Showing papers on "Infestation published in 1984"

Alternative to the Use of Probit 9 Mortality as a Criterion for Quarantine Treatments of Fruit Fly (Diptera: Tephritidae)-Infested Fruit

Abstract: Problems with the use of a probit 9 mortality rate as a criterion for quarantine disinfestation treatments for fruit flies (Diptera; Tephritidae) are discussed. We recommend that a maximum infestation level in shipped fruit be set (as an acceptable risk limit) and that this infestation level be used as the criterion for quarantined fruit. The infestation level should be set based on calculations of the probability of a mating pair surviving a shipment.

Monogenean infestations and mortality in wild and cultured Red Sea fishes.

Abstract: Hyperinfection by the gill-infesting monogeneanAllobivagina sp. (Microcotylea) caused mass mortalities in juveniles ofSiganus luridus cultured in seawater earthen ponds and holding tanks in Eilat (Gulf of Aqaba, Red Sea). Other species ofSiganus and adults ofS. luridus cultured in the same systems acquired a low intensity of infestation. Most hyperinfected fish were emaciated and anaemic with hematocrit values below 10 %. Skin and mouth infestations by the monogeneanBenedenia monticelli (Capsaloidea) caused mass mortalities in grey mullets (Mugilidae). These mortalities occurred in large individuals in wild populations ofLiza carinata from lagoonal habitats in the Gulf of Suez and in most species of grey mullets cultured in Eilat. The intensity of infestation correlated positively with severity of infestation, and the common sites of infestation corresponded with areas of severe pathological alterations. Spontaneous recovery followed the climax of an epizootic, both for infestedS. luridus and infested grey mullets. Decline in infestation coincided with remission of the pathological signs.

The effect of aphid-resistance in cowpea on infestation and development of Aphis craccivora and the transmission of cowpea aphid-borne mosaic virus

Abstract: SUMMARY The virus-vector-host relationships of cowpea aphid-borne mosaic virus (CAMV) and its vector, Aphis craccivora, were studied in cowpea lines differing in resistance to aphid infestation. CAMV was acquired and inoculated by its vector during brief probes, confirming that it is non-persistently transmitted. On aphid-resistant cowpea lines, the abundance and the relative sizes of aphids was less than in aphid-tolerant and aphid-susceptible lines. However, aphids were observed to make more numerous probes and probes of shorter duration on aphid-resistant lines than on aphid-susceptible lines. Resistance to aphid infestation in cowpea did not provide resistance to infection with CAMV.

Compositions and methods for reducing pest infestation

Abstract: A composition for reducing pest infestation of animals, such as domesticated animals, by topical application of the composition to the animal. The composition is effective in both reducing future infestation by acting as a pest repellent and also acting as a pesticide to aid in also reducing present infestation. The composition comprises a eucalyptus oil, present in an amount of 4% to about 22% by weight, a lower molecular weight, low carbon content alcohol, such as isopropyl alcohol which is miscible with water, present in an amount of about 9% to about 33% by weight, and water generally present in an amount of about 45% to about 85% by weight, all being based on the total fluid weight of the composition. The invention provides a method of reducing pest infestation by topically applying to an animal, on a periodic basis, a selected amount of the pest repellent composition. In addition, the present invention provides a method of improving a shampoo agent by adding to that shampoo agent the composition of the present invention.

Small-sized euryhaline fish as intermediate hosts of the digenetic trematodeCryptocotyle concavum

Abstract: Cercariae of the trematodeCryptocotyle concavum, which encyst in skin and/or kidney of sticklebacks and gobies, were studied in the Schlei Fjord (western Baltic Sea). Mean incidence of dermal cysts was 48 % inGasterosteus aculeatus and 37 % inPungitius pungitius. No cysts were found in the kidneys of sticklebacks. While 97 % ofPomatoschistus microps had encysted metacercariae in the kidneys, only 2 % had cysts in the skin.Pomatoschistus minutus, however, showed hardly any cyst infestation of either skin or kidney. InP. microps the intensity of infestation by metacercariae was frequently more than 50 cysts; in contrast, sticklebacks rarely exhibited more than 5 dermal cysts. Infested fish were larger than 10 mm in total length, the incidence rate increasing with growth. Parasitic infestation depends on ambient salinity:C. concavum was not found at salinities below 4 ‰. In contrast to the high incidence in fish, the first hosts — the snailsHydrobia stagnalis andH. neglecta — showed remarkably low infection rates (3 to 5 %). The findings reported are related to the distribution ofC. concavum, the mode of life of infested fish, the feeding habits of the final hosts and the infestation ofP. microps by other parasites. Evidently,P. microps represents an optimal second host forC. concavum.

Studies on occurrence and succession of pests of okra at Gwalior.

Abstract: The pests feeding on okra were monitored during kharif 1980 and summer 1981 seasons at Gwa1ior (M.P.). The jassid (Amrasca biguttula biguttula Ishida) remained active throughout the crop in both the seasons. Low humidity during kharif appeared to be conducive for the population build up. Shoot and fruit infestation due to borer (Earias vitella F.) in kharif ranged between 5.5- to 23.9 and 25.93 to 40.91% and in summer season it ranged bet. ween 4.65 to 17.15 and 1.75 to 16.62% respectively. Temperature and humidity had no apparent effect on pest activity in kharif but in summer the pest activity increased with the rise in humidity. Plant infestation due to petiole maggot on kharif and summer okra ranged from 2.56 to 22.91 and 1.27 to 16.31% respectively. Aphid, green semilooper, leaf roller, grey weevil, white fly and mite were found feeding on the leaves and red cotton bug, dusky cotton bug and green plant bug on the stem and fruits. Blister beetle activity was noted for a short period on the flowers.

Establishment and damage of the sugarcane borer (Lepidoptera: Pyralidae) in corn as influenced by plant development.

Abstract: Infestations of Diatraea saccharalis (F.) on corn caused significant yield reductions ( P < 0.05) averaging 11.8, 9.9, and 14.1% per established larva per plant when infestations were initiated at early-whorl, midwhorl, and early-tassel stages of development, respectively. Although losses mainly were attributable to reductions in average ear weight, this response appears to have been caused by different types and combinations of injury in each case, i.e., stalk tunnelling for the early-whorl infestation, stalk and ear feeding for the midwhorl infestation, and ear feeding for the early-tassel infestation. Intraplant movement and feeding site selection were influenced both by plant development and by late-stage larval behavior. Most larval mortality occurred within the first 4 days after infestations, with survival stabilizing by day 9. Results indicate that tightly appressed upper leaf sheaths on the corn plant offer greater resistance ( P < 0.05) to larval establishment than do leaf sheaths at and below the ear.

Feasibility of Establishing an Aesthetic Injury Level for German Cockroach Pest Management Programs

Abstract: We investigated the feasibility of applying the aesthetic injury level (AIL) concept to pests such as cockroaches in urban pest control programs. A random survey was conducted in public housing projects in Roanoke, Va., Norfolk, Va., and Baltimore, Md. One hundred surveys were taken in each of the cities. The results of the survey indicate that the AIL is variable based on the extent of the pest infestation. The larger the infestation, the greater the tolerance to some level of pest infestation. However, we speculate that as infestation level declines, tolerance of the pest will also decline. This will require designing pest control programs to address the specific attitudes of the target audience.

Nantucket Pine Tip Moth (Lepidoptera: Tortricidae) Infestation Rates Related to Site and Stand Characteristics in Nacogdoches County, Texas

Abstract: Twenty-two pine stands with a variety of site and stand characteristics and management strategies were analyzed using discriminant analysis to determine factors which influence Nantucket pine tip moth infestations. A whole-tree sequential sampling scheme designed to estimate absolute infestation rates (±5%) was used. An 8% infestation rate was used as the dividing line between high and low tip moth infestations. A sequential sampling program was used in the field to estimate populations. Absolute infestation rates ( p ˆ ± 5 % ), were obtained through random selection of pines for whole-tree sampling. Four equations were developed which gave 91% correct classification of initial data. The discriminating variables included site preparation intensity, pine height, pine age, site index, soil texture at 61 cm depth, depth of A horizon multiplied by soil texture code, and depth of clay.

Effects of rice stem borer infestation on grain yield and yield components

Abstract: Greenhouse studies were conducted by artificially infesting potted rice plants with first instar larvae of Maliarpha separate/la and Sesamia botanephaga Tarns and Bowden at two stages of plant growth, namely: early tillering stage and at the booting stage Early infestation by M separatella resulted in reduction of plant height and the number of filled grains At the booting stage, the number of filled grains and their weight were higher in uninfested plants Infestation by S botanephaga at both stages of plant growth mainly affected the number of productive tillers Grain weight was unaffected Field studies on individual hills gave erratic results and there were instances when hills containing tillers bored by M separatella produced higher yields than unattacked hills

Seasonal changes in frequency of diseases in dab,Limanda limanda, from the southern North Sea

Abstract: Infestation rates of flatfishLimanda limanda from the southern North Sea (German Bight) were investigated in 1981 and 1982. At three stations, including a dumping area of acid-iron wastes northwest of Helgoland, dabs were examined for the occurrence of lymphocystis and epidermal papillomas. Marked seasonal changes of infestation rates were observed with maxima of diseased fish in March and May (epidermal papillomas 2 % in 1981, 4.1 % in 1982; lymphocystis 7.5 % in 1981, 17.2 % in 1982). Infestation minima were found from June to October. Differences in incidence rates were observed between stations in winter and spring, but not in summer. Both diseases turned out to be size-dependent. Seasonality of the two diseases is discussed in relation to spawning cycle and water quality, including pollution.

Suppressive effect of Azotobacter chroococcum on Rhizoctonia solani infestation of potatoes

Abstract: Isolates ofAzotobacter chroococcum were found to be promising for the control of infestation of potato plants withRhizoctonia solani. Inoculation with an isolate ofVerticillium biguttatum in combination with isolates ofA. chroococcum effectively protected sprouts, stems and stolons against infestation withR. solani. The effect of inoculation varied with soil temperature.

The effects of growth stage in wheat on yield reductions caused by the rose-grain aphid Metopolophium dirhodum.

Abstract: SUMMARY Field-caged populations of the rose-grain aphid Metopolophium dirhodum were established on winter wheat (cv. Bounty) during the summer of 1981. An early wheat growth stage (G.s.) (40 to 69) and a late (G.s. 65 to 73) aphid infestation treatment were compared; only the early infestation resulted in a significant reduction in grain weight (15%), although the infestation sizes were similar in the two treatments. Baking quality of the flour was unaffected by both treatments. Caged populations were also established on winter wheat (cv. Avalon) in 1982 but, in spite of aphid numbers as large as in 1981, no significant yield loss was recorded. An infection of take-all fungus Gaeumannomyces graminis developed during the course of this experiment and may have masked the effect of the aphids.

Harrison: Fall Armyworm Symposium-1984 333 'OBSERVATIONS ON THE INFESTATION OF CORN BY FALL ARMYWORM (LEPIDOPTERA: NOCTUIDAE) WITH REFERENCE TO PLANT MATURITY

Abstract: A series of corn plantings were closely observed for evidence of the effects of plant maturity on infestation by fall armyworm, Spodoptera frugiperda (J. E. Smith). Plants in the early whorl stage and younger were preferred for oviposition. Plants infested early in their development were less tolerant than plants infested later.

[Head Louse Infestation Among Primary School Children In Seosan-Gun, Chungnam Province]

Abstract: The head louse infestation had been no problem since 1960s in Korea. However, the present study revealed highest infestation rate among the primary school children in Seosan-gun, Chungnam Province in July 1983. The cases of louse positive were determined by identifying the adult worms and/or their nits on scalp and hairs. The overall louse positive rate among 615 children examined was 73.5 percent. The rate was higher in girls (78.8 percent) than in boys (67.6 percent) and was highest in 3rd-4th school grades. It was observed that the more the number of family members the higher the infestation rate of children. The positive children were treated with 20 percent benzyl benzoate solution after the test for louscidal effect in petri dish. However, establishment of intensive control measure is needed to prevent further infestation.

Blood Leukocyte Response in Hosts Parasitized by the Hematophagous Arthropods Triatoma protracta and Lutzomyia longipalpis

Abstract: The kinetics of peripheral blood basophil and eosinophil responses in guinea pigs to multiple infestation by nymphal and adult Triatoma protracta (vessel feeder) and adult Lutzomyia longipalpis (pool feeder) were examined. Hosts exhibited significant blood basophil and eosinophil responses to feeding by both arthropods. Basophilia was slow to develop and mild in intensity following primary Triatoma infestation but exhibited immediate anamnestic-type responses to secondary infestation, with marked but delayed-type responses to tertiary infestation. Basophilia developed quickly in guinea pigs infested with Lutzomyia, and this response remained fairly consistent throughout the three infestation periods. Eosinophils did not respond to primary Triatoma infestation but exhibited marked immediate responses to both secondary and tertiary infestations. Lutzomyia-infested hosts exhibited marked eosinophilia in response to all infestations. Eosinophil levels returned to control levels 10 days post-tertiary infestation in Triatoma hosts, whereas Lutzomyia hosts exhibited normal eosinophil levels within 3-4 days after peak response. This study demonstrates that hosts respond to fast-feeding hematophagous arthropods with a peripheral blood basophilia and eosinophilia, as reported for slow-feeding (ticks) hematophagous arthropods. The difference in feeding strategy, whether vessel or pool feeder, appears to be reflected by differences in host blood leukocyte kinetics in response to parasitization by specific arthropods.

Coiling of alfalfa pods in relation to resistance against seed chalcids: additional observations

Abstract: A study of seed chalcid (Bruchophagus roddi) infestation of pods in an Iowa nursery of diverse populations of alfalfa revealed the same selective pattern previously discovered in an Ottawa nursery. Although possessing fewer and lighter seeds, and present in the nurseries in lesser proportion, pods with limited or no coiling were much more heavily infested than highly coiled pods. In uncoiled pods infestation was highest in the middle portion of the pod. However, with increasingly coiled pods, infestation became progressively restricted to the ends of the pod. These observations are consistent with the hypothesis that pod coiling per se provides protection against seed chalcids. Avoidance of glandular pods by the chalcid was not evident, although this has been indicated elsewhere.Key words: Medicago sativa, Bruchophagus roddi, breeding

Impact of Acyrthosiphon kondoi (Homoptera: Aphididae) on Alfalfa: Field and Greenhouse Studies

Abstract: Damage to alfalfa by Acyrthosiphon kondoi Shinji depended on the number of aphids per stem and the length of infestation. In field studies, first-harvest yields were not significantly reduced at populations of 87 aphids per stem, if they were controlled immediately. However, delaying control as few as 8 days at this infestation level resulted in significant yield reductions. These data expand on previous work and set upper levels for aphid infestation. There was no yield loss in the second or third harvest, indicating that no effects carried over from damage sustained before the first harvest. In greenhouse studies, plants subjected to a heavy aphid infestation produced significantly more leaf dry matter but were significantly shorter than noninfested plants. There was no significant difference in quality, as determined by the percentage of protein and total digestible nutrients, between infested and noninfested plants in either the field or greenhouse study.

[Head Louse Infestation Among The Students In Yongyang-Gun, Kyongsangbuk-To]

Abstract: The purpose of this study is to know the present situation of head louse infestation among the students in Yongyang-gun, Kyongsangbuk-to From May 11 to June 20, 1984, a total of 5,937 students in 23 primary and 3 middle schools were examined to identify the adult worms of head louse and/or their nits on the hair. The results are as follows: 1. The overall infestation rate was 44.5 percent and the rates ranged from 19.6 percent to 88.6 percent by each school. 2. In primary schools, the rate was 53.0 percent and in middle schools, 27.1 percent. 3. The school boys' rate was 33.2 percent and the school girls' 55.6 percent, and the difference was statistically significant (p<0.001). 4. The rates were different by grades in middle schools. 5. The rates were different by areas (Myons) (p<0.001). 6. The adult worms collected from the students were Pediculus humanus var. capitis.