bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of environmental humidity and dietary protein on pyramidal growth of carapaces in African spurred tortoises (Geochelone sulcata)
Authors: Wiesner C. S. , Iben C.
Published: March 2003

The carapaces of captive‐raised tortoises (terrestrial chelonians of the zoological family Testudinidae, often develop pyramidal‐shaped osseous growth centrally within the horny plates. With very few exceptions (e.g. Geochelone elegans, Psammobates sp.), this conical growth pattern is considered to be pathologic. This very common defect is believed to be an important indicator of the quality of captive tortoise management. This study was designed to examine the effect of dietary protein level and environmental humidity on the degree of pyramidal growth in the carapaces. Fifty recently hatched African spurred tortoises (G. sulcata) were raised for 5 months under artificial conditions of varying environmental humidity and dietary protein content (14% vs. 19% vs. 30% crude protein in dry matter). Humps of the carapaces that developed and blood values of calcium, phosphorus and haematocrit were measured and compared among groups. Dry environmental conditions (24.3–57.8% and 30.6–74.8% relative humidity) produced taller humps than humid conditions (45‐99% relative humidity). Hump formation differed significantly (p ≤ 0.001) between these three groups kept under different humidity conditions. Variable dietary protein had a minor, positive impact on this pathological formation of humps (pyramidal growth syndrome, PGS). Analysis of blood (calcium, phosphorus and haematocrit) offered no further explanation as to the development of the humps.
Shoot feeding and overwintering in the lesser pine shoot beetle Tomicus minor (Col., Scolytidae) in north‐west Spain
Authors: Fernández M. M. Fernández , Alonso J. A. Pajares , Costas J. M. Salgado
Published: March 2003

During 1991, 1992, &, 1993 a study on shoot feeding, overwintering and the presence of Tomicus minor inside pine shoots was carried out in the province of León (NW Spain). This paper deals with the duration of these processes, overwintering sites and pine shoot feeding characteristics: age, diameter, length, occurrence of exit holes, multiple attacks and length of the burrowed tunnels. It also refers to the degree of shoot occupation, sex‐ratio and detected adult mortality.
Parasitism of the herbivore Pieris brassicae L. (Lep., Pieridae) by Cotesia glomerata L. (Hym., Braconidae) does not benefit the host plant by reduction of herbivory
Authors: Coleman R. A. , Barker A. M. , Fenner M.
Published: March 2003

Models of tritrophic interactions often imply that attraction of herbivore natural enemies by the plant constitutes a defence. Parasitoid attack on herbivores is assumed to result in a reduction in herbivory and/or an increase in plant fitness. Coupled with the active involvement of the plant in producing signals, this can be seen as indirect mediation of wound‐induced defence. The assumption that parasitism of Pieris brassicae L. by the parasitoid Cotesia glomerata L. reduces leaf consumption of cabbage is tested. The effect of parasitism on the growth and feeding rates of P. brassicae larvae compared to unparasitized larvae. Either the defensive mechanism, if it exists, is more subtle, or the natural enemy is using an incidental chemical produced as a by‐product of the herbivores feeding action as a cue for host‐finding, with no increaction effects. This has implications for the study of tritrophic interactions, particularly in the context of agricultural systems and the assumption that in IPM strategies, parasitoids are a plant benefit.
A new character for sex differentiation of adults of Anthonomus pomorum L. (Col., Curculionidae)
Authors: Duan J. J. , Weber D. C. , Hirs B. A. , Dorn S.
Published: March 2003

Microscopic examination of adults of the apple blossom weevil, Anthonomas pomorum L. reveals distinct differences between sexes in the last two (seventh and eighth) abdominal tergites. The last two abdominal tergites in males are clearly divided by a suture, whereas the division is not visible in females, in which these two tergites form a single triangular plate. In addition, the last (eighth) abdominal tergite of the male is covered with dense setae, and is about one‐third of the size of the last abdominal plate of the females. These differences permit sex differentiation of adult apple blossom weevils with complete accuracy.
Studies on predation of Prostephanus truncatus (Horn) (Col., Bostrichidae) and Sitophilus zeamais Mots. (Col., Curculionidae) at different densities on maize by Teretriosoma nigrescens Lewis (Col., Histeridae)
Authors: Ayertey J. N. , Meikle W. G. , Borgemeister C. , Camara M. , Markham R. H.
Published: March 2003

Laboratory experiments using whole cobs were conducted to examine the effect of varying densities of the larger grain borer, Prostephanus truncatus and the maize weevil, Sitophilus zeamais on rate of population increase by the histerid beetle, Teretriosoma nigrescens, a predator primarily of P. truncatus. Densities of all species of insects were determined at the end of the experiment, and an electrophoretic analysis of gut content was conducted on larval and adult T. nigrescens sampled during the experiments. Results indicated that T. nigrescens has a strong preference for P. truncatus and densities of T. nigrescens were associated only with densities of P. truncatus. The maize weevil played little role as an alternative prey or in interfering with T. nigrescens reproduction.
Intestinal modifications of oak leaf tannins by Lymantria dispar L. (Lep., Lymantriidae) and possible effect on larval development
Authors: Henn M.
Published: March 2003

The mode of action of polyphenols within an insect is not well understood and it would be useful to investigate the behaviour pattern of single phenolic compounds within the gut of an insect in this context. In the present study, the phenolic composition of the food of the gypsy moth, Lymantria dispar, was compared with that of its frass by using high‐performance liquid chromatography. The main difference was a shift in the concentration of phenolics in the frass with short retention times to those with longer ones, which, additionally, resulted in the appearance of new phenolic compounds. These new phenolics were hydrolysable tannins because after a cleavage via hydrolysation the hydrolysate contained high amounts of gallic acid. The appearance of these new phenolics in the frass of the larvae influenced growth negatively, as there was a negative correlation (P < 0.05) between their concentrations and the growth percentages of the larvae.
Efficacy of two tropical plant extracts for the control of mosquitoes
Authors: Pushpalatha E. , Muthukrishnan J.
Published: March 2003

The larvicidal activity of seed and leaf extracts of Calophyllum inophyllum and leaf extract of Rhinacanthus nasutus on the juveniles of Culex quinquefasciatus, Anopheles stephensi and Aedes aegypti was determined. Ethyl acetate (EA) soluble fractions of C. inophyllum and petroleum ether (PE) fraction of R. nasutus extracts showed very high larvicidal activity. Irrespective of the species of the mosquitoes tested, at concentrations ranging from 3.91 to 9.39 ppm, 9.04 to 35.49 ppm and 13.21 to 28.92 ppm of the active fractions of seed and leaf extracts of C. inophyllum and the leaf extract of R. nasutus, respectively, killed 50% of the treated larvae. The fractions also interfered with adult emergence. Exposure of the mosquitoes at any stage of their larval development to less than 0.86, 5.49 and 6.81 ppm of the active fractions of seed and leaf extracts of C. inophyllum and the leaf extract of R. nasutus, respectively, inhibited 50% of the treated larvae from emerging as adults. Experiments under laboratory and semi‐field conditions showed that the activity of the extracts persisted for up to 10 days.
Sex pheromone of the spotted tentiform leafminer moth Phyllonorycter blancardella (Fabr.) (Lep., Gracillariidae)
Authors: Mozuraitis R. , Borg‐Karlson A‐K. , Buda V. , Ivinskis P.
Published: March 2003

Dodecyl acetate (12:OAc) (E)‐10‐dodecenyl acetate (E10‐12:OAc) and (E)‐10‐dodecenol (E10‐12:OH) in the ratio 8 : 80 : 12 were collected by solid phase micro‐extraction of the volatiles emitted by virgin signalling females of the spotted tentiform leafminer moth, Phyllonorycter blancardella. The same compounds in the ratio 8 : 79 : 13 were extracted from the sex pheromone glands of virgin signalling females of the same species. The chemical structures of the compounds were identified by gas chromatography and mass spectrometry. Trapping results obtained from field tests using synthetic components of the sex pheromone demonstrated that only one component, E10–12:OAc, was essential for the attraction of conspecific males and should be considered as a sex pheromone.
Evaluation of synthetic food‐based attractants for female Mediterranean fruit flies (Dipt., Tephritidae) in McPhail type traps
Authors: Katsoyannos B. I. , Papadopoulos N. T. , Heath R. R. , Hendrichs J. , Kouloussis N. A.
Published: March 2003

During summer 1997 field experiments were conducted on the island of Chios, Greece, to compare captures of female Mediterranean fruit flies (medflies), Ceratitis capitata (Wiedemann), in traps baited with either synthetic female‐targeted lures or a standard protein bait (NuLure and borax). The synthetic lures contained ammonium acetate,1,4 diaminobutane (putrescine), and trimethylamine. Two trap types (International Pheromone’s McPhail Trap (IPMT) and the Tephri trap) were tested as either wet or dry. Wet IPMT traps baited with the synthetic attractants were the most attractive of all trap combinations tested and captured 2.1 times more female medflies and 1.8 times more total medflies than traps baited with NuLure and borax. Traps containing the synthetic attractant captured approximately 4.6 times fewer nontarget insects than NuLure baited traps. Vapona used in IPMT traps was repellent to medflies and dry traps with lower concentrations of Vapona were approximately 1.5 times less attractive to female medflies than traps containing water. Even with a decrease in attractiveness, the dry traps were significantly more effective for females and more practical for mass trapping and monitoring than the currently used traps baited with protein solutions.
Comparative effects of deltamethrin and Neem kernel solution treatments on Diamondback moth and Cotesia plutellae (Hym., Braconidae) parasitoid populations in the Cotonou peri‐urban area in Benin
Authors: Goudegnon A. E. , Kirk A. A. , Schiffers B. , Bordat D.
Published: March 2003

A comparison between deltamethrin and Neem kernel solution treatments on Plutella xylostella (L.) populations was made in the Cotonou peri‐urban area. Diamondback moth populations were 10 times larger in deltamethrin plots, than in Neem plots after treatment. The number of marketable cabbages from Neem‐treated plots was 1.5 times greater than the number from deltamethrin‐treated plots. There was no apparent effect of either treatments on Cotesia plutellae (Kurdjumov) populations, the only parasitoid of the pest that was present in the area.
Sublethal effects of chlorfluazuron on reproductivity and viability of Spodoptera litura (F. ) (Lep., Noctuidae)
Authors: Perveen F.
Published: March 2003

Abstract: Chlorfluazuron is an insect growth regulator for controlling the major insect pests in crops. To clarify the sublethal effects of chlorfluazuron on reproductivity and viability of common cutworm, Spodoptera litura, some experiments were conducted under laboratory conditions. The LD50 was found to be 12.0 ng/larva when evaluated up to pupation and 9.9 ng/larva up to adult emergence. At lethal dosages the development of different instars, moulting to pupae and emergence into adults were found to be more affected. Reduction in the body weight was also observed in the larvae and pupae when treated with a sublethal dose (LD30 : 3.75 ng/larva) and in the adults when treated with sublethal doses (LD10 : 1.00 ng/larva; LD30 : 3.75 ng/larva) as newly moulted fifth instar larvae of S. litura, although the number of matings per female and life span of adult females and males remained unaffected by the same treatments. When sublethal doses were applied only to females or only to males, or both sexes, the average fecundity reduction was up to 35–44%. When only females were treated with sublethal doses, fertility was reduced by 49–58%; when only males were treated fertility was reduced by 65–81% and when both sexes were treated, fertility was reduced by 68–83%. Hatchability was reduced by 22–26% when only females were treated, by 44–66% when only males were treated and by 45–72% when both sexes were treated with LD10 or LD30 doses as newly moulted fifth instars. The results from these observations suggest that the fecundity was reduced to a similar degree when only females or only males or both sexes were treated with LD10 or LD30 doses as newly moulted fifth instars. However the fertility and hatchability were affected more when only males were treated with LD10 and much more when treated with LD30. Currently, work is in progress to find out the main reasons for the sublethal effects of chlorfluazuron on reproductivity and viability.
Aetiology of melanized inclusions in the body cavity ofNeodiprion sertifer(Geoffroy) (Hym., Diprionidae) adults
Authors: Olofsson E.
Published: March 2003

Abstract:The aetiology of large melanized inclusions occurring in the haemocoel of adults of some diprionid sawflies is not fully understood. Their occurrence has been associated with nuclear polyhedrosis virus (NPV), but also with extreme temperatures, parasitism, and prolonged diapause. High frequencies of inclusions are found most often during NPV epizootics. In laboratory experiments withNeodiprion sertiferlarvae, ingestion of large doses of a common bacterium,Enterobacter cloacae, was shown to induce inclusions indistinguishable from those associated with NPV infection. It is argued that a bacterial aetiology is not contradicted by the other conditions reported to be associated with inclusions. The bacterial aetiology provides an explanation for the low frequencies of inclusions inN. sertiferpopulations with no NPV infection. It is proposed that the ability to form inclusions may have evolved as a defence against bacterial infection.
Endogenously entrained emergence and oviposition rhythm in the African rice gall midge, Orseolia oryzivora H. and G. (Dipt., Cecidomyiidae)
Authors: Omoloye  , Odebiyi
Published: March 2003

Studies on the rate, period and cycle of emergence and oviposition of African rice gall midge, Orseolia oryzivora kept in screenhouses revealed an endogenously entrained circadian rhythm. Emergence commenced 23 days after infestation (at 27 ± 2°C and 70 ± 12% relative humidity) at 1800 h and stopped at 2400 h daily for a 5 day period of emergence. Each female mated once throughout life and oviposition occurred after mating between 1800 h and 2400 h daily. This 6 h cycle of oviposition continued until the ovipositing female died.
Assessment of temperature effects on the development and fecundity of Pullus mediterraneus (Col., Coccinellidae) and consumption of Saissetia oleae eggs (Hom., Coccoida)
Authors: Ba M'Hamed T. , Chemseddine M.
Published: March 2003

Eggs, larval and nymphal periods and fecundity of Pullus mediterraneus were examined under 16 h light : 8 h dark combined with six constant temperatures: 15, 20, 25, 30, 35 and 40°C. Eggs of Saissetia oleae were used as prey. The developmental time at 15, 20, 25, 30 and 35°C was 17.23, 4.5, 2.64, 1.67, 1.28 days for eggs and 98.47, 68.88, 53.94, 28.96, 36.51 days for larval–pupal duration, respectively. At 7°C no eggs hatched, and at 40°C all the stages died after 36 h of maximum exposure except the three last stages. The fecundity of females rearing at different temperatures ranged between 1.7 eggs at 15°C and 601.86 eggs at 30°C. The pre‐oviposition period ranged between 23.75 days at 15°C and 3.47 days at 35°C. The consumption of S. oleae eggs by the larvae reached 597.69 eggs during the pre‐imaginal development. Females attacked more eggs than males averaging 77.69 ± 22.34 eggs per 4 day period compared with 46.97 ± 10.12 eggs per 4 day period for males.
Intrinsic rate of population increase ofAmitus fuscipennisMacGown and Nebeker (Hym., Platygasteridae) according to climatic conditions and bean cultivar
Authors: Manzano M. R. , Van Lenteren J. C. , Cardona C.
Published: March 2003

Data on adult longevity, reproduction and intrinsic rate of population increase of insect parasitoidAmitus fuscipennisMacGown and Nebeker (Hym., Platygasteridae) were obtained under different climatic conditions on two bean cultivars. The insect host was the greenhouse whiteflyTrialeurodes vaporariorum(Westwood) (Hom., Aleyrodidae). On cv. Chocho, at 19°C, 75 ± 5% RH and at 22°C, 70 ± 5% RH, mean longevity of adultAmitusfemales on the host insect was 9.3 and 5.7 days; mean fertility was 64.1 eggs and 52.7 eggs; and rmvalues were 0.102 day–1and 0.144 day–1for the respective conditions. On cv. ICA‐Pijao, at 19°C, 75 ± 5% RH, mean longevity was 15.2 days; mean fertility was highest (162.8 eggs); and rmvalue was 0.117 day–1. The rmvalues ofAmituswere higher than those of its host under the same test conditions. This parasitoid may therefore be a suitable candidate for use in inoculative or seasonal inoculative control programs againstT. vaporariorum.
Seasonal abundance, spatial distribution and sampling indices of thrip populations on cotton; a 4‐year survey from central Greece
Authors: Deligeorgidis P. N. , Athanassiou C. G. , Kavallieratos N. G.
Published: March 2003

Abstract: Field studies were carried out in order to assess the populations of thrips on cotton leaves, by developing a sampling program to estimate the density with an acceptable level of precision. Thus, in a cotton field (1.1 ha) in central Greece, 45 leaves were collected (one leaf per cotton plant) at 10‐day intervals from May to September, for four consecutive growing seasons (1995–98). Five species of thrips were found: Frankliniella intonsa was the most abundant species followed by Thrips angusticeps, Thrips tabaci, Frankliniella occidentalis and Aeolothrips intermedius. Although considerable differences were observed in the population fluctuations among species, the highest population densities, for all species found, were recorded in July and August. As indicated by Taylor's power law estimates, all species presented aggregated distribution among sampling units. As this type of spatial pattern indicates, the accuracy obtained in estimating mean population density increased with the increase of the mean. Furthermore, the increase of the mean caused an exponential decrease in sample size. However, the precision level is acceptable only in high mean values, while at the same time the benefit from an increase in sample size is of no practical value.
Relationship between the microhabitat and trophic conditions and the numbers of Pissodes piceae (Ill.) (Col., Curculionidae) in stumps of Abies alba Mill. in the Świeętokrzyski National Park (Poland)
Authors: Podlaski R.
Published: March 2003

Abstract:  The objective of this study was to analyse the relationship between selected ecological factors (insolation, degree of cover of stump side surface with mosses and lichens, degree of bark and wood decomposition, wood moisture) and the numbers of Pissodes piceae in stumps of Abies alba. A total of 688 fir stumps were chosen at random in partially protected forest reserves of the Świętokrzyski National Park. Out of the analysed fir stumps, 36% (247 stumps) were inhabited by P. piceae. The mean number was 10.5 individuals of P. piceae per stump, and the mean colonization density was 107.0 individuals per m2. A geometric distribution (event probability was 0.0872) correctly approximated the real distribution of P. piceae numbers in fir stumps. Pissodes piceae was most abundant in fir stumps from about 40 cm to about 60 cm in the top surface diameter, and from about 35 cm to about 50 cm in height. This insect species preferred fir stumps occurring in places that were slightly insolated (in stand openings from about 5 m to about 15 m in diameter), devoid of moss and lichen cover, with the bark moderately decomposed, and the wood slightly decayed and moderately moist.
Dispersal of Podisus nigrispinus (Het., Pentatomidae) nymphs preying on tomato leafminer: effect of predator release time, density and satiation level
Authors: Torres J. B. , Evangelista W. S. , Barras R. , Guedes R. N. C.
Published: March 2003

Abstract:  The dispersal potential of nymphal stinkbug, Podisus nigrispinus (Dallas, 1851) (Het., Pentatomidae) preying on larvae of the tomato leafminer Tuta absoluta (Meyrick, 1917) (Lep., Gelechiidae) was studied in an open‐sided greenhouse. The parameters investigated were (1) the density of nymphs released per plant (one or five); (2) the release time (0600 and 1800 h); and (3) predator satiation level (satiated and 24‐h‐starved nymphs). Tomato plants were infested with larvae of the tomato leafminer (one third or fourth instar per leaf). The evaluations started 30 min after the release of predators second instar and hourly evaluations were carried out over 36 and 24 h for release times of 0600 and 1800 h, respectively. Starved nymphs released in the morning, either alone or in groups of five, dispersed faster than satiated nymphs. All of the starved individuals had left the plant by the end of the observation period, whereas 25 and 36% of the satiated nymphs released alone and in groups, respectively, stayed on the plant until the end of the observation period. Both satiated and starved nymphs showed slower rates of dispersal when released at 1800 h. Satiated nymphs delayed prey attack up to 9 h, whereas starved individuals started to attack T. absoluta caterpillars 1 h after their release at both densities. Our findings suggest more effective biological control of T. absoluta is possible with the release of second instar nymphs of P. nigrispinus when starved for 24 h prior to release and then released either in the morning or in the evening.
Laboratory studies on the effects of pollen from Bt‐maize on larvae of some butterfly species
Authors: Felke M. , Lorenz N. , Langenbruch G.‐A.
Published: March 2003

Abstract:  Three lepidopteran species were tested to determine their susceptibility against the ingestion of pollen from genetically modified maize plants. To prove the existence of dose–response relations between the applied amount of pollen (Bt‐maize) and the damages on the tested larvae, a method was developed which makes it possible to feed caterpillars with defined amounts of pollen. If their food plants were contaminated with pollen of a cultivar of the Bt‐176 maize‐line Pieris brassicae, Pieris rapae and Plutella xylostella‐larvae fed less, grew more slowly and showed a higher mortality than caterpillars of an untreated control group. The 50% lethality (LD50)‐values were calculated for P.xylostella (L4) with 19.2, for P. rapae (L2) with 39.0 and also for P. brassicae (L2) with 139.2 pollen of the transgenic maize Pactol CB. Studies with P. brassicae‐caterpillars of different larval stages indicated, that older individuals showed a higher tolerance against pollen from Bt‐maize than younger ones. It must be stated on the basis of the present studies, that ingestion of non‐transgenic maize pollen has neither a positive nor a negative effect on caterpillars. It becomes clear from the information presented here that it is still difficult to make general statements about the endangering of butterflies, arising from cultivation of genetically modified maize lines. Further investigations on this issue are needed. Initially, the LD50‐values concerning the larvae of certain butterfly species have to be determined to anticipate the risks, and in addition the distances between habitats with caterpillar host plants and maize fields, and the abundance of these plants have to be considered.
Soluble carbohydrates in the nutrition of house longhorn beetle larvae, Hylotrupes bajulus (L.) (Col., Cerambycidae): from living sapwood to faeces
Authors: Höll W. , Frommberger M. , Straßl C.
Published: March 2003

Abstract: Water‐soluble carbohydrates from (a) living sapwood of Scots pine (Pinus sylvestris L); (b) dry sapwood blocks from Scots pine (EUROPEAN STANDARD EN 46, 1988); and (c) faeces from Hylotrupes bajulus (L) larvae feeding from these blocks were analysed. Living sapwood contains high amounts of sucrose, glucose, fructose and starch. These carbohydrates seem to be hydrolysed and metabolized during the production of the sapwood blocks. The faeces contain carbohydrates which are not present either in living sapwood or in the sapwood blocks: xylose and an oligosaccharide of uncertain composition. This oligosaccharide is the dominant water‐soluble carbohydrate in the faeces. In contrast to living sapwood and sapwood blocks, the faeces contain considerable amounts of soluble β‐glucans. The results show that the composition and the amounts of carbohydrates differ significantly from that in the sapwood blocks (fodder for the larvae). The α‐glucans (starch) present in the wood are not significantly utilized by the larvae. Regarding soluble carbohydrates, diet wood has only little in common with the living wood of the standing tree.
The Lipoxygenase Pathway is Involved in Elicitor‐induced Phytoalexin Accumulation in Plane Tree (Platanus acerifolia) Cell‐suspension Cultures
Authors: Alami I. , Jouy N. , Clérivet A.
Published: March 2003

The Ceratocystis fimbriata f.sp. platani 66 kDa glycoprotein elicitor‐induced secretion of soluble coumarins by plane tree (Platanus acerifolia (Aiton) Wild) cell‐suspension cultures was investigated by studying the possible involvement of the octadecanoid pathway in the cell response. When cell‐suspension cultures were treated with the glycoprotein elicitor, the cells exhibited a rapid and transient increase in lipoxygenase activity, in synthesis of endogenous jasmonic acid prior to the accumulation of coumarin phytoalexins. The treatment of cells with an inhibitor of lipoxygenase (ETYA) before elicitor addition, drastically reduced the lipoxygenase activity, the production of endogenous jasmonic acid and phytoalexin accumulation. The results demonstrate the role of the jasmonate pathway in the intracellular signal cascade.
Competition Alters Temporal Dynamics of Sporulation in the Wheat Stem Rust Fungus
Authors: Newton M. R. , Wright A. S. , Kinkel L. L. , Leonard K. J.
Published: March 2003

To investigate the effects of competition on the timing of pathogen reproduction, urediniospores of two strains of Puccinia graminis f.sp. tritici (SR22 and SR41) were inoculated onto leaves of wheat seedlings singly and in 1 : 1 mixture at three inoculum densities. On randomly sampled leaves, uredinia were counted 9 days after inoculation and urediniospores were collected and quantified every other day from the seventh to the 29th day after inoculation. Increases in inoculum density resulted in progressively smaller increases in uredinial numbers. However, total urediniospore production per leaf was not significantly affected by inoculum, and hence uredinial, density over a range of approximately 10‐300 uredinia on the leaf. Total urediniospore production per uredinium generally decreased with increasing inoculum or uredinial density. At high densities, sporulation per uredinium peaked earlier in the sporulation period, had a less distinct peak, and dropped off earlier than for the lower densities. Logistic model fits to cumulative sporulation curves over time revealed that strain SR41 had a greater epidemic rate parameter (r) than SR22 at low and intermediate inoculum or uredinial densities, while SR22 had a higher r‐value than SR41 at high density. Both strains also exhibited greater r‐values in the presence of the other strain than when alone. Results suggest that strains may have different ecological strategies in their timing of reproduction, and that both intra‐ and interstrain competition can have complex effects on the temporal dynamics of sporulation in pathogen strains.
ARIS, Fruit and Grape Research Centre, Čačak, Yugoslavia, the Institute for Molecular Genetics and Genetic Engineering and the Faculty of Biology, Belgrade, Yugoslavia
Authors: Paunović S. , Maksimović V. , Ranković M. , Radović S.
Published: March 2003

Pear stony pit associated isolate WT, which originated from diseased pear cultivar Württemberg, was characterized by biological tests on woody and herbaceous indicator plants, by serological test with polyclonal antisera against apple stem pitting virus (ASPV), as well as by the molecular methods of dsRNA analysis and reverse transcription‐polymerase chain reaction (RT‐PCR) with ASPV‐specific primers. The reactions of indicator plants Jules d’Airolles, Beurre Hardy, Nouveau Poiteau, Pyronia veitchii, seedlings Pyrus communis, Nicotiana occidentalis 37B and Nicotiana occidentalis obliqua infected by WT isolate indicated the relatedness of WT isolate to ASPV. The positive serological reaction of coat protein of the WT isolate with polyclonal antibodies against ASPV in Western blot reaction was obtained. The slowest migrating dsRNA band associated with pear stony pit co‐migrated with dsRNA having the highest molecular weight in different ASPV isolates from apple and pear. The dsRNA pattern of WT isolate was identical to dsRNAs associated with quince fruit deformation and sooty ringspot. In RT‐PCR, the fragments were obtained of the expected 351 and 291 bp sizes using two sets of ASPV‐specific primers from dsRNA templates in the WT isolate, as well as in control ASPV isolates ST and CJ. The results obtained have shown the WT isolate associated with pear stony pit in cv Württemberg, to be one of the apple stem pitting isolates.
The Role of Extracellular pH‐homeostasis in Potato Resistance to Ring Rot Pathogen
Authors: Romanenko A. S. , Riffel A. A. , Graskova I. A. , Rachenko M. A.
Published: March 2003

Different cultivars of in vitro plants of potato Solanum tuberosum L. were cultivated with a bacterium Clavibacter michiganensis ssp. sepedonicus (Spieck. et Kott.) Skaptason et Burkh., causing wilt of the overground part and ring rot of tubers. Development of disease symptoms (chlorosis, growth suppression) closely correlated with strong acidification of the medium, caused by the bacterium producing extracellular polysaccharides. However, root cells of the host plant (potato) and other non‐host plants (seedlings of tomato, wheat and radish) were able to restore extracellular pH. The efficiency of such restoration correlated with the resistance of the potato cultivar to bacteriosis. Plasma membrane and vacuolar H+‐ATPases were not involved in the stabilization of extracellular pH‐homeostasis, but a significant role was played by the buffer capacity of the cells. The maintenance of pH‐homeostasis in the plants is inferred to be one of the main factors of nonspecific resistance.
Induction of Local and Systemic Resistance to Colletotrichum coccodes in Pepper Plants by	dl ‐β‐Amino‐n‐Butyric Acid
Authors: Hong Jeum Kyn , Hwang Byung Kook , Kim Chung Hoe
Published: March 2003

dl‐β‐amino‐n‐butyric acid (BABA) that was applied as a foliar spray or soil drench to pepper plants induced local and systemic resistance to a challenge infection with Colletotrichum coccodes. About 85 and 100% protections against the anthracnose were achieved by a relatively high concentration of BABA at 1000 μg/ml, which had no antifungal activity in vitro against C. coccodes. Protection was expressed as a reduction in the number and size of lesions.
dl‐α‐amino‐n‐butyric acid (AABA) was not so effective as BABA, whereas
dl‐γ‐amino‐n‐butyric acid (GABA) provided a little protection against anthracnose. At least 5 days were needed after BABA treatment as a soil drench in order to induce resistance in pepper plants. After BABA treatment as a soil drench, the plants remained protected over 15 days. Application of BABA to the lower leaves significantly protected the leaves above the treated leaves from C. coccodes infection, which suggested that systemic resistance to the anthracnose was induced in pepper plants by BABA. The leaves above the BABA‐treated lower leaves were strongly protected by reduction of the number and size of lesions.
Cacopsylla costalis (Flor 1861), as a Vector of Apple Proliferation in Trentino
Authors: Frisinghelli C. , Delaiti L. , Grando M. S. , Forti D. , Vindimian M. E.
Published: March 2003

Recently, a epidemic of apple proliferation (AP) in an orchard area of Trentino (North Italy) occurred. The most affected cultivars were Golden Delicious, Florina and Renetta Canada grafted on different rootstocks. In this area the known or supposed vectors of the disease were not present. At the same time as the AP symptoms appeared, a notable increase of the presence of psyllids was observed on apple trees so a correlation between these insects and the AP was hypothesized. Four different psyllid species were found in the orchard: Cacopsylla melanoneura (Förster 1848), Cacopsylla costalis (Flor 1861), Cacopsylla mali (Schmidberber 1836) and Trioza urticae (Linnaeus 1758). The first two were more frequent in spring at the adult stage. In 1997 C. costalis was particularly numerous and was used to plan AP transmission trials. The transmission from infected AP apple trees to the insect in field and from the psyllids to non‐infected Golden Delicious and Florina plants in the greenhouse were conducted. For the control of phytoplasma presence in the psyllids and in the apple plants polymerase chain reaction (PCR), nested PCR and restriction fragment length polymorphism analysis were used. In autumn 1997, some inoculated plants showed symptoms of AP. Molecular results were consistent with the presence of phytoplasma in C. costalis and in inoculated apple cultivars.
Evaluation of Resistance of Stone Fruit Rootstocks to Phytophthora Crown Rot*
Authors: Elena K. , Tsipouridis K.
Published: March 2003

The pathogenicity of Phytophthora citrophthora, Phy‐tophthora cactorum and Phytophthora megasperma strains was confirmed on 2‐year‐old stone fruit rootstocks artificially inoculated in the field. Phytophthora mega‐sperma was not virulent or less virulent than P. cactorum or P. citrophthora. The rootstocks Damas and AN 1/7 were resistant whereas the rootstocks Jl, Titan x Nemaguard 5/1, GF 677, Myrandier 613, Italian x Nemaguard 1 and Myrandier 617 were susceptible to P. citrophthora. The rootstocks Tsukuba 9, Tit‐an x Nemaguard 4/7, AN 1/2, AN 1/3, St. Mien 655/2 and Bl showed medium susceptibility to this species. The isolates of P. cactorum induced more extensive necrosis in Myrandier 617 and Italian x Nemaguard than in Myr‐andier 613, GF 677, Jl (ADAFUEL), Tsukuba 9 and St. Julien 655/2. Among seven rootstocks, Tsukuba 5 and St. Julien 655/2 were more resistant than Myrandier 613, Myrandier 617, Jl (ADAFUEL), Tsukuba 9 and St. Julien 655/2.
Effect of Nutrition and Physical Factors on Mycelial Growth and Production of Pigments and Nonchromatic UV‐absorbing Compounds ofAlternaria eichhorniae
Authors: Shabana Y. M. , Elwakil M. A. , Charudattan R.
Published: March 2003

Alternaria eichhorniaeis a host‐specific biocontrol agent for managing waterhyacinth (Eichhornia crassipes) in Egypt. An important diagnostic characteristic of this fungus is the production of crimson‐red phytotoxic pigments in the medium under certain conditions. A virulent isolate,A. eichhorniae5 (Ae5), was studied to determine the optimum conditions for its growth and production of pigments and nonchromatic UV‐absorbing metabolites (UVACs). The maximum production of pigments was obtained when cultures were grown on potato dextrose agar (PDA) with 20% dextrose, an initial pH of 4.5 at 25–30°C under continuous darkness or diurnal light, and without wrapping the culture plates. The maximum yields of the nonchromatic, 229‐ and 286‐nm‐absorbing compounds were obtained on PDA with 20–50% of dextrose at 20–30°C under continuous darkness. Culture plates, unwrapped or wrapped with only one layer of Parafilm at pH from 3.8 to 6.2 were favourable in this respect. There was a strong inverse relationship between linear mycelial growth and pigmentation as a function of light. Furthermore, the reduction in aeration, presumably proportional to the number of layers of Parafilm wrappings, led to lower levels of the red pigment(s) and the nonpigmented UVACs, to reduced mycelial growth, and a suppression of sporulation. Different culture‐filtrate fractions of Ae5 were tested for phytotoxicity. At the concentrations of 0.5 and 1% w/v of the partially purified culture filtrate fractions, all except the butanol 1 fraction, had no toxic effect on waterhyacinth leaf‐segments. Butanol fractions at 10% (w/v) concentration were significantly more damaging than aqueous fractions (10% w/v) and the area of necrosis increased with time.
Distribution and Severity of Bacterial Diseases on Dry Beans (Phaseolus vulgaris L.) in South Africa
Authors: FOURIE D.
Published: March 2003

Disease surveys were conducted during 1995/96 in seed production fields, and 1996/97 and 1997/98 in commercial dry bean‐producing areas to determine incidence, severity and spread of bacterial diseases in South Africa. A total of 682 seed production fields at 31 localities and 81 commercial fields at 24 localities were surveyed. Common bacterial blight occurred in 83 and 85% of localities in seed and commercial production areas, respectively. Halo blight was restricted to cooler production areas and occurred in only 10% of seed production fields and 37% of commercial fields surveyed. Bacterial brown spot was the most widespread bacterial disease occurring in 93% of seed production fields and 100% commercial fields. Although incidences of bacterial diseases were high, severity was generally low. The widespread distribution of bacterial diseases in both seed and commercial production areas questions the effectiveness of disease‐free seed as a primary control method.
Comparison of Whole‐Cell Fatty Acid Compositions of Isolates of Rhizoctonia solani AG 2 from Tobacco and Tulip, AG 2–1 and AG‐BI
Authors: PRIYATMOJO A. , YAMAUCHI R. , NAITO S. , KAGEYAMA K. , HYAKUMACHI M.
Published: March 2003

Abstracts

Isolates of Rhizoctonia solani AG 2 from tobacco (Nt‐isolates) were reported to anastomose with isolates of AG‐BI in high frequency (fusion frequency [FF] ≥ 50%) compared to isolates of AG 2–1 (FF < 50%), even though mature culture and thiamine requirement of the isolates were closely similar to AG 2–1. In this study, whole‐cell fatty acid compositions of Nt‐isolates (four isolates), isolates of AG 2–1 (eight isolates) and AG‐BI (two isolates) were compared by gas‐liquid chromatography analysis. Four isolates of AG 2 from tulip (AG 2‐t) were also included. Palmitic (16 : 0), oleic (18 : 1 cis9) and linoleic (18 : 2 cis9,12) acids were the three major fatty acids identified which constituted 89.6–93.4% of whole‐cell fatty acid content. Myristic (14 : 0), pentadecanoic (15 : 0), palmitoleic (16 : 1 cis9), stearic (18 : 0) and linolenic (18 : 3 cis9,12) acids were present at low levels. Heptadecanoic (17 : 0) and 9‐heptadecenoic (17 : 1 cis9) acids were also present in Nt‐isolates and isolates of AG 2–1 but not in isolates of AG 2‐t and AG‐BI. With the exception of oleic acid, percentage composition of fatty acids of Nt‐isolates were similar with those of isolates of AG 2–1 and AG 2‐t but were different from isolates of AG‐BI. Although fatty acid compositions of Nt‐isolates and isolates of AG 2–1 were qualitatively and quantitatively similar, principal component and cluster analyses based on all detected fatty acids showed separation of the former from the latter groups indicating that Nt‐isolates are a homogenous population in AG 2–1. Additionally, isolates of AG 2‐t were closely related to isolates of AG 2–1. Isolates of AG‐BI were distinctly separated from isolates of AG 2–1, AG 2‐t and Nt‐isolates. Results of fatty acid analysis support the designation of Nt‐isolates as a member of AG 2–1 based on sequence similarity of rDNA‐ITS.
Host Range of an Iranian Isolate of Watermelon Chlorotic Stunt Virus as Determined by Whitefly‐mediated Inoculation and Agroinfection, and its Geographical Distribution
Authors: Bananej K. , Ahoonmanesh A. , Kheyr‐Pour A.
Published: March 2003

Virus like symptoms appeared on most watermelon plants grown at different locations in southern provinces of Iran. The symptoms included chlorotic patches on leaves, vein yellowing and stunting of watermelon plants. The causal agent of watermelon chlorotic stunt disease was transmitted to healthy watermelon, jimsonweed and bean by the whitefly Bemisia tabaci, but not by sap inoculation. Coat protein and nucleic acid of Watermelon chlorotic stunt virus (WmCSV) were detected in infected plants using a dot‐immunobinding assay (DIBA) and squash‐blot hybridization, respectively. The data obtained confirmed that watermelon chlorotic stunt disease in Iran is caused by WmCSV. Agroinoculation of some plant species by the cloned genomic components (DNA‐A and DNA‐B) of a non‐sap‐transmissible Iranian isolate of WmCSV (WmCSV‐Ir) has been demonstrated. Host range studies using agroinoculation indicated that most plant species in the Cucurbitaceae and some species of the Solanaceae are susceptible to WmCSV‐Ir. Infection of agroinoculated plants was confirmed by DIBA and polymerase chain reaction. The virus from agroinfected plants was transmissible by the whitefly Bemisia tabaci. Results obtained from a limited survey during 1997–2000 indicated the presence of WmCSV‐Ir in some watermelon‐growing provinces of southern but not in northern, central, and north‐eastern provinces of Iran. WmCSV has apparently not yet spread to these regions.
Detection of a Fovea‐like Virus in African Oil Palms Affected by a Lethal ‘Ringspot’ Disease in South America
Authors: Morales F. J. , Lozano I. , Velasco A. C. , Arroyave J. A.
Published: March 2003

A virus with filamentous particles ca. 800 nm long was consistently associated with a lethal disease of young African oil palms, referred to as ‘ringspot’ in Colombia, Ecuador and Peru, South America. Partial molecular characterization showed the virus to be distinct but related [51–67% amino acid (AA) sequence identities in ORF 1] to two tentative species of the genus Foveavirus, namely Cherry green ring mottle virus and Cherry necrotic rusty mottle virus; 40–62% AA sequence identities were observed for the same region of the African oil palm virus and the foveaviruses Apple stem pitting virus and Rupestris stem pitting‐associated virus, respectively.
Phenotypic Instability of Cercospora beticola Sacc. Strains Expressing Resistance to the Sterol Demethylation‐Inhibiting (DMI) Fungicide Flutriafol after Cold Exposure
Authors: Karaoglanidis G. S. , Thanassoulopoulos C. C.
Published: March 2003

A study was conducted in order to elucidate whether decreased sensitivities of Cercospora beticola Sacc. strains to sterol demethylation‐inhibitors (DMIs) is a temporary adaptation or a stable trait. Phenotypic stability of resistance to the DMI fungicide flutriafol was tested with 30 single‐spore strains collected from diseased sugar beet plants. Strains used in the study represented a wide range of sensitivity to flutriafol. Two different sets of experiments were conducted. The first set of experiments studied the effect of successive transfers on the pathogen's sensitivity to flutriafol, both in vitro and in vivo. In the second set of experiments, the effect of cold storage on the sensitivity to flutriafol was tested for mycelial isolates and for conidia of the pathogen. Results showed that after successive transfers of isolates either in vitro or in vivo in the absence of flutriafol, sensitivity was not changed significantly in comparison with the initial sensitivity, suggesting a stable genetically controlled trait. Conversely, when fungal strains were exposed to cold conditions, either as mycelial isolates or as conidia, an increase in sensitivity was observed. This increase was most pronounced for strains with moderate and high levels of resistance to DMIs.
Development of a Root Colonization Bioassay for Rapid Screening of Rhizobacteria for Potential Biocontrol Agents
Authors: Silva Harllen Sandro Alves , Romeiro Reginaldo da Silva , Mounteer Ann
Published: March 2003

The ability to colonize roots is a sine qua non condition for a rhizobacteria to be considered a true plant growth‐promoting rhizobacteria (PGPR). A simple screening method to detect such a potential ability of PGPR is described. Tomato seeds were surface sterilized for 30 s in 50% ethanol and this was followed by 3 min dipping in 2% NaClO. They were then washed three times in sterile water, left immersed in a propagule suspension of the rhizobacteria for 24 h, and transferred onto sterile 0.6% water‐agar in tubes. The young, developing root system shows a tendency to grow downwards in the agar‐gel column. When the rhizobacterium has a potential ability to colonize roots it is possible to visualize, by transparency, bacterial growth (turbid, milky and narrow zone) along and around roots. Testing 500 rhizobacteria isolated from tomato rhizosphere for their ability to induce systemic resistance against Pseudomonas syringae pv. tomato, 28 of them did reduce infection to less than 40% and all 28 colonized roots according to the described bioassay. Therefore the bioassay may turn into an important auxiliary tool for helping in selecting rhizobacteria with PGPR potentiality.
Role of the Cholinergic Pathway in Mediating Platelet‐Activating Factor‐induced Pulmonary Dysfunctions in Unsedated Calves
Authors: Van de Weerdt M. ‐L. , Husson C. , Lekeux P.
Published: March 2003

The purpose of this study was to investigate the possible role of the cholinergic pathway in mediating platelet‐activating factor (PAF)‐induced pulmonary dysfunctions in unsedated calves. In a placebo group, PAF infusion challenge induced significant dysfunctions in the pattern of breathing [a significant increase in respiratory rate (RR) and a significant decrease in tidal volume (VT)], the mechanics of breathing [a significant increase in total lung resistance (RL) and a significant decrease in dynamic lung compliance (CLdyn)] and gas exchange, whereas in atropine pre‐treated calves, PAF infusion challenge induced a significant increase in RR, VT and HR and a significant decrease in CLdyn. The RL increase was prevented by atropine pre‐treatment. On the basis of our findings, we suggest that, in cattle, the PAF‐induced pattern of breathing dysfunctions and the diffuse bronchoconstriction and microvascular leakage of small airways are not mediated through the cholinergic pathway. By contrast, our data suggest that PAF‐induced bronchoconstriction of upper airways is at least partly mediated through muscarinic receptors.
Laboratory of Microbiology and Infectious Diseases, Aristotle University, Faculty of Veterinary Medicine, 540 06 Thessaloniki, Greece
Authors: Mavromatis J. , Koptopoulos G. , Kyriakis S. C. , Papasteriadis A. , Saoulidis K.
Published: March 2003

Four groups of 12 pregnant sows of the same genetic background, with similar litter size, living under the same housing conditions and having the same hygienic and nutritional standards, were used. In control animals (gC), a basic feed was provided, in which the dietary level of α‐tocopherol was 20 mg/kg of feed and that of selenium (Se) was 0.45 mg/kg of feed (standard ration). Sows in the second group (gE) received basic feed supplemented with 30 mg α‐tocopherol per kg (50 mg/kg of feed, in total). To those in the third group (gSe) basic feed was provided but additionally they were injected with 30 mg Se (sodium selenite) on days 30, 60 and 90 of pregnancy. For the sows in the fourth group (gESe), basic feed was supplemented with 30 mg α‐tocopherol per kg. In addition they received 30 mg injectable Se (sodium selenite) on days 30, 60 and 90 of pregnancy. The experiment started on day 30 of pregnancy and lasted until weaning day (28 days post‐farrowing). It was found that α‐tocopherol and selenium act synergistically. Piglets born from sows in gESe had the highest immunoglobulin concentration level up to weaning day. All productive and clinical parameters (number of piglets born/litter, number of weaned piglets/litter, and piglets’ average body weight at birth and on weaning day) were greater in these piglets in comparison with the animals of the other groups. Diarrhoea problems were minimal in the piglets in gESe.