First report of Diplodia mutila causing leaf blight on Magnolia grandiflora in China

Magnolia grandiflora is a widely cultivated ornamental tree in China. In June 2020, a leaf blight disease was observed on M. grandiflora in Guizhou University (26° 44' 57'' N, 106° 65' 94'' E) in Guiyang, China. The initial symptoms on leaves were expanding round necrotic lesions with a grey center and dark brown edge, and twigs were withered when the disease was serious. Of the 100 plants surveyed 65% had symptoms. To isolate the potential causal pathogen, diseased leaves were collected from an M. grandiflora tree at Guizhou University. Isolations from made form the junction between healthy and symptomatic tissue and disinfested by immersing in 75% ethanol for 30 seconds, 3% NaOCl for 2 minutes, and then washed 3 times in sterile distilled water. Symptomatic tissue was then plated on potato dextrose agar (PDA) and incubated at 25ºC with 12-hour light for 3–5 days. Three isolates (GUCC 21235.1, GUCC 21235.2 and GUCC 21235.3) were obtained. Colonies on PDA after 7 d were dark brown, pycnidia embedded in the mydelium were dark brown to black, single and separated. Conidiophores were transparent measuring 7–12.5 × 2.5–4.5 µm (mean = 9.5 × 3.6 µm, n = 30) in length. Conidia were transparent becoming brown when mature with a diaphragm, with round ends measuring, 21–27 × 10–15 µm (mean = 23.6 × 12.6 µm, n = 30). To confirm the pathogen by molecular characterization, four genes or DNA fragments, ITS, LSU, tef1 and β-tubulin, were amplified using the following primer pairs: ITS4-F/ ITS5-R (White et al., 1990), LR0R/ LR5 (Rehner & Samuels, 1994), EF1-688F/ EF1-986R (Carbone & Kohn, 1999) and Bt2a/ Bt2b (O'Donnell & Cigelnik, 1997). The sequences of four PCR fragments of GUCC 21235.1 were deposited in GenBank, and the accession numbers were MZ519778 (ITS), MZ520367 (LSU), MZ508428 (tef1) and MZ542354 (β-tubulin). Bayesian inference was performed based on a concatenated dataset of ITS, LSU, tef1 and β-tubulin gene using MrBayes 3.2.10, and the isolates GUCC 21235.1 formed a single clade with the reference isolates of Diplodia mutila (Diplodia mutila strain CBS 112553). BLASTn analysis indicated that the sequences of ITS, LSU, tef1 and β-tubulin revealed 100% (546/546 nucleotides), 99.82% (568/569 nucleotides), 100% (302/302 nucleotides), and 100% (437/437 nucleotides) similarity with that of D. mutila in GenBank (AY259093, AY928049, AY573219 and DQ458850), respectively. For confirmation of the pathogenicity of this fungus, a conidial suspension (1×105 conidia mL-1) was prepared from GUCC 21235.1, and healthy leaves of M. grandiflora trees were surface-disinfested by 75% ethanol, rinsed with sterilized distilled water and dried by absorbent paper. Small pieces of filter paper (5 mm ×5 mm), dipped with 20 µL conidial suspension (1×105 conidia mL-1) or sterilized distilled water (as control), were placed on the bottom-left of the leaves for inoculation. Then the leaves were sprayed with sterile distilled water, wrapped with a plastic film and tin foil successively to maintain high humidity in the dark dark. After 36 h, the plastic film and tin foil on the leaves was removed, and the leaves were sprayed with distilled water three times each day at natural condition (average temperature was about 25 °C, 14 h light/10 h dark). After 10 days of inoculation, the same leaf blight began to appear on the leaves inoculated with conidial suspension. No lesion was appeared on the control leaves. The fungus was re-isolated from the symptomatic tissue. Based on the morphological information and molecular characterization, the isolate GUCC 21235.1 is D. mutila. Previous reports indicated that D. mutila infects a broad host range and gives rise to a canker disease of olive, apple and jujube (Úrbez-Torres et al., 2013; Úrbez-Torres et al., 2016; Feng et al., 2019). This is the first report of leaf blight on M. grandiflora caused by D. mutila in China.

Curcuma longa L. Prevents the Loss of β-Tubulin in the Brain and Maintains Healthy Aging in Drosophila melanogaster

Loss of tubulin is associated with neurodegeneration and brain aging. Turmeric (Curcuma longa L.) has frequently been employed as a spice in curry and traditional medications in the Indian subcontinent to attain longevity and better cognitive performance. We aimed to evaluate the unelucidated mechanism of how turmeric protects the brain to be an anti-aging agent. D. melanogaster was cultured on a regular diet and turmeric-supplemented diet. β-tubulin level and physiological traits including survivability, locomotor activity, fertility, tolerance to oxidative stress, and eye health were analyzed. Turmeric showed a hormetic effect, and 0.5% turmeric was the optimal dose in preventing aging. β-tubulin protein level was decreased in the brain of D. melanogaster upon aging, while a 0.5% turmeric-supplemented diet predominantly prevented this aging-induced loss of β-tubulin and degeneration of physiological traits as well as improved β-tubulin synthesis in the brain of D. melanogaster early to mid-age. The higher concentration (≥ 1%) of turmeric-supplemented diet decreased the β-tubulin level and degenerated many of the physiological traits of D. melanogaster. The turmeric concentration-dependent increase and decrease of β-tubulin level were consistent with the increment and decrement data obtained from the evaluated physiological traits. This correlation demonstrated that turmeric targets β-tubulin and has both beneficial and detrimental effects that depend on the concentration of turmeric. The findings of this study concluded that an optimal dosage of turmeric could maintain a healthy neuron and thus healthy aging, by preventing the loss and increasing the level of β-tubulin in the brain.

Multi-Gene Phylogeny and Taxonomy of Hypoxylon (Hypoxylaceae, Ascomycota) from China

The Hypoxylon species play an important ecological role in tropical rainforest as wood-decomposers, and some might have benefical effects on their hosts as endophytes. The present work concerns a survey of the genus Hypoxylon from Hainan Tropical Rainforest National Park of China. Four new species: H. wuzhishanense, H. hainanense, H.chrysalidosporum, and H.cyclobalanopsidis, were discovered based on a combination of morphological characteristics and molecular data. Hypoxylon wuzhishanense is characterized by Rust pulvinate stromata, amyloid apical apparatus and brown ascospores, with most of the perispore being indehiscent in 10% KOH. Hypoxylon hainanense has effused–pulvinate and Violet stromata, amyloid apical apparatus, light-brown to brown ascospores with straight germ slit and dehiscent perispore. Hypoxylonchrysalidosporum is distinguished by glomerate to pulvinate stromata, highly reduced or absent inamyloid apical apparatus, and light-brown to brown ascospores with very conspicuous coil-like ornamentation. Hypoxyloncyclobalanopsidis has Livid Purple pulvinate stromata, highly reduced amyloid apical apparatus, faint bluing, brown ascospores and dehiscent perispore, and it grows on dead branches of Cyclobalanopsis. Detailed descriptions, illustrations, and contrasts with morphologically similar species are provided. Phylogenetic analyses inferred from ITS, RPB2, LSU, and β-tubulin sequences confirmed that the four new species are distinct within the genus Hypoxylon.

Molecular Evolution of Tubulins in Diatoms

Microtubules are formed by α- and β-tubulin heterodimers nucleated with γ-tubulin. Tubulins are conserved eukaryotic proteins. Previously, it was shown that microtubules are involved in diatom silica frustule morphogenesis. Diatom frustules are varied, and their morphology is species-specific. Despite the attractiveness of the problem of elucidating the molecular mechanisms of genetically programmed morphogenesis, the structure and evolution of diatom tubulins have not been studied previously. Based on available genomic and transcriptome data, we analyzed the phylogeny of the predicted amino acid sequences of diatom α-, β- and γ-tubulins and identified five groups for α-tubulins, six for β-tubulins and four for γ-tubulins. We identified characteristic amino acids of each of these groups and also analyzed possible posttranslational modification sites of diatom tubulins. According to our results, we assumed what changes occurred in the diatom tubulin structures during their evolution. We also identified which tubulin groups are inherent in large diatom taxa. The similarity between the evolution of diatom tubulins and the evolution of diatoms suggests that molecular changes in α-, β- and γ-tubulins could be one of the factors in the formation of a high morphological diversity of diatoms.

First Report of Gnomoniopsis idaeicola Causing Cane Wilt and Canker in Commercial Blackberry Fields in Oregon

Oregon is the leading producer of blackberries in the United States (USDA 2021). In November 2020, we visited a seven-year-old, 5.6 HA field of thornless trailing cultivar ‘Columbia Star’ in Marion County, Oregon in response to grower reports of rapid plant death that they called ‘Blackberry Collapse.’ The pattern of disease in the field was semi-circular patches of dead plants. We estimate that ca. 17% of the plants were killed. Symptoms included fewer and stunted primocanes, floricane reddening, premature floricane senescence, or elliptical or irregular brown to purple cane lesions often near the base of necrotic petioles clasping the cane. Twenty-two cane lesions were collected, surface-disinfested, and placed on potato dextrose agar with streptomycin. In addition to common Rubus cane pathogens (Kalmusia coniothyrium, Botrytis spp., Diaporthe spp., and Seimatosporium lichenicola), Gnomoniopsis idaeicola was isolated from 23% of the samples. After isolation of G. idaeicola from ‘Columbia Star’, we also isolated the pathogen from symptomatic ‘Black Diamond’ blackberry in fields in Washington and Linn Counties in Oregon. G. idaeicola grew as white- to cream-colored circular colonies on the agar surface with sparse to dense aerial hyphae. Some isolates produced cream-colored exudate from irregular conidiomata. Conidia were single-celled, hyaline, oval to ellipsoid, and ranged from 4.9 to 6.9 µm long and 1.2 to 2.5 µm wide (n = 100). Perithecia and ascospores were not seen on canes or in culture; molecular methods were used to identify the fungus. Genomic DNA was extracted from nine isolates and β-tubulin, ITS region, and tef-1α were amplified using the primers and conditions described by Walker et al. (2010). Amplicons were Sanger sequenced in both directions by the Core Facilities of the Center for Quantitative Life Sciences of Oregon State University, Corvallis, OR. Sequences were deposited in GenBank (β-tubulin OK539758-OK539766; ITS OK348854-OK348862; tef-1α OK539767-OK539775). β-tubulin sequences (737 bp) were 100% identical to sequence of G. idaeicola from Rubus procerus, Oregon (GU320783). ITS sequences (518 bp) were 99.2 to 100% identical to G. idaeicola CBS125674T (GU320796). tef-1α sequences (860 bp) were 99.9 to 100% identical with reference sequences of G. idaeicola. Phylogenetic analyses of concatenated sequences using Tamura-Nei neighbor-joining (Tamura et al. 2004) confirmed identity. Pathogenicity of G. idaeicola isolates was tested in repeated experiments on four to five detached ‘Black Diamond’ primocanes and potted ‘Columbia Star’ plants with 4 mm hyphal plugs placed on fresh wounds and wrapped in parafilm; controls were treated with sterile agar plugs (Ellis et al. 1984; Stevanović et al. 2019). By 14 days, in each experiment, expanding necrotic lesions were observed on canes inoculated with G. idaeicola, but not with sterile agar plugs. ITS-sequence of fungi isolated from lesions confirmed identity as G. idaeicola, fulfilling Koch’s postulate. G. idaeicola was described as a new species by Walker et al. (2010) from perithecia collected from wild Rubus spp. in the Pacific Northwest. Despite its presence on native Rubus, G. idaeicola has not been reported in commercial blackberry fields in OR. Stevanović et al. (2019) identified G. idaeicola as an important pathogen causing canker, wilt, and death of blackberry in Serbia. Surveys of Oregon blackberry fields for G. idaeicola are ongoing, along with research on the epidemiology and management of this emerging pathogen.

First Report of Pleurostoma richardsiae Associated with Twig and Branch Dieback of Olive Trees in Spain

Pleurostoma richardsiae has been described as an olive tree pathogen causing decline and brown wood streaking (Carlucci et al., 2013). A survey was carried out in plots under olive cultivation (Olea europaea L., cv. Picual; 10 year-old plants) at La Garrovilla, (Spain) in September 2020, in which a putative Verticillium wilt had been visually diagnosed. In Plot 1 (2.6 ha; 741 plants), 20.4% of the plants exhibited wilt, foliar browning and leaf drop, twig, and branch dieback. While the level of incidence in plots 2 (4.8 ha; 1368 plants), 3 (3.20 ha; 912 plants), and 4 (1.85 ha; 527 plants) was 25.0%, 19.5%, and 42.9% respectively, which meant for that harvest an average reduction in olive production, and an economic loss, of 30.2%. Three trees from each plot were uprooted and analyzed. Five out of 12 intriguingly showed brown streaking under the bark extending from the root system and ascending up the trunk, a symptom that is never associated with Verticillium dahliae wich does not produce necrosis and cankers in the wood (López-Escudero and Mercado-Blanco, 2011). Samples from the 5 tree trunks showing necrosis were taken to the lab and surface sterilized. Small pieces of discolored wood were placed onto malt extract agar plates containing chloramphenicol (0.25 g/L) and incubated for 21 days at 25°C in darkness. The growing fungal colonies were then transferred to potato dextrose agar (PDA). Isolates were identified by micromorphological characteristics, according to Vijaykrishna et al. (2004), as P. richardsiae. Colonies on PDA were cottony, brown with whitish edge, and produced abundantly two types of conidia: brown (spherical or subglobose), or hyaline (allantoids to cylindrical) that appeared on septated and inconspicuous phialides respectively. Identification was confirmed by amplification and sequencing of the internal transcribed spacer (ITS) region using ITS1/ITS4 primers (White et al., 1990), and partial sequencing of the β-tubulin gene using T1 (O’Donnell and Cigelnik, 1997) and Bt2b (Glass and Donaldson, 1995) primers. ITS sequence showed a 99.82% identity with that of P. richardsiae IFM51337 (CBS406.93 type strain; GenBank AB364703.1), whereas β-tubulin sequence exhibited a 99.77% identity with P. richardsiae CBS406.93 β-tubulin gene (GenBank MT501304.1). ITS and β-tubulin sequences were deposited in GenBank (MZ519916 and MZ542764 respectively). The P. richardsiae isolate has been deposited in the Spanish Type Culture Collection (CECT 21196). Pathogenicity tests were conducted on 1-year old potted olive plants cv. Picual, maintained in a growth chamber at 25ºC and 12-h dark/12-h light. Twelve plants were inoculated in a wound made in the stem with a scalpel, and mycelial plug (5 mm diameter) from 15-day-old PDA plates were inserted into the wound. Another set of 12 plants were inoculated with sterile agar plugs and used as negative control plants. Four months after inoculation, 66% of the plants inoculated with mycelia plugs, showed wilting, necrosis under the bark, or even had died. P. richardsiae was successfully reisolated from necrotic areas in 75% of the plants inoculated with mycelia plugs. A total of 10 reisolates were identified as P. richardsiae by the above molecular techniques to confirm Koch's postulates. No symptoms were observed in the negative control plants and the pathogen was not re-isolated from them either. To our knowledge, this is the first report of P. richardsiae associated with twig and branch dieback of olive trees in Spain.

Phylogenetic analysis shows that New Zealand isolates of Neonectria ditissima are similar to European isolates

Neonectria ditissima causes a debilitating apple tree canker disease. We determined the efficacy of polymerase chain reaction primers, originally designed for European strains, by sequencing New Zealand strains. The concatenated ribosomal inter-transcribed spacer and β-tubulin gene regions of 17 New Zealand isolates were compared with those of two European strains by phylogenetic analysis. New Zealand and European isolates of N. ditissima were in the same clade, suggesting that there has been little change in these gene regions following introduction to New Zealand. There was 100% homology with Bt-FW135 and Bt-RW284 primers. Based on sequencing 17 New Zealand isolates from several locations, these polymerase chain reaction primers can be relied upon to amplify New Zealand isolates of N. ditissima.

First Report of Pulp Rot in the Externally Asymptomatic Pomegranate Fruit Caused by Talaromyces albobiverticillius in Henan Province, China

As a popular deciduous fruit tree, pomegranate (Punica granatum L.) is grown from tropical to temperate zones worldwide, therein China has at least 120000 hm2 cultivation area. In August 2020, severe pulp rot occurred in the externally asymptomatic pre-harvest pomegranate fruit on a 3-year-old soft-seeded variety (Tunisia) in the Zhanghe village (32º40´34˝N, 111º44´20˝E) of Jiuchong township, Xichuan county in Henan province, China with 6.4-20 (av. 12.6) % pulp rot incidence evaluated from 11 freshly sampled fruits (360 pulps per fruit investigated). The fruits showed no external symptoms, however, browning occurred on part of their pulps before harvest compared to the normal ones with white or pink color. The surface of the externally asymptomatic fruits was sterilized with 75% ethanol, and air-dried in a clean bench. The surface-disinfected fruits were dissected with a sterilized knife. Brown pulps from the fruits were picked up using flame-sterilized tweezers and placed on potato dextrose agar (PDA) plates. After five days of incubation at 28 °C, pure fungal cultures with similar phenotypic features developed from the affected pulps. Two randomly selected isolates Tp-2 and Tp-8 were used for the study. The colony surface of the isolates was greyish-green with claret-red exudates. Claret-red pigments were commonly secreted into the medium from the colonies. Conidia were unicellular, hyaline to greyish, mostly rugby ball-shaped with a dimension of 2.2-3.5 (2.7) µm × 1.6-2.0 (1.8) µm (n=50) for Tp-2, and 2.2-3.1 (2.6) µm × 1.6-2.2 (1.8) µm (n=50) for Tp-8. The rDNA internal transcribed spacer (ITS) and β-tubulin gene sequences of the isolates were amplified with primers ITS1/ITS4 and Bt2a/Bt2b, respectively. Sequences were submitted to GenBank with accession numbers MW132153 and MW132077 for the rDNA-ITS sequences, and MW507822 and MW507823 for the β-tubulin gene sequences of Tp-2 and Tp-8, respectively, with a maximal sequence identity greater than 99 % to multiple strains of Talaromyces albobiverticillius (TA) based on BLAST analyses. In the Neighbor-joining phylogenetic trees constructed using rDNA-ITS and β-tubulin gene sequences, both Tp-2 and Tp-8 formed a clade with mutiple strains of TA, clearly separated from other Talaromyces spp. Conidial suspensions (106 spores ml-1) of Tp-2 and Tp-8 were separately injected into five pomegranate fruits (Tunisia) sampled from an orchard free of the disease with a sterilized syringe. Five fruits inoculated with sterilized water were used as control (CK). The inoculated fruits were incubated at 25 °C for 10 days and cut out through the inoculated sites. Pulp rot symptoms occurred in the Tp-2/Tp-8-inoculated fruits, being similar to the naturally affected pulps. The CK pulps remained symptomless during the inoculation tests. Fungal cultures with the same phenotypic features as the inocula were constantly isolated from the brown pulps of the inoculated fruits, verifying both Tp-2 and Tp-8 as the causal agents of the disease based on Koch’s postulates. During a long-term (30-40 days) storage at ambient conditions, fruits sampled from affected orchards developed brown lesions on their peels from which TA cultures could be isolated. TA was reported as the pathogen causing postharvest fruit rot on pomegranate in Italy (Mincuzzi et al. 2017). This is the first report of TA causing pulp rot in the externally asymptomatic pomegranate fruit in China.

Enhanced Oxygen Utilization Efficiency With Concomitant Activation of AMPK-TBC1D1 Signaling Nexus in Cyclophilin-D Conditional Knockout Mice

We have previously reported in HEK 293 T cells and in constitutive cyclophilin-D (Cyp-D) knockout (KO) mice that Cyp-D ablation downregulates oxygen consumption (VO2) and triggers an adaptive response that manifest in higher exercise endurance with less VO2. This adaptive response involves a metabolic switch toward preferential utilization of glucose via AMPK-TBC1D1 signaling nexus. We now investigated whether a similar response could be triggered in mice after acute ablation of Cyp-D using tamoxifen-induced ROSA26-Cre-mediated (i.e., conditional KO, CKO) by subjecting them to treadmill exercise involving five running sessions. At their first treadmill running session, CKO mice and controls had comparable VO2 (208.4 ± 17.9 vs. 209.1 ± 16.8 ml/kg min−1), VCO2 (183.6 ± 17.2 vs. 184.8 ± 16.9 ml/kg min−1), and RER (0.88 ± 0.043 vs. 0.88 ± 0.042). With subsequent sessions, CKO mice displayed more prominent reduction in VO2 (genotype & session interaction p = 0.000) with less prominent reduction in VCO2 resulting in significantly increased RER (genotype and session interaction p = 0.013). The increase in RER was consistent with preferential utilization of glucose as respiratory substrate (4.6 ± 0.8 vs. 4.0 ± 0.9 mg/min, p = 0.003). CKO mice also performed a significantly higher treadmill work for given VO2 expressed as a power/VO2 ratio (7.4 ± 0.2 × 10−3 vs. 6.7 ± 0.2 10−3 ratio, p = 0.025). Analysis of CKO skeletal muscle tissue after completion of five treadmill running sessions showed enhanced AMPK activation (0.669 ± 0.06 vs. 0.409 ± 0.11 pAMPK/β-tubulin ratio, p = 0.005) and TBC1D1 inactivation (0.877 ± 0.16 vs. 0.565 ± 0.09 pTBC1D1/β-tubulin ratio, p < 0.05) accompanied by increased glucose transporter-4 levels consistent with activation of the AMPK-TBC1D1 signaling nexus enabling increased glucose utilization. Taken together, our study demonstrates that like constitutive Cyp-D ablation, acute Cyp-D ablation also induces a state of increased O2 utilization efficiency, paving the way for exploring the use of pharmacological approach to elicit the same response, which could be beneficial under O2 limiting conditions.

First Report of Fusarium solani Causing Leaf Sheath Rot of Bush lily in China

Bush lily (Clivia miniata) is an important indoor flower. It is the city flower of Changchun City and has important ornamental and medicinal value in China where it is culitvated on an area of 125 hectare. During the summer of 2018, symptoms of a leaf sheath rot disease were observed on bush lily in 103 greenhouses in Changchun city, Jilin Province. The disease incidence ranged from 25 to 60% in 11 surveyed greenhouses. At the early stage, the diseased plants displayed symptoms as initial leaf sheath lesions. Progressively, the whole leaves wilted, and even the plant ultimately died. Once a leaf exhibits leaf sheath lesions, the whole plant’s ornamental value significantly drops. To identify the pathogen, symptomatic leaves were cut into pieces, surface sterilized, placed on potato dextrose agar (PDA) and incubated for 7 days at 25°C in the dark (Cao et al. 2013; the e-Xtra description for details). Fusarium single-spore isolates were obtained from characteristic colonies (Leslie et al. 2006). Two single-spore isolates were selected for further study. The isolates were identified as Fusarium spp. based on microscopic morphology on PDA. Fusarium-like colonies were white to slightly yellow with abundant cottony mycelia. Single or two-celled (single septum) microconidia were reniform or oval, 8.0 to 9.6×4.0 to 6.0m in size. The elongated conidiophores bearing microconidia in monophialides were observed (Summerbell et al. 2002). Macroconidia were abundant, sickle shaped, 18.8 to 34.8×6.4 to 6.8m, with one to three septa (Taylor et al. 2019). For molecular identification, five regions of ITS, EF1-α, RPB1, RPB2 and β-tubulin genes were amplified and sequenced. Sequences of five different regions exhibited at least 97.98% similiarity with the corresponding DNA sequences in F. solani species complex (FSSC) (the e-Xtra description for details). The phylogenetic analysis based on the EF1-α, RPB1, RPB2 and β-tubulin region sequences revealed that the isolated strain in this study was clustered with only F. solani species in the phylogenetic tree for each region. Based on morphological and molecular analysis, the isolated fungal strains were identified as F. solani. Pathogenicity was confirmed by injecting a conidial suspension (106 spores/mL) of the isolated strains in to surface surface-disinfested leaf sheath of 2-year-old potted healthy plants. As a negative control, four plants were injected with sterilized water. All plants were kept in a greenhouse with controlled conditions: 26°C, 50% to 75% relative humidity. The similar rot symptoms were observed on the leaf sheathes in the inoculated plants 30 days after inoculation whereas the control plants remained asymptomatic. The fungi reisolated from the experimental plants were confirmed to be F. solani by morphology and sequences analysis, thus completing Koch’s postulates. To the best of our knowledge, this is the first report of F. solani causing leaf sheath rot of bush lily in China, where this pathogen has been reported to cause rot diseases of other economically important ornamental plants such as Phalaenopsis, Dendrobium according to the U.S. National Fungus Collections (Farr et al. 2020). In recent years, other Fusarium species have been reported to cause rot diseases on bush lily, including F. proliferatum and F. oxysporum (Farr et al. 2020). This study will also provide critical information on the causal agent for growers to implement disease management strategies.