acibenzolar-S-methyl Research Articles

When a Plant Resistance Inducer Leaves the Lab for the Field: Integrating ASM into Routine Apple Protection Practices.

Plant resistance inducers, also called elicitors, could be useful to reduce the use of pesticides. However, their performance in controlling diseases in the field remains unsatisfactory due to lack of specific knowledge of how they can integrate crop protection practices. In this work, we focused on apple crop and acibenzolar-S-methyl (ASM), a well-known SAR (systemic acquired resistance) inducer of numerous plant species. We provide a protocol for orchard-effective control of apple scab due to the ascomycete fungus Venturia inaequalis, by applying ASM in combination with a light integrated pest management program. Besides we pave the way for future optimization levers by demonstrating in controlled conditions (i) the high influence of apple genotypes, (ii) the ability of ASM to prime defenses in newly formed leaves, (iii) the positive effect of repeated elicitor applications, (iv) the additive effect of a thinning fruit agent.

Leaf gas exchange and chlorophyll a fluorescence in soybean leaves infected by Phakopsora pachyrhizi

AbstractAsian soybean rust (ASR), caused by Phakopsora pachyrhizi, is one of the most important foliar diseases affecting soybean production worldwide. This study aimed to investigate the photosynthetic performance (leaf gas exchange, chlorophyll (Chl) a fluorescence images and photosynthetic pigment pools) of soybean plants sprayed with Acibenzolar‐S‐Methyl (ASM) and the fungicide epoxiconazole + pyraclostrobin (Epo+Pyr) and further inoculated with P. pachyrhizi. The ASR symptoms progressed much faster on the leaves of plants from the control treatment (water spray) in comparison with the ASM and Epo+Pyr treatments. In general, the values for the leaf gas exchange parameters net carbon assimilation rate (A), stomatal conductance to water vapour (gs), internal CO2 concentration (Ci) and transpiration rate (E) increased for the infected plants sprayed with ASM or Epo+Pyr in comparison with plants from the control treatment. The values for the initial fluorescence (Fo), maximal fluorescence (Fm), maximal photosystem II quantum efficiency (Fv/Fm), effective photosystem II quantum yield (Y(II)) and quantum yield of regulated energy dissipation (Y(NPQ)) were consistently higher for the ASM and Epo+Pyr treatments in comparison with the control treatment at advanced stages of fungal infection. By contrast, the values for quantum yield of non‐regulated energy dissipation (Y(NO) were significantly lower for the ASM and Epo+Pyr treatments. The concentrations of total Chl a+b and carotenoids significantly increased for infected plants sprayed with ASM and Epo+Pyr in comparison with plants from the control treatment. The results of this study demonstrated that the spray of soybean plants with either ASM or Epo+Pyr contributed to reduce the negative effect of ASR on the photosynthesis of soybean plants.

Soil applications of acibenzolar-S-methyl induce defense gene expression in tomato plants against bacterial spot

Acibenzolar-S-methyl (ASM), a plant activator known to induce plant resistance, has been used as foliar sprays to manage several plant diseases including bacterial spot on tomato caused by four distinct Xanthomonas species. This study aimed to investigate the effects of soil application rates of ASM on bacterial spot of tomato and the expression levels of the two pathogenesis-related (PR) genes, PR1a and PR1b, in leaf tissues. Tomato seedlings were leaf-applied with ASM at 18.8 mg/l corresponding to the labeled rate, soil-applied with ASM at 0.84 and 10 mg/l, and sprayed with water served as an untreated control. The soil application of ASM at 10 mg/l consistently reduced the final disease severity and disease progress compared to the untreated control in four growth chamber experiments, whereas the soil application of ASM at 0.84 mg/l and foliar spray of ASM significantly reduced the final disease severity and area under disease progress curve (AUDPC) in three out of the four experiments. The expression levels of PR1a and PR1b in the leaf tissues were significantly induced by both soil and foliar applications of ASM. In addition, field trial results suggested that the soil applications of ASM at 10 mg/l markedly reduced disease progress compared to the control and copper standard. Although the control efficiency of soil applications of ASM depends on rates used, this study suggests that ASM can be used as soil applications to induce tomato resistance against bacterial spot.

Evaluating spray programs for managing copper resistant Pseudomonas syringae pv. tomato populations on tomato in the Limpopo region of South Africa

Bacterial speck of tomato caused by Pseudomonas syringae pv. tomato is an economically important disease in the Limpopo production region of South Africa. Two field trials were conducted to evaluate different spray programs for management of the disease. In the first trial, applications were only made in the field, and the main product evaluated was acibenzolar-S-methyl (ASM), with and without copper + mancozeb. In the second trial, spray programs were already started in the nursery and then continued in the field. The main products evaluated in the second trial were ASM and biological products. In the first trial, ASM field programs included a South African registration (3.75 g/100 L every 21 days), a USA registration (1.16 g/100 L to 2.63 g a.i./100 L every 14 days) and an ASM low rate (1.16 g/100 L weekly) application. These spray programs were all effective, and comparable in suppressing foliar infections and severely infected fruit (fruit with more than five lesions). The addition of copper + mancozeb to ASM spray programs did not improve control. In most of the first and second set of trials, the commercial standard of weekly applied copper + mancozeb was ineffective in suppressing foliar and fruit damage. It furthermore resulted in a significant increase in fruit infections in most trials. The ineffectiveness of copper + mancozeb spray programs, and programs that contained these compounds, were due to copper resistant P. syringae pv. tomato strains. The strains were identified in all trials through in vitro copper sensitivity testing. This was further confirmed through a tomato seedling bioassay using a copper resistant strain. In the second trial, starting spray programs in the nursery was beneficial. ASM applications in the nursery, followed by ASM + copper + mancozeb field applications were more effective in suppressing fruit infections, compared to only field applications of the latter products. The application of B. subtilis in the nursery, followed by field applied biologicals (B. subtilis and Microbacterium maritypicum) combined with ASM sprays, also improved the reduction of infected fruit, when compared to field only applications of ASM + copper + mancozeb.

Elicitor induction of defence genes and reduction of bacterial canker in kiwifruit

Pseudomonas syringae pv. actinidiae (Psa), which causes bacterial canker, is the most serious global pathogen of kiwifruit. Like most bacterial pathogens, control options are limited, but elicitors can reduce disease significantly, particularly those that induce the salicylic acid (SA) pathway. Acibenzolar-S-methyl (ASM), a SA analogue, is one of the most effective elicitors for Psa control. In this study, real-time PCR (qPCR) was used to measure the expression of 18 putative defence genes in Actinidia chinensis var. chinensis ‘Hort16A’ in response to Psa and ASM. Application of ASM led to up-regulation of RPM1 interacting protein 4 (RIN4), phenylalanine ammonia lyase (PAL), a hypersensitivity-induced response protein (HIRP), and β-1,3-glucosidase. Expression of PAL and HIRP was further enhanced when elicitor application and Psa-inoculation were combined. Elevated gene expression was correlated with decreased disease expression, and supports the hypothesis that elicitor-treated plants are primed to react more rapidly and/or strongly to pathogens.

Effect of acibenzolar-S-methyl on energy metabolism and blue mould of Nanguo pear fruit

Cellular energy is closely related to fruit ripening, senescence, physiological disorder and disease resistance after harvest. Nanguo pear fruit were immersed in 100mgL−1 Acibenzolar-S-methyl (ASM) for 10min, then air-dried at ambient conditions and stored for 12 d at 20°C to investigate the effect of ASM on the activity of enzymes involved in energy metabolism. The effect of ASM on lesion development of the pear fruit inoculated with Penicillium expansum was also investigated in this study. Same treament with distilled water was used as control. The results demonstrated that ASM dipping treatment significantly decreased lesion diameter on the pear fruit inoculated with P. expansum. ASM dipping treatment enhanced ATP content, energy charge, the activity of H+-ATPase, Ca2+-ATPase, cytochrome C oxidase and succinic dehydrogenase in pear fruit. These results suggest that postharvest ASM treatment induced disease resistance in Nanguo pear fruit through mediating energy metabolism.

Metabolic Effects of Acibenzolar-S-Methyl for Improving Heat or Drought Stress in Creeping Bentgrass.

Acibenzolar-S-methyl (ASM) is a synthetic functional analog of salicylic acid which can induce systemic acquired resistance in plants, but its effects on abiotic stress tolerance is not well known. The objectives of this study were to examine effects of acibenzolar-S-methyl on heat or drought tolerance in creeping bentgrass (Agrostis stolonifera) and to determine major ASM-responsive metabolites and proteins associated with enhanced abiotic stress tolerance. Creeping bentgrass plants (cv. ‘Penncross’) were foliarly sprayed with ASM and were exposed to non-stress (20/15°C day/night), heat stress (35/30°C), or drought conditions (by withholding irrigation) in controlled-environment growth chambers. Exogenous ASM treatment resulted in improved heat or drought tolerance, as demonstrated by higher overall turf quality, relative water content, and chlorophyll content compared to the untreated control. Western blotting revealed that ASM application resulted in up-regulation of ATP synthase, HSP-20, PR-3, and Rubisco in plants exposed to heat stress, and greater accumulation of dehydrin in plants exposed to drought stress. Metabolite profiling identified a number of amino acids, organic acids, and sugars which were differentially accumulated between ASM treated and untreated plants under heat or drought stress, including aspartic acid, glycine, citric acid, malic acid, and the sugars glucose, and fructose. Our results suggested that ASM was effective in improving heat or drought tolerance in creeping bentgrass, mainly through enhancing protein synthesis and metabolite accumulation involved in osmotic adjustment, energy metabolism, and stress signaling.

Acibenzolar-S-methyl on Meloidogyne javanica control in lettuce

ABSTRACTNematodes are among the main limiting factors of the vegetables productivity, especially due to management restriction this crop to obtain an efficient control of pathogen. Resistance induction using acibenzolar-S-methyl (ASM) has presented promising results in the management of diseases, but to plant-parasitic nematodes the time required to activate latent defense mechanisms is a limiting factor, which can be prevented with the treatment of seedlings in trays. Thus, the present study aimed to assess different times of ASM application to Meloidogyne javanica control in lettuce. Lettuce seedlings were produced in trays, transplanted to pots 25 days after germination and inoculated with 2000 eggs of the nematode. The seedlings were pulverized on shoots with ASM 10 or 5 days before of transplant (DBT), on the day of transplant (DT), 5 or 10 days after transplant (5 or 10 DAT), 10 DBT + DT and 10 DBT + 5 DAT. The untreated plants formed the control group. Fifty days later, these plants were collected and evaluated the nematological and vegetative parameters. The treatments promoted a decrease in M. javanica population higher than 60% when applied until 5 DAT and generally did not interfere with the vegetative parameters of lettuce, and ASM can be adopted as an alternative for the root-knot nematodes management.

Epidemiology and management of bacterial leaf spot on watermelon caused by Pseudomonas syringae.

Bacterial leaf spot of watermelon caused by Pseudomonas syringae has been an emerging disease in the southeastern United States in recent years. Disease outbreaks in Florida were widespread from 2013 to 2014 and resulted in foliar blighting at the early stages of the crop and transplant losses. We conducted a series of field trials at two locations over the course of two years to examine the chemical control options that may be effective in management of this disease, and to investigate the environmental conditions conducive for bacterial leaf spot development. Weekly applications of acibenzolar-S-methyl (ASM) foliar, ASM drip, or copper hydroxide mixed with ethylene bis-dithiocarbamate were effective in reducing the standardized area under the disease progress curve (P < 0.05). Pearson's correlation test demonstrated a negative relationship between the average weekly temperature and disease severity (-0.77, P = 0.0002). When incorporated into a multiple regression model with the square root transformed average weekly rainfall, these two variables accounted for 71% of the variability observed in the weekly disease severity (P < 0.0001). This information should be considered when choosing the planting date for watermelon seedlings as the cool conditions often encountered early in the spring season are conducive for bacterial leaf spot development.

Induced Resistance to Fusarium wilt (&lt;i&gt;Fusarium oxysporum&lt;/i&gt;) in Tomato using Plant Growth Activator, Acibenzolar-S-methyl

Acibenzolar-s-methyl (ASM) is a plant systemic-acquired resistance (SAR) elicitor that belongs to the benzothiadiazole group and it induces SAR in tomato plant ( Solanum lycopersicum L .) against Fusarium oxysporum f. sp. lycopercisi (FOL), the causative organism of vascular wilt of tomato. It is a good substitute to chemical fungicides which often resulted in environmental damage and increased pathogen resistance. Two tomato accessions FUNAABTO 0168 (Accession I) and FUNAABTO 0178 (Accession II) were used. This study assessed the resistance of two accessions of ASM-treated tomato to FOL, identified the most effective method of ASM application and examined the influence of applied ASM on yield indices of the accessions. Tomato plants not treated with ASM (Nn) had the highest disease severity at 5th to 8th week after transplanting with corresponding value of 1.33, 2.00, 2.17 and 3.33 in Accession I and 1.00, 1.33, 1.50 and 1.67 in II. Primed and sprayed (Ps) method was the most effective of ASM application with least severity (0.00) and also had the highest yield in Accession I (3.35 ton/ha) and II (4.14 ton/ha), while tomato plant untreated (Nn) had the least yield in Accession I (2.16 ton/ha) and II (1.23 ton/ha) respectively. It is recommended that tomato seeds be first primed in ASM followed by spraying of seedlings with ASM at transplant to significantly reduce incidence and severity of Fusarium wilt and increase yield of tomato fruits. Keywords: Acibenzolar-S-methyl, SAR, FUNAABTO, tomato, wilt

Induction of Systemic Acquired Resistance Aids Restoration of Tree Health in Field-Grown Pear and Apple Diseased with Fire Blight.

Induction of systemic acquired resistance as a therapeutic aid to restoration of tree health was evaluated in 3- to 14-year-old pear and apple trees diseased with fire blight. Acibenzolar-S-methyl (ASM) was applied to diseased trees in late spring near the time of removal of primary fire blight cankers, which had originated from floral infection. Suspensions of ASM (7.5 to 22.5 g of active ingredient per liter plus silicone surfactant) were painted onto a 30- to 45-cm length of branch tissue immediately below primary pruning cuts or sprayed onto an 80- to 100-cm length of central trunk. In some experiments, a second ASM treatment was made in late June to early July in conjunction with secondary pruning of redeveloped cankers. After pruning primary cankers, effects of ASM were measured by assessing weight and length of secondary cankers that were the result of fire blight redevelopment. Over 5 years of field experiments, trees that received an ASM treatments yielded 62% less diseased wood at the time of secondary and tertiary canker removal compared with non-ASM-treated trees. Moreover, tree mortality and proportion of pruning cuts where fire blight redeveloped were reduced by ASM. Induction of systemic acquired resistance could prove practical as an aid to pruning therapy in young, fire-blight-susceptible pear and apple trees where, after canker removal, disease symptoms frequently redevelop owing to residual cells of the pathogen distributed within symptomless portions of the tree.

Foliar Applications of Acibenzolar-S-Methyl Negatively Affect the Yield of Grafted Tomatoes in Fields Infested with Ralstonia solanacearum.

Three field experiments were conducted in Florida from 2012-2014 to assess the impact of acibenzolar-S-methyl (ASM), a systemic acquired-resistance inducer, applied as foliar spray or through drip-irrigation lines, on bacterial wilt incidence and yield of grafted tomatoes. The experiments were conducted in a field with race 1, biovar 1 strain of Ralstonia solanacearum, causal agent of tomato bacterial wilt. In all three experiments, the susceptible tomato variety BHN 602, grafted onto a resistant rootstock BHN 998, was compared with nongrafted BHN 602, treated with or without foliar applications of ASM and with grafted plants treated with foliar applications of ASM. In two experiments, an additional treatment of drip applications of ASM on grafted and nongrafted plants was evaluated. Grafting alone or in combination with drip applications of ASM (178.6 μM) significantly reduced disease incidence and increased total marketable yield relative to nongrafted treatments. There were no significant differences between grafted plants with or without drip ASM applications in terms of bacterial wilt incidence or total marketable yield. However, we demonstrate for the first time that foliar ASM applications on grafted plants negatively affects the total marketable yield compared with drip ASM applications on grafted plants or nontreated grafted control.

Management of Asiatic Citrus Canker Under Field Conditions in Saudi Arabia Using Bacteriophages and Acibenzolar-S-Methyl.

Applications of formulated bacteriophages with skim milk and sucrose or nonformulated bacteriophages combined with acibenzolar-S-methyl (ASM) were compared with copper bactericides applications for suppressing Asiatic citrus canker (ACC) caused by Xanthomonas citri subsp. citri (Xcc) on leaves under greenhouse and field conditions in Saudi Arabia. Bacteriophages were applied one day prior to inoculation of Mexican lime (Citrus aurantifolia) plants with Xcc, then twice a week until the end of the trials. Copper hydroxide was applied once prior to inoculation and then every seven days afterward, whereas ASM was applied one week prior to inoculation and then every 21 days afterward. Under greenhouse conditions, the incidence of ACC on leaves was reduced significantly from 75.2 to 12.8% or 18.3% for plants treated with copper hydroxide or bacteriophages in combination with ASM, respectively. Applications of formulated phages in combination with ASM as soil drench under field conditions significantly decreased disease incidence by 14.8% (Trial 1) and 16.8% (Trial 2) compared with untreated control plants. Overall, the Xcc-inoculated plants treated with bacteriophages + ASM combination showed significant ACC reduction under greenhouse and field conditions. The bacteriophages + ASM combination tested in these trials can be an effective tool in the integrated management programs of Asiatic citrus canker disease.

Cultivation of resistant soybean varieties and application of silicon (Si) on biology of Euschistus heros (Hemiptera: Pentatomidae)

Seed-sucking insects are economically important pests affecting soybean in Brazil. The objective of this study was to evaluate the effect of chemical inducers on insect resistance in soybean on the neotropical brown stink bug, Euschistus heros (F.) (Hemiptera: Pentatomidae) using varying levels of inherent resistance in soybean. Seedpods from of the soybean varieties ‘IAC 100’ and ‘IAC 17’ (antibiosis resistant and non-preference resistant varieties, respectively), ‘Conquista’ (moderately resistant), and ‘Jatai’ (susceptible) that had been treated with one of several inducers, or untreated, were evaluated in choice- and no-choice tests. In addition to analyses of feeding preference, effects of the treatments on the development of E. heros were also studied. The nonpreference and antibiosis resistances of varieties ‘IAC 17’ and ‘IAC 100’ were observed when plants of these varieties treated with resistance inducers were fed to E. heros. Potassium silicate, calcium magnesium silicate, and acibenzolar-S-methyl (ASM) inducers were found to have a synergistic effect on the resistance of ‘IAC 17’ and ‘IAC 100’ to E. heros. These soybean varieties can be directly used by farmers or associated with silicon application to prevent damage caused by E. heros.

Direct nematicidal effects of methyl jasmonate and acibenzolar-S-methyl against Meloidogyne incognita

The aim of this study was to examine the nematicidal properties of two defence inducers against the root-knot nematode Meloidogyne incognita. A direct-contact bioassay was applied to evaluate the nematicidal effects of acibenzolar-S-methyl (ASM) and methyl jasmonate (MEJA) on second-stage juveniles (J2). Nematodes were incubated in different concentrations of these compounds, and the numbers of immobile nematodes were counted after 24 and 48 h post incubation. Tap water was then added to verify whether the nematodes recovered or remained dead at 72 h. The percentage of dead nematodes was used as indicator for the toxicity of the different solutions. Our results show that ASM, in the formulation of Bion®, and MEJA have nematicidal properties.

Evaluation of soil applied systemic acquired resistance inducers integrated with copper bactericide sprays for control of citrus canker on bearing grapefruit trees

Soil application of systemic neonicotinoid insecticides and the commercial systemic acquired resistance (SAR) inducer, acibenzolar-S-methyl (ASM), provides season-long control of foliar infection by Xanthomonas citri subsp. citri, the causal agent of citrus canker. Reduction in leaf disease incidence with ASM is comparable to protection with 21-day interval foliar sprays of copper hydroxide (CH). Soil applications of ASM alone, rotated with the neonicotinoids imidacloprid (IMID), thiamethoxam (THIA), and clothianidin (CLOTH), or combined with foliar sprays of CH were compared for canker disease control on fruit of 5- to 7-year-old bearing ‘Ruby Red’ grapefruit trees in Southeast Florida. All treatments significantly reduced the incidence of canker lesions on fruit compared to the untreated check. Soil drenches of ASM and season-long rotations with IMID, THIA, and CLOTH were as effective for suppressing fruit canker as season-long foliar sprays with CH. SAR inducers combined with CH sprays provided optimum control of fruit canker when initiated before the onset of the susceptible foliar flush in the spring. Additional control of canker with soil-applied SAR inducers may enable reduction in the frequency of copper sprays and reduce disease loss from copper resistant Xcc strains where they are prevalent.

Acibenzolar-S-methyl doses and application methods to Pratylenchus brachyurus control in maize

ABSTRACTPratylenchus brachyurus is one of the main limiting factors of agricultural yield in annual crops, particularly due its difficult management. Methods to reduce populations are constantly sought, and the use of resistance inducers deserves attention. Thus, the study aimed to assess the effect of acibenzolar-S-methyl (ASM) application in different doses to P. brachyurus control in maize. Initially, 1000 specimens of P. brachyurus were inoculated in maize for the multiplication. After 60 days, the aerial part (AP) was discarded and maize was sown under the treatments: seed treatment (ST), application in the AP and ST + AP, in the doses of 0.125, 0.25, 0.5 and 1.0 g i.a./L. Vegetative and nematological parameters were assessed 60 days later. ASM did not affect plant growth, but reduced nematode population in all the treatments. The treatment methods did not differ and reduced the number of nematodes/g root by 64.25 to 80.14% compared to the control. The doses of 0.6, 0.51 and 0.65 g i.a./L promoted the most reductions in the number of nematodes/g root when applied in ST, AP and ST + AP, respectively. Thus, we recommend the use of ASM applied on shoot in a dose of 0.50 g i.a./L.

Intervals and Number of Applications of Acibenzolar-S-Methyl for the Control of Bacterial Spot on Processing Tomato.

Acibenzolar-S-methyl (ASM) is a plant activator that triggers systemic acquired resistance that is labeled for use in Brazil for managing tomato bacterial spot. The aim of this study was to define the optimum relationship between interval and number of applications of ASM for the most efficacious control of bacterial spot on processing tomato. Four intervals between applications (4, 7, 10, and 14 days) and four application frequencies (4, 6, 8, and 10 applications) were evaluated in five trials performed between 2010 and 2011 in Brasília, Distrito Federal, and in Morrinhos, in the state of Goiás. Copper hydroxide (CH) was applied after ASM applications to complete 13 applications per growing season. Two check treatments were added: standard CH weekly applications and untreated. The following variables were evaluated: severity of bacterial spot, yield, percentage of ripe and rotten fruit, soluble solids content, and the benefit/cost ratio. Disease severity varied between treatments in three trials and yield varied in two trials. A greater number of applications resulted in a reduction of bacterial spot, and the ideal interval between applications was between 8 to 10 days. However, there was a reduction in yield with 10 ASM applications. The temporal effect of ASM applications on bacterial spot severity was evaluated under greenhouse conditions. Reduction in disease severity was observed up to 6 days following ASM application. Additionally, the weekly treatment of seven applications of ASM followed by six applications of CH was compared with a standard program of CH under commercial production conditions in Itaberaí, Goiás, where bacterial spot occurred naturally. The program with ASM and CH resulted in significantly less foliar disease severity than the standard program, which did not result in yield gains. In addition, no differences were detected between the two programs for soluble solids content, industrial yield, plant height, and percentage of ripe and rotten fruit.

Integration of acibenzolar-S-methyl with antibiotics for protection of pear and apple from fire blight caused by Erwinia amylovora

Orchard experiments on integration of acibenzolar-S-methyl (ASM) with antibiotics for protection of pear and apple from fire blight were conducted in the west coast region of the United States over a period of 5 years. In 11 pathogen-inoculated trials, a single treatment of streptomycin or oxytetracycline provided an average of 84 and 60% disease control, respectively. The addition of one or two treatments of acibenzolar-S-methyl (ASM) to the single antibiotic program contributed an additional 6 and 11% disease control, respectively, for both antibiotic materials. Among trials, ASM treatment timings were varied from early to late bloom but an effect of timing on disease control could not be determined. In mature commercial pear orchards, ASM treatments at full bloom and petal fall were superimposed onto the grower’s antibiotic program used in each orchard. For the 15 orchards with fire blight, the ASM-treated plots showed 38% fewer infections than adjoining plots that received antibiotic program only. When integrated with antibiotics, ASM provides added disease suppression to fire blight control programs, but the modest degree of protection provided will likely limit its use to high disease risk situations, which includes orchards with a previous disease history, and those planted recently to highly susceptible cultivars.

Improved resistance to disease and mites in strawberry, through the use of acibenzolar-S-methyl and harpin to enhance photosynthesis and phenolic metabolism

The objective of this study was to evaluate the effect of acibenzolar-S-methyl (ASM) and harpin protein, applied pre-harvest, in the induction of resistance in strawberry to pathogens and mites. The experiment was conducted in a greenhouse, in a randomized block design with three replications. Treatments with harpin protein and ASM were established through biweekly applications of these elicitors in plants of strawberry, from 60 to 120 days after transplanting of seedlings. The application of ASM and harpin protein induced resistance in the strawberry plants, resulting in an increase in phenylalanine ammonia-lyase activity and total phenol production, while reducing leaf blight and grey mould. The application of harpin protein also caused a reduction in mite damage, while increasing photosynthetic rate and the production of marketable fruits. The elicitors ASM and harpin, applied pre-harvest, can be used as part of the integrated pest management of diseases and pests of strawberry.