Natural infection with two genotypes of Cryptosporidium in red squirrels (Sciurus vulgaris) in Italy

We investigated the genotypes of Cryptosporidium infecting red squirrels (Sciurus vulgaris L.) in two areas of the Western Alps in Italy. Examination of 141 faecal samples from 70 red squirrels revealed oocysts of Cryptosporidium in 17 animals (24.3%). Based on 18S rRNA gene sequencing, two genotypes of Cryptosporidium species were found: 15 squirrels were positive for the Cryptosporidium ferret genotype and 2 for the Cryptosporidium chipmunk genotype I. The occurrence and intensity of Cryptosporidium infection did not differ between the study areas or sex. More than 85% of the positive animals were adults; however no difference was found between Cryptosporidium infection in the juvenile and adult age groups. Oocysts of the Cryptosporidium ferret genotype measured 5.5 +/- 0.3 x 5.2 +/- 0.2 microm (shape index 1.06) and the Cryptosporidium chipmunk genotype I 5.8 +/- 0.3 x 5.4 +/- 0.3 microm (shape index 1.07). Neonatal and adult CD1 and BABL/c mice inoculated with 1 x 10(3) fresh oocysts of both genotypes did not produce detectable infection.     

Studies on the life cycle of Cryptosporidium coccidia in experimentally infected chickens

Experimental infections of 7-28-day-old chickens with Cryptosporidium oocysts isolated from spontaneously infected chickens demonstrated that the endogenous development of this parasite takes place simultaneously in the organs of digestive, respiratory and excretory systems and in bursa of Fabricius. It was demonstrated for the first time that the oocysts of Cryptosporidium are shed through the respiratory tract into the beak cavity. A novel rapid and simple method has been developed for the detection of oocysts. Its principle is the rinsing of the beak cavity. This method enabled to isolate the oocysts from experimentally infected chickens and immediately use them in the dose of 6 X 10(5) for peroral infection of a 37-day-old chicken. The prepatent period was 8 days, patent period 12 days. On days 4-7 after the first detection of Cryptosporidium oocysts in chicken excrements, the oocysts were detected also by the method of beak cavity rinsing. This indicates that the oocysts released from the respiratory tract are infective. This fact is important from the epizootological viewpoint in relation with possible spreading of Cryptosporidium infections in chicken farms.     

An unusual localization of developmental stages of Cryptosporidium parvum Tyzzer, 1912 in the cells of small intestine of a gnotobiotic piglet

In a gnotobiotic piglet infected with 50.10(6) oocysts of Cryptosporidium parvum, developmental stages of the parasite were found in the duodenum, anterior jejunum and middle jejunum on the first day post infection (1 DPI). During the studies of the ultrastructure, trophozoites and meronts of C. parvum were encountered in the microvillous zone of enterocytes, and the outer membrane of parasites was a continuation of the membrane of microvilli. Unusual was the attachment of C. parvum trophozoite on the opening of a goblet cell, as well as a meront localized in the cytoplasm in the enterocyte of anterior jejunum. These findings show that C. parvum is very adaptive and capable of developing in a still undescribed location.     

Influence of Soil Temperature and Matric Potential on Sugar Beet Seedling Colonization and Suppression of Pythium Damping-Off by the Antagonistic Bacteria Pseudomonas fluorescens and Bacillus subtilis

ABSTRACT Pseudomonas fluorescens B5 and Bacillus subtilis MBI 600 colonized sugar beet seedlings at matric potentials of -7 x 10(3), -140 x 10(3), and -330 x 10(3) Pa and under five temperature regimes ranging from 7 to 35 degrees C, with diurnal fluctuations of 5 to 22 degrees C. No interaction between matric potential and temperature was observed. In situ bioluminescence indicated physiological activity of Pseudomonas fluorescens B5. Colonization of the root at >/=4 cm below the seed decreased at very low matric potential (-330 x 10(3) Pa). Total population size of Pseudomonas fluorescens B5 per seedling was significantly increased at -140 x 10(3) Pa. However, matric potential had no significant effect on the population density of Pseudomonas fluorescens per gram of root fresh weight and did not affect the distribution of the population down the root. Total population size per seedling and downward colonization by Pseudomonas fluorescens B5 were significantly reduced at high temperatures (25 to 35 degrees C). Maximum colonization down the root occurred at intermediate temperature (15 degrees C) at both matric potentials (-7 x 10(3) and -140 x 10(3) Pa). Addition of B. subtilis MBI 600 to the seed had no effect on rhizosphere populations of Pseudomonas fluorescens B5. Populations of B. subtilis MBI 600, which consisted largely of spores, were slightly reduced at lower matric potentials and were not affected by temperature. Survival and dry weight of plants in soils infested with Pythium spp. decreased with increasing soil temperature and matric potential, indicating an increase in disease pressure. However, there was no significant interaction between the two factors. At -330 x 10(3) Pa, soil dryness but not Pythium infection was the limiting factor for plant emergence. At temperatures of 7 to 25 degrees C and matric potentials of -7 x 10(3) to 120 x 10(3) Pa, treatment with Pseudomonas fluorescens B5 increased plant survival and dry weight. At 7 degrees C and -120 x 10(3) Pa, there was almost complete emergence of seeds treated with Pseudomonas fluorescens B5. Antagonistic activity of Pseudomonas fluorescens B5 decreased with increasing soil temperature and decreasing matric potential. At 25 to 35 degrees C and -7 x 10(3) Pa, no effect was observed. In regimes with different day and night temperatures, the maximum (day) temperature was decisive for disease development and antagonistic activity. B. subtilis MBI 600 displayed no significant antagonistic effect against Pythium ultimum and did not influence the performance of Pseudomonas fluorescens B5 in combined inocula.     

Experimental transmission of Caryospora kutzeri (Apicomplexa: Eimeriidae) by rodent hosts

Four laboratory-hatched European kestrels Falco tinnunculus L. were fed on laboratory mice and common voles Microtus arvalis Pallas previously inoculated with different doses of sporulated oocysts of Caryospora kutzeri B?er, 1982. Two kestrels that were fed infected mice shed C. kurtzeri oocysts 6 days after ingesting murine tissues. To compare direct and indirect transmissions, two of the kestrels were subsequently directly inoculated with 10(5) sporulated C. kutzeri oocysts and became patent on days 8 and 9 and shed caryosporan oocysts up to day 25 post inoculation. Additionally, four mice were inoculated with 10(6) oocysts in order to examine mouse tissues for the presence of developmental stages of C. kutzeri. No coccidian stages were found in the tissues of inoculated mice. The experiment showed that developmental stages of C. kutzeri are able to survive in mouse tissues and cause infection of suitable host after their ingestion.     

The endogenous development, described by light and electron microscopy, of Eimeria jamescooki sp. n. (Apicomplexa: Eimeriidae) from the skink Cryptoblepharus virgatus

Eimeria jamescooki sp. n. was recovered from the skink Cryptoblepharus virgatus (Garman) found on the grounds of James Cook University, Townsville (type locality), North Queensland, Australia. Oocysts were 17.5-25.0 (22.1 +/- 1.9) x 15-22.5 (17.7 +/- 1.6) microm and sporocysts 6.25-10.0 (7.9 +/- 1.15) x 3.75-6.25 (5.3 +/- 1.0) microm in size. Endogenous stages are described from histological material examined by light microscope and by transmission electron microscope. Both merogony stages and gamonts were found to develop in the cytoplasm of the anterior gut mucosal epithelium. Meront progeny were comprised of 10 to 21 merozoites. Premature macrogamonts were elongate; some host cells contained two elongate macrogamonts. Unique to the presently described species were the Golgi "plaques" and an enclosure of tubuli. Mature macrogamonts and young oocysts ranged in size from 14 x 7 to 21 x 11 microm and contained two types of wall-forming bodies, canaliculi and amylopectin granules. Differentiating microgamonts conformed in fine structure with that observed in other eimerians. Their sizes increased from 15.4 x 4.2 to 28 x 8.4 microm while dividing to over 70 nuclei, which formed a corresponding yield of microgametes.     

Two new species of isospora (Apicomplexa: Eimeriidae) from geckoes of the genus Rhacodactylus (Sauria: Gekkonidae) endemic to New Caledonia

Coprological examination of New Caledonian geckoes of the genus Rhacodactylus Fitzinger, 1843 revealed two new species of coccidia. Isospora leachiani sp. n. from R. leachianus (Cuvier, 1829) has oval, colourless oocysts, measuring 21-26 x 16-18.5 microm. Sporocysts are ellipsoidal, 11-12.5 x 6.5-8 microm, with distinct Stieda and substieda bodies. Oocysts of Isospora sykorai sp. n. from R. ciliatus (Guichenot, 1866) are elongately oval to cylindrical, 20-23.5 x 11-14 microm; sporocysts of this species are ellipsoidal, 10-11.5 x 7-8 microm, with a slightly pointed end and Stieda and substieda bodies. Infected geckoes did not exhibit any alteration of their health status.     

A description of two new species of coccidia (Apicomplexa: Eimeriidae) from African reptiles with nomenclatural corrections for two Caryospora and one Eimeria species from snakes

Two new species of coccidian parasites are described from African reptiles. Oocysts of Eimeria foulshami sp. n. from the plated lizard Gerrhosaurus major bottegoi Del Prato of Sudan are ellipsoidal, 24.1 x 14.9 (23-26.5 x 14-17.8) microm with a bilayered, colourless oocyst wall and lack polar granules. The ellipsoidal sporocysts average 8.6 x 4.6 (7-10.6 x 4.4-7) microm and possess a prominent, globular, sporocyst residuum. Oocysts of Caryospora regentensis sp. n. from the Eastern green mamba Dendroaspis augusticeps Smith, 1849 [corrected] of Kenya are spherical to subspherical, 16.8 x 16.4 (16-17.6 x 15-17.2) microm with a bilayered oocyst wall and a single polar granule. The ellipsoidal sporocysts average 13.0 x 10.3 (10.2-14 x 9.2-11) microm and possess a Stieda and substieda body and a prominent globular sporocyst residuum. Oocysts of Caryospora legeri Hoare, 1933 are reported from a hissing sand snake, Psammophis sibilans sibilans L. from Nigeria, representing a new geographical record. The oocysts are slightly larger than the type, but otherwise identical. Caryospora psammophi Bray, 1960 and C. hermae Bray, 1960 from Psammophis sibilans phillipsi, oocysts of which are morphologically similar to and overlap in dimensions with C. legeri Hoare, 1933, are synonymised with the latter species. Eimeria samiae Iskander et Tadros, 1979 is emended to E. samyadeli to reflect the gender of the person the species was named after and because E. sani is preoccupied. In addition to these findings, Eimeria bohemi Modry, Slapeta et Koudela, 2000 and oocysts of an unidentified spherical Eimieria sp. are reported from Chamaeleo dilepis dilepis Leach from Cameroon.     

New species of Choleoeimeria (Apicomplexa: Eimeriidae) from the veiled chameleon, Chamaeleo calyptratus (Sauria: Chamaeleonidae), with taxonomic revision of eimerian coccidia from chameleons

Coprological examination of 71 samples from a breeding colony of veiled chameleons, Chamaeleo calyptratus Duméril et Duméril, 1851, revealed a presence of two species of coccidia. In 100% of the samples examined, oocysts of Isospora jaracimrmani Modry et Koudela, 1995 were detected. A new coccidian species, Choleoeimeria hirbayah sp. n., was discovered in 32.4% of samples from the colony. Its oocysts are tetrasporocystic, cylindrical, 28.3 (25-30) x 14.8 (13.5-17.5) microm, with smooth, bilayered, -1 microm thick wall. Sporocysts are dizoic, ovoidal to ellipsoidal, 10.1 (9-11) x 6.9 (6-7.5) microm, sporocyst wall is composed of two plates joined by a meridional suture. Endogenous development is confined to the epithelium of the gall bladder, with infected cells being typically displaced from the epithelium layer towards lumen. A taxonomic revision of tetrasporocystic coccidia in the Chamaeleonidae is provided.     

Biological Control of Botrytis cinerea in Cyclamen with Ulocladium atrum and Gliocladium roseum Under Commercial Growing Conditions

ABSTRACT The effect of treatments with conidial suspensions of Ulocladium atrum and Gliocladium roseum on leaf rot of cyclamen caused by Botrytis cinerea was investigated under commercial greenhouse conditions. Spraying U. atrum (1 x 10(6) conidia per ml) or G. roseum (2 x 10(6) conidia per ml and 1 x 10(7) conidia per ml) at intervals of 2 to 3 weeks during the production period and spraying U. atrum (1 x 10(6) conidia per ml) at intervals of 4 to 6 weeks resulted in a significant reduction of natural infections of petioles by B. cinerea. U. atrum or G. roseum (1 x 10(7)conidia per ml) was as effective as the standard fungicide program. B. cinerea colonized senesced leaves within the plant canopy and infected adjacent petioles and leaves later. The antagonists colonized senesced leaves and reduced B. cinerea development on these leaves. Thus, the inoculum potential on petioles adjacent to necrotic leaf tissues was reduced. The fate of U. atrum conidia on surfaces of green cyclamen leaves during a 70-day period after application was studied. The number of conidia per square centimeter of leaf surface remained relatively constant during the entire experiment. Sixty percent of the conidia sampled during the experiments retained the ability to germinate. When green leaves were removed from the plants to induce senescence and subsequently were incubated in a moist chamber, U. atrum colonized the dead leaves. Senesced leaves also were colonized by other naturally occurring fungi including B. cinerea. On leaves treated with U. atrum from all sampling dates, sporulation of B. cinerea was significantly less as compared with the untreated control. Our results indicate that early applications of U. atrum before canopy closure may be sufficient to achieve commercially satisfactory control of Botrytis leaf rot in cyclamen.     

Mice serve as paratenic hosts for the transmission of Caryospora duszynskii (Apicomplexa: Eimeriidae) between snakes of the genus Elaphe

Caryospora duszynskii Upton, Current et Barnard, 1984 was successfully transmitted to snakes of the genus Elaphe by feeding them previously infected mice. Fifty thousand oocysts were orally administered to two mouse strains, BALB/c and Crl:CD-1(ICR)BR, which were subsequently fed to captive-born coccidia-free Elaphe guttata (L.) in two respective independent experiments. Both E. guttata expelled C. duszynskii oocysts in their faeces, beginning on day 18 and 26 post infection (p.i.) and shed oocysts continuously through the end of the experiment, day 230 and 135 p.i., respectively. There were no parasitic stages or lesions in mice, as revealed by histological examination. Experiments proved that rodents serve as paratenic hosts for C. duszynskii. In summary we discuss the life-cycle strategies of Caryospora spp. in reptiles and present three general modes of their development.     

Immune response in rabbits experimentally infected with Ascaris suum

Immune response of rabbits experimentally infected with Ascaris suum was studied by indirect haemagglutination method. The animals were infected with the doses of 5,000, 10,000 and 20,000 infective eggs per animal. Positive reactions were observed from days 5-11 p.i., maximum reactions on days 11-19 p.i. A reinfection with the same doses (1x or 2x after 35 and 65 days) increased the antibody titre. The strongest individual reaction was recorded on day 19 p.i. in the group infected with the highest dose (titre 1 : 4096). The increased antibody titres persisted til the end of the experiment (82th day p.i.) in all groups.     

博斯腾湖浮游植物种群结构初步评价

对博斯腾湖浮游植物自1987年7月至1989年9月连续进行了12次采样,布设12个采样点,进行了种类组成、种群数量、生物量、优势种、多样性指数、叶绿素a、初级生产力等群落生态学的调查和初步研究,并对博斯腾湖水质污染及营养水平进行了总评和分区评价。本次调查共发现浮游植物7门78属131种。浮游植物数量年均达388.19万/升(细胞数)。秋季最高,为786.79%/升,冬季最低,为47.47万/升,春季为265.93万/升,夏季为428.55万/升。秋季各点多以蓝藻门的微囊藻占优势,春、夏季多以绿藻门的骈胞藻占优势。冬季多以绿藻门的栅列藻占优势。甲藻门的飞燕角甲藻为全湖性的广布种,它不因季节和点位改变而变化。硅藻门的种类最丰富。优势种主要是β—中污生物带种,其次是α—中污带种。多样性指数在1.96—2.13之间。从多样性指数和初级生产力计算结果及其它多项指标看,博斯腾湖大湖区水域已受到不同程度的污染。其污染区趋势为:Ⅲ区>Ⅴ区>Ⅳ区>Ⅱ区>I区。博斯腾湖属于绿—蓝甲藻型中营养湖泊。与70年代博斯腾湖浮游植物调查资料对比,表明近年来,人为因素使博斯腾湖富营养化的进程正在加快。     

Redescription of Eimeria dorcadis Mantovani, 1966 (Apicomplexa: Eimeriidae) from the dorcas gazelle (Gazella dorcas) in Saudi Arabia

Eimeria dorcadis Mantovani, 1966 is redescribed from dorcas gazelle (Gazella dorcas (L.)) from Saudi Arabia. Oocysts were detected in 7 out of 22 faecal samples (32%) using floatation method. The sporulated oocysts are cylindrical, slightly flattened at the micropylar pole, measure in average 32 x 19 microm (27-36 x 16-24 microm), length/width ratio being 1.7 (1.5-2.1). Oocyst wall is 1.2 microm thick, smooth, double-layered; outer layer is slightly thicker, light blue in colour; inner layer brownish, with micropyle in the inner layer and apparently continual outer one, measures 2.2 microm, but lacks a micropylar cap. The sporocyst elongate-ellipsoidal, measures 14 x 8 microm (12-17 x 6-9 microm), length/width ratio being 1.8, with sporocyst residuum as circular compact, coarse, refractile granules. Stieda body is present, while substieda body is absent. Sporozoites banana-shaped, measure 11 x 2.5 microm, each with a large spheroidal refractile body at the wider pole. Sporulation time is 2-3 days at 25 +/- 2 degrees C.     

Range of phytoplasma concentrations in various plant hosts as determined by competitive polymerase chain reaction

ABSTRACT For competitive polymerase chain reaction (PCR), an internal standard DNA template was developed that consisted of a highly conserved, internally deleted 16S rDNA fragment of an aster yellows phytoplasma. The internal standard was calibrated using a quantified culture of Acholeplasma laidlawii. Serial dilutions of the internal standard and fixed amounts of target templates from infected plants were coamplified with the same primers, and the products obtained were quantified using an enzyme-linked immunosorbent assay procedure. Analysis of the data revealed that the phytoplasma concentration in the plants examined differed by a factor of about 4 x 10(6). Phytoplasma concentrations of 2.2 x 10(8) to 1.5 x 10(9) cells per g of tissue were identified in periwinkles infected with various phytoplasmas. High to moderate concentrations were detected in Malus domestica (apple) genotypes infected with the apple proliferation phytoplasma, Alnus glutinosa (alder) genotypes infected with the alder yellows phytoplasma, and most aster yellows-infected Populus (poplar) genotypes examined. Very low phytoplasma concentrations, ranging from 370 to 34,000 cells per g of tissue, were identified in proliferation-diseased apple trees on resistant rootstocks 4551 and 4608, yellows-diseased Quercus robur (oak) trees, and Carpinus betulus (hornbeam) trees. Such low concentrations, which corresponded to about 4 to 340 cells in the reaction mixture, could only be detected and quantified by nested PCR.     

Effects of antagonist cell concentration and two-strain mixtures on biological control of fusarium dry rot of potatoes

ABSTRACT Eighteen bacterial strains were individually assayed against Gibberella pulicaris (5 x 10(5) conidia per ml) by coinoculating antagonist and pathogen in wounds in cv. Russet Burbank potatoes. All antagonist concentrations (10(6), 10(7), and 10(8) CFU/ml) decreased disease (38 to 76% versus control, P < 0.05). When four strains were assayed at 11 concentrations (range 10(5) to 10(8) CFU/ml) against G. pulicaris, linear regression of the log-dose, log-response data was significant for all four strains (P < 0.001 to 0.01, R(2) = 0.50 to 0.74). Challenging G. pulicaris with all possible antagonist pairings within 2 sets of 10 antagonist strains (5 x 10(5) CFU of each strain per ml) resulted in 16 of 90 pairs controlling disease better than predicted based on averaging the performance of the individual strains making up the pair (P < 0.10). Successful pairs reduced disease by ~70% versus controls, a level of control comparable to that obtained with 100 times the inoculum dose of a single antagonist strain. Neither strain genus nor soil of origin were useful in predicting successful antagonist pairs. Factors potentially influencing dose-response relationships and the effectiveness of antagonist pairs in controlling disease are discussed.     

An index technique to monitor broadcast calibration and bait pick up, plus rodent and avian sign under arid conditions

As part of product-performance and wildlife-hazards studies of 2% zinc phosphide (Zn3P2) steam-rolled-oat baits (11.2 kg ha-1) to reduce vole populations (Microtus spp) in alfalfa (Medicago sativa), we used randomly located, brushed-dirt plots (eight approximately 930-cm2 plots per 0.2-ha enclosure) to monitor bait-broadcast and -removal patterns, as well as to index vole and avian sign. Research was conducted in 18 x 0.2-ha enclosures containing 2.5-year-old stands of alfalfa; a 2-day pre-bait (placebo baits broadcast in all enclosures) period followed by a 14-day test-bait period (placebo and 2% Zn3P2 baits in nine enclosures each) characterized the bait exposures. Baits were broadcast manually by two certified pesticide applicators (CPAs) using Spyker Model-75 spreaders. Baits that fell onto plots were counted < 30 min later to assess the uniformity of bait distribution. The main statistical design was a 2 (placebo or Zn3P2 baits) x 3 (vole-only, vole-pheasant, vole-quail exposures) x 14 (days) factorial, with days considered repeated measurements. In the six vole-only enclosures, baits were removed from the brushed-dirt plots and replaced with four 0% or 2% Zn3P2 baits (one per 232.6-cm2 quadrant; 32 per enclosure); these 'placed' baits were then monitored daily for removal, while the surfaces of all plots were monitored daily for the presence:absence of animal/bird sign. Key results were: (a) 3.51 (+/- 2.66) and 3.39 (+/- 3.52) mean (+/- SD) baits were found on plots after pre-bait and test-bait broadcasts, respectively--less than the predicted 4.52 particles per 930-cm2 plot; (b) baits 'placed' on plots in placebo-baited enclosures were removed earlier than those in Zn3P2-baited enclosures--data in agreement with observed vole mortality; and (c) species x bait interactions occurred for both the vole- and pheasant-sign counts, but not quail-sign counts--data also indirectly confirming Zn3P2-induced mortality effects on voles and pheasants. This technique has utility for a variety of wildlife biology and chemical registration studies; although limited to arid conditions, the technique affords useful indices of broadcast calibration, bait pick-up, as well as target and non-target species mortality.     

Eimeria burdai sp. n. (Apicomplexa: Eimeriidae), a new parasite species from subterranean African silvery mole-rat, Heliophobius argenteocinereus

A new coccidian parasite of the genus Eimeria Schneider, 1875 is described from the subterranean African silvery mole-rat Heliophobius argenteocinereus Peters, 1846. Oocysts of Eimeria burdai sp. n. were subspherical to broadly ellipsoidal 17.8 (16-19) x 14.1 (12-15), with a shape index 1.2 (1.1-1.4). Oocyst wall was bilayered, smooth and colourless, approximately 1.0 thick. Outer layer was significantly thicker than inner one. A micropyle and oocyst residuum were absent. One or two ellipsoidal or spherical polar granules were present. Sporocysts were ellipsoidal, 10.8 (9-12) x 6.2 (5-8) with a shape index 1.7 (1.5-1.9). Sporocyst wall was single-layered, thin, smooth and colourless, with small Stieda body at the pointed end. In freshly sporulated oocysts, spherical sporocyst residuum was composed of small granules enclosed by a thin membrane. Sporozoites were elongate, lying length-wise in the long axis of the sporocyst, partially curled around each other, with single large refractile body located posteriorly. Faintly distinguishable nucleus was in the central part of the sporozoite. This eimerian represents the first coccidian species described from subterranean African silvery mole-rat (Rodentia: Bathyergidae).     

Effect of Carbon, Nitrogen, and C:N Ratio on Growth, Sporulation, and Biocontrol Efficacy of Talaromyces flavus

ABSTRACT Engelkes, C. A., Nuclo, R. L., and Fravel, D. R. 1997. Effect of carbon, nitrogen, and C:N ratio on growth, sporulation, and biocontrol efficacy of Talaromyces flavus. Phytopathology 87:500-505.Five-day biomass production by the biocontrol fungus Talaromyces flavus was measured in a liquid basal medium, pH 5.5, containing each of 37 carbon (C) sources with a single nitrogen (N) source, and each of 42 N sources with a single C source. In general, production of biomass was greatest on complex sugars such as polysaccharides (32 g/liter of medium) and beta-glucosides (2.4 g/liter of medium), and was least on monosaccharides (1.3 g/liter of medium). Ascospore production at 6 weeks on solid basal medium with the same amount of these same 37 degrees C sources was greatest on oligosaccharides (2.9 x 10(8) spores per 5.5-cm-diameter petri dish), and least on polysaccharides and monosaccharides (1.6 and 1.4 x 10(8) spores per 5.5-cm-diameter petri dish, respectively). For C sources, there was no correlation between production of ascospores and hyphal dry weight. The various N sources yielded 0 to 10(9) ascospores per 5.5-cm-diameter petri dish and 10(-4) to 10(-5) g of hyphal dry weight per milliliter. In general, N sources that resulted in the greatest number of ascospores also yielded the greatest hyphal dry weights. For the two C and two N sources tested, the number of ascospores increased as the ratio of C to N increased from 5:1 to 30:1. This effect was most obvious as the C:N ratio increased from 5:1 to 15:1. At low C:N ratios (<15:1), treatments with hypoxanthine as a N source resulted in significantly greater production of biomass than treatments with ammonium tartrate; no difference was observed at C:N ratios >/=15:1. Incidence of Verticillium wilt was 50% lower for eggplants drenched with ascospores grown on potato dextrose agar (PDA) compared with eggplants either nondrenched or drenched with ascospores grown on media with hypoxanthine plus lactose or maltose. Thus, C and N sources that slightly increased ascospore production of T. flavus reduced efficacy of biocontrol of Verticillium wilt compared with ascospores produced on PDA.