bluuebunny/crossref_metadata_2025 huggingface dataset:
High intakes of l+ and	d− lactic acid are efficiently metabolized by pigs and rats
Authors: Everts II. , Salden N. , Lemmens A. G. , Wijers J. , Beynen A. C.
Published: March 2003

On farms that apply the feeding of fermented, carbohydrate‐rich liquid by‐products there have been occasional cases of muscle stiffness and impaired gait in growing pigs. The hypothesis that high intakes of a racemic mixture of d− and
l+ lactic acid could be the cause of the abnormalities was tested in a trial with growing pigs and rats. In the pig diet, wheat starch was replaced by racemic lactic acid on a weight basis and the control and test diets thus obtained were fed to pigs and rats. The pigs that were fed the test diet containing 107g lactic acid per kg dry matter showed no signs of muscle stiffness. The feed conversion and daily live weight gain in the test group did not differ from those in the control group. The amounts of lactic acid in the urine were < 1% of the ingested total lactic acid. These data indicate a high metabolizability of
l+ and
d− lactic acid and an energy value of lactic acid that was similar to that of wheat starch. The rats in the test group consumed 134g lactic acid per kg dry matter and showed normal behaviour and the results concerning daily gain and feed conversion and lactic acid excretion in urine agreed well with those found in the pigs. Three conclusions were drawn from the present experiment: (a) a racemic mixture of lactic acid up to 10% of the dietary dry matter had no negative effects on animal health and performance, at least not in the short term; (b)
l+ and
d− lactic acid are both utilized as efficiently as wheat starch; and (c) the cause of the muscle stiffness, as observed in practice, remains unknown.
Influence of increased vitamin A supplements on α‐tocopherol and retinoids in serum and lipoproteins of Shetland ponies
Authors: Gück T. , Sallmann H.‐P. , Fuhrmann H.
Published: March 2003

The effects of feeding 75 versus 750 IU vitamin A/kg body mass (BM) per day to eight healthy pony geldings were studied in a cross‐over design experiment for 20 weeks. The vitamin E intake was 2 mg/kg BM per day. α‐tocopherol and retinoid distribution was examined in serum and lipoproteins. No effect was seen on retinol, α‐tocopherol, cholesterol, triglycerides, phospholipids and protein. The α‐tocopherol was distributed between high‐density lipoprotein (69%), low‐density lipoprotein (LDL; 22%) and very‐low‐density lipoprotein (VLDL; 9%). A retinol dose response (RDR)‐test was carried out in both experimental groups to analyse the vitamin A status. The RDR‐test indicated in some cases a false insufficient supply in spite of increased dietary vitamin A. However increased retinyl ester concentrations were found in serum and lipoproteins. Therefore concentrations of retinyl esters seems to be an excellent indicator for the vitamin A status of ponies. In lipoproteins, retinyl ester were measurable in VLDL and LDL. The main ester was retinyl stearate followed by retinyl palmitate. Data suggest that feeding increased concentration of vitamin A did not influence the serum vitamin E status and lipid parameters in ponies, but increased the retinyl esters in serum, VLDL and LDL.
Responses of milk production to the intravenous infusion of amino acids in dairy cows given diets of grass silage and cereal‐based supplements
Authors: Kim C.‐H. , Choung J.‐J. , Chamberlain D. G.
Published: March 2003

Three experiments were carried out to examine responses of milk production to the intravenous infusion of amino acids in dairy cows given diets of grass silage and supplements based on barley, with or without added soyabean meal and ranging in crude protein content from 16 to 19% in dry matter. Particular attention was given to histidine, administered alone or in combination with methionine, lysine and tryptophan. Responses of milk protein secretion to infusion of histidine were seen only when the diet contained a supplement of barley alone. When soyabean meal was included, there were no responses of milk production to infusion of any of the infused amino acids. Calculations suggested that, although histidine remained first‐limiting when soya was included in the diet, any response to infusion of histidine was blocked by the rapidly emerging deficiency of another amino acid, probably leucine. The results confirm that, for diets based on grass silage and supplements of cereal only, histidine is first‐limiting such that increases of milk protein secretion can be obtained in response to infusion of histidine alone. In assessing the practical significance of this finding, it should be remembered that greater responses in the yield of milk protein can probably be obtained by substituting 1 kg of soyabean meal for 1 kg of cereal, which is likely to be an easier and cheaper option.
Reduction of the energy density of cat foods by increasing their fibre content with a view to nutrients’ digestibility
Authors: Fekete S. , Hullár I. , Andrásofszky E. , Rigó Z. , Berkényi T.
Published: March 2003

Indigestible compounds are useful for reducing the energy density of food for obese cats, but the acceptance and digestibility of such components must also be taken into consideration. In this trial, dried apple pomace was investigated as a compound having sweet taste, aromatic flavour and high fibre content (207 g/kg dry matter). It was mixed in a meat‐based diet at a ratio of 10, 20, and 40%. These diets were fed to adult cats in digestibility trials. As could be predicted, by increasing the percentage of apple pomace in the mixtures the digestibility of nutrients significantly decreased (p < 0.01; p < 0.001). However, the digestibility of ether extract decreased much less than that of the other nutrients. The addition of apple pomace to the diets at an inclusion rate of 10 or 20% reduced their energy density but only slightly changed the digestibility of fat. However, the digestibility of crude protein decreased considerably. According to the present findings, the energy density of mixed diets decreases proportionally to the percentage of apple pomace added. However, due to the much lower digestibility, the protein supply to the cat will be worse. It was concluded that the addition of palatable fibrous components is the best method for reducing the energy content of food for obese cats, as it maintains a normal level of food intake. When calculating the required protein content of a diet supplemented with a fibrous component, in addition to the degree of dilution the reduced protein digestibility must be taken into account.
Hydrolysis of phytic acid by intrinsic plant and supplemented microbial phytase (Aspergillus niger) in the stomach and small intestine of minipigs fitted with re‐entrant cannulas
Authors: Rapp C. , Lantzsch H.‐J. , Drochner W.
Published: March 2003

Hydrolysis of phytate in the stomach and the small intestine as influenced by intrinsic plant (wheat) and supplemented microbial phytase (Aspergillus niger) were investigated with six minipigs (40–50 kg initial body weight) fitted with re‐entrant cannulas in the duodenum, 30 cm posterior to the pylorus (animals 1, 4, 5 and 6) and ileocecal re‐entrant cannulas, 5 cm prior the ileocecal junction (animals 1, 2 and 3), respectively. Dietary treatments were as follows: (1) diet 1, a corn‐based diet [43 U phytase/kg dry matter (DM)]; (2) diet 2, diet 1 supplemented with microbial phytase (818 U/kg DM); and (3) diet 3, a wheat‐based diet (1192 U/kg DM). At 07 30 h and 19 30 h, each animal was fed 350 g diet mixed with 1050 ml de‐ionized water. Digesta were collected continuously and completely during a 12‐h period after feeding. Mean hydrolysis rates of IP6in the stomach as measured at the proximal duodenum of animals 1, 4, 5 and 6 were 9.0, 77.2 and 66.2% for diet 1, 2 and 3, respectively. Microbial phytase was much more effective in phytate hydrolysis than wheat phytase. Mean IP6hydrolysis rates of the respective diets in the stomach and small intestine as measured at the distal ileum of animals 1, 2 and 3 were 19.0, 62.6 and 64.6% and were lower than treatment means of the stomach only. Differences existed between experimental animals with respect to their ability to hydrolyse IP6in the stomach independent of the presence and source of dietary phytase. Considerable amounts of hydrolysis products occurred in both the duodenal and ileal digesta when diets 2 and 3 were fed; however, only traces were determined after ingestion of diet 1. Independent of dietary treatment, four IP5isomers were detected, but in different amounts.
Study of the optimum ideal protein level for weaned piglets
Authors: Warnants N. , Van Oeckel M. J. , De Paepe M.
Published: March 2003

The amount of ideal protein, represented by the first limiting valine (Val), for optimising the growth performances of weaned hybrid piglets was studied. Feeds were formulated based on the ideal protein concept and on a constant essential/nonessential amino acid (AA) ratio and net energy (NE) level. The animal performance trial was composed of five dietary treatments ranging from 0.57 to 0.81% calculated apparent (app.) ileal (il.) digestible (dig.) Val. The piglets, male and female in equal numbers (11 replicates × 6 piglets/pen × 5 treatments) entered the trial at about 4 weeks old (average live weight 8.1 kg). The piglets were a cross product of Piétrain sire × hybrid dam. Feed intake and weight were recorded every two weeks until the end of the trial at 10 weeks of age (average live weight 20.6 kg). The requirement was expressed in st. il. dig. AA‐units, as this unit approaches available AA better than app. il. dig. AA. The standardised (st.) il. AA digestibility coefficients (DCAA) were determined for two feeds, close to the animal performance optima, in a digestion trial with four T‐cannulated piglets of approximately 6 weeks old. The feed independent endogenous nitrogen excretion was measured with a protein‐free feed; although this technique underestimates the actual endogenous N‐losses, it provides a reasonable estimate of basal endogenous N‐losses. The determined st. il. DCAA were lower than the calculated st. il. DCAA, based on the CVB (2000); this might be linked to the higher than expected crude fibre content of the experimental feeds. The Val‐requirement necessary to optimise ADG and FCR was similar and amounted 0.70% st. il. dig. Val, which corresponded with a st. il. dig. Lys‐level of 1.03%.
Parasitoids and biocontrol of Russian wheat aphid,Diuraphis noxia(Kurdj.) expanding in central Europe
Authors: Starý P.
Published: March 2003

Hymenopterous parasitoids found on the Russian wheat aphid (RWA),Diuraphis noxia(Kurdj.) since the aphid was detected in the Czech Republic in 1995 have been studied. Parasitoids were obtained from aphid samples taken in small grains and from field exposures of banker‐units containing laboratory mass‐reared RWA. The parasitoid species are listed. Their presence on RWA was verified and their host species alternation was also tested in the laboratory. Evidence on some species was obtained only through unnatural host propagation.Aphidius colemaniVier. (a Chilean strain) was purposely introduced, released and became established; its host range, which included both target and non‐target species, is listed. Prediction versus determination of RWA parasitoid complex in central Europe are discussed and the field samples and the exposure trials are compared. The RWA presence in relation to biodiversity in the small‐grains agroecosystem is analysed. An overall parasitoid spectrum of RWA in the Old World (and the world background) is reviewed in relation to the RWA native range and the distribution (expansion) range, respectively. A corresponding analysis of the central European situation, derived from the expansion route of RWA to the Mediterranean, is presented.
Prey‐predator relationship between Lipaphis erysimi Kalt. (Hom., Aphididae) and Coccinella septempunctata L. (Col., Coccinellidae). II. Effect of host plants on the functional response of the predator
Authors: Kumar A. , Kumar N. , Siddiqui A. , Tripathi C. P. M.
Published: March 2003

The present paper examines the effect of the host plants Brassica oleracea, Raphanus sativus and Brassica campestris on which Lipaphis erysimi was reared, on the functional response of the grub of Coccinella septempunctata. The functional response of the grub of C. septempunctata is of type II. The amount of prey consumption increases significantly with the increase of prey density and is maximum in B. oleracea‐reared aphids, followed by those reared on R. sativus and B. campestris. The percentage prey consumption declined throughout. This decrease was a maximum for aphids reared on B. campestris followed by R. sativus‐ and B. oleracea‐reared aphids. Analysis of variance also confirmed that the number and percentage prey consumption was significantly influenced between the three host plants and between 12 prey densities. Results show that C. septempunctata has a greater liking for aphids reared on B. oleracea rather than those reared on the other plants that were tested.
Effect of mating status and age of Microplitis rufiventris (Hym., Braconidae) females on the growth pattern and number of their teratocytes
Authors: Hegazi E. M. , Khafagi W. E.
Published: March 2003

The effect of mating status and age of the female of Microplitis rufiventris parasitoid on the growth pattern of its teratocytes during the larval development is described as well as the changes in the number of these cells. The growth pattern of teratocytes derived from haploid eggs significantly differed from that of eggs deposited by mated females. Both cell diameter and the number of maturing M. rufiventris teratocytes was fertilization‐dependent. Following the parasitization of Spodoptera littoralis larvae with virgin parasitoid females, the host larvae hosted a large number of cells of smaller size at the end of parasitoid development. The opposite effect was seen when the host larvae contained female parasitoid larvae. The age of the female at parasitization had an effect on the maximum cell size attained prior to parasitoid emergence. It seems that there are two factors other than mating which affect the number of teratocytes: degeneration inside the host haemolymph and to some degree accidental ingestion by parasitoid larva.
Olfactory responses of seed wasps Megastigmus pinus Parfitt and Megastigmus rafni Hoffmeyer (Hym., Torymidae) to host‐tree odours and some monoterpenes
Authors: Luik A. , Ochsner P. , Jensen T. S.
Published: March 2003

Megastigmus pinus and Megastigmus rafni are able to colonize the seed cones in eight different species of Abies in Denmark. Olfactory responses of M. pinus females from Abies alba and Abies procera seeds and of M. rafni females from A. alba and Abies grandis seeds to odours of different host‐trees cones, needles and pure alpha‐pinene and limonene were studied in a Y tube Plexiglas olfactometer. The odours of young cones significantly influenced the behaviour of females. The results obtained in experiments with cones from different trees indicate the occurrence of biotypes depending on the host tree within the M. pinus and M. rafni species. Megastigmus pinus females from A. procera cones preferred the cone odours of A. procera and were significantly repelled by the cone odours of other possible host trees. Megastigmus pinus females from A. alba cones preferred A. alba cone odour but were not indifferent to A. procera cones. This suggests that the M. pinus population in A. alba apparently originates from the A. procera population. Megastigmus rafni from A. grandis cones preferred only A. grandis cone odours. Megastigmus rafni females from A. alba cones preferred A. alba cone odour but were also significantly attracted by A. grandis cone odours. This probably indicates that the M. rafni population living in A. alba originates from the A. grandis population. Neither M. pinus nor M. rafni responded to the odours of the host‐tree needles or alpha‐pinene. The limonene odour significantly acted as a repellent to both seed chalcid species, independent of the origin‐tree.
Possible storage of Coccinella undecimpunctata (Col., Coccinellidae) under low temperature and its effect on some biological characteristics
Authors: Abdel‐Salam A. H. , Abdel‐Baky N. F.
Published: March 2003

Developmental stages of Coccinella undecimpunctata L. were stored at 6.0°C for various storage periods in a refrigerator. Egg hatching was 65.0% after 7 days of storage. However, no egg hatching were observed after 15, 30, 45 and 60 days of storage. The survival of the third and fourth instar larvae was higher than the first and second instar. The survival of larvae declined sharply after 15 days. No larvae survived after 30 or 60 days of storage. Emergence percentage of adults from stored pupae varied from 85.0 to 25.0% after storage for 7 up to 30 days. The survival percentage of adults differed and appeared to depend on prior feeding before storage. From the present results, it appears that the adult stage may be better able to survive extended periods of storage than the other developmental stages. In addition, it was found that prior feeding of adult stage affected the longevity, fecundity and consumption rate.
Enumerative sampling plans for grasshopper egg pods in northern Benin
Authors: Shah P. A. , Godonou I. , Gbongboui C. , Hossou A. , Lomer C. J.
Published: March 2003

The spatial distributions of egg pods of two grasshopper species, Hieroglyphus daganensis Krauss and Cataloipus fuscocoeruleipes Sjöstedt, collected from three oviposition sites, Piliostigma thonningi (Schumach.) Milne‐Redhead, Vetiveria nigritana (L.) and Sorghum bicolor (L.) Moench, are described using Taylor's power law. Both grasshopper species showed a highly aggregated distribution with Taylor's index of dispersion ranging between 1.380 and 1.709, except for C. fuscocoeruleipes from S. bicolor where an index of dispersion of 0.885 indicated a regular distribution. Enumerative sampling plans incorporating Taylor's power law are presented to estimate mean grasshopper egg pod densities with predefined levels of reliability for future studies. For egg pod densities of < 1.0 m−2, optimal sample sizes at a site consist of 50 P. thonningi shrubs, 125 V nigritana clumps and 150 S bicolor patches with a reliability level of D = 0.3. This would demand a team of seven people to work for approximately 15 h.
Comparison of searching strategies of five parasitoid species of Bemisia argentifolii Bellows and Perring (Hom., Aleyrodidae)
Authors: Drost Y. C. , Qiu Y. T. , Posthuma‐Doodeman C. J. A. M. , Van Lenteren J. C.
Published: March 2003

Amitus bennetti Viggiani and Evans, Encarsia formosa Gahan (two strains), Eretmocerus eremicus Rose and Zolnerowich, Eretmocerus mundus Mercet and Eretmocerus staufferi Rose and Zolnerowich, which are parasitoids of Bemisia argentifolii Bellows and Perring were compared with respect to their searching behaviour as part of a pre‐introduction evaluation programme. Within a 5 cm arena, host‐finding time was independent of the release distance from the host. Before oviposition, A. bennetti walked fastest, the E. formosa strains walked slowest and the Eretmocerus species intermediate. Leg length was not the most significant factor determining the differences in walking speed. After oviposition, A. bennetti and Er. eremicus had a lower walking speed and higher turn rate which is an indication of area‐restricted search. The effect was strongest for A. bennetti. All species showed preference for counter‐clockwise turns. Based on the walking speed alone, it is expected that A. bennetti will be the most efficient natural enemy of B. argentifolii, the Eretmocerus species intermediate and the E. formosa strains the least.
Towards pheromone‐based monitoring of nun moth, Lymantria monacha (L.) (Lep., Lymantriidae) populations
Authors: Morewood P. , Gries G. , Liška J. , Kapitola P. , Häußler D. , Möller K. , Bogenschütz H.
Published: March 2003

The research objective was to develop pheromone‐based monitoring of the nun moth, Lymantria monacha (L.), an important defoliator of spruce and pine forests in central Europe. In 38 spruce or pine forests in central Europe, captures of male L. monacha in nonsaturating Unitraps and saturating Delta sticky traps baited with 0.2, 2, 20, or 200 μg of the L. monacha (pheromone) volatile blend [(±)‐disparlure, (±)‐monachalure, and 2‐methyl‐Z7‐octadecene at a 20 : 20 : 1 ratio] were compared with estimates of population densities obtained by counts of larval faecal pellets, pupal cases, and adult moths resting on tree trunks. Total captures of male L. monacha throughout the flight season in both types of trap were correlated with numbers of larval faecal pellets, irrespective of pheromone dose. Nonsaturating Unitraps baited with 2 μg of the L. monacha volatile blend seem to provide a cost‐effective tool for monitoring densities of L. monacha populations. Long‐term testing of this monitoring system has been initiated to substantiate the quantitative relationship between larval populations and trap captures of male L. monacha and to determine the threshold number of captured male moths that indicates an incipient outbreak.
Effects of fertilizer and herbicide application on Nantucket pine tip moth infestation (Lep., Tortricidae)
Authors: Sun J. H. , Kulhavy D. L. , Roques A.
Published: March 2003

A study of fertilizer and herbicide effects on Nantucket pine tip moth (NPTM), Rhyacionia frustrana (Comstock) infestations was conducted in loblolly pine (Pinus taeda L.) plantations in Nacogdoches Co., Texas, from 1988 to 1989. Both fertilizer and herbicide applications had effects on NPTM infestation level, pupal weight and host tree oleoresin production. Nitrogen fertilization increased infestation levels; whereas, phosphorus applications tends to decrease infestation rate. Herbicide treatment had a negative effect on NPTM infestations possibly because of decreased moisture stress and increased tree vigour. This is in contrast to general observations of increased NPTM infestations associated with reducing competing vegetation. Fertilizer application alone did not significantly improve pine growth due to competing vegetation. A combination of fertilizer and herbicide achieved the best growth.
The ‘island method’– a new laboratory test method to determine side‐effects of plant protection products on the predatory mite Typhlodromus pyri Scheuten (Acari, Phytoseiidae)
Authors: Joisten M.
Published: March 2003

Abstract: The model introduced here is an open test which produces experimental results of the same quality as a former test model and at the same time achieves considerable savings in both time and materials. The characteristic feature of the present method is that the mites are kept on a treated glass surface floating on water. The water forms a natural barrier ensuring that the mites cannot escape from the treated area.
The occurrence of Aceria tosichella Keifer (Acari, Eriophyidae) as a vector of wheat streak mosaic virus in Poland
Authors: Kozłowski J.
Published: March 2003

Abstract:

In the years 1997–98, observations were conducted on the occurrence of eriophyid mites and virus diseases on winter wheat. Plant samples of 13 wheat cultivars were collected in four localities from the experimental plots belonging to the Research Centre for Cultivars Testing. As a result of these observations three eriophyid mite species were found to occur on wheat. The dominant species was Aceria tosichella Keifer, a vector of wheat streak mosaic virus.
Bark borer Semanotus japonicus (Col., Cerambycidae) utilization of Japanese cedar Cryptomeria japonica: a delicate balance between a primary and secondary insect
Authors: Shibata E.
Published: March 2003

Abstract: The bark borer, Semanotus japonicus (Col., Cerambycidae), attacks living Japanese cedar, Cryptomeria japonica, with newly hatched larvae mainly feeding within the inner bark of the trunk. To understand how S. japonicus is affected by host nutrition and resin flow, newly hatched larvae were introduced into stressed cedar trees. Stress was induced by either heavy pruning, stem cutting (i.e. removing the side branches and top of tree), or girdling. Larval mortality due to resin flow in the ‘heavy pruning treatment’ and the ‘stem cutting treatment’ tended to be lower than that in the untreated control cedar trees where all larvae were drowned by resin flow. Parasitism to the larval stage was observed in the stem‐cutting trees, not in living trees, suggesting that S. japonicus may avoid parasitism in living cedar trees because few volatiles are produced. In the ‘stem‐girdling treatment’, although more than 90% of the introduced larvae died due to poor nutrition below the girdle, 7.8% of the larvae above the girdle reached the adult stage. The live body weight of the adults collected from above the girdle was similar to those taken from naturally infested cedar trees. These results suggest that S. japonicus requires adequate host nutrition but that larvae are defenceless against high resin flow. Thus, S. japonicus seems to be in a transition state between being primary or secondary with respect to its attack behavior on living cedar trees.
Rearing and breeding of the Moroccan locust Dociostaurus maroccanus (Thunberg) (Orthop., Acrididae) under laboratory conditions
Authors: Quesada‐Moraga  , Santiago‐Álvarez
Published: March 2003

The objective of the present work was to design a rearing method for the Moroccan or Mediterranean locust Dociostaurus maroccanus and to breed it. The duration of the post‐embryonic development from N1 to adult ranged between 35 and 38 days, independently of whether nymphs were reared at constant temperature or in cages with incandescent light bulbs that afford heat for thermo‐regulation. In contrast, the number of nymphs reaching the adult stage was directly related to the power of the bulb from 0 to 60 W. The rearing density did not affect the survival and developmental time of nymphs over the range 100–400 nymphs per cage. The survival of D. maroccanus nymphs under optimal conditions, which were a 60 W bulb and 400 nymphs per cage, was around 60%. The mean number of egg‐pods per female ranged between 2.6 and 3.5, and no difference was observed among rearing densities, with 16 pairs per cage being the optimal breeding condition. The number of eggs per egg pod ranged from 15 to 25, the egg viability from 20 to 50% and the adult longevity from 30 to 40 days. Eggs deposited by D. maroccanus females reared under these laboratory conditions were viable and thus the present study has ‘closed’ the life cycle of this species for the first time. The rearing method developed in this study will provide elements for studies of biology and physiology and it can be used in the design of new, environmentally sound pest management measures.
Spread of zucchini yellow mosaic potyvirus in squash in Hungary
Authors: Basky  , Perring  , Tóbiás
Published: March 2003

The temporal and spatial distribution of zucchini yellow mosaic potyvirus (ZYMV) was studied in a 3000‐m2 zucchini squash field. The first infected plants were found 4 weeks after the field was exposed to virus source plants. The infection increased to nearly 74% by the end of the study. Alate aphids were active from the beginning of the study and 43 species were trapped in the field. Flights of vector species Acyrthosiphon pisum and Myzus persicae peaked during the fourth week which resulted in high virus incidence 4 weeks later. There was a significant correlation between the number of vectors caught in yellow pan traps and the number of infected plants in the field. In laboratory studies evaluating 11 aphid species, Aphis pomi de Geer was identified as a new vector species of ZYMV. Although this aphid was not caught in our field studies, it may be an important contributor in other areas where cucurbits are grown in close proximity to apple or other hosts of this aphid.
Threats to pine stands by the pine shoot beetles Tomicus piniperda (L.) and Tomicus minor (Hart.) (Col., Scolytidae) around a sawmill in southern Poland
Authors: Borkowski A.
Published: March 2003

Forest stands growing around sawmills are especially exposed to damage due to the feeding by the pine shoot beetles Tomicus piniperda (L.) and Tomicus minor (Hart.) (Col., Scolytidae) in the pine shoots, causing a considerable loss of increment. The purpose of this study was to determine the relation of the distance zone of a stand from a sawmill to the density of the pine shoot fall, width of annual rings, and pine stand quality. The investigations were carried out between 1992 and 1996 in a Pinus silvestris–Abies alba stand adjacent to a sawmill in the Zagnańsk Forest District. In the investigated stand, eight zones situated at different distances from the sawmill were marked out, in which the fallen pine shoots were collected and dendrometric measurements taken. The study results showed that the pine shoot fall in the area up to 300 m away from the sawmill was significantly greater than the fall in zones situated further away. In addition, the mean current annual and 10‐year radial increments at breast height were significantly smaller, and the pine stand quality class was lower within that area. The radial increment at breast height in the area up to 300 m away from the sawmill was almost twice as low as that in the control area, and about 40% lower than the increment in the area situated 300–900 m away. The increment pattern of pine in this area differed from that of fir, suggesting that the incremental loss and lower pine stand quality are the result of long‐term feeding of the pine shoot beetles in the pine shoots. These results indicate that other causes, such as differences in site class, climatic factors or air pollution, can be excluded.
Efficacy of neem and diatomaceous earth against cowpea aphids and their deleterious effect on predating Coccinelidae
Authors: Ulrichs CH. , Mewis I. , Schnitzler W. H.
Published: March 2003

Philippine vegetable farmers commonly use synthetic insecticides to control insect pests on yardlong beans (Vigna unguiculata ssp. sesquipedalis). An important pest on yardlong beans is the cowpea aphid, Aphis craccivora Koch. Overuse of chemical insecticides and the adverse consequences for farmer health and for the environment have been reported. The natural enemies of A. craccivora, such as the coccinelidae beetle, Menochilus sexmaculatus (Fabr.), do not provide economic control on their own. In the present study the efficacy of the biological insecticide neem (both commercial and homemade) alone, and in combination with diatomaceous earth against A. craccivora was evaluated. The same insecticides were also examined to investigate their deleterious effect on M. sexmaculatus. The efficacies of different treatments with biological insecticides were compared with the use of the synthetic insecticide Hostathion (triazophos). Experiments were conducted under Philippine lowland conditions during the dry season when the occurrence of pest problems in yardlong beans is very great. Commercial neem, NeemAzal‐T/S (Trifolio‐M GmbH, Lahnau, Germany), significantly reduced the number of A. craccivora. NeemAzal‐T/S and diatomaceous earth in combination produced the best control of A. craccivora and were less toxic to M. sexmaculatus than treatment with Hostathion (triazophos). Aqueous homemade neem solution did not control the A. craccivora populations.
Effects of parasitization or injection of parasitoid‐derived factors from the endoparasitic wasp Glyptapanteles porthetriae (Hym., Braconidae) on the development of the larval host, Lymantria dispar (Lep., Lymantriidae)
Authors: Nussbaumer C. , Stradner A. , Schopf A.
Published: March 2003

Second instar larvae of Lymantria dispar were parasitized or injected with parasitoid‐derived factors such as venom, calyx fluid or parasitoid eggs from Glyptapanteles porthetriae. Growth and development of the host larvae were affected in all different groups compared to control larvae of the same age, injected with Ringer solution. The greatest impact on host growth and on the duration of the 3rd instar was caused by injecting parasitoid eggs. Treated larvae showed melanized capsules or nodules in the hemocoel. While the wasp age had no effect on parasitization efficiency or on the percentage of melanized particles in the hemocoel, significantly more encapsulations were found in larvae parasitized by old wasps as opposed to young wasps. Superparasitization (double or quadruple oviposition) increased the parasitization efficiency markedly. While none of the control larvae showed melanized particles, in the groups of single and superparasitized (2× and 4×) hosts a high percentage of melanized particles (capsules and nodules) occurred.
Predatory effect of Orius niger (Wolff) (Hem., Anthocoridae) on Frankliniella occidentalis (Pergande) and Thrips tabaci Lindeman (Thysan., Thripidae)
Authors: Deligeorgidis P. N.
Published: March 2003

The predatory effect of adult female Orius niger (Wolff) (Hem., Anthocoridae) on the larvae I–II and adults of two injurious thrips, Frankliniella occidentalis (Pergande) and Thrips tabaci Lindeman (Thysan., Thripidae), was examined in June 1997, in controlled environment chambers (temperature 22 ± 0.2°C, 65 ± 3% RH, a 16 h light : 8 h dark photoperiod and light intensity 9000 Lux). This study took place on sweet pepper leaves (Capsicum annuum L.) in transparent small plastic cages at proportions of 1/5, 1/10, 1/20 and 1/30 predator/number of thrips for larvae I–II and adults separately for each thrips species. O. niger was proved an effective predator for the immature stages (larvae I–II) and for the adults of the two thrips species. We concluded that O. niger could be used with success for the biological control of thrips in greenhouses crops.
Inert reusable substrates as potential replacements for wheat bran in larval diets for Mediterranean fruit fly, Ceratitis capitata (Wied.) (Dipt., Tephritidae)
Authors: Fay H. A. C. , Wornoayporn V.
Published: March 2003

Two small‐scale experiments were undertaken to evaluate the substitution of various inert substrates for wheat bran in the bulk larval diets of Mediterranean fruit fly. In the first experiment, the bran component was removed from the standard Seibersdorf diet and the remaining ingredients added to either diced high‐density (HD) sponge, sheet HD sponge, diced low‐density (LD) foam, sheet LD foam, moquette (synthetic) or woollen carpet. When the performance criteria for these treatments were compared against those for the standard Seibersdorf bran diet the pupal recovery levels were halved, the larval duration was extended by more than 2 days and the mean pupal size was reduced by ≥10%. Adult emergence and flight ability were unaffected. In the second experiment, yeast (YS) or bran‐based (BS) starter diets were applied to finisher diets that contained various inert substrates instead of wheat bran. Pupal recoveries were similar for the YS applied to diced HD sponge (50.1%), BS applied to either diced HD sponge, sheet HD sponge and woollen carpet (60.6, 55.6 and 54.5%, respectively) and the standard Seibersdorf diet (59.7%). For all the other substrate treatments (sheet HD sponge, diced LD foam, fine synthetic grass, coarse synthetic grass and woollen carpet) to which yeast starters were applied pupal recovery levels were inferior (P < 0.05) to that of the standard diet. Mean larval duration was comparable (P > 0.05) in the BS treatments (as above) (7.03, 7.58 and 7.46 days) and standard Seibersdorf diet (6.87 days), but was significantly longer for the YS applied to diced HD sponge (8.40 days) and for all the other treatments. The mean pupal size of flies produced from any treatment with an inert substrate was less (P < 0.05) than that of flies from the Seiberdorf standard diet, but generally remained within an acceptable size range for medfly. It is suggested that the inclusion of torula yeast and wheat germ in the yeast‐based starter diet should enhance the performance of diced HD sponge as a bulking agent substitute, and that this needs further investigation at mass‐rearing levels.
Distribution and sampling of Maruca vitrata (Fabricius) (Lep., Pyralidae) larvae on Lonchocarpus sericeus (Poir) H.B. and K.
Authors: Atachi P. , Dannon E. A. , Arodokoun Y. D. , Tamò M.
Published: March 2003

Abstract:  The spatio‐temporal distribution of the pod borer Maruca vitrata was assessed on Lonchocarpus sericeus over a period of 6 months, in order to develop sampling plans and facilitate sampling on this host plant. Lonchocarpus sericeus, one of the preferred alternative host plants of M. vitrata is widely spread in Benin and should therefore be included in the ecological management of the insect. Some experiments were conducted at an ecological site in south Benin, where L. sericeus can be found. The analysis of 17 weekly samples showed that tree canopy did not have a significant effect (P=0.3471) on larval distribution. Significant differences (P=0.0001) were obtained between the sizes of flowers (10, 20, 30 and 40 racemes). Geographical quadrants consisting of the upper east branches, lower east branches, upper west branches and lower west branches did not differ significantly (P=0.8713). The time of infestation of L. sericeus by M. vitrata was investigated by taking samples every 2 days. Data analysis of these samples revealed that L. sericeus was infested at the open flower stage. Temporal distribution of larvae showed the greatest abundance of larvae occurred in June. The index of aggregation was 1.37 with the Taylor law and 1.26 with the Iwao procedure. These values showed that the larval dispersion pattern is negative binomial. On this basis, sequential sampling plans were developed and these could permit an accurate estimate of tree data for sampling.
Ascospore Discharge, Leaf Infestation and Variations in Pathogenicity as Criteria to Predict Impact of Leptosphaeria maculans on Oilseed Rape
Authors: Thürwächter F. , Garbe V. , Hoppe H. ‐H.
Published: March 2003

The aim of this investigation was to evaluate criteria for the forecast and targeted control of basal stem canker (blackleg) caused by Leptosphaeria maculans on oilseed rape. Ascospore discharge, ratio of aggressive and non‐aggressive isolates and leaf and stem infestations were determined during 1991/92–1993/94 at 6–10 sites in Northern Germany. On a 1–9 scale, blackleg intensity varied from 2.3 to 6.3 at BBCH 81 between different sites and years. Ascospore discharge started in September or October, and reached maxima 1 or 2 months later, without an apparent relationship to blackleg or leaf infestation. There was a positive relationship between leaf infestation and blackleg. However, correlation coefficients were too low to be used as a basis for forecasting. On plant residues from the stem base, aggressive isolates were dominant (>80%) on all sites. From higher parts of the stem and from leaves also, non‐aggressive isolates were isolated with higher frequencies on some locations, but the proportion of aggressive isolates was not related to the blackleg intensity. Taken all together, the three criteria alone seem to be insufficient for the development of a system of blackleg forecasting and targeted control. Further factors (e.g. climatic factors, seed‐and soilborne inoculum, cultural practices) have to be included in models for forecasting the impact of blackleg on oilseed rape.
Cis ε‐viniferin: A New Antifungal Resveratrol Dehydrodimer from Cyphostemma crotalarioides Roots
Authors: Bala A. E. A. , Kollmann A. , Ducrot P.‐H. , Majira A. , Kerhoas L. , Leroux P. , Delorme R. , Einhorn J.
Published: March 2003

Six antifungal constituents were isolated from the roots of Cyphostemma crotalarioides (Vitaceae): a new product, Cis‐ε‐viniferin 3, along with five known compounds: trans‐resveratrol I and its oligomers: trans ε‐viniferin 2, gnetin C 4, pallidol 5 and gnetin E 6. It is the first time such compounds have been reported in this plant species. The roots tissues were found to be rich in other resveratrol oligomers, however, the available amounts of the other purified products did not allow structure investigations. No fungicidal activity was detected in the leaves of this plant.
Histopathology of Leaf Rust Infection and Development in Wheat Genotypes containing Lr12 and	Lr13
Authors: Bender C. M. , Pretorius Z. A. , Kloppers F. J. , Spies J. J.
Published: March 2003

Evidence exists that certain genes for resistance to leaf rust in wheat, e.g. Lr13 and
Lr34, may interact with other genes to condition higher levels of resistance than that conferred by each gene individually. In this study, the hypothesis that
Lr12 and
Lr13, both genes for adult plant resistance to Puccinia recondita Roberge ex. Desmaz f. sp. tritici Eriks. and Henn., interact to confer an improved level of resistance, was investigated using fluorescence and phase‐contrast microscopy. Flag leaf segments of monogenic and digenic Thatcher lines, sampled 64 and 240 h post‐inoculation, were stained with Uvitex 2B and screened, using fluorescence microscopy, for development of infection structures or host response. To study cell wall appositions, specimens were stained with trypan blue and a solution of picric acid in methyl salicylate. Aborted penetration, consisting of nonpenetrating appressoria and aborted substomatal vesicles, showed that inhibition of fungal growth in wheat lines containing
Lr12 and/or
Lr13 was activated, to a certain degree, before haustoria were formed. At 240 h after inoculation colony size indicated that fungal colonies in the
Lr gene combination lines were generally smaller than in the parents, but not necessarily smaller than those in a line with
Lr13 only. Host cell necrosis was more frequently associated with infection sites, specifically of pathotype UVPrt2, in the combination lines than in the parents. The morphology of cell wall appositions varied considerably from a narrow, luminous zone slightly wider in the centre, to a thick central part opposite the haustorium mother cell, sharply decreasing towards both ends. Histological assessments could, however, not conclusively prove pronounced resistance enhancement or unconventional resistance mechanisms due to combining the genes
Lr12 and
Lr13.
Sweet Potato Virus Disease in Sub‐Saharan Africa: Evidence that Neglect of Seedlings in the Traditional Farming System Hinders the Development of Superior Resistant Landraces
Authors: Gibson R. W. , Jeremiah S. C. , Aritua V. , Msabaha R. P. , Mpembe I. , Ndunguru J.
Published: March 2003

Sweet potato virus disease (SPVD) occurs in sweet potato at all localities on the perimeter of Lake Victoria areas surveyed in Uganda and Tanzania, and was particularly common in Kagera District in Tanzania and in Rukungiri District in Uganda. All fields were planted with landraces and the most important control practices, as perceived by farmers, were the planting of cuttings derived from only symptomless parents and destroying diseased plants. Although SPVD‐resistant landraces were available, they were perceived by most farmers to have poor and late yields. Most farmers considered that their greatest need was new, more acceptable, SPVD‐resistant genotypes. Few farmers had seen either sweet potato seeds (15%) or sweet potato seedlings (11%) and, of those that had, most had ignored them. The lack of seedlings and their neglect by farmers is likely to be hindering the evolution of more acceptable, SPVD‐resistant landraces, and is probably responsible for SPVD being a long‐term disease problem.
Effects of Metalaxyl, Fosetyl‐Al, Dimethomorph and Cymoxanil on Phytophthora cactorum of Peach Tree
Authors: Thomidis T. , Elena K.
Published: March 2003

The activity of metalaxyl, fosetyl‐Al, dimethomorph, and cymoxanil against Phytophthora crown rot of peach trees was examined. Application of fosetyl‐Al or metalaxyl by painting the trunk (150 g/l) of 3‐year‐old PR204 trees was inhibitory to growth of the fungus but neither dimethomorph nor cymoxanil were effective. Application of metalaxyl as a soil drench suppressed canker development when the treated trees were subsequently inoculated with Phytophthora cactorum. Fosetyl‐Al significantly reduced the growth of fungus compared with cymoxanil, dimethomorph and control but it was not as effective as metalaxyl. Again, dimethomorph and cymoxanil did not influence canker development. Both metalaxyl and fosetyl‐Al were active for at least 21 days after applications. Strips of trunk bark were removed from trees, that had been drenched with the tested chemicals 20 days before, and inoculated on the cambium side with P. cactorum. Metalaxyl was the most effective fungicide and fosetyl‐Al significantly reduced the development of fungus compared with dimethomorph, cymoxanil and the untreated strips. Colonization of strips treated with dimethomorph was significantly less than untreated strips. In contrast, cymoxanil did not inhibit the growth of fungus. Application of metalaxyl or fosetyl‐Al as trunk paint or a soil drench appear to be effective procedures for preventing Phytophthora rot of peach trees.
A Survey of Tospoviruses in Bulgaria
Authors: Hristova D. , Karadjova O. , Yankulova M. , Heinze C. , Adam G.
Published: March 2003

A survey of tospoviruses present in Bulgaria was conducted during three vegetation periods. A total of 258 different virus isolates were obtained from tobacco, tomato, weeds and ornamentals in the open fields and from glasshouses. Virus isolates were identified by inoculation to test plants and serology as Tomato spotted wilt virus (TSWV). No indications were obtained that other Tospovirus species were present in Bulgaria. In addition the transmission ability and efficiency of several Bulgarian populations of Thrips tabaci (Lind.) and Frankliniella occidentalis (Perg.) was determined. The experimental results indicated that Bulgarian TSWV isolates are transmitted with high efficiency by F. occidentalis and that only arrhenotokous and not thelytokouse populations of T. tabaci could transmit TSWV.
Histochemical Detection and Role of Phenolic Compounds in the Defense Response of Lactuca spp. to Lettuce Downy Mildew (Bremia lactucae)
Authors: Sedlářová M. , Lebeda A.
Published: March 2003

The occurrence of phenolic compounds (PC) in the defence reaction of Lactuca spp. was detected by histochemical methods. Four staining methods, including three for light and one for fluorescence microscopy, were used for imaging the location of PC in cells of genotypes with different resistance mechanisms after infection by Bremia lactucae, race NL16. The results showed that the major role of phenolic compounds in studied Lactuca spp. is connected with their overexpression and localized accumulation during a hypersensitive response (HR). In incompatible interactions a slight accumulation of phenols near the cell wall of infected cells was detected. The negative reaction to staining with aniline sulphate verified the absence of lignin creation. In both compatible and incompatible interactions structural modifications in the host cells occurred as a callose deposition. Frequently, these deposits were widespread in susceptible genotypes. Intensive and rapid accumulation of autofluorescent phenolics was linked with the onset of HR, the main cytological feature of resistance to lettuce downy mildew in Lactuca spp.