Dynamics of infection by Leptosphaeria maculans on canola (Brassica napus) as influenced by crop rotation and tillage

Abstract

This study, intending to understand the effects of crop rotation and tillage on blackleg disease, was conducted in a field at Carman, Manitoba, Canada, from 1999 – 2002. Canola, wheat and flax were among the rotated crops. Rotations were performed under conventional or zero-till conditions. The number of infected plants, infected leaves per plant, lesions per plant, and percentage of leaf coverage with lesions decreased when canola was rotated with wheat and flax under zero till. The number of lesions per plant and percentage of leaf coverage with lesions were strongly correlated with stem disease severity, and the number of infected plants with stem disease incidence. Ascospores and pycnidiospores of Leptosphaeria maculans were reduced by crop rotation and tillage. This study suggests that the appropriate combination of rotation and tillage may lower airborne inoculum and reduce infection of canola plants by L. maculans.     

Effect of plant density and nitrogen on wheat F1 hybrids and their parents

The autonomous spread of Gaeumannomyces graminis var. tritici from discrete sources of inoculum, consisting of naturally infected stubble and roots, was measured in three field experiments. Spread occurred from only half of the inoculum sources and when it did occur it averaged a distance of only 10 cm.     

Epidemiology of grey mildew and Alternaria blight of cotton

Grey (Areolate) mildew (Ramularia areola) and Alternaria blight (Alternaria macrospora) are two important fungal foliar diseases affecting cotton in India. Both the diseases are polycyclic in nature. The primary inoculum for grey mildew is through conidia or ascospores from infected debris and/or perennial cottons and the secondary spread is through primarily infected leaves. Whereas for Alternaria blight the spread is initially from seed-borne inoculum (in Gossypium herbaceum and Gossypium arboreum cottons) and/or crop debris and the secondary spread is from sporulating lesions on older leaves. Both R. areola and A. macrospora require a temperature regime of 20–30?°C with prolonged high humidity (>80%) and frequent rains for infection and disease development. However, it has been observed that cool weather coupled with prolonged dewy periods in the absence of rains has also been found conducive for the development of both the diseases. So, suitable epidemiological tools and models are required to predict the disease development, spread and to design suitable management practices.     

Modeling the impact of a biocontrol agent, Puccinia lagenophorae, on interactions between a crop, Daucus carota, and a weed, Senecio vulgaris

The impact of a biocontrol agent spreading from a point source on crop–weed interactions was modeled. The model encompassed: (i) severity of crop–weed competition as affected by a rust pathogen, (ii) velocity of spread of the rust pathogen, and (iii) density of infected plants introduced in the weed population as starting points (inoculum sources) for an epidemic. The model was parameterized for a study system encompassing the crop Daucus carota (carrot), the weed Senecio vulgaris (common groundsel), and its antagonist Puccinia lagenophorae. The parameters of (i) were estimated in a greenhouse study using a response-surface design. Estimates of the parameter of (ii) were obtained from the literature. The density of infected plants (iii) was varied to simulate crop loss as function of density. Simulations were run for various densities of the weed and various velocities of rust pathogen spread. The results of the simulations indicated a crop-loss ranging from 5 to 10% at levels of relatively weak D. carota–S. vulgaris competition. Density of inoculum sources and velocity of P. lagenophorae spread had only minor effects on crop loss. In contrast, density of inoculum sources and velocity of spread had major effects on crop loss at levels of intermediate (range of 10–35% loss) and severe competition (range of 30–70% loss). The results are discussed both with respect to biological control of S. vulgaris using P. lagenophorae as biocontrol agent and as a general model describing the impact of the spatial dynamics of a pathogen (natural enemy) on plant competition.     

Biotransformation of Panax notoginseng saponins into ginsenoside compound K production by Paecilomyces bainier sp. 229

Aims: Development and optimization of an efficient and inexpensive biotransformation process for ginsenoside compound K production by Paecilomyces bainier sp. 229. Methods and Results: We have determined the optimum culture conditions required for the efficient production of ginsenoside compound K by P. bainier sp. 229 via biotransformation of ginseng saponin substrate. The optimal medium constituents were determined to be: 30 g sucrose, 30 g soybean steep powder, 1 g wheat bran powder, 1 g (NH₄)₂SO₄, 2 g MgSO₄·7H₂O and 1 g CaCl₂ in 1 l of distilled water. An inoculum size of 5–7·5% with an optimal pH range of 4·5–5·5 was essential for high yield. Conclusions: The Mol conversion quotient of ginseng saponins increased from 21·2% to 72·7% by optimization of the cultural conditions. Scale‐up in a 10 l fermentor, under conditions of controlled pH and continuous air supply in the optimal medium, resulted in an 82·6% yield of ginsenoside compound K. Significant and Impact of the Study: This is the first report on the optimization of culture conditions for the production of ginsenoside compound K by fungal biotransformation. The degree of conversion is significantly higher than previous reports. Our method describes an inexpensive, rapid and efficient biotransformation system for the production of ginsenoside compound K.     

Aerial dispersal of the potato gangrene pathogen, Phoma exigua var. foveata

A semi-selective medium for isolating the potato gangrene pathogen, Phoma exigua var. foveata, from air is described. Airborne propagules of P. exigua var. foveata were generated for at least 57 min after the start of simulated raindrop impaction on senescent potato stems bearing pycnidia from a natural infection. The number of propagules generated as aerosols was 0·17% of that available for aerosolisation. The aerodynamic particle size of at least 92% of the aerosols was in the range 2·1–4·7 μm in diameter. Using a Casella High Volume Bacterial Sampler airborne propagules of P. exigua var. foveata were detected in the open air during rainfall from September to November at three sites in Southern Scotland. They were recovered at least 800 m down wind from the nearest potato crop. P. exigua var. exigua and P. eupyrena were also recovered from the air during rainfall. Very low numbers of P. exigua var. foveata were occasionally detected in the absence of rain. The role of airborne inoculum of P. exigua var. foveata is discussed in relation to reinfection of virus-tested stocks of seed potatoes derived from stem cuttings.     

Comparison of natural and artificial epidemics of take-all in sequences of winter wheat crops

Winter wheat was grown for six successive years (Expt 1) and for three successive years (Expt 2) in field experiments on different soil types. Artificial inoculum of the take-all fungus (Gaeumannomyces graminis var. tritici cultured on autoclaved oat grains) was incorporated in the soil of some of the plots just before, or at, sowing of the first winter wheat crop. Expt 1 tested the incorporation of similar amounts of inoculum (212 kg ha^-1) at different depths. Expt 2 tested different amounts of inoculum at the same, shallow depth. Early sowing (September), late sowing (October) and spring inoculation were additional treatments, applied to the first crop only, in Expt 2. Seasonal factors apart, the disease outcome in the first year after inoculation depended on amounts and placement of applied inoculum, as well as date of sowing. Deeper inoculum resulted in less disease (Expt 1). Severe take-all was produced in Expt 2 by incorporating inoculum shallowly in sufficient quantities (400 kg ha^-1 or more). Less inoculum (200 kg ha^-1) generated less disease, especially in earlier-sown plots. Differences in disease amongst inoculum treatments were greatest in the first year and diminished subsequently, particularly where sowing had been early in the first year. In Expt 1, where first crops exposed to artificial inoculum developed moderate-to-severe disease, disease in subsequent second and/or third crops was less. In the fourth crop a second peak of disease occurred, coinciding with a first peak in sequences without added inoculum. Take-all decline (TAD) appeared to be expressed in all sequences thereafter. In Expt 2 in sequences without added inoculum, TAD occurred after a peak of disease in the second crop. Where 400 kg ha^-1 or more of inoculum were added, disease was severe in the first year and decreased progressively in successive years. Disease was less patchy in plots that received artificial inoculum. However, it remains uncertain mat severe disease caused by artificial inoculation achieved an early onset of true TAD. The infectivity of the top 12 cm of soil in the first 3 yr of Expt 1, determined by bioassay, depended on the depth of added inoculum and amount of disease in subsequent crops. However, at the time of the naturally occurring peak of disease severity (in either inoculated or non-inoculated plots) it did not predict either disease or TAD. Differences and similarities amongst epidemics developing naturally and those developing from different amounts and placement of applied inoculum have been revealed. The epidemiological implications of adding inoculum and the potential value of artificially-created epidemics of take-all in field trials are discussed.     

Aggregation of Colletotrichum acutatum in Response to Simulated Rain Episodes

The influence of rain splash dispersal on the aggregation and variability of spores of Colletotrichum acutatum, the causal agent of strawberry anthracnose, was studied with simulated rain over a soil surface. In the first experiment, rains with intensities of 15 and 30 mm/h were generated and sampling plates, with a selective medium for Colletotrichum, were positioned under rainshields at both 20 and 60 cm from an inoculum point source (five infected fruit) for 1-min exposure periods. Number of colonies growing in plates were used to measure spore density. For each distance, time, rain intensity, and replication, the mean (m), variance (v), and Lloyd's index of patchiness (LIP) were calculated. Estimated (LIP) exceeded 1, indicating the high variability and clustering of colonies, and hence spores, resulting from splash dispersal. LIP increased with distance from the source and with rain intensity at the greater distance. Aggregation was further quantified by Taylor's power law describing the linear relation between ln (v) and ln (m). The slope (b) of the relation for all data points was 1·67, which was significantly (P < 0·01) greater than 1, a further indication of clustering. Distance form the source had a slight positive effect on b. Colony means (Y) were transformed to Y*=Y^1/5 based on an approximate b of 1·6. Analysis of Y* indicated an expected significant main effect of rain duration and a significant interaction of distance and rain intensity. In another experiment, six infected fruit and the sampling plates were uniformly placed over the surface. LIP again exceeded 1, and Taylor's b equaled 1·63. In a final study, the inoculum source and sampling plates were raised 46 cm above the soil surface. There was a drastic reduction in Y* compared to surface values, supporting the prior hypothesis that surface topography strongly affects splash dispersal. Results indicate that the physical process of splash dispersal produces a degree of aggregation similar to that produced by population dynamic and other ecological processes.     

Chitinase Production in Solid-State Fermentation by Enterobacter sp. NRG4 Using Statistical Experimental Design

The optimization of nutrient levels for chitinase production by Enterobacter sp. NRG4 in solid-state fermentation conditions (SSF) was carried out using response surface methodology (RSM) based on central composite design (CCD). The design was employed by selecting wheat bran-to-flake chitin ratio, moisture level, inoculum size, and incubation time as model factors. The results of first-order factorial design experiments showed that all four independent variables have significant effects on chitinase production. The optimum concentrations for chitinase production were wheat bran-to-flake chitin ratio, 1; moisture level, 80%; inoculum size, 2.6 mL; and incubation time, 168 h. Using this statistical optimization method, chitinase production was found to increase from 616 U · g⁻¹ dry weight of solid substrate to 1475 U · g⁻¹ dry weight of solid substrate.     

Inulinolytic activity of broths of Aspergillus niger ATCC 204447 cultivated in shake flasks and stirred tank bioreactor

It is the first detailed study of an inulinolytic fungus Aspergillus niger ATCC 204447 since its discovery, covering submerged cultivations both in shake flasks and a stirred tank bioreactor. Various carbon sources were applied to induce the inulinolytic activity in shake flask cultures. The highest volumetric and specific (per gram of biomass) activities (respectively 0.68 U/mL and 184 U g/X) were observed for the initial inulin and sucrose concentrations equal to 20 g/L. The fungus grew as large (>3 mm) spherical pellets. The influence of inoculum density and application of microparticle‐enhanced cultivation (MPEC) were studied in the batch bioreactor cultivations. Inoculum density moderately affected the inulinolytic activities, whose highest values were 0.7 U/mL and 165 U g/X at the lowest studied spore density of 3.33·10⁸ L^?1. Dispersed hyphae evolved in the bioreactor made the broth difficult to aerate due to high apparent viscosity (exceeding 200 Pa sⁿ at shear rate about 0.05 s^?1) and shear thinned properties (flow behavior index below 0.2). In MPEC (10 μm talc microparticles) the pellets of diameter between 1 and 2 mm were formed, which facilitated the aeration of the broth and increased the specific inulinolytic activity 3.5‐fold.     

Factors affecting incidence and severity of leaf spot disease on lettuce caused by Septoria birgitae

In the 1990s during wet seasons a new disease causing brown leaf spots on lettuce (Lactuca sativa) was found for the first time in many lettuce‐growing areas of Austria and Germany. The causal agent, a new pathogenic species called Septoria birgitae, may be responsible for total crop loss. To study how temperature, inoculum density and leaf wetness period influence disease incidence and severity of leaf spot on lettuce caused by S. birgitae, we carried out in vivo experiments in growth chambers and in the field. Additionally, we evaluated the relevance of infected plant debris acting as a primary inoculum source in soil for subsequent crops. S. birgitae produces spores over a wide temperature range between 5°C and 30°C, and can infect plants at temperatures between 10°C and 30°C, with an optimum between 20°C and 30°C. Spores of S. birgitae at a density of at least 10³ conidia mL^–1 are essential for disease outbreak on lettuce. Because leaf wetness is crucial for releasing conidia from pycnidia, we studied the impact of leaf wetness duration on disease development under various temperature conditions. For relevant leaf spot disease development on lettuce in vivo, a leaf wetness duration of at least 24 h and temperatures higher than 10°C were necessary. Leaf spot disease development in the field required several leaf wetness periods longer than 20 h at approximately 15°C at the beginning of crop cultivation. Incorporating S. birgitae infected plant debris in soil as a primary inoculum was not relevant for leaf spot disease outbreak in the next year. However, in cases of continuous cropping of lettuce on the same field and in the same season, Septoria‐infected lettuce debris may become more relevant.     

Relationship between inoculum density and vector phenology on the incidence of potato virus Y in tobacco

The epidemiology of potato virus Y (PVY) in the tobacco crop, Nicotiana tabacum, was examined in the context of the seasonal abundance of aphid vectors, rate of disease progress, and disease gradient from a known virus source. The spring potato crop, Solanum tuberosum, was suspected of being the main source of inoculum; therefore, varying numbers of infected potato plants were used as the inoculum source in different test plots. A 3-wk lag phase was present in all disease progress curves prior to an exponential increase in disease incidence. The relatively low numbers of aphid vectors, primarily transient species, alighting on the crop during the lag phase were responsible for the primary spread of PVY from potato to tobacco. The arrival of large numbers of colonising aphid vectors, Myzus persicae, presumably from the harvested potatoes, coincided with the exponential increase in PVY incidence in tobacco. The initial number of potato plants infected with PVY was positively correlated with the final disease incidence, rate of disease progress, and the magnitude of radial dispersion of PVY into the tobacco. Aphid vector pressure was not a significant variable in the differences in spatial and temporal characteristics of PVY epidemics among test plots.     

The role of the whitefly,Bemisia tabaci (Gennadius), and farmer practices in the spread of cassava brown streak ipomoviruses

Cassava brown streak disease (CBSD) is arguably the most dangerous current threat to cassava, which is Africa's most important food security crop. CBSD is caused by two RNA viruses: Cassava brown streak virus (CBSV) and Ugandan cassava brown streak virus (UCBSV). The roles of the whitefly Bemisia tabaci (Gennadius) and farmer practices in the spread of CBSD were investigated in a set of field and laboratory experiments. The virus was acquired and transmitted by B. tabaci within a short time (5–10 min each for virus acquisition and inoculation), and was retained for up to 48 hr. Highest virus transmission (60%) was achieved using 20–25 suspected viruliferous whiteflies per plant that were given acquisition and inoculation periods of 24 and 48 hr, respectively. Experiments mimicking the agronomic practices of cassava leaf picking or the use of contaminated tools for making cassava stem cuttings did not show the transmission of CBSV or UCBSV. Screenhouse and field experiments in Tanzania showed that the spread of CBSD next to spreader rows was high, and that the rate of spread decreased with increasing distance from the source of inoculum. The disease spread in the field up to a maximum of 17 m in a cropping season. These results collectively confirm that CBSV and UCBSV are transmitted by B. tabaci semipersistently, but for only short distances in the field. This implies that spread over longer distances is due to movements of infected stem cuttings used for planting material. These findings have important implications for developing appropriate management strategies for CBSD.     

Soil-applied fungicides for controlling take-all in field experiments with winter wheat

Soil treatment fungicides were tested against take-all (Gaeumannomyces graminis var. tritici) in three field experiments with winter wheat. Fungicides were applied as drenches either before sowing in autumn, and incorporated by rotary harrowing, or to the crop in spring. The most effective treatments were autumn applied benomyl (20 kg/ha) and nuarimol (0·55-4·4 kg/ha). However, the highest nuarimol concentration depressed yield. Benomyl sometimes induced a resurgence of take-all in the second wheat crop after treatment. Nuarimol had no adverse effects in subsequent crops, and neither fungicide hindered the onset of take-all decline in a third crop after treatment. The possible value of soil treatment in future control strategies is discussed.     

Short‐term survival and movements of Atlantic sharpnose sharks captured by hook‐and‐line in the north‐east Gulf of Mexico

Ultrasonic telemetry was used to compare post‐release survival and movements of Atlantic sharpnose sharks Rhizoprionodon terraenovae in a coastal area of the north‐east Gulf of Mexico. Ten fish were caught with standardized hook‐and‐line gear during June to October 1999. Atlantic sharpnose sharks were continuously tracked after release for periods of 0·75 to 5·90 h and their positions recorded at a median interval of 9 min. Individual rate of movement was the mean of all distance and time measurements for each fish. Mean ± s.e . individual rate of movement was 0·45 ± 0·06 total lengths per second (L_T s^?1) and ranged from 0·28 to 0·92 L_T s^?1 over all fish. Movement patterns did not differ between jaw and internally hooked Atlantic sharpnose sharks. Individual rate of movement was inversely correlated with bottom water temperature at capture (r² = 0·52, P ≤ 0·05). No consistent direction in movement was detected for Atlantic sharpnose sharks after release, except that they avoided movement towards shallower areas. Capture‐release survival was high (90%), with only one fish not surviving, i.e. this particular fish stopped movement for a period of 10 min. Total rate of movement was total distance over total time (m min^?1) for each Atlantic sharpnose shark. Mean total rate of movement was significantly higher immediately after release at 21·5 m min^?1 over the first 1·5 h of tracking, then decreased to 11·2 m min^?1 over 1·5–6 h, and 7·7 m min^?1 over 3–6 h (P ≤ 0·002), which suggested initial post‐release stress but quick recovery from capture. Thus, high survival (90%) and quick recovery indicate that the practice of catch‐and‐release would be a viable method to reduce capture mortality for R. terraenovae.     

Patterns of spread of two non-persistently aphid-borne viruses in lupin stands under four different infection scenarios

Patterns of spread of Bean yellow mosaic virus (necrotic type, BYMV‐N) and Cucumber mosaic virus (CMV) were examined in stands of narrow‐leafed lupin (Lupinus angustifolius) where naturally occurring aphid vectors moved them from external or internal primary virus sources. The lupin stands were: commercial crops near BYMV‐infected clover pasture with or without an intervening non‐host barrier crop; a large rectangular block with BYMV‐N and CMV sources on opposite sides and a narrow, non‐host barrier crop facing the BYMV‐N source; and a plot within which seed‐infected lupin plants acted as internal CMV sources. When BYMV‐N spread into commercial crops in the absence of a non‐host barrier, there was a steep decline in its incidence with distance from the crop edge. However, when a 20 m‐wide perimeter barrier of oats intervened between the two, there was only a shallow decline. When CMV and BYMV‐N spread from opposite directions into a block with a 0.25 m‐wide oat barrier between it and the BYMV‐N source, the BYMV‐N incidence gradient was shallow but in the opposite direction the CMV gradient was steep. When CMV spread from primary sources within a plot, infection was concentrated in large internal patches. Spread of BYMV‐N was more diffuse with more isolated symptomatic plants and small clusters than occurred with CMV, spread of which was more comprehensive, reacting the near monocyclic and polycyclic patterns of spread with BYMV‐N with CMV respectively. Spread of both viruses was greater along than across rows, especially with CMV. With BYMV‐N, three different phased cycles of secondary spread were evident in the individual symptomatic plants within the small clusters that formed away from the edges of lupin stands. These findings help validate inclusion of perimeter non‐host barriers within an integrated disease management strategy for BYMV‐N in lupin.     

The effect of drought stress and temperature on spread of barley yellow dwarf virus (BYDV)

1 The effect of drought stress and temperature on the dispersal of wingless aphids Rhopalosiphum padi (L.) and the pattern of spread of BYDV (barley yellow dwarf virus) within wheat plants in controlled environment chambers was quantified. Combinations of three different drought stress levels, unstressed, moderate and high stress level, and three different temperatures, 5 ± 1 °C, 10 ± 1 °C, and 15 ± 1 °C, were investigated. 2 With increased temperature there was an increase in the mean distance of visited plants from the point of release and in the number of plants visited and infected with BYDV. Drought stress had no effect on mean distance moved by aphids at any temperature or on plants infected with virus at 10 °C and 5 °C. When plants were drought stressed, the numbers of plants visited and infected were greater at 15 °C than at 10 °C and 5 °C. 3 A greater proportion of plants visited by aphids was infected with BYDV when plants were stressed than when not stressed. At 15 °C a greater proportion of these plants was infected than at lower temperatures. There was no difference between treatments in the numbers of aphids present at the end of the experiment. 4 It is concluded that drought stress and temperature are of considerable importance in virus spread.     

The development of silver scurf (Helminthosporium solani) disease of potato

The main source of inoculum of Helminthosporium solani was the seed tuber; the fungus was not detected in soils in which infected potatoes had been grown the previous year. Lesions spread rapidly on seed tubers after planting, so that within a few weeks the entire surface was covered. As lesions aged they lost the capacity to sporulate, so most inoculum was produced in the first few weeks after planting. Infection of progeny tubers was first detected at the heel (stolon attachment) end soon after their initiation. Once established, lesions spread slowly on the surface of progeny tubers when in the soil; more rapid spread took place during storage. Potatoes which seemed unaffected at lifting became diseased during storage.     

Temporal and spatial spread of Lettuce mosaic virus in lettuce crops in central Spain: factors involved in Lettuce mosaic virus epidemics

Lettuce mosaic virus (LMV) is transmitted by aphid vectors in a nonpersistent manner as well as by seeds. The virus causes severe disease outbreaks in commercial lettuce crops in several regions of Spain. The temporal and spatial patterns of spread of LMV were studied in autumn 2002 in the central region of Spain. Symptomatic lettuce (var. Cazorla) plant samples were collected weekly, first at the seedling stage from the greenhouse nursery and later outdoors after transplantation. The exact position of symptomatic plants sampled in the field was recorded and then material was tested by enzyme‐linked immunosorbent assay to assess virus infection. Cumulative spatial data for infected plants at different growth stages were analysed using spatial analysis by distance indices. For temporal analysis, the monomolecular, Gompertz, logistic and exponential models were evaluated for goodness of fit to the entire set of disease progress data obtained. The results indicated that the disease progress curve of LMV epidemics in the selected area is best described by a Gompertz model and that the epidemic follows a polycyclic disease progression. Our data suggest that secondary cycle of spread occurs when noncolonising aphid species land on the primary infected plants (probably coming from infected seed) and move to adjacent plants before leaving the crop. The role of weeds growing close to lettuce fields as potential inoculum sources of virus and the aphid species most likely involved in the transmission of LMV were also identified.     

Effects of two parasites, Schistocephalus solidus (Cestoda) and Bunodera spp. (Trematoda), on the escape fast-start performance of three-spined sticklebacks

The fast‐start performance of three‐spined sticklebacks Gasterosteus aculeatus infected with Schistocephalus solidus and Bunodera spp. was determined and two distinct fast‐start responses (A and B) were observed. ‘A’ starts were of higher flexibility than B and three‐way ANOVA showed significant effects of A and B starts (P < 0·05), time (P < 0·05) and per cent standard body length, L_S (P < 0·05) on the orientation angle (angle of an individual segment of the fish with respect to the direction of travel). Schistocephalus solidus infection reduced maximum velocity (P < 0·05) and maximum acceleration (P < 0·05) of infected fish. Uninfected fish and fish infected with S. solidus up to a parasite index (parasite mass divided by the sum of fish and parasite mass) of 0·1 executed both types. Infected fish exclusively executed B starts for parasite index between 0·1 and 0·2. This was not due to a reduction in body flexibility associated with mechanical obstruction caused by S. solidus as no significant difference in the ratios of body width (P > 0·05) or depth (P > 0·05) to L_S were found between uninfected and infected fish. At a parasite index >0·2, infected fish were unable to perform escape fast‐starts increasing the likelihood of predation by their definitive hosts such as loons or belted kingfishers. Three‐spined sticklebacks infected with S. solidus with a parasite index of c. 0·2–0·3, however, were compromised by a suite of behavioural (e.g. increased foraging activity and amount of food consumed, increased risk associated with feeding and increased response latency to predatory stimuli), physiological (e.g. increased rate of oxygen consumption, slower growth, delayed sexual maturation and breeding success) and biomechanical (e.g. decreased fast‐start performance) factors. Bunodera spp. did not affect the escape fast‐start performance of three‐spined sticklebacks and no significant difference for maximum velocity (P > 0·05) and maximum acceleration (P > 0·05) was found.