Dry Rot Severity Research Articles

Exploration of non-phytopathogenic Aspergillus spp. isolates recovered from soil and compost as potential source of bioactive metabolites for potato Fusarium dry rot control.

During storage, infected potato tubers by Fusarium species leads to significant losses. Searching natural-based alternatives to chemical fungicides for the control of tuber dry rot pathogens is becoming essential. Nine Aspergillus spp. (A. niger, A. terreus, A. flavus, and Aspergillus sp.) isolates, recovered from soil and compost samples, were explored and evaluated for their ability to suppress Fusarium sambucinum the main causal agent of potato tuber dry rot disease in Tunisia. All conidial suspensions of Aspergillus spp. tested and their cell-free culture filtrates had significantly inhibited the in vitro pathogen growth by 18.5 to 35.9% and by 9 to 69% compared to control, respectively. A. niger CH12 cell-free filtrate was the most active against F. sambucinum at the three concentration tested (10, 15, and 20% v v-1). Chloroform and ethyl acetate extracts from four Aspergillus spp., tested at 5% v v-1, had limited F. sambucinum mycelial growth by 34-60% and 38-66%, respectively, compared to control, with A. niger CH12 ethyl extract being the most active. Tested on potato tubers inoculated with F. sambucinum, all tested Aspergillus spp. isolates, their cell-free filtrates and organic extracts had significantly decreased the external diameter of dry rot lesion compared to pathogen-inoculated and untreated control tubers. For the rot penetration, all Aspergillus spp. isolates, their organic extracts and only filtrates from A. niger CH12 and MC2 isolates had significantly limited dry rot severity compared to pathogen-inoculated and untreated control. The highest reductions in the external diameter of dry rot lesion (76.6 and 64.1%) and the average rot penetration (77.1 and 65.1%) were achieved using chloroform and ethyl acetate extracts from A. niger CH12, respectively. These results clearly demonstrated the presence of bioactive compounds in Aspergillus spp. that can be extracted and explored as an eco-friendly alternative for the control of the target pathogen.

Antifungal activity of potato glycoalkaloids and its potential to control severity of dry rot caused by Fusarium sulphureum

AbstractIdentifying novel sources of antifungal agents from common food waste (i.e., green potato peel) could provide an inexpensive alternative for botanical fungicides. Identification of the potato (Solanum tuberosum L.) glycoalkaloids (PGAs) content in the green peel by high performance liquid chromatography (HPLC), and the antifungal activity of PGAs against the potato dry rot pathogen Fusarium sulphureum were evaluated using addition of PGAs to the medium in vitro and injection of it into potato tubers in vivo. The results of HPLC showed that the average content of PGAs per kilogram green potato peel was 2238.76 mg, and the α‐chaconine content was about 1.8 times higher than that of α‐solanine. Antifungal activity test of PGAs in vitro uncovered that mycelium growth rate of F. sulphureum was inhibited in potato dextrose agar (PDA) medium with varying concentrations of PGAs, and the inhibition rate was positively correlated with PGAs concentration. Moreover, PGAs were also capable of reducing the contents of malondialdehyde, total phenols, flavonoids as well as the activities of peroxidase and superoxide dismutase induced by F. sulphureum through inhibiting or killing part of mycelium. These findings suggest that the protective effect of PGAs against potato dry rot might be associated with the direct fungistatic effect on the pathogen. Thus, PGAs can serve as a promising botanical fungicide to substitute, at least partially, the use of synthetic fungicides in the disease management of potato.

The effect of nanoparticles of metals and nonmetals of multicomponent trace element preparation «Avatar-2 protection» and microbial preparation «Azogran» on the incedence and severity of infectious diseases of potato

The aim of the research was to study the influence of nanoparticles (NPs) of metals and nonmetals of multicomponent trace element preparation «Avatar-2 protection» and microbial preparation «Azogran» on infectious diseases of potato in vivo. Affection of potato cultivar Suvenir Chernihivskyi by diseases was evaluated in two small plot studies on soddy podzolic soil and alkaline chernozem. Symptoms of common scab and dry rot in tubers were identified visually and then the severity and the rate of the diseases were calculated. The presence of viruses in plants was examined by agglutination tests and the rates of the viral infections were calculated. The results of the study indicate that on the soddy podzolic soil the composition of Se+I NPs significantly decrease disease severity of both common scab and dry rot by 20.00 and 17.50% respectively, whereas «Avatar-2 protection» preparation, «Azogran» preparation and the combination of «Azogran» preparation with the composition of Se+I NPs significantly decreased only the severity of dry rot by 22.50%. The combination of «Azogran» preparation with the composition of Se+I NPs significantly decreased the incidence and the disease severity of common scab, the incidence and the disease severity of dry rot on the alkaline chernozem by 40.00; 30.00; 25.00 and 30.00% respectively; whereas «Avatar-2 protection» preparation significantly decreased the incidence of viral diseases by 33.33–66.67% on both soils. The effect of the composition of Se+I NPs, «Avatar-2 protection» preparation and «Azogran» preparation is promising for further investigation. Particularly, an abundance of different groups of microorganisms in potato’s rhizosphere under the treatment with studied substances needs to be evaluated in order to understand the mechanisms diseases’ incidence and severity decrease. The effect of the studied NPs and preparations on other diseases of potato and diseases of other agricultural crops needs to be studied. The results of these studies can be useful for the development of the control methods for various infectious diseases of agricultural crops.

Effect of chitosan for the control of potato diseases caused by Fusarium species

AbstractThe antifungal activity of chitosan against Fusarium spp. was investigated based on in vitro and in vivo assays, and its possible modes of action were also explored. Chitosan applied at 4.0 g/L of acetic acid‐distilled water solution significantly decreased the mycelial growth of Fusarium oxysporum, Fusarium sambucinum and Fusarium graminearum by 88.4%, 89.0% and 89.8%, respectively. Tuber treatment by chitosan (4.0 g/L) of acetic acid‐distilled water solution, prior to inoculation, reduced dry rot severity induced by F. oxysporum and F. sambucinum by 60.0% and 48.2%, respectively. When tested as plant treatment, potato plants inoculated with Fusarium species, exhibited 33.5%–45.3% less wilting severity as compared to the control. This abiotic treatment improved the phenolic compounds activities and defence‐related enzymes such as peroxidase and polyphenoloxidase in potato tubers inoculated with Fusarium spp. Results clearly demonstrated that chitosan could be explored as an alternative agent to chemical fungicides for the control of tuber dry rot and Fusarium wilt through induction of the plant defence system.

The mechanism of induced resistance against Fusarium dry rot in potato tubers by the T-2 toxin

Potato (Solanum tubersosum L) is the most important non-grain source of human diet for the people living at poverty line. Potato suffers from many notorious biotic stresses, including dry rot caused by Fusarium spp. Treatments of potato tubers with 1 mg L−1 of T-2 toxin produced by Fusarium spp. induced resistance against Fusarium sulphureum by new elicitor-like activity. To investigate the mechanism of induced resistance by T-2 toxin against dry rot of potato, tuber slices were treated with T-2 toxin, followed by the inoculation with F. sulphureum spores. Results in this study showed that the reduction of disease area was linked with higher abundance of reactive oxygen species (ROS) and new phenylpropanoid metabolites. T-2 toxin treatment increased ROS accumulation and induced the activities of enzymes involved in ROS and phenylpropanoid metabolism. At the same time, T-2 toxin treatment also up-regulated proteins involved in ROS and phenylpropanoid metabolism determined by iTRAQ (isobaric tags for relative and absolute quantitation) assay, as well as genes encoding proteins involved ROS and phenylpropanoid metabolism. Taken together, this study provides substantial evidences that T-2 toxin induced resistance related proteins and genes in potato tuber slices to suppress the dry rot severity of F. sulphureum.

Control of Fusarium Dry Rot Incited by Fusarium oxysporum f. sp. tuberosi Using Sargassum vulgare Aqueous and Organic Extracts

Aqueous and organic extracts of Sargassum vulgare, removed from four Tunisian coastal sites, were evaluated for their antifungal potential against the soilborne fungus Fusarium oxysporum f. sp. tuberosi, one of the main causal agents of potato Fusarium dry rot in Tunisia. Assessed using the poisoned food technique on Potato Dextrose Agar, the antifungal activity of S. vulgare extracts varied depending on extract types (aqueous/organic), alga sampling sites (Tunis, Monastir, Mahdia1 and Mahdia2) and concentrations used (1-100 mg/ml). Mycelial growth inhibition, noted after 4 days of incubation at 25°C, reached 28.99% using S. vulgare aqueous extract at 100 mg/mL. Up to 43% growth inhibition was achieved using 50-100 mg/ml of petroleum ether extract of S. vulgare removed from Tunis and Mahdia2, and up to 50% with those from Mahdia1. S. vulgare aqueous and organic extracts decreased Fusarium dry rot severity, noted after 21 days of incubation at 25°C, in a concentration dependant manner. Applied prior to pathogen challenge, treatment with aqueous extract (at 100 mg/mL) led to 24 and 30% decrease in lesion diameter and rot penetration over the untreated control. Tubers treated with aqueous extracts of alga sampled from Tunis showed the lowest dry rot severity compared to those from the other sampling sites. Chloroformic and methanolic extracts exhibited the highest disease-suppressive effects relative to untreated control and to the other organic extracts. Applied at 100 mg/mL, the methanolic and chloroformic extracts have lowered disease severity by more than 53 and 55%, respectively. This study clearly demonstrated that this brown alga can be valorized as a potential source of antifungal compounds useful in agriculture.

Soil-borne and Compost-borne Aspergillus Species for Biologically Controlling Post-harvest Diseases of Potatoes Incited by Fusarium sambucinum and Phytophthora erythroseptica

Nine isolates of Aspergillus spp., isolated from soil and compost were tested in vitro and in vivo for their antifungal activity against Fusarium sambucinum and Phytophthora erythroseptica, the causal agents of the Fusarium dry rot and pink rot of potato tubers. Tested using the dual culture method, the pathogen growth of F. sambucinum and P. erythroseptica was inhibited by 27 to 68% and 16 to 25% by all Aspergillus species, respectively. The highest inhibitory activity against both pathogens was induced by the isolate CH12 of A. niger. A significant reduction of the mycelial growth of both pathogens tested using the inverse double culture method involves the presence of volatile antifungal metabolites. Their effectiveness was also evaluated as tuber treatment prior to inoculation with the pathogens. The highest effectiveness in reducing Fusarium dry rot severity was recorded on tubers treated with the isolate CH12 of A. niger. This study also revealed that the efficacy of Aspergillus spp. as biocontrol agents may be enhanced by varying the timing of their application. In fact, the lesion diameter of dry and pink rots was reduced by 54-70 and 52% with preventive application, respectively. However, this parameter decreased by 21-48 and 47% when the Aspergillus spp. were applied simultaneously with pathogens, respectively. Similarly, diseases’ severity, estimated based on average penetration of F. sambucinum and P. erythroseptica, was reduced by 57-77 and 55% with preventive treatments and by 29-68 and 44% with simultaneous application, respectively. This study reveals that Aspergillus spp., isolated from compost and soil, exhibits an interesting antifungal activity toward F. sambucinum and P. erythroseptica and may represent a potential source of biopesticide. Testing of their culture filtrates, their organic extracts and their toxicity may give additional information on their safe use as biocontrol agents.

<b>Effects of wounding, humidity, temperature, and inoculum concentrations on the severity of corky dry rot caused by <i>Fusarium semitectum</i> in melon fruits

Corky dry rot, caused by Fusarium semitectum, is the main postharvest disease of melons in Brazil. This study investigated the effects of wounding, humidity, temperature, and inoculum concentration on the severity of corky dry rot under controlled conditions. Cantaloupe and honeydew melon types were inoculated by spraying conidial suspensions of three F. semitectum isolates. In all experiments, the tested F. semitectum isolates did not differ in relation to disease severity, but, the cantaloupe melon showed higher levels of severity. No lesions appeared on fruits that lacked wounds, and increasing wound age reduced lesion severity. Melons that were inoculated with F. semitectum developed symptoms regardless of the presence or absence of a moist chamber at the post-inoculation stage, but the lesions were larger under moist chamber conditions. There were no symptoms at 10°C, but a temperature increase from 15 to 25°C resulted in a disease severity increase. The largest lesions were observed when both melon types were inoculated with a concentration of 106 conidia mL-1, but even the lowest concentration (101 conidia mL-1) was sufficient for causing lesions. Injury reduction and/or the acceleration of melon healing, as well as environmental variable control and a reduction of inoculum sources, are essential to reducing corky dry rot severity.

Efficacy of Pseudomonas syringae in the management of potato tuber diseases in storage

Silver scurf caused by Helminthosporium solani and dry rot caused by Fusarium spp. are tuber diseases of economic importance in potato-growing areas worldwide. Recently, the two pathogens have developed resistance to thiabendazole (TBZ), a post-harvest fungicide commonly used for their control. Therefore, alternative disease control strategies are needed. The present study assessed the efficacy of the biopesticides Bio-Save 10LP (Pseudomonas syringae-strain ESC-10; Ps10) and Bio-Save 11LP (P. syringae-strain ESC-11; Ps11) against silver scurf and dry rot. Approximately 30 isolates representing the genus Fusarium were obtained from symptomatic potato specimens with dry rot from New Brunswick (NB), Nova Scotia (NS), Prince Edward Island (PE) and Alberta (AB), Canada. Species isolated were Fusarium sambucinum, Fusarium tumidum, Fusarium coeruleum, Fusarium culmorum, and Fusarium avenaceum. H. solani isolated from AB, NB and PE was included in the study as the causal agent of silver scurf. The efficacy of P. syringae against F. sambucinum and H. solani was tested in vitro. Ps10 and Ps11 inhibited the growth of H. solani up to 68% (NB isolate) and 73% (PE isolate), respectively and the inhibition was more or less comparable with that of TBZ. F. sambucinum was not significantly inhibited by Ps10; however Ps11 significantly inhibited AB, PE and NB isolates by 43%, 28% and 54%, respectively. Conversely, TBZ inhibited AB, PE and NB isolates of Fusarium spp. in vitro by 86%, 88% and 100%, respectively. TBZ in combination with either Ps10 or Ps11 did not always reduce the growth of H. solani or Fusarium spp. in vitro compared to that of TBZ alone. Storage trials conducted in NB and PE assessed the efficacy of P. syringae against H. solani or Fusarium spp. in vivo and confirmed that the application of P. syringae or TBZ alone or in combination significantly reduced the incidence and/or severity of silver scurf and Fusarium dry rot. Ps11 alone or in combination with TBZ was significantly more effective than Ps10 in controlling silver scurf disease severity. The reduction in disease severity of dry rot and silver scurf in storage due to Ps10, Ps11, or TBZ or their combinations was consistently comparable. Results indicate that the use of P. syringae (strains ESC-11 or ESC-10) as a post-harvest treatment can contribute to the management of both silver scurf and Fusarium dry rot in potato storages.

Biological control of Fusarium dry rot and other potato tuber diseases using Pseudomonas fluorescens and Enterobacter cloacae

Dry rot caused by various species of Fusarium is a disease of significant importance in potatoes. Field trials were conducted in 2005 and 2006 in New Brunswick, Canada to assess the efficacy of Pseudomonas fluorescens and Enterobacter cloacae applied as a seed treatment in suppressing Fusarium dry rot of potato ( Solanum tuberosum L.) ‘Russet Burbank’ under field conditions. In 2005, the trial consisted of five treatments namely (1) non-treated, non-inoculated control; (2) non-treated control inoculated with Fusarium sambucinum; (3) seed inoculated with F. sambucinum and treated with P. fluorescens; (4) seed inoculated with F. sambucinum and treated with E. cloacae; and (5) seed inoculated with F. sambucinum and treated with the fungicide fludioxonil. In 2006, a mustard meal treatment was added. After harvest, tubers were assessed for disease severity of dry rot in addition to other tuber diseases, including silver scurf ( Helminthosporium solani), and common scab ( Streptomyces scabiei). In addition, tubers were graded and assessed for total yield, tuber size, tuber number, and tuber weight. Significant reduction in dry rot severity was obtained with all treatments compared to the non-treated control inoculated with Fusarium sambucinum. The highest dry rot reduction averaged over the two years of the study was for the fludioxonil treatment (55.7%) followed by the treatment with mustard meal (47.5%; 2006 only), Pseudomonas fluorescens (35%) and Enterobacter cloacae (26.5%). All treatments significantly reduced the severity of common scab and silver scurf compared to the non-treated, non-inoculated control. In both years, on an average, seed treated with P. fluorescens and E. cloacae produced higher total number of tubers. Both total and marketable tuber yields were significantly higher for the E. cloacae treatment compared to the non-treated, inoculated control. The results of this study suggest that P. fluorescens, E. cloacae and mustard meal are viable options for controlling potato tuber diseases along with fludioxonil. This is the first study to investigate the effect of these bacteria on potato diseases under field settings.

Pathogenicity of Scutellonema bradys populations from different geographical areas in Benin on yam ( Dioscorea spp.)

Scutellonema bradys is the most important nematode species affecting yam production in Benin. Two experiments were conducted to assess the variation in pathogenicity of three separate populations of S. bradys (IsoSave, IsoToui and IsoGlaz) on seven yam cultivars of three species: Kpouna, Tabane, TDr131, Moroko ( Dioscorea rotundata), Banioure, Kokoro ( D. cayenensis) and Aloungan ( D. alata). This was done over two consecutive yam growing seasons; 2002–2003 at the International Institute of Tropical Agriculture (IITA) Cotonou Station, Benin experimental farm and 2003–2004 in a farmer's field at Save in central Benin. S. bradys populations were obtained from yam originating from different geographical areas of Save and Toui in the northern Guinea savannah and Glazoue in the southern Guinea savannah, respectively. Four-week-old plants were each inoculated with ca. 1000 S. bradys juveniles and adults in chopped, infected pieces of yam peel. The experiments were harvested at 9 and 10 months after planting, respectively, at IITA and Save. Some differences were observed in the pathogenicity of the different nematode populations, although differences were not consistent between experiments and between yam cultivars. At harvest, in 2002–2003, the various S. bradys populations did not affect tuber weight, number of tubers produced or dry rot severity on the tubers. Highest nematode population density was observed with IsoGlaz, and Banioure was the yam cultivar most susceptible to nematode infestation. In 2003–2004, nematode inoculation reduced ( P ≤ 0.05) tuber weight for yam cv's Aloungan, Moroko and TDr131. Weights of tubers from IsoToui- and IsoSave-inoculated plants were lower than those from control plants. Dry rot severity was more pronounced on cv's Moroko and TDr131 tubers than on cv's Aloungan and Banioure, while no dry rot symptoms were observed on cv Tabane tubers. IsoToui and IsoGlaz caused higher ( P ≤ 0.05) tuber dry rot severity than IsoSave. Differences in nematode population densities occurred across S. bradys populations for cv's Tabane, TDr131 and Aloungan with IsoSave resulting in the highest nematode population densities on cv's Aloungan and TDr131. IsoToui caused the highest percentage weight loss. During 5 months storage, infected tubers lost more ( P ≤ 0.05) weight than uninfected control tubers. The differences in weight loss of infected tubers differed on tubers infected by the various nematode populations. Nematode multiplication during the storage period also differed among populations.

Effect of different salts on the development of Fusarium solani var. coeruleum, a causal agent of potato dry rot

The objectives of this study were (1) to evaluate the effect of different salts on the in vitro development of Fusarium solani var. coeruleum, and (2) to evaluate the efficacy of the salts for reducing dry rot severity caused by the pathogen in potato tubers. The study showed that several salts significantly inhibited the mycelial growth of F. solani var. coeruleum. Aluminium acetate, aluminium chloride, sodium benzoate, sodium metabisulfite, potassium sorbate and trisodium phosphate completely inhibited mycelial growth. Exposure of F. solani var. coeruleum conidia to aluminium acetate, potassium sorbate, sodium benzoate, sodium metabisulfite or trisodium phosphate at 0.2 M resulted in 100% mortality of the conidia after 1 h while aluminium chloride and aluminium lactate caused 100% mortality after an exposure of 24 h. In order to evaluate the effect of salts on potato dry rot development, F. solani var. coeruleum-inoculated tubers were treated with the different salts and disease severity was evaluated following an incubation period of 7 d. Among the test salts, only aluminium chloride caused a significant reduction in potato dry rot compared with the control. The study points out the possibility of using aluminium chloride to control potato dry rot.

Influence of crop rotation and conservation tillage practices on the severity of soil-borne potato diseases in temperate humid agriculture

A field trial was established in 1994 in Prince Edward Island, Canada, to determine the effects of 2- and 3-year crop rotations, with either conventional or minimum tillage treatments, on the severity of potato diseases caused by soil-borne pathogens. The 2-yr rotation consisted of spring barley and potato (cv. Russet Burbank) and the 3-yr rotation was barley (undersown with red clover), red clover and potato. In the potato years only, the main plots were split to examine conventional and minimum tillage (sub-plot) treatments. Potato diseases were assessed during the period 2000–2002, 6–8 yr after the initial establishment of the field trial. In each year of the study, potato plants grown in 3-yr rotations developed significantly (P = 0.05) lower levels of stem and stolon canker and black scurf (Rhizoctonia solani) compared with those from 2-yr rotations. Overall, rotation duration (not tillage type) was the main factor contributing to reduction of disease caused by R. solani. The severity of silver scurf (Helminthosporium solani) was significantly (P = 0.05) lower in tubers from plots managed in 3-yr rotations under minimum tillage practices in 2000, significantly higher in plots managed with minimum tillage in 2001, and unaffected by treatment in 2002. The severity of dry rot (Fusarium spp.) was significantly (P = 0.05) lower in tubers from plots managed with 3-yr rotations under minimum tillage practices in 2000, but was unaffected by either tillage regime in 2001 and 2002. The severity of common scab (Strep tomyces scabiei) was low and not influenced by tillage or rotation in any year of study. In summary, a 3-yr crop rotation combined with minimum tillage reduced potato diseases caused by R. solani and did not affect disease caused by other soil-borne pathogens. From a crop health perspective, there appear to be no constraints to the use of minimum tillage practices in association with 3-yr rotations in potato production in regions of temperate humid agriculture. Key words: Crop rotation, minimum tillage, potato, Solanum tuberosum, soil-borne pathogens, Rhizoctonia solani

Developing disease-suppressive soils through crop rotation and tillage management practices

A field laboratory was established in Prince Edward Island, Canada, to determine the effects of 2- and 3-year crop rotations, with conventional and minimum tillage treatments, on the severity of soilborne diseases of potato. The 2-year rotation consisted of spring barley and potato (cv. ‘Russet Burbank’), and the 3-year rotation was barley (undersown with red clover), red clover and potato. Examination of potato stem, stolon, and tuber tissues revealed significantly ( P=0.05) lower levels of canker and black scurf caused by Rhizoctonia solani, in plants grown in 3-year vs. 2-year rotations. The severity of dry rot ( Fusarium spp.) and silver scurf ( Helminthosporium solani) was significantly ( P=0.05) lower in tubers from plots managed with 3-year rotations and minimum tillage practices. Potato tubers harvested from 3-year rotational soils were significantly ( P=0.05) less diseased than those from 2-year rotational soils following inoculation with Phytophthora erythroseptica, causal agent of pink rot. In greenhouse experiments using field soils from 2- and 3-year rotations, we found that potato plants growing in 3-year rotational soils were significantly ( P=0.05) less diseased than those growing in 2-year rotational soils following inoculation with P. erythroseptica. Analysis of root zone bacteria recovered from the rhizosphere (exoroot) and potato root tissues (endoroot) showed that the greatest antibiosis activity inhibiting the growth of soilborne pathogens in vitro occurred in bacterial isolates recovered from the endoroot tissues of 3-year rotation crops under minimum tillage management. Our evidence supports the view that soil agroecosystems can be modified through rotation and conservation tillage practices to improve disease suppression by enhancing the antibiosis abilities of endophytic and root zone bacteria (endo- and exoroot).

Effects of benzothiadiazole and acetylsalicylic acid on β‐1,3‐glucanase activity and disease resistance in potato

Benzothiadiazole (BTH), as Bion WG50, and acetylsalicylic acid (ASA) treatments of potato foliage of field‐ and glasshouse‐grown potato plants were compared for control of two foliar diseases, early blight (Alternaria solani) and powdery mildew (Erysiphe cichoracearum). The effect of these treatments on harvested tubers wound‐inoculated with the dry rot fungus (Fusarium semitectum) was also evaluated. BTH (50 mg a.i. L−1) gave almost complete control of both foliar pathogens on inoculated glasshouse‐grown plants and reduced the severity of leaf spotting diseases (mainly early blight) in the field. BTH (100 mg a.i. L−1) and ASA (400 mg a.i. L−1) reduced the severity of dry rot in field‐grown tubers in some post‐harvest wound‐inoculated treatments but not others and a similar reduction occurred with tubers inoculated post‐harvest from BTH‐treated plants grown under glasshouse conditions. BTH treatment increased β‐1,3‐glucanase activity in leaves > stem > tubers > stolons but not in roots. Increased enzyme activity was recorded for up to 45 days post‐treatment.