marked difference in food consumption between infested and control rabbits. Oxygen consumption rates were 0.00206 and 0.00076 μl O2/h/mite for female and male mites, respectively, at 75% RH and 34°C. Based on these rates, mite density on the host, and the infested host body surface area, the energy demand by the mites on a heavily parasitized host was insignificant relative to the metabolic rate of the host. Parasite energy demand was not responsible for the weight loss or reduced weight gains exhibited by the parasitized hosts. All of the infested rabbits became free of mites within 2 wk after treatment with an acaricide and rapidly regained the lost weight.
TL;DR: Rabbits infested with different stages ofAmblyomma variegatum Fabricius, 1794 became resistant to subsequent infestations by the same tick, and developed into adults which had an atypical scutal ornamentation pattern.
Abstract: Rabbits infested with different stages ofAmblyomma variegatum Fabricius, 1794 became resistant to subsequent infestations by the same tick. Resistance was manifested by a reduction of 73.6% in the mean engorged weight of female ticks by the 3rd infestation. By the 5th infestation, only 70% of the nymphs engorged and their mean engorged weight was 57.7% of that of nymphs fed on tick-naive control rabbits. In the case of larvae, there was a 22.8% reduction in their mean engorged weight by the 6th infestation. Based on increases in body length while feeding on tick-naive rabbits, the nymphs could be divided into four feeding categories, i.e. Nl (unfed), N2, N3 and N4 (increasing states of engorgement). While 92–96% of ticks which dropped from susceptible rabbits fitted into feeding category N4, only 28% of those that dropped from tick-resistant rabbits fitted into that category. The remainder of the ticks fitted into categories N3 (60%) and N2 (12%). The majority of those ticks with reduced weight developed into adults which had an atypical scutal ornamentation pattern, in that an additional pair of lateral spots was regularly observed on the males. The females of such ticks deposited small numbers of eggs from which no larvae hatched.
TL;DR: Overall, compared with caged controls, yields were significantly reduced when plants were infested at VE, V2, or V4; the plants later outgrew effects of the infestation.
Abstract: Greenhouse and field experiments were conducted to quantify the effects of infestation by the onespotted stink bug, Euschistus variolarius (Palisot de Beauvois), on growth and yield of corn. Four growth stages (VE, V2, V4, and V6) of corn were infested with adult and nymphal stink bugs and compared with caged controls. Infested plants exhibited growth deformities and occasionally died. Overall, compared with caged controls, yields were significantly reduced when plants were infested at VE, V2, or V4. Plants infested at V6 were significantly shorter in height only at 3 d after treatment compared with caged controls; the plants later outgrew effects of the infestation. Confining one stink bug on seedling corn at VE, V2, and V4 resulted in growth anomalies and significant yield reductions. Yield decreased linearly with duration of infestation through 14 d.
TL;DR: The ease of application and high dermal LD 50 (> 2000 mg/kg rabbit) make Marshal 25 ST a very attractive option for use by small-scale farmers as a component of an integrated pest management strategy in locations where these pests are important and adequate levels of genetic resistance are not available.
TL;DR: Data confirmed that the more rapid visual exam of wheat is not reliable for indicating the hidden, internally-developing weevils, and analysts should be aware of the possibility that wheat inspected visually could be passable with respect to insect-damaged kernels, but still may produce violative flour due to high insect fragment counts when processed.
01 Jan 1988
TL;DR: The results suggest that in the Nigerian derived savanna the initial wet-season herbage infestation in pastures grazed by infected cattle during the dry and wet seasons will consist of L3 from late dry-season and early rains pasture contaminations, the former being the major contributor to the infestation.
TL;DR: In a large breeding colony of squirrel monkeys, a previous study demonstrated apparent universal infestation of adult animals with enteric trichomonads, and in vitro techniques were utilized to determine sensitivity to metronidazole of a number of isolates.
Abstract: In a large breeding colony of squirrel monkeys, a previous study demonstrated apparent universal infestation of adult animals with enteric trichomonads. The potential of these organisms to act as a source of experimental variability and the potential pathogenic effects of parasitism in this species stimulated this study of organism acquisition and treatment. Age of natural infestation with trichomonads was determined from results of microscopic examination and culture of fecal samples from infants of different ages. A majority of squirrel monkey infants showed first evidence of trichomoniasis at 2 to 4 weeks of age, with apparent 100% infestation by 8 weeks of age. Treatment of adult monkeys was investigated. In vitro techniques were utilized to determine sensitivity to metronidazole of a number of isolates. An effective regimen for treatment of adult monkeys was determined to be 25 mg/kg body weight of metronidazole given orally, twice daily for 5 days.
15 Jun 1988
TL;DR: Two thousand and one lines of Cicer arietinum and 20 lines of wild Cicer spp.
Abstract: Two thousand and one lines of Cicer arietinum and 20 lines of wild Cicer spp. were tested in a plastic-house for their reaction to infestation by Heterodera ciceri. Evaluation of root infestation using a 0-5 rating scale based on the number of females and cysts of the nematode occurring on the roots revealed that none of the lines was free of the nematode. However, 20 lines of C. arietinum were rated 2; 482 were rated 3 and 14994 or 5. Among wild species the lines of C. bijugum ILWC 8 and ILWC 34 were rated 2 and ILWC 7 rated 3 while all remaining lines were rated 4 or 5.
TL;DR: Major findings indicate that, under normal planting conditions, infestation of the sorghum shootfly, Atherigona soccata is very low in farmers’ fields in Burkina Faso and this pest appears to be restricted to research stations.
Abstract: This paper reports the results of extensive pest surveys conducted on farmers' fields and pest population studies at two national research stations between 1979 and 1981 in Burkina Faso. Major findings indicate that, under normal planting conditions, infestation of the sorghum shootfly, Atherigona seccata is very low in farmers' fields. This pest appears to be restricted to research stations. Stem borer infestation is caused by a complex of species, and species predominance varies with rainfall. South of latitude 12°N, Busseola fusca is the predominant species but further north it is replaced by Acigona ignefusalis, which is a primary pest of pearl millet. Panicle damage caused by the sorghum midge, Contarinia sorghicola, varies with season; is usually very low in the dry northern Sahelian zone but severe south of latitude 13°N. Maximum midge populations occurred between mid-September and early October.
TL;DR: The results suggested that alkaline conditions are an important component of larval (L. cuprina) infestation of sheep.
01 Jan 1988
TL;DR: In a study of parasitological prevalence in El Salvador, stool specimens of 210 children with diarrhea were examined for intestinal parasites, and intestinal helminths and protozoa were found.
Abstract: In a study of parasitological prevalence in El Salvador, stool specimens of 210 children with diarrhea were examined for intestinal parasites. In 104 cases (49%), intestinal helminths and protozoa were found. 53.4% of the specimens showed single infestation, 31.7% showed double. 3% triple and 1% quadruple infestation. Of the helminths, 31% were Trichuris trichiura, 18% Ascaris lumbricoides and 5% Hymenolepis nana. Of the pathogenic protozoa, 7% were identified as Giardia intestinalis, 6% Entamoeba histolytica, 4% Cryptosporidium sp. and 3% Blastocystis hominis.
TL;DR: In this article, Walker et al. showed that S. incertulas feeding neither causes significant structural damage nor seriously interrupts nutrient flow; also, the passage of a larva through a nodal septum is not detrimental.
Abstract: Using several methods, claims that stem-borers, especially Scirpophaga incertulas (Walker), cause serious crop loss in deepwater rice were tested in Bangladesh. Insecticides were used to control different borer broods. Early season, pre-flood applications reduced infestation, but did not affect yield. One to three mid- to late-season applications of monocrotophos at 250 g a.i./ha significantly reduced infestation and/or whitehead numbers, with yield savings (7-10%) similar to those which earlier workers obtained by applying diazinon 20 times in a season. In each of six years, tiller populations peaked before flooding, then steadily declined until harvest, but stem-borer infestation varied, remaining low until late season in two of the years. In 1981, infestation lower than 24% pre-flood and 42% at harvest did not affect yield. In 1982, eighty-four correlation calculations showed no consistent significant effects of infestation (27-60%, C.V. 40%) on yield (25 000 stems were dissected). Anatomical studies of elongated stems revealed S. incertulas feeding neither causes significant structural damage nor seriously interrupts nutrient flow; also, the passage of a larva through a nodal septum is not detrimental. Irrespective of stem-borer attack, the submerged lower internodes commonly die, the fibrous remains anchor the upper stem, and nodal roots take over nutrient uptake. Studies of panicle-bearing stems (n = 838) showed that, even with 97% stem infestation, most yield loss results from infestation of the terminal internode and is manifested predominantly as whiteheads. In a specific study, 94% whiteheads (n = 205) were associated with terminal internode infestation, where larval feeding in the narrow stem had disrupted food conduction, so preventing grain-filling. The apparent tolerance of S. incertulas by deepwater rice varieties is consistent with their being a primitive group of cultivated rices.
01 Jan 1988
TL;DR: Infestation of rice by Heterodera o yzicola and Mebidogyne grantinicola caused reduction in nitrogen, phosphorus, iron, and reducing sugars in shoots and roots and total sugars, protein, IAA, cytokinin and thiamine were reduced and phenols were reduced with root-hot nematode infested plants.
Abstract: SUMMARY Infestation of rice by Heterodera o yzicola and Mebidogyne grantinicola caused reduction in nitrogen, phosphorus, iron, and reducing sugars in shoots and roots. Total sugars, protein, IAA, cytokinin and thiamine were reduced in the cyst nematode infested plants and phenols were reduced with root-hot nematode infested plants. Phenols decreased in shoots and increased in roots due to cyst nematode, while the rootknot nematode caused similar changes in potassium, manganese and magnesium. There was an increase in calcium, sodium, soluble amino-acids, ABA and starch in both shoots and roots of the cyst nematode infested plants and of total sugars, protein, DNA and RNA with the root-knot nematode infested plants. Infestation by both the nematodes caused nutritional disorders limiting the uptake of nitrogen and phosphorus and chlorosis of leaves.
01 Jan 1988