bluuebunny/crossref_metadata_2025 huggingface dataset:
Estimates of direct and maternal genetic effects for weights from birth to 600 days of age in Nelore cattle
Authors: Galvão de Albuquerque  , Meyer
Published: March 2003

Estimates of direct and maternal variance and heritability for weights at each week (up to 280 days of age) and month of age (up to 600 days of age) in Zebu cattle are presented. More than one million records on 200 000 animals, weighed every 90 days from birth to 2 years of age, were available. Data were split according to week (data sets 1) or month (data sets 2) of age at recording, creating 54 and 21 data sets, respectively. The model of analysis included contemporary groups as fixed effects, and age of dam (linear and quadratic) and age of calf (linear) effects as covariables. Random effects fitted were additive direct and maternal genetic effects, and maternal permanent environmental effect. Direct heritability estimates decreased from 0.28 at birth, to 0.12–0.13 at about 150 days of age, stayed more or less constant at 0.14–0.16 until 270 days of age and increased with age after that, up to 0.25–0.26. Maternal heritability estimates increased from birth (0.01) to a peak of 0.14 for data sets 1 and 0.07–0.08 for data sets 2 at about 180–210 days of age, before decreasing slowly to 0.07 and 0.05, respectively, at 300 days, and then rapidly diminished after 300 days of age. Permanent environmental effects were 1.5 to four times higher than genetic maternal effects and showed a similar trend.
Novel biodegradable plastics in sheep nutrition ‐ Effects of NaOH pretreatment of poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) on in vivo digestibility and on in vitro disappearance (Rusitec)
Authors: Forni D. , Bee G. , Kreuzer M. , Wenk C.
Published: March 2003

The use of biodegradable polymers in animal nutrition can be considered not only as a possible way of waste recycling but could also be beneficial in the derivation of animal products from the conversion of these energy‐rich substances within the nutritional chain. However, earlier studies with swine and sheep as well as in vitro studies have shown a poor digestibility of untreated biodegradable plastics (Kunkel and Seo 1994; Forni et al. 1999a,b). The low accessibility of the polymeric chains, particularly if only coarsely milled, to the gastric juices, enzymes and gastrointestinal micro‐organisms of farm animals, and the relatively short incubation time during the passage through the digestive tract obviously limit the degradation of these biodegradable polymers. Therefore, the present study focused on the effects of pretreatment and of increasing the dietary proportion of the biodegradable plastic poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV). PHBV is an aliphatic biodegradable polymer produced by bacteria (de Koning et al. 1996). Pretreatment with NaOH was chosen to reduce the chain length and to form absorbable monomers such as β‐hydroxybutyrate, a natural metabolite in the digestive turnover and metabolism of ruminants. NaOH is an inexpensive and effective substance for breaking down PHBV, which was found to increase the apparent PHBV digestibility by 37 % in swine (Forni et al. 1999a). In addition, NaOH pretreatment is commonly used in ruminant nutrition to enhance the digestibility and intake of straw and poor quality hay which are both rich in biological polymers such as cellulose and lignin (Flachowsky 1987).
Effect of dietary linoleic acid concentration and vitamin E supplementation on cell desquamation and susceptibility to oxidative damage of pig jejunal mucosa
Authors: López Bote C. J. , Isabel B. , Flores J. M.
Published: March 2003

Sixty Large White × Great York pigs weighing approximately 60 kg were individually fed on six experimental diets. The experiment was organized in a 3 × 2 factorial arrangement design with three different fat sources and a basal or supplemented (200 mg/kg diet) level of α‐tocopheryl acetate. All diets contained the same concentration of saturated fatty acids (15 ± 0.2 g/kg dry matter) but differed in the concentration of C18 : 2 (14 ± 0.5, 18 ± 0.4 and 21 ± 0.6 g/kg) and monounsaturated fatty acids (19 ± 0.2, 15 ± 1.2 and 10 ± 1.3 g/kg). No effect of dietary treatment was observed on weight gain and feed consumption. A histological study of the jejunal mucosa showed lower cell desquamation in groups containing a supplemental level of α‐tocopheryl acetate (p=0.080). A higher cell desquamation was found in the groups fed diets containing the higher concentration of C18 : 2 (p=0.087). We also observed an interaction effect (p < 0.001) of dietary fat source and vitamin E supplementation on jejunal cell desquamation in which the effect of dietary vitamin E was lower when diets with a low concentration of C18 : 2 were administered. In vitro‐induced oxidation of jejunal mucosa homogenates was lower in pigs fed diets supplemented with α‐tocopheryl acetate (p < 0.002). The dietary concentration of C18 : 2 significantly affected oxidation of pig jejunal mucosa (p < 0.002).
Fermentation of liquid coproducts and liquid compound diets: Part 1. Effects on chemical composition during a 6‐day storage period
Authors: Scholten R. H. J. , Rijnen M. M. J. A. , Schrama J. W. , Boer H. , Vesseur P. C. , Den Hartog L. A. , Van Der Peet‐Schwering C. M. C. , Verstegen M. W. A.
Published: March 2003

The effects of a 6‐day storage period on changes in dry matter, crude ash, crude protein, true protein, crude fat, starch, soluble starch, sugar and lactose of three liquid coproducts and two liquid compound diets were studied. The three liquid coproducts studied were: liquid wheat starch (LWS), mashed potato steam peel (PSP) and cheese whey (CW), and the two liquid compound diets were: liquid grower diet (LGD) and liquid finisher diet (LFD). The loss of corrected dry matter after a 6‐day storage, expressed in relation to the initial content, was 1.9, 6.2, 9.6, 4.6 and 4.2% for LWS, PSP, CW, LGD and LFD, respectively. During storage, the total amount of starch decreased 2.7, 24.0, 28.1 and 33.3% for LWS, PSP, LGD and LFD, respectively. The total amount of lactose decreased 23.5% for CW. The gross energy value of the products did not change remarkably during the 6‐day storage period; gross energy losses being less than 3% of the initial gross energy content.
The effect of a commercial high‐fibre diet and an iso‐malto‐oligosaccharide‐supplemented diet on post‐prandial glucose concentrations in dogs
Authors: Hesta M. , Debraekeleer J. , Janssens G. P. J. , De Wilde R.
Published: March 2003

In order to evaluate the effect of insoluble and soluble fibre on the levels of post‐prandial glycaemia, six healthy dogs were fed three different diets: a low‐fibre control diet, a high‐fibre diet (HF; mainly insoluble fibre) and the control diet with 10% iso‐malto‐oligosaccharides (IMO) added. The diets were fed for 2 days before the blood collections were started on the third day. Serial blood samples were taken 20, 60, 90, 150, 180, 240 and 360 min after feeding and one sample was taken just before the feeding after a fasting period of at least 20 h. There were no problems concerning the faecal consistency. The post‐prandial glycaemia curve was significantly lower in the HF and IMO group in comparison with the control group. At 20 and 60 min the glucose concentration was significantly lower in the HF and IMO groups. At 90 and 150 min only the IMO group had a significantly lower glucose concentration. At 360 min there was a trend for a lower glucose concentration in the IMO group. The results show that both the HF and the IMO diets had a beneficial effect on post‐prandial hyperglycaemia. Substitution of IMO may have the same or a slightly better effect, but this has to be confirmed in diabetic dogs and the effect may depend on the composition of the basal diet.
Residues of ochratoxin A in pet foods, canine and feline kidneys
Authors: Razzazi E. , Böhm J. , Grajewski J. , Szczepaniak K. , Kübber‐Heiss A. J. , Iben C. H.
Published: March 2003

The occurrence of ochratoxin A (OTA) in canned (26 samples) as well as dry pet foods (17 samples) for cats and dogs was investigated. In addition, 26 feline kidney samples with or without kidney alterations were surveyed for OTA‐residues. The separation and detection of OTA was carried out by an isocratic high‐performance liquid chromatography system based on reversed phase with fluorescence detection. After homogenization and extraction steps, immuno‐affinity columns were applied for sample clean up. OTA could be detected in 47% (n=40) of the pet food samples. Those found positive contained generally low amounts of OTA (0.1–0.8 μg/kg original substance). Higher levels were only detected in two pet food samples (3.2 and 13.1 μg/kg toxin, respectively). Low concentrations of ochratoxin A could also be found iIn tissue of cat kidneys, with 16 of the analysed kidneys (n=26) being positive. The concentration levels were between 0.35 and 1.5 μg/kg OTA in tissue. No relation between pathological findings and ochratoxin levels in feline kidneys could be assessed.
Factors influencing the food preference of cats
Authors: Hullár I. , Fekete S. , Andrásofszky E. , Szöcs Z. , Berkényi T.
Published: March 2003

Four individual preference tests were carried out using the same 10 castrated adult cats. The main questions investigated were: (i) do the cats prefer diets having one dominant taste or diets made from a relatively wide range of compounds of animal origin and (ii) can the preference be connected to one taste? In test 1 a dry diet (K) made by a world‐renowned company having a beef taste was compared with four others (I, II, III, IV) dry foods prepared at the authors’ institute in order to prevent any one of the mixtures having a predominant taste. In test 2 diets I, II, III and IV were compared with each other in the absence of diet K. In test 3 another four diets with different dominant tastes (fish, liver, poultry with fat addition and poultry without fat addition) were investigated. In test 4 the same three tastes (beef, fish and poultry) were compared with each other by using diets of three world‐renowned companies. From the results the following conclusions can be drawn. Cats undoubtedly use smell in the detection and selection of food. If cats find the odour of a certain food is significantly more attractive than that of the other, they will consume it exclusively and without tasting the less attractive food. If none of the diets are especially attractive, according to smell, cats will also taste the foods and make their decision on the basis of both senses. Diets having one dominant taste result in a higher feed intake than that reached by diets without a dominant taste. If a diet is manufactured well, its dominant taste may have less effect on diet consumption. Food preference does not seem to be connected to one exclusive taste but is significantly influenced by other factors connected to the manufacturing of the diets.
Efficiency of amino acid utilization in the growing pig at suboptimal levels of intake: lysine, threonine, sulphur amino acids and tryptophan
Authors: HEGER J. , PHUNG T. VAN , KŘÍŽOVÁ L.
Published: March 2003

A series of N balance experiments using growing pigs was conducted to study the efficiency of utilization of lysine, threonine, sulphur amino acids and tryptophan and to estimate their maintenance requirements. Purified diets based on casein and crystalline amino acids as the sole source of N contained graded levels of each amino acid, corresponding to expected protein accretion rate of 0, 33, 66, 99 and 132 g/day, respectively. N retention increased linearly (p < 0.01) as the dietary concentration of the limiting amino acid increased. Based on linear regression equations relating amino acid deposition in body protein to amino acid intake, marginal efficiencies of ileal digestible amino acid utilization were calculated to be lysine 0.91, threonine 0.83, sulphur amino acids 0.85 and tryptophan 0.66. Extrapolating the regression equations to zero N retention, the daily requirements of amino acids for N equilibrium were estimated to be (mg/kg0.75) lysine 39, threonine 49, sulphur amino acids 46 and tryptophan 16.
Comparison of the endogenous ileal and faecal amino acid excretion in the dog (Canis familiaris) and the rat (Rattus rattus) determined under protein‐free feeding and peptide alimentation
Authors: Hendriks W. H. , Sritharan K. , Hodgkinson S. M.
Published: March 2003

The aim of the study was to determine and compare the endogenous ileal excretions of nitrogen and amino acids under protein‐free and peptide alimentation by the dog and rat. Two diets were prepared, one that was devoid of protein and the other containing 23% enzyme hydrolysed casein. Chromic oxide was included in the diets as an indigestible marker. A total of 10 mixed breed dogs were fed hourly either a protein‐free or enzymatically hydrolysed casein diet for a total of 10 days. A faecal sample was obtained from each dog on day 9 while digesta was obtained from the terminal 20 cm of the ileum directly after euthanasia on day 10. A total of 12 8‐week‐old Sprague–Dawley rats received the same diets as the dogs. A faecal sample from each rat was obtained on day 7 while ileal digesta samples were obtained on day 8. The endogenous ileal excretions of most amino acids were greater in the dogs and rats that received the enzymatically hydrolysed casein diet compared with those receiving the protein free diet. Whereas the pattern of endogenous amino acid excretion was similar in the rats and dogs, the dogs excreted a significantly greater amount of nitrogen (1.91 vs. 2.27 and 1.63 vs. 4.12 g/kg dry matter intake for the protein‐free and peptide alimentation method, respectively) and all amino acids except for glycine, isoleucine and leucine. Endogenous ileal amino acid excretions are higher in dogs compared to omnivorous animals such as rats and pigs but similar to the carnivorous cat.
Attempts to control cabbage root flies Delia radicum L. and Delia floralis (Fall.) (Dipt., Anthomyiidae) with entomopathogenic fungi: laboratory and greenhouse tests
Authors: Vänninen I. , Hokkanen H. , Tyni‐Juslin J.
Published: March 2003

One laboratory and three greenhouse experiments were conducted to study the pathogenicity and efficacy of Finnish isolates of entomopathogenic hyphemycetous fungi against cabbage root flies. In Petri dishes, exposure to 1.5 × 1010 spores of Metarhizium anisopliae per dish caused 40–50% mortality of undifferentiated second‐ and third‐stage larvae of Delia floralis, and 1 × 107 spores per dish caused 40–50% mortality of Delia radicum larvae. In one greenhouse test, 1 × 108 and 1 × 109 spores of M. anisopliae and Paecilomyces fumosoroseus reduced the root damage of head cabbage by 20–70% compared with untreated controls, although this was not accompanied by significant reductions in the number of pupae. Only M. anisopliae consistently grew out of larvae and pupae of D. floralis during incubation that followed their recovery from the soil at the end of an experiment testing different formulations of M. anisopliae and Beauveria bassiana, but the frequency of the latent infections of the pest by M. anisopliae was not associated with reduced severity of damage to seedlings of head cabbage.
Biochemical identification and comparative insecticidal activity of nucleopolyhedrovirus isolates pathogenic for Heliothis armigera (Lep., Noctuidae) larvae
Authors: Figueiredo E. , Muñoz D. , Escribano A. , Mexia A. , Vlak J. M. , Caballero P.
Published: March 2003

Three Nucleopolyhedrovirus (NPVs) originally isolated from Heliothis armigera larvae, collected from Portugal (HearNPV‐PO) and two places in Spain (HearNPV‐SP1 and HearNPV‐SP2), and three previously described NPVs were compared biochemically and biologically. Restriction endonuclease analysis of the virus genome with several enzymes revealed that isolates HearNPV‐SP1 and HearNVP‐SP2 are unique but closely related genotypes which represent two new strains of the NPVs of H. armigera. The DNA fragment profiles of HearNPV‐PO were distinct from those of the HearNPV‐SP1 and HearNPV‐SP2, with all the enzymes used, while they were identical to the Mamestra brassicae NPV strain present in the commercial product MAMESTRIN®. Bioassays in third‐instar H. armigera larvae showed that the LD50 value obtained for HearNPV‐SP1 (68 occlusion bodies/larva) was about two‐ and six‐times lower than those of HearNPV‐SP2 and a Russian isolate, HearNPV‐RU, respectively. The corresponding LT50 values were not found to differ significantly between these three virus isolates at comparable doses.
Occurrence and phenology of parasitic Chalcidoidea on the horse chestnut leafminer, Cameraria ohridella Deschka & Dimic (Lep., Gracillariidae)
Authors: Grabenweger G. , Lethmayer C.
Published: March 2003

Abstract: The parasitoid spectrum of the horse chestnut leafminer, Cameraria ohridella, was examined for its adaptation to a newly introduced host. A total of 15 parasitic species belonging to the suprafamilies Ichneumonoidea and Chalcidoidea was reared, all of them are polyphagous and common on other leafminers in Europe. The abundance of the moth and its natural enemies were studied during one entire vegetation period. The phenology of some of its major parasitic species was investigated and compared with the occurrence of the leafminer with special regard to its possible use in biological pest control.
Life history of Aulacaspis marina Takagi and Williams(Hom., Coccoidea), a new pest of mangrove plantations in Indonesia, and its damage to mangrove seedlings
Authors: Ozaki K. , Kitamura S. , Subiandoro E. , Taketani A.
Published: March 2003

Scale insects of a newly described species, Aulacaspis marina Takagi and Williams, have killed a large number of mangrove (Rhizophora mucronata Lamk.) saplings planted in abandoned shrimp ponds on Bali island, Indonesia. The mean fecundity of A. marina was 141 eggs. The generation time of this species was between 34 and 42 days, based on four generations, suggesting that the species has nine to 10 generations a year on Bali island where the temperatures are seasonally constant. When crawlers of A. marina were transferred to potted seedlings of R. mucronata, they settled on all leaves of the seedlings. Newly expanded leaves were not infested by the first generation crawlers but were attacked by the following generations. The insect attack induced browning of the leaves and finally caused leaf fall; the leaves fell 25–159 days after the crawler transfer. Consequently, the seedlings died on average 128 (range 82–159) days after infestation. This suggests that once a large number of crawlers attack R. mucronata seedlings, A. marina can kill them within several months. When crawlers were transferred to potted seedlings of three mangrove species (R. mucronata, Rhizophora apiculata Bl. and Bruguiera gymnorrhiza L.), which were the main species planted at the study site, the numbers that developed into adult females did not differ significantly among these species. This suggests that these mangrove species are almost equally susceptible to A. marina.
Duration times of the immature stages of Cacopsylla pyri L. (Hom., Psyllidae), estimated under field conditions, and their relationship to ambient temperature
Authors: Kapatos E. T. , Stratopoulou E. T.
Published: March 2003

The duration of the immature stages of Cacopsylla pyri L. was studied under field conditions by artificially infesting pear branches on several dates during the year. The duration of the egg stage decreased from winter to summer, as the season progresses and temperature rises, and slightly increased in September. It ranged from 27.4 to 6.7 days. The same trend was observed in the duration of the first three larval stages (L1−3) which ranged from 18.8 to 10.3 days. For eggs deposited during the period February–August the duration of the last two larval stages (L4−5) ranged from 17.5 to 12.1 days. However, the duration of L4−5 developed from eggs deposited in September and which give rise to winter‐form adults were the longest observed. The rate of egg development was related to average ambient temperature with a highly significant linear relationship. This relationship indicates that the egg stage requires a constant number of 158.9 (SD = 5.0) of day‐degrees above an average temperature of 2.31°C to complete development. The rate of development both of L1−3 and L4−5 were related to average ambient temperature with curvilinear relationships. These relationships indicate a proportional increase in the developmental rate as temperature rises between 10–22°C. At the higher average temperatures that occurred in the summer experiments (24–27°C) the acceleration of development of L1−3 is reduced and the developmental rate of L4−5 decreases. The developmental rates of L4−5 developed from eggs deposited in September did not follow the established relationship with temperature and they were lower than those in the other periods of the year with the same average temperature.
Cold tolerance of the leafminer Liriomyza sativae (Dipt., Agromyzidae)
Authors: Zhao Y. X. , Kang L.
Published: March 2003

The cold tolerance of larvae and pupae of the vegetable leafminer Liriomyza sativae was examined by using measurements of supercooling points and mortality statistics at low temperatures. Recently pupated (≶6 h ) individuals were separately held at 0, 2.5, 5, 10°C for 1, 4, 7, 10, 13 and 16 days. No pupae were able to survive prolonged exposure to 0 and 5°C for 10 days. The cold tolerance of pupae of different stages was significantly different. Of the 6 h, 1, 4, 6.5 and 8‐day‐old pupae tested, the 4‐day‐old pupae was the most cold tolerant. The lethal time (T50: time of median survival at 0°C) of 4‐day‐old pupae was 4.53 days. The supercooling point (SCP) of the larvae declined with larval development. Second instar larvae had a SCP at ‐22.35°C, which declined to ‐24.36°C for third instar larvae that had emerged from leaves. In contrast to the larvae, the SCP of the pupae increased during pupation. Prepupae and 6‐h‐old pupae had SCPs of ‐20.91°C and ‐14.34°C, respectively. The SCPs of 1, 4, 6.5 and 8‐day‐old pupae varied, ranging from ‐11.80 to ‐11.35°C and there was no significant difference between the stages. Analysis of mean soil temperatures at several locations indicated that the leafminer could not overwinter outdoors in northern areas beyond latitude 34°N in China. The potential distribution of the leafminer in China is discussed.
Biology and host specificity of Spurgia capitigena (Bremi) (Dipt., Cecidomyiidae), for the biological control of Euphorbia esula L. in North America
Authors: Sobhian R. , Littlefield J. , Cristofaro M. , Mann K.
Published: March 2003

Abstract: Spurgia capitigena (Bremi) was evaluated as a potential biological control agent of leafy spurge, Euphorbia esula L. (species complex) in North America. To ascertain the host specificity of this gall midge, tests were conducted in the field at Cavaillon, France, and at laboratories located in Rome, Italy and Bozeman, Montana, USA, in 1994 and 1995. Twenty‐nine plant species, including eight native North American euphorbias and biotypes of E. esula, were evaluated. In the laboratory, the gall‐midge was able to induce galls on seven species of spurges (all belonging to the subgenus Esula) and the three accessions of leafy spurge. In field tests, S. capitigena infested only E. esula. The biology and host specificity of S. capitigena from France appears to be similar to that observed for Spurgia esulae Gagné from Italy (=Bayeria capitigena Bremi). In France, this gall‐midge was commonly observed from early May until October in habitats of very heavy and moist soils located along water channels, roadsides and in fruit orchards. Galls were induced on meristematic tissues, and thereby prevented flowering.
Notes on the biology and ecology of the parasitoids of the poplar clearwing moth, Paranthrene tabaniformis (Rott.) (Lep., Sesiidae) in Bulgaria. II. Eriborus terebrans (Gravenhorst, 1826) (Hym., Ichneumonidae)
Authors: Georgiev G.
Published: March 2003

The biology and ecology of Eriborus terebrans (Grav.), a parasitoid of the poplar clearwing moth, Paranthrene tabaniformis (Rott.), were studied during the period 1987–98. One‐year‐old poplar (Populus spp.) shoots infested with P. tabaniformis larvae were collected from poplar seedlings at 11 localities in Bulgaria and examined in both field and laboratory conditions. Eriborus terebrans was recorded in seven localities as a solitary internal larval parasitoid of P. tabaniformis which developed two generations in early and mid‐stage host larvae. Eriborus terebrans overwintered as a larva in P. tabaniformis overwintering larvae. In the field adult parasitoids of the overwintering generation appeared between late April/early May, and June or July. The peak activity of E. terebrans adults only coincided with the beginning of host emergence, which resulted in low levels of parasitism, being no more than 6.2%. Parasitoid adults of the summer generation appeared in late June–mid August. In this period enough larvae of the host were suitable for attacking and parasitism reached 24.4–39% in some cases. The average mortality of P. tabaniformis overwintering larvae caused by this parasitoid in Bulgaria during the period of the study was 4.7%. A significant part of the parasitized P. tabaniformis larvae constructed tunnel structures of frass and silk threads over the external openings of the galleries. It is possible that these structures protect the parasitoid cocoons from natural enemies – hyperparasitoids and predators.
An in vitro assessment of phylloxera (Daktulosphaira vitifoliae Fitch) (Hom., Phylloxeridae) life cycle
Authors: Forneck A. , Walker M. A. , Blaich R.
Published: March 2003

Phylloxera single founder lineages were maintained in an aseptic, dual‐culture system to investigate the phylloxera life cycle, focusing on holocycle induction. Holocyclic morphs were developed on the grape rootstock 41B and they produced vital sexuales. The morphological development of sexual stages was studied and an assessment of genetic variation within a single founder lineage was performed. Twenty individual phylloxera of differing stages (apterous parthenogenetic, pre‐sexual nymphs, sexuparae and sexuals) were genetically fingerprinted using amplified fragment length polymorphism‐polymerase chain reaction technology. Four individuals displayed differing banding patterns, exhibiting three different independent genotypes. No influence of the morphal stage on these patterns could be detected. This study did not achieve phylloxera matings. However, the system could serve as a tool for future studies, performing controlled and systematic crosses and back‐crosses to examine Mendelian genetics.
Effect of predator size and temperature on the predation of Deroceras reticulatum (Muller) (Mollusca) by carabid beetles
Authors: Ayre K.
Published: March 2003

Twenty‐one carabid species were used in a laboratory study to determine the effect of beetle size and temperature on the predation of one day old Deroceras reticulatum (Muller) slugs. The beetles were caught in arable land at the study site. None of the five small‐sized beetle species killed slugs, whereas five of the seven medium‐sized beetle species and eight of the nine large‐sized beetle species killed slugs. Four of the most abundant beetle species at the study site were used to assess the effect of temperature on the predation of 1‐day‐old slugs. There were significant differences in the proportion of beetles predating slugs at the different temperatures. Regression analysis showed that there was a significant increase in the proportion of Pterostichus madidus (Fabricius) and Harpalus rufipes (Degeer) beetles predating slugs as temperature increased. Nebria brevicollis (Fabricius) inflicted its highest level of slug mortality at 8°C and its larvae were the only predators to significantly increase slug mortality at 4°C, the lowest experimental temperature. Harpalus aeneus (Fabricius) inflicted significant levels of slug mortality at 20°C, the highest experimental temperature. It appeared that the predatory activity of these beetle species at the five experimental temperatures reflected their annual activity periods in the field.
Effect of foliar tomentosity on phenotypic plasticity in Bemisia tabaci (Hom., Aleyrodidae)
Authors: Guershon M. , Gerling D.
Published: March 2003

Some whitefly species, as well as members of other insect families, are known to develop different phenotypes under different environmental conditions. In this study, the identification of an environmental trigger and its sensitive stage for the development of the setose phenotype of Bemisia tabaci nymphs are reported. Quantification tests revealed phenotypic plasticity manifested by positive correlation between trichome density on tomentose leaves and the percentage of setose nymphs found upon them. Artificial simulation of leaf tomentosity provided sufficient stimulation to induce the setose nymph phenotype. The crawler was found to be the only sensitive stage for this induction. Polymorphism of the nymphal phenotypes correlated with additional biological features of both nymph and adult, which could be treated as proxies of fitness. Setose nymphs were smaller and developed (from eggs to adult) faster. Adults emerging from such nymphs were smaller and had shorter lives. Adaptivity of the detected phenotypic plasticity and of the correlating nymphal and adult features are discussed.
Survey of natural populations of Trichogramma (Hym., Trichogrammatidae) in the vineyards of Alsace (France)
Authors: Barnay O. , Hommay G. , Gertz C. , Kienlen J. C. , Schubert G. , Marro J. P. , Pizzol J. , Chavigny P.
Published: March 2003

Activity of Trichogramma, assessed by trapping with host‐eggs, was observed as early as April and continued until October in the vineyards and their surrounding biotops. Trichogramma showed the greatest activity in April‐May, July and September. Parasitized eggs were found before the main laying period of the first generation of the grapevine moths Lobesia botrana Den. and Schiff. and Eupoecilia ambiguella Hb. Four native species, Trichogramma cacoeciae Marchal, Trichogramma daumalae Dugast and Voegelé, Trichogramma evanescens Westwood and Trichogramma principium Sugonjaev and Sorokina were found.
Biology and efficacy of the predatory mite, Amblyseius longispinosus (Evans) (Acari, Phytoseiidae) as a biological control agent of Eotetranychus cendanai Rimando (Acari, Tetranychidae)
Authors: Thongtab T. , Chandrapatya A. , Baker G. T.
Published: March 2003

Egg, larval, protonymphal and deutonymphal stages of Amblyseius longispinosus (Evans) that fed on Eotetranychus cendanai, required 2.02 ± 0.13, 0.57 ± 0.17, 1.07 ± 0.31 and 1.16 ± 0.53 days, respectively. The total developmental time was 4.79 ± 0.61 days. Female longevity averaged 14.61 ± 2.88 days in which 19.54 ± 6.36 eggs/female or 1.33 ± 0.29 eggs/female per day were laid. The highest predation rate was detected at a prey density of 40–50. Amblyseius longispinosus could be employed as the biological control agent of E. cendanai both in laboratory and greenhouse conditions at the predator : prey ratio of 1 : 30 to 1 : 50.
Day‐degree models for predicting the generation time and flight activity of local populations of Lobesia botrana (Den. & Schiff.) (Lep., Tortricidae) in Greece
Authors: Milonas P. G. , Savopoulou‐Soultani M. , Stavridis D. G.
Published: March 2003

The generation time of Lobesia botrana (Den. & Schiff.) was estimated as the number of day‐degrees required between the start of a flight and the start of the following flight in two regions in northern Greece. The day‐degrees required for the first generation (x=339.3, Naoussa; x=275.6, Thessaloniki) were significantly shorter than for the second (x=751.5, Naoussa; x=833.8, Thessaloniki) and the third generations (x=899.5, Naoussa; x=1197.0, Thessaloniki). Nonlinear models were developed using trap catches of male L. botrana during 1987–1989 for predicting its flight activity. A lower threshold temperature of 6.45°C was used in calculating daily day‐degrees from 1 March. The models predicted with sufficient accuracy the accumulated male moth catch and they accounted for the 60–78% and 86–91% of year‐to‐year variation in male flight activity in Thessaloniki and Naoussa, respectively.
Effect of temperature and host stage on performance of Aphelinus varipes Förster (Hym., Aphelinidae) parasitizing the cotton aphid, Aphis gossypii Glover (Hom., Aphididae)
Authors: Röhne O.
Published: March 2003

Development time, mummification, pupal mortality, host feeding and sex ratio of a Norwegian strain of Aphelinus varipes Förster parasitizing the cotton aphid, Aphis gossypii Glover were studied at 20, 25 and 30°C in controlled climate cabinets. Petri dishes with cucumber (Cucumis sativus L) leaves on agar were used as experimental units. Cotton aphids in different larval instars and as adults, reared at the three different temperatures, were presented to A. varipes in a `no‐choice' situation for 6 h. These presentations were done at 25°C in each experiment to avoid an influence of temperature on parasitization rate. More first instar aphids were parasitized than third and fourth instars among the aphids reared at 20°C. Pupal mortality of the parasitoid was not influenced by temperature. It was lower in aphids parasitized as adults than in aphids parasitized in second instar. The sex ratio of A. varipes was female‐biased, and varied between 92% females developed from aphids reared at 25°C and 70% from aphids reared at 20°C. The sex ratio was not significantly influenced by host stage. The development time of A. varipes ranged from 17.5 days at 20°C to 9.8 days at 30°C.
Exposure to fenitrothion causes malfunctions of Spodoptera exigua Hübn. (Lep., Noctuidae) eggs
Authors: Fila K. , Adamski Z. , Ziemnicki K.
Published: March 2003

A long‐term exposition of Spodoptera exigua (Hübner) larvae to fenitrothion caused abnormalities in egg structure. When examined under a scanning electron microscope, the eggs revealed diminutions and cracks around the micropylar and aeropylar region. The damage was proportional to the concentration of the insecticide. The observed changes may be one of the reasons for the decreased survival of populations exposed to fenitrothion.
Effect of methanolic extracts of neem (Azadirachta indica A. Juss) and bakain (Melia azedarach L) seeds on oviposition and egg hatching of Earias vittella (Fab.) (Lep., Noctuidae)
Authors: Gajmer T. , Singh R. , Saini R. K. , Kalidhar S. B.
Published: March 2003

Abstract: The effects of methanolic extracts of neem (Azadirachta indica) and bakain (Melia azedarach) seeds on the oviposition behaviour and hatchability of eggs of Earias vittella were investigated under laboratory conditions. Treatments included 2, 4, 6, 8 and 10% concentrations of both extracts to compare with nimbecidine and untreated control. When able to choose, the adults preferred to lay a greater number of eggs on the untreated portion of the oviposition substrate (muslin) compared with the extract‐treated portion. However, under no‐choice conditions, higher concentrations of extracts caused proportionate reductions in the number of eggs laid. The extracts also manifested repellent activity by reducing the number of eggs laid even when the ovipositing females were not in direct contact with the extracts. Eggs laid on extract‐treated oviposition substrate exhibited reduced hatching and marked adverse effects on hatching were noticed when the eggs were dipped in different concentrations of extracts. Adults fed on an extract‐containing sucrose diet laid significantly fewer eggs with poor hatching. There was no egg laying when the moths were fed on a sucrose diet containing 6, 8 and 10% neem and 10% bakain extracts.
A new method for sampling eriophyoid mites from architecturally complex plant structures
Authors: Davies J. T. , Williams M. A. , Allen G. R.
Published: March 2003

Abstract: In this study the effectiveness of the sticky tape method of eriophyoid mite extraction (Harvey and Martin, J. Econ. Entomol. 81, 731–734, 1988) was evaluated with and without the addition of a new method – a supplementary synthetic pyrethroid spray – for estimating the critical abundance of eriophyoid mites from within architecturally complex plant structures. To do so the eriophyoid mite, Acalitus essigi (Hassan) was sampled from within the architecturally complex fruit of blackberries (Rubus fruticosus L. aggregate). Even though damage symptoms were not observed, sticky tape extraction supplemented with a synthetic pyrethroid spray was the significantly most successful method of mite extraction, with on average over twice the number of mites extracted from blackberry fruit using this method compared with sticky tape alone. Visual counts of A. essigi on the receptacle region of blackberry fruit were correlated to the number of mites extracted using the sticky tape method both with and without a spray treatment. However, due to the low numbers that were visually assessed, the use of visual methods alone appears limited.
Septoria Leaf Spot of Stevia rebaudiana in Canada and Methods for Screening for Resistance
Authors: Reeleder R.
Published: March 2003

The herb Stevia rebaudiana is a potential source of low‐calorie sweeteners. In 1995, a severe leaf spot and blight was observed in stevia production fields and research plots in the provinces of Ontario and British Columbia, Canada. The disease was characterized by angular, shiny, olive‐grey lesions that rapidly coalesced and were often surrounded by a chlorotic halo. Leaves quickly became necrotic and often dropped off the plant. The disease progressed upwards in the foliage during the growing season. A Septoria sp. was isolated from diseased leaves. Ten isolates (five from each of the two provinces) of the Septoria sp. were compared with respect to conidial size. Across isolates, conidia lengths and widths overlapped (grand means for length and width were 71.4 μm and 1.4 μm, respectively). Conidiogenesis was holoblastic. Morphological characteristics and disease symptoms were similar to those of Septoria steviae, previously reported only from Japan. It was concluded that the Canadian isolates belonged to S. steviae. Isolates from Canada did not differ significantly from one another with respect to effects of temperature on colony growth or germination of conidia. Optimum temperatures for these parameters were between 20 and 25°C. In field trials, the pathogen was shown to successfully over‐winter in diseased leaf tissue. In order to develop procedures for identification of resistant germplasm and greenhouse screening of candidate fungicides, effects of leaf wetness period, inoculum concentration, and plant age on disease development were determined. Thirty‐six hours of leaf wetness were required for consistent development of leaf spots. Inoculum concentrations of 5 × 105 conidia/ml or more were required to produce high disease severities; 6‐week‐old plants were more susceptible than older plants. In the growth chamber, greenhouse, and field trials, germplasm selections with high levels of resistance to S. steviae were identified. This is the first report of resistance to this disease in S. rebaudiana.
The Relative Importance of Seed‐borne Inoculum to Common Scab Disease of Potato and the Efficacy of Seed Tuber and Soil Treatments for Disease Control
Authors: Wilson C. R. , Ransom L. M. , Pemberton B. M.
Published: March 2003

The importance of both seed and soil‐borne inoculum in the epidemiology of common scab disease under Australian conditions was clearly demonstrated. In field trials the severity of disease in harvested potatoes was directly related to the severity of disease on the planted seed tubers. Chemical seed dressing treatments were assessed for common scab disease control under field conditions in four trials over 5 years. Where seed treatments were applied to both diseased and visibly clean seed pieces significantly more disease was found in tubers harvested from diseased seed than the corresponding clean seed treatment. In all but one trial, the treatments applied to diseased seed significantly reduced the incidence of common scab. Fluazinam, flusulfamide (at elevated rates), fenpiclonil, pentachloronitrobezene and mancozeb seed treatments were particularly effective as seed dressing treatments. Applications to visibly clean seed failed to significantly diminish disease levels below that found on untreated seed. Preliminary investigations of some chemical soil treatments gave disappointing levels of control.
Susceptibility and Tolerance of New French Prunus domestica Cultivars to European Stone Fruit Yellows Phytoplasmas
Authors: Jarausch W. , Eyquard J. P. , Lansac M. , Mohns M. , Dosba F.
Published: March 2003

Five new cultivars of French prune (Prune d'Ente) and 11 cultivars or new clones of greengage (Reine Claude) were bud‐inoculated with European stone fruit yellows (ESFY) phytoplasmas and evaluated for their host response in the nursery over a period of 6 years. The ESFY infection was confirmed by specific polymerase chain reaction (PCR) detection and 4′,6‐diamidino‐2‐phenylindole (DAPI) staining in all Prunus domestica cultivars tested which were, thus, all susceptible to ESFY phytoplasmas. The new Prune d'Ente cultivars were more sensitive as they generally developed ESFY symptoms and showed a mortality of 19%. The fruit weight was significantly reduced. No mortality was observed with Reine Claude genotypes and only two cultivars exhibited weak ESFY symptoms. A new sensitive method was developed to measure the impact of ESFY phytoplasmas on the shoot growth. A significant growth reduction was found in all Prune d'Ente cultivars but only in four out of 11 Reine Claude genotypes. Therefore, the latter were found to be tolerant of ESFY infection.
A rapid method based on the one‐step reverse transcriptase‐polymerase chain reaction (RT‐PCR) technique for detection of different strains of citrus tristeza virus
Authors: Hung T. H. , Wu M. L. , Su H. J.
Published: March 2003

A rapid and sensitive assay based on the one‐step reverse transcriptase‐polymerase chain reaction (RT‐PCR) technique was developed for the detection of citrus tristeza virus (CTV) in citrus plants. This method combines reverse transcription (RT) and polymerase chain reaction (PCR) in one tube using an optimized buffer condition and efficient enzyme mix. In comparison with the two‐step RT‐PCR and enzyme‐linked immunosorbent assay (ELISA) tests, the one‐step RT‐PCR method has a higher sensitivity in CTV detection especially when the CTV concentration is low in its host. After graft‐inoculation, CTV in the infected plant was first monitored by the one‐step RT‐PCR method at the fourth week which is one week earlier than by the two‐step RT‐PCR method and two weeks earlier than by the ELISA test. Three major strains of CTV in Taiwan: seedling yellows (SY), sweet orange stem‐pitting (SO/SP), and pummelo stem‐pitting (Pum/SP) strains, could be accurately detected by this method with a CTV‐specific primer pair. These CTV strains have their different pathogenicities in citrus cultivars grown in Taiwan such as Ponkan mandarin (Citrus poonensis Hort.), Luchen sweet orange (C. sinensis Osb.), and Wentan pummelo (C. grandis f. buntan Hay.). CTV is usually latent in these hosts, and the apparent symptoms appear only in the Luchen host infected by SO/SP strain and the Wentan host infected by Pum/SP strain. RT‐PCR detection of CTV demonstrated that both SY and SO/SP strains could infect Ponkan and Luchen whereas Pum/SP could infect Luchen and Wentan. The one‐step RT‐PCR assay could detect CTV in both fresh and dried tissues. Detection in dried tissues offers a safe way for international cooperation in CTV‐strain research without the possible spreading of exotic CTV strains.
Sequences of Tobacco Rattle Viruses from Potato
Authors: Heinze C. , Von Bargen S. , Sadowska‐Rybak M. , Willingmann P. , Adam G.
Published: March 2003

The RNA2 of the tobacco rattle virus (TRV) isolate ‘Rostock’ (TRV‐R), and the coat protein gene (CP) of TRV isolate ‘Mirow’ (TRV‐M) were sequenced. Both were isolated from potato. Sequence analysis revealed a 5′ noncoding‐region (NCR) and a CP gene, which are among the shortest of any tobravirus RNA2 sequenced so far. Downstream of the CP open reading frame (ORF) there was an ORF for a 8 k protein, that is probably a truncated 9 k protein, followed by an ORF for a 16 k protein and the 3′ NCR. The 16 k protein and the 3′ NCR showed a considerable sequence identity with the 3′ end of TRV RNA1 and RNA2 from other TRV isolates. The high identity in the amino acid sequences of the CPs from TRV‐R and TRV‐M as well as other TRV isolates suggested that they are related to the TCM group of the genus Tobravirus and belong serologically to the RQ‐serotype. This could be confirmed using a rabbit antiserum that was prepared against recombinant TRV‐R CP expressed in bacteria. This serum was found to be suitable for differentiation of TRV‐isolates.
Environmental Factors Influencing the Dispersal of Venturia inaequalis Ascospores in the Orchard Air
Authors: Rossi V. , Ponti I. , Marinelli M. , Giosuè S. , Bugiani R.
Published: March 2003

A 6‐year study was carried out in an apple‐growing region of North Italy by trapping airborne ascospores of Venturia inaequalis with a volumetric spore trap operated continuously during the ascospore season, with the aim of better defining the weather conditions that allow ascospores both to discharge and to disperse into the orchard air. A total of more than 60 ascospore trapping events occurred. Rain events were the only occurrences allowing ascospores to become airborne (a rain event is a period with measurable rainfall ≥0.2 mm/h – lasting one to several hours, uninterrupted or interrupted by a maximum of two dry hours); on the contrary, dew was always insufficient to allow ascospores to disperse into the air at a measurable rate, in the absence of rain. In some cases, rain events did not cause ascospore dispersal; this occurred when: (i) rain fell within 4–5 h after the beginning of a previous ascospore trapping; (ii) rain fell at night but the leaf litter dried rapidly; (iii) nightly rainfalls were followed by heavy dew deposition that persisted some hours after sunrise. Daytime rain events caused the instantaneous discharge and dispersal of mature ascospores so that they became airborne immediately; for night‐time rainfall there was a delay, so that ascospores became airborne during the first 2 h after sunrise. This delay did not always occur, and consequently the ascospore trapping began in the dark, when: (i) the cumulative proportion of ascospores already trapped was greater than 80% of the total season's ascospores; (ii) more than one‐third of the total season's ascospores was mature inside pseudothecia and ready to be discharged.
Acquisition and Retention of Potato virus Y Helper Component in the Transmission of Potato aucuba mosaic virus by Aphids
Authors: Manoussopoulos I. N.
Published: March 2003

Potato aucuba mosaic virus (PAMV) is transmissible by aphids in a non‐persistent manner but only in the presence of a Potyvirus helper component (HC) such as that of Potato virus Y (PVY) that must be acquired beforehand or simultaneously. To compare the acquisition and persistence of PAMV and PVY‐HC, the PVY‐HC was acquired first and then PAMV. The acquisition access and post‐acquisition fasting periods were varied. The results show that PAMV and PVY particles, and also PVY‐HC could be acquired in 10 s. Some PVY‐HC activity could be detected in fasting aphids at least 6 h after acquisition whereas PAMV infectivity was retained for only 2 h. These findings are compatible with the non‐persistent transmission concept being controlled by enzymatic release of PAMV particles bound to aphid mouthparts by PVY‐HC.