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Showing papers on "Infestation published in 1986"


01 Jan 1986
TL;DR: In this paper, the effect of neighbor relatedness in seedling populations was investigated, where propagules of six Anthoxanthum odoratum parents, produced from a reciprocal diallel cross, were planted into the parental source population, a mown field.
Abstract: To investigate the effect of neighbor relatedness in seedling populations, propagules of six Anthoxanthum odoratum parents, produced from a reciprocal diallel cross, were planted into the parental source population, a mown field. The propagules were either surrounded by four unrelated neighbors in a 1 cm square, four sibling neighbors, or no neighbors. About 45% of the emerging seedlings were attacked by aphids (Schizaphis graminum). Aphid infestation significantly reduced seedling survivorship and did not differ with parental genotype or neighbor relatedness; plants without neighbors had a slightly higher infestation risk. Plants without neighbors had lower survivorship than those surrounded by unrelated neighbors although this difference was only significant for plants infested by aphids. When infested by aphids, plants surrounded by siblings had lower survivorship than plants surrounded by non-relatives, suggesting the operation of mi- nority advantage. These results are consistent with the frequency-dependent selection hypothesis for the evolution and maintenance of sexual reproduction.

105 citations


Journal ArticleDOI
TL;DR: To investigate the effect of neighbor relatedness in seedling populations, propagules of six Anthoxanthum odoratum parents, produced from a reciprocal diallel cross, were planted into the parental source population, a mown field.
Abstract: To investigate the effect of neighbor relatedness in seedling populations, propagules of six Anthoxanthum odoratum parents, produced from a reciprocal diallel cross, were planted into the parental source population, a mown field. The propagules were either surrounded by four unrelated neighbors in a 1 cm square, four sibling neighbors, or no neighbors. About 45% of the emerging seedlings were attacked by aphids (Schizaphis graminum). Aphid infestation significantly reduced seedling survivorship and did not differ with parental genotype or neighbor relatedness; plants without neighbors had a slightly higher infestation risk. Plants without neighbors had lower survivorship than those surrounded by unrelated neighbors although this difference was only significant for plants infested by aphids. When infested by aphids, plants surrounded by siblings had lower survivorship than plants surrounded by non-relatives, suggesting the operation of minority advantage. These results are consistent with the frequency-dependent selection hypothesis for the evolution and maintenance of sexual reproduction.

98 citations


Journal ArticleDOI
TL;DR: Analysis of over 1000 tick collections from cattle indicated that infestation rates of the most important species, Amblyomma variegatum andRhipicephalus appendiculatus vary in different ecological habitats.
Abstract: A study of the seasonality and infestation rates of ticks was carried out in 11 cattle herds in different ecological habitats in Zambia between 1980 and 1982. Wherever possible supplementary data were obtained from opportunistic collections from cattle and other hosts. Analysis of over 1000 tick collections from cattle indicated that infestation rates of the most important species,Amblyomma variegatum andRhipicephalus appendiculatus vary in different ecological habitats: (i) In Western Province, infestations are much lower than elsewhere; (ii) in Central and Southern Provinces, moderate to high infestations occur; and (iii) in Eastern Province,R. appendiculatus numbers are generally low andA. variegatum numbers are moderate. These two species, however, have similar life cycles throughout their range with one generation per year. Larvae occur mainly from March to May, nymphae from May to September, and adults ofA. variegatum from October to December and ofR. appendiculatus from December to April. Boophilus decoloratus appears to have two to four generations per year but is uncommon during the rainy season. In some areas in central ZambiaRhipicephalus compositus adults are seasonally common in September–October whereasRhipicephalus evertsi is more or less ubiquitous. Low to moderate infestations ofHyalomma truncatum andHyalomma rufipes occur in most areas. At least 14 other less common or rare species ofRhipicephalus, Amblyomma, Haemaphysalis andIxodes were taken infrequently from cattle. These and other host-specific species were also collected from dogs, sheep, various wildlife hosts and the environment. Infestation rates, seasonality and host-relationship of tick species are discussed in relation to their ecology. Relevant biosystematic and disease relationships are reviewed briefly. The baseline data derived from this study are adequate for integrated analysis with those from other ecological and economic investigations to formulate tick control strategies.

77 citations


Journal ArticleDOI
TL;DR: Of the factors investigated, it was found that leaf tannin level had the strongest influence on the degree of fungal infestation, and fungal infestation is lowest in regions of high Leaf tannins.
Abstract: Emergence success was determined for 1300 galls of the cynipid waspDryocosmus dubiosus. Galls were collected throughout a single host tree (a California coast live oakQuercus agrifolia). Each gall was reared individually in small gelatin capsules. For each gall data was recorded on 17 parameters characterizing hyperparasitism, fungal infestation, leaf tannin levels, inter- and intraspecific competition, and spatial position within the tree. Using contingency table analysis and logistic regression, we determined that the most significant factors influencing the success ofD. dubiosus galls are 1) fungal infestation and 2) chalcid hyperparasitism, both having negative effects. Of the factors investigated we found that leaf tannin level had the strongest influence on the degree of fungal infestation. Fungal infestation, in turn, is lowest in regions of high leaf tannins.

66 citations


Journal ArticleDOI
TL;DR: Three maize cultivars that had shown differences in response to Chilo partellus adults and larvae were evaluated for their relative ability to withstand larval infestation and damage, and foliar damage correlated better with yield loss than stalk tunneling.
Abstract: Three maize cultivars that had shown differences in response to Chilo partellus (Swinhoe) adults and larvae were evaluated for their relative ability to withstand larval infestation and damage. Three treatment regimes, protection by insecticides, artificial infestation, and natural infestation, were adopted. C. partellus was the predominant species during the whorl stage of crop development. Eldana saccharina Walker appeared during the tassel emergence stage and persisted through harvest. Treatment, cultivar, and interaction effects were significant for maize foliar damage, stalk breakage, and ear drop. Stalk tunneling was affected by treatment and cultivar effects but number of entrance holes per plant was affected by treatment only. A larval survival index, the ratio of exit to entrance holes per stem, was higher for ‘Inbred A’ than for the other cultivars, suggesting some antibiosis in the other cultivars. Yield reduction between the protected and infested treatments was 71.4% for ‘Inbred A’ compared with 3.1% for ‘ICZ2-CM’. Of the primary damage symptoms, foliar damage correlated better with yield loss than stalk tunneling. When the yield reduction and leaf damage responses of each cultivar were partitioned into quadrants, resistance in ‘ICZ1-CM’ and ‘ICZ2-CM’ appeared to be antibiosis perhaps together with tolerance or nonpreference, whereas ‘Inbred A’ had none of these qualities.

50 citations


Journal ArticleDOI
TL;DR: Of 1270 schoolchildren from 33 urban and rural primary schools in different regions of Kenya who were examined for head lice, 17.1% were infested; Negroid children had lower infestation rates than non-Negroid children, and the criterion seems to be hair type.
Abstract: Of 1270 schoolchildren (651 girls and 619 boys) from 33 urban and rural primary schools in different regions of Kenya who were examined for head lice, 17.1% were infested (8% with living lice or nits, 9.1% with dead nits). The over-all difference between infestation rates in urban and rural schools was not significant, but there was considerable variation in the five different regions selected. Infestation was not sex-related. Infestation rates tended to be higher in older children and in children with longer hair. Negroid children had lower infestation rates than non-Negroid children. The criterion seems to be hair type. Prevalence of infestation was higher in private schools because non-Negroid children predominate in these schools. There was no correlation between infestation and the sharing of a towel or comb, but infestation tended to be higher in those who wash less, in those who share their bed, and in those who sleep with room-mates. Levels of infestation were low, with most harbouring only one or two lice.

35 citations


Journal ArticleDOI
TL;DR: Mass-trapping of male oriental fruit flies with methyleugenol plus malathion at the rate of nine saturated fiberboard blocks per ha produced male population reductions >99% in a papaya orchard, but because the surrounding jungle was not trapped, fruit infestation rate was reduced only 48%.
Abstract: Mass-trapping of male oriental fruit flies, Dacus dorsalis Hendel, with methyleugenol plus malathion at the rate of nine saturated fiberboard blocks per ha produced male population reductions >99% in a papaya orchard (63 ha). However, because the surrounding jungle was not trapped, fruit infestation rate was reduced only 48%.

32 citations


Journal ArticleDOI
TL;DR: The results suggest that the pharmacological mediators released by degranulation of mast cells and basophils are perhaps the major effectors of resistance in cattle to H.a. anatolicum.
Abstract: The cutaneous cellular reactions associated with acquisition of resistance by cattle to Hyalomma anatolicum anatolicum feeding were investigated by comparing the nature and sequence of cellular events at H.a. anatolicum feeding sites following primary and tertiary infestations. Cattle acquired resistance to H.a. anatolicum feedings after a single infestation. The resistance was manifested by a significant reduction in the mean weight of engorged females and mean weight of egg mass produced, failure to lay eggs and sometimes death of ticks in situ. The acquisition of resistance corresponded with pronounced epidermal vesiculation and a significant change in the nature of the cellular infiltrate at tick feeding sites indicating the development of cutaneous hypersensitivity. On primary infestation the cellular infiltrate was dominated by neutrophils (43-71%) followed by mononuclear cells (25-35%). Basophil and eosinophil infiltration in small numbers was noticed for the first time at 72 and 144 h, respectively, post-primary infestation. Unlike primary infestation, the dermal infiltrate on tertiary infestation, 24 h after attachment, was characterized by infiltration of basophils (6%) and eosinophils (3%) and a marked degranulation of mast cells and basophils. Basophils showed a consistent increase in absolute as well as relative numbers as the feeding advanced. They were the second most abundant cell types after neutrophils (48-68%) at 72 h (16%), and 144 h (23%). Eosinophils (3-9%) and mononuclear cells also showed a significant increase in their mean numbers as compared with primary infestation. There was a progressive decrease in the number of detectable mast cells following tick infestation and they were significantly lower post-tertiary infestation, compared to primary infestation. These results suggest that the pharmacological mediators released by degranulation of mast cells and basophils are perhaps the major effectors of resistance in cattle to H.a. anatolicum.

30 citations


Journal ArticleDOI
TL;DR: A working hypothesis is presented that attempts to correlate the developing humoral response and the depressed T-cell response with both an increasing dermatitis and mite population with the development of anti-P.

29 citations


Journal ArticleDOI
TL;DR: In this paper, a comparison of mountain pine beetle infestation with a history of western pine beetle, D. brevicomis LeConte, revealed large differences in biochemical diversity between the two geographic areas.
Abstract: To determine if mountain pine beetle, Dendroctonus ponderosae Hopkins, influences patterns of biochemical diversity in ponderosa pine, Pinus ponderosa Laws., monoterpene composition of xylem resin of trees that survived an infestation was compared with a random sample of living trees adjacent to the infestation. No significant differences were detected in means or variances between the two groups of trees. A comparison of these populations to populations of ponderosa pine with a history of western pine beetle, D. brevicomis LeConte, infestation revealed large differences in biochemical diversity between the two geographic areas. Association of geographic differences in biochemical diversity with insect species exhibiting different feeding habits suggests possible causal relationships between these two patterns.

27 citations


Journal ArticleDOI
TL;DR: A sampling study was conducted in Sugarcane to estimate infestation levels of the sugarcane borer (SCB), Diatraea saccharalis, and showed that SCB populations usually were aggregated in sugarCane.
Abstract: A sampling study was conducted in sugarcane to estimate infestation levels of the sugarcane borer (SCB), Diatraea saccharalis (F.). A single sample consisted of five stalks per plant from five plants spaced 3 m apart. A mean of 7 min was required for one scout to take one sample in cane 0.6–1.2 m tall; 16 min was required in cane 3.0–3.6 m tall. Variance to mean ratios, Green’s coefficient of dispersion, and a simple linear regression of log10( s 2)against log10( x ¯) showed that SCB populations usually were aggregated in sugarcane. Number of SCB larvae per sample followed the negative binomial distribution. In 0.4- to 0.8-ha areas of sugarcane, aggregation was not detected at low population densities but was pronounced at high densities. Estimated SCB infestation levels (mean number of borers per 25 stalks × 100) ranged from 0.4 to 48.0% in the different fields sampled. Based on 90% CL and a mean of nine samples per 0.4- to 0.8-ha area, accuracy of estimates for SCB infestation levels ranged from ±0.8 to ±26.6% with an overall average of ±7.4% based on simple variance or ±7.1% based on a regression estimate of variance. At infestation levels <10%, estimates of SCB infestation levels were generally within ±4.5% of the true levels based on simple variance or ±3.9% based on regressed variance. Accuracy of infestation level estimates generally decreased as SCB infestation levels increased.

Journal ArticleDOI
TL;DR: This study examined tick resistance expressed by Hartley guinea pigs upon repeated infestation with Dermacentor andersoni, and describes longitudinal development of antigen specific immunoglobulin over approximately 180 days.
Abstract: Acquired resistance to ixodid tick infestation is expressed by cattle and laboratory animals. Humoral factors appear to be involved in host acquired resistance to tick bite; however, specific immune responses have yet to be fully characterized. This study examined tick resistance expressed by Hartley guinea pigs upon repeated infestation with Dermacentor andersoni, and describes longitudinal development of antigen specific immunoglobulin over approximately 180 days. Guinea pigs were infested either 4 times with D. andersoni adults, or twice with nymphs. Both infestation groups, adults and nymphs, demonstrated a significant level of resistance to re-infestation, following initial exposure. Dot enzyme-linked immunosorbent assay (Dot-ELISA) was employed to detect antibody reactive with D. andersoni salivary gland antigens (SGA). Animals infested with adults had antibody that increased at a relatively constant rate until the fourth infestation, which was differentiated by a sharp increase in titer, that was maintained for approximately 2 wk. Guinea pigs that received nymph infestations had SGA-specific antibody; however, titers were lower than those in the adult infestation group. Antibody levels continued to increase approximately 80 days beyond the final (second) infestation for this group. A direct correlation between resistance and antibody titer was not evident, since resistance was relatively stable after the second infestation in both infestation groups, and tick-specific immunoglobulin levels continually increased.

Journal ArticleDOI
TL;DR: Results of these studies indicated that at least part of the increased resistance of ‘Williams’ to damage from T. urticae was due to a greater hypersensitive response of “Williams” to mite attack, resulting in an extensive loss of carotenoids and chlorophyll.
Abstract: Effects of feeding of the twospotted spider mite, Tetranychus urticae Koch, on leaf and seed composition and dry matter accumulation in two soybean, Glycine max (L.) Merr., cultivars previously found to respond differently to mite infestation were investigated to gain a greater understanding of resistance mechanisms in soybeans to this wide host range plant pest. The two soybean cultivars, ‘Bonus’ and ‘Williams’, were infested with mites at the V3, V6, and R2 stages of development with 0, 10, and 200 mites per first fully expanded trifoliolate leaf. A relatively greater reduction in dry matter accumulation was seen in ‘Williams’ than in ‘Bonus’ at the same mite population level on the foliage. However, mite population increase was significantly lower on ‘Williams’ than on ‘Bonus’. Increasing mite infestation levels caused a slight increase in total soluble sugars and starch and a small decrease in total nitrogen and phosphorus levels of the leaves of both cultivars. Mite infestation had no effect on composition of seeds. Increasing mite damage caused a large reduction (55.26%) in leaf chlorophyll content and an even more dramatic loss (79.3%) in leaf carotenoid content with a greater loss in ‘Williams’ at the low mite infestation level. Results of these studies indicated that at least part of the increased resistance of ‘Williams’ to damage from T. urticae was due to a greater hypersensitive response of ‘Williams’ to mite attack. This response increased oxidizing conditions in the leaves, resulting in an extensive loss of carotenoids and chlorophyll. Increased oxidizing conditions in ‘Williams’ decreased mite population increases to a greater extent than it decreased net photosynthesis (dry matter accumulation).

Journal ArticleDOI
TL;DR: The performance of 35 soybean germplasms including 16 cultivars, 6 plant introductions and 13 lines derived from the soybean improvement program against stink bugs, was evaluated for two consecutive years, 1983/1984 and 1984/1985, in relation to the stink bugs.
Abstract: The performance of 35 soybean germplasms including 16 cultivars, 6 plant introductions and 13 lines derived from the soybean improvement program against stink bugs, was evaluated for two consecutive years, 1983/1984 and 1984/1985, in relation to the stink bugs (Hemiptera, Pentatomidae) species Piezodorus guildinii (Westwood), Euschistus heros (F.) and Nezara viridula (L.). The two experiments were conducted under field conditions at the Experimental Center of Instituto Agronomico located in Campinas, State of Sao Paulo, Brazil. A complete randomized block design with 35 treatments and 4 replications was used. The individual plot was a single row 2 meters long. Artificial infestations with adults were made to supplement the natural field infestation of stink bugs. The infestation level was moderate in the first year and severe in the second. Three criteria were used to judge the resistance to stink bugs: the percentual index of pod damage, the percentage of foliar retention after pod maturation and yield. The percentual index of pod damage is given by the formula 1/2 (% of pods with intermediate damage) + % of pods completely damaged. The percentage of foliar retention was visually estimated upon maturation of the pods. The cultivar Parana was the most susceptible treatment being recommended for use as a susceptible check for stink bugs. The lines IAC80-4228 and IAC80-598-2-4, obtained through the soybean breeding program for resistance to stink bugs, had good performance. They still present however some undesirable agronomic features and cannot be recommended for distribution to the farmers.

Journal ArticleDOI
TL;DR: Differences in seasonal damage and damage at harvest were observed between weeks, between levels of infestation, and between the week × level interaction for all of the third-instar H. zea larval infestations.
Abstract: Artificial infestations of Heliothis zea (Boddie) and Spodoptera exigua (Hubner) were made on three field plantings of processing tomatoes on a weekly basis in 1982 and 1983 to establish the damage relationship between infestations of each species during the season and damage at harvest. Comparisons of damage by both species were made to determine differences by week, level of infestation, and the week × level interaction. Damage was higher in the sampled plots during the season than in plots infested at the same time but sampled for damage at harvest. In general, the amount of damage recorded at harvest was greater as the date of infestation approached the harvest date. Differences in seasonal damage and damage at harvest were observed between weeks, between levels of infestation, and between the week × level interaction for all of the third-instar H. zea larval infestations, but only for the highest infestation levels of third-instar S. exigua . During 1982, when lower infestation levels were used, differences in damage due to timing of damage were not significant, although the general pattern held. During 1983, late instars were used, resulting in less mortality, higher levels of damage, and less variable damage.

Journal ArticleDOI
TL;DR: Plants with more infestation at the young stages of growth showed the most yield reduction, which was caused by reduced numbers and weights of primary tillers and by the secondary tillers produced being less effective.
Abstract: The effects of cuitivar, time and amount of Chilo partellus Swinhoe infestation on sorghum yield components were investigated. Damage to plants was greater on young plants with higher levels of infestation. Secondary tiller production was influenced by damage to primary tillers, which was related to the time and amount of infestation. The time of infestation was critical for panicle production and young plants in the vegetative phases were the most affected. The total grain yields were reduced in the infested plants and the extent was dependent on the cuitivar, time and level of infestation. Plants with more infestation at the young stages of growth showed the most yield reduction, which was caused by reduced numbers and weights of primary tillers and by the secondary tillers produced being less effective. The implications of these findings for the management of the pest are discussed.

Journal ArticleDOI
TL;DR: Chironomid infestation varied seasonally; it was greatest in May and July-August at an upstream station, and peaked in June at the downstream stations, and the remaining mortality appeared to be due to siltation.
Abstract: SUMMARY. 1. Up to 40% of hydropsychid pupal cases (from three stations on the Credit and Humber Rivers, Ontario, Canada) contained insects already dead when collected; chironomid infestation accounted for up to 82% of total mortality within a taxon from any one station. The remaining mortality appeared to be due to siltation. 2. For all taxa (Cheumatopsyche Wallengren and four species of Hydropsyche Pictet), and at all stations, prepupae suffered significantly more chironomid-related mortality than did fully-developed pupae. 3. Chironomid infestation generally affected all species of Hydropsyche equally; at some stations, Cheumatopsyche pupae appeared to suffer less chironomid-related mortality than did co-existing Hydropsyche species. 4. Chironomid infestation affected a greater proportion of pupae at the station where the density of pupal cases (per sampling quadrat) was greatest. 5. Vertical distribution of the pupation site had no apparent influence on mortality attributed to either siltation or chironomid infestation. 6. Chironomid infestation varied seasonally; it was greatest in May and July-August at an upstream station, and peaked in June at the downstream stations. 7. Mortality attributed to siltation was relatively constant for all stages and taxa, at all stations, throughout the sampling programme.

Journal ArticleDOI
01 Oct 1986-Botany
TL;DR: After 10 days of aphid infestation, all leaf areas were significantly lower in infested plants, and plant dry weight, mean relative growth rate, and unit leaf rate were significantlyLower in all plant–aphid combinations except for pea – pea aphids.
Abstract: The effects of cowpea aphids (Aphis craccivora Koch) and pea aphids (Acyrthosiphon pisum (Harris)), both Homptera: Aphididae, on nitrogen (N) and phosphorus (P) uptake by and growth of cowpea (Vigna unguiculata (L.) Walp. cv. Caloona), broad bean (Vicia faba L. cv. Aquadulce), and garden pea (Pisum sativum L. cv. Victory Freezer) seedlings were investigated. After 10 days of aphid infestation, all leaf areas were significantly lower in infested plants, and plant dry weight, mean relative growth rate, and unit leaf rate were significantly lower in all plant–aphid combinations except for pea – pea aphids. The mean leaf area ratio was the same for infested and control plants indicating that infested plants did not reallocate their assimilate resources in response to aphid feeding. The accumulation of N and P as a percentage of plant dry weight did not differ between control and infested plants and was specific to the species examined. However, control plants all had greater absolute amounts of N and P after ...


Journal Article
TL;DR: Assessment of the infestation-rate of engorging female ticks during the period that their mass ranged between 15 and 21 mg/kg sheep body mass indicated that toxicity is quantitatively identical and exhibits no intraspecific gradations.
Abstract: Simultaneous infestation of 3-6 month-old Black-head sheep with 15 South African wild strains of Rhipicephalus evertsi evertsi males and females as well as a strain from Rwanda clearly showed that all strains are capable of inducing paralysis Assessment of the infestation-rate of engorging female ticks during the period that their mass ranged between 15 and 21 mg/kg sheep body mass indicated that toxicity is quantitatively identical and exhibits no intraspecific gradations The period between the beginning of infestation to the manifestation of the first clinical symptoms is, however, strain dependent: 4 days for ticks from Warmbaths, and at least 5 days for all other strains

Journal ArticleDOI
TL;DR: The most conspicuous parasites of the kingklip Genypterus capensis are the nematode Anisakis sp.
Abstract: The most conspicuous parasites of the kingklip Genypterus capensis are the nematode Anisakis sp. and the trypanorhynch cestode Hepatoxylon trichiuri (both endoparasites) and the ectoparasitic copepod Sphyrion laevigatum. The incidence and the degree of infestation of kingklip by all these parasites are given, but in terms of pathological destruction, all can be classified as minor enemies of the species. Although kingklip co-occur with the Cape hakes and both endoparasites are found in both species, the degree of infestation varies substantially between them. The possible reasons for this difference and also the economic effects of the ectoparasite are discussed.

Journal ArticleDOI
TL;DR: A trial of shampoo which has not previously been used in the U.K. which contains a pyrethroid Phenothrin which is a synthetic derivative of the naturally occurring substance pyrethrin is described.
Abstract: was 2.45% and the estimated total number of children infested in schools was 193,806’. Routine statistics on head infestation since 1975 for England and Wales have been compiled by Central Government. These do not indicate that the situation has improved, indeed it may have deteriorated. The basic problem is’that this unwanted parasite persists largely because of the late detection of cases and the inadequate tracing and treating of contacts. Non-compliance with treatment, particularly with adult contact, is related to ~ reluctance to use the lotions. There is no doubt that in practice shampoo is a more acceptable method of treatment as compared to lotions. There have been objections to this method of treatment. Maunder points out that a much greater effective dose is given to the insects by lotions rather than shampoos &dquo;nobody would dream of killing any other insect with a shampoo; nor should they with lice&dquo;2. Nevertheless, field trials with shampoos containing Malathion and Carbaryl have shown very satisfactory results3 4. However, anecdotal evidence from many school nurses suggests that this form of treatment is unsatisfactory. It is also known that the insecticide is not always released in adequate quantities from the shampoo formulation. This paper describes a trial of shampoo which has not previously been used in the U.K. which contains a pyrethroid Phenothrin which is a synthetic derivative of the naturally occurring substance pyrethrin. The shampoo is formulated as a liquid with 0.2% pyrethroid and will be sold under the trade name of Phenoderm (Napp Laboratories Ltd.). The shampoo is compared with the traditional Carylderm shampoo (Napp Laboratories Ltd.) which is 1.5% in a gel formulation. (Now available as a liquid shampoo.) BACKGROUND


Journal ArticleDOI
TL;DR: Growing sorghum in association with cowpea or lablab reduced Sorghum stem borer infestation and prevented oviposition by gravid females of C. partellus for up to six days.
Abstract: Growing sorghum in association with cowpea or lablab reduced sorghum stem borer infestation. On sorghum as a pure crop, 32.6% stem borer damage was recorded, while intercropped with lablab or cowpea it was 9.2 and 16.4% respectively. Sorghum raised with lablab or cowpea yielded 4652 and 4567 kg of grain per ha respectively while pure sorghum yielded 3509 kg. When the phytochemicals extracted from the legumes lablab or cowpea were sprayed on sorghum they prevented oviposition by gravid females of C. partellus for up to six days.

Journal ArticleDOI
TL;DR: In this paper, the authors conducted laboratory studies to assess the post-harvest susceptibility of Callosobruchus maculatus (Fab.) on 12 elite and one local cowpea cultivars which were stored under subtropical conditions.
Abstract: Laboratory studies were conducted to assess the infestation potential of Callosobruchus maculatus (Fab.) on 12 elite and one local cowpea cultivars which were stored under subtropical conditions. Index of susceptibility, loss in grain quality and the number of adult progeny that emerged from previously infested grain were the criteria used to assess the vulnerability of the cowpeas to post-harvest infestation. Cultivars TV × 309-1C and TV × 1193-10F showed some degree of resistance to post-harvest infestation by C. maculatus and could therefore be stored safely for a relatively long time. TV × 1192-01D and TV × 1999-ID were the most susceptible cultivars to post-harvest attack by C. maculatus. Length of storage adversely affected the ability of the cultivars to resist the insect attack. Crop resistance, adequately supplemented with good sanitation, can be profitably applied to control insect infestations in grains during storage.

Journal ArticleDOI
TL;DR: The population density of crayfish intermediate host and infestation rates for thecrayfish with encysted larvae of Paragonimus westermani in Ulchin county of Kyungpook province is relatively high.
Abstract: A study on the population density of crayfish intermediate hosts and infestation status of crayfish with encysted larvae of Paragonimus westermani in Ulchin county, Kyungpook Province, Korea was conducted from May to October in 1986. The population density of the crayfish ranged from 1 to 13, with an average of 4 per man-hour. Among the six habitats, Ducheon had a somewhat higher density than that of the others. Of eight hundred and seventeen crayfish examined, 127 or 15.5 per cent harboured the metacercarial larvae of Paragonimus westermani. The majority of the larvae were found in three parts of the body: most frequently in the cephalothorax, next in the gills, and then in the liver. The average number of metacercarial larvae per infected crayfish ranged from 1.0 to 1.9, with an average of 1.7. Summarizing the results, this study indicates that the population density of crayfish intermediate host and infestation rates for the crayfish with encysted larvae of Paragonimus westermani in Ulchin county of Kyungpook Province is relatively high.