Botrytis cinerea causes substantial losses in tomato and chili pepper crops worldwide. Endophytes have shown the potential for the biological control of diseases. The colonization ability of native endophyte strains of Beauveria bassiana and their antifungal effect against B. cinerea were evaluated in Solanaceae crops. Root drenching with B. bassiana was applied, and endophytic colonization capacity in roots, stems, and leaves was determined. The antagonistic activity was evaluated using in vitro dual culture and also plants by drenching the endophyte on the root and by pathogen inoculation in the leaves. Ten native strains were endophytes of tomato, and eight were endophytes of chili pepper. All strains showed significant in vitro antagonism against B. cinerea (30–36%). A high antifungal effect was observed, and strains RGM547 and RGM644 showed the lowest percentage of the surface affected by the pathogen. Native strains of B. bassiana colonized tomato and chili pepper tissues and provided important levels of antagonism against B. cinerea.

The tomato, Solanum lycopersicum L. is one of the most consumed vegetables in the world; nevertheless, it is affected by biotic and abiotic factors that reduce its productivity. The whitefly is globally considered as the main pest under protected crop conditions, where biologic control using endophytic fungi emerges as a sustainable alternative. We evaluated the indirect effects of five native endophytic strains of Beauveria bassiana on the reproduction of greenhouse whiteflies and the growth of tomatoes. The plant growth substrate was inoculated with five strains of this endophyte and the resulting plants were then exposed to whiteflies afterwards. The effect that endophytic strains had on phosphate solubilization, iron siderophore production, plant height, and plant biomass were evaluated. The evaluated endophytes reduced the number of eggs per cm² on leaflets compared to the control and behaved similarly to the commercial synthetic insecticide. Leaflets inoculated with strains RGM-557, RGM-644 and RGM-731 showed fewer nymphs than the control and those treated with insecticide. RGM-557 and RGM-731 produced the greatest plant heights; RGM-731 obtained the greatest plant biomass. Our study provides evidence that native endophytic strains of B. bassiana have a biocontrol effect on whiteflies and could be used to promote tomato growth.

Metarhizium anisopliae (Metschnikoff) Sorokin is an entomopathogenic fungus used for controlling different insect pests. It is most frequently applied to berry fruit crops, where fungicides are also used for disease control. Fungicides: azoxystrobin, benomyl, captan, chlorothalonil, fenhexamid, fludioxonil, iprodione, and metalaxyl in concentrations of 0.01, 0.1, 1.0, 10, and 100 mg L-1 were evaluated in this research study. Vegetative growth, conidia germination, and conidia germination tube length were measured on the Qu-M82, Qu-M151b, Qu-M253, Qu-M430, and Qu-M984 Metarhizium anisopliae var. anisopliae fungus strains. Those strains were selected because of their present use against different insect pest in bramble fruits. Vegetative growth was measured through the colony rate growth in agar media, and those reaching up to 50% of the check growth were considered compatible. Results indicate that the benomyl and fenhexamid fungicides were compatible with the five isolates whereas, azoxystrobin and fludioxonil were incompatible. Furthermore, benomyl and fludioxonil reduced conidia germination by 53 and 91%, and germination tube length by 18 and 37%, respectively.

Silverleaf caused by the basidiomycete Chondrostereum purpureum affects numerous woody species, including fruit tree crops like apple, resulting in wood necrosis and foliar silvering. There are no curative alternatives for this disease, and its management is by prevention methods. Therefore, the aim of this study was to develop a rapid diagnostic tool for the detection and identification of C. purpureum directly from woody tissues to help distinguish the pathogen from other basidiomycetes that are commonly found on apple. The silverleaf pathogen was isolated from different hosts and locations, and Koch’s postulates were performed by inoculating the isolates on apple cuttings and measuring internal necrosis. A previously described APN 1 pair of primers specificity was also tested against 25 C. purpureum isolates in this study, using other wood rotting species as negative controls. Seven virulent isolates were inoculated on apple cuttings, and DNA was extracted from the cuttings’ sawdust and amplified using APN 1, after 22 days of incubation. To prove the efficiency of the method in the field, DNA from healthy nursery plants inoculated with two virulent isolates, and naturally infected plants showing different levels of foliar symptoms, were tested. Presence of the fungus was verified by reisolation on APDA in all assays. Koch’s postulates indicated that all C. purpureum isolates were pathogenic, showing different virulence levels, and APN 1 primers were able to discriminate them from other basidiomycetes. The method was also able to detect C. purpureum from artificially inoculated plants as well as naturally infected ones, demonstrating that the protocol may become a rapid minimally destructive diagnostic tool to detect the pathogen without the need to isolate it from tissues, and thus taking measures to prevent its dissemination.

Cichorium intybus var. sativum is an Astereacae plant grown for its fleshy roots, which are rich in inulin, oligofructose and other fructans, and are used as functional food. It was introduced to Chile in 2006, where climate conditions allowed high yields. However, during crop adaptation period a severe crown rot was observed, with yield losses of up to 31% and reduced efficiency in inulin extraction process. Field collections of rotted plants from all cultivated areas, were between 2009 and 2013. Root symptoms started as dark, small, sunken lesions on the crown, turning to firm, black colored cavities as the crop developed. Signs were not visible. Sections of tissue were aseptically excised from the margins of necrotic lesions and placed into Petri plates, containing either water agar or acidified 25% potato dextrose agar. Pure cultures were obtained through hyphal tips. Isolates were identified on the basis of their morphological characteristics on oatmeal agar (OA) and malt agar (MEA), the metabolite ‘E’ test (Aveskamp et al. 2010) and molecular features. DNA was extracted from pure cultures and multilocus sequence typing was performed (Aveskamp et al. 2009). The internal transcribed spacer (ITS) sequence, actin and β-tubulin genes were amplified and sequenced. Primers ITS1 and ITS4 were used for ITS region, Act-512F and Act-783R for actin, and Bt2a and Bt2b for β-tubulin. Acquired sequences were subjected to NCBI BLAST search. Bootstrap analyses were performed on each dataset using neighbour-joining with 1000 replicates. After seven days, colonies grew 39 to 70 mm in diameter on OA and 47 to 82 mm on MEA. Colonies on MEA were olivaceous gray with irregularly scalloped margins, floccose, white to pale olivaceous-gray aerial mycelium and olivaceous-gray to black reverse. Pycnidia were dark, submerse, globose to subglobose, glabrous, solitary or confluent with a yellowish conidial matrix and a non-papillated ostiole. Conidia were hyaline and unicellular, ellipsoidal to oblong (n=100), ranging from 1.9 - 3.2 µm wide (2.8 ± 0.9 µm) x 4.2 - 6.8 µm long (5.7 ± 4.2 μm), with bipolar guttules. Swollen cells were olivaceous and constricted at the septa. Chlamydospores were absent (Boerema et al. 2004). All isolates were E+. Multilocus sequence alignment and tree construction assigned the isolates to Boeremia exigua var. exigua. Pathogenicity tests were performed with four different inoculation methods. Mycelium plugs 70 mm diameter, from colonies on PDA, were inoculated on surface sterilized root discs 50 - 70 mm diameter and incubated in humid chamber, at 22°C and dark. Plugs were also inoculated on surface sterilized entire roots and incubated both in humid chamber and in pasteurized soil, in the greenhouse for 20 days. Controls were inoculated with sterile agar plugs. Subsequently, the fungus was massified in sterile millet grains and mixed with pasteurized soil (0.1 % v/v), where healthy plants were transplanted. The pathogen was able to colonize the root, either with or without injuries to the crown, reproducing black root rot symptoms in all the inoculations. For all the tests, the pathogen was reisolated on PDA, fulfilling Koch’s postulates. Consequently, this is the first report of B. exigua var. exigua on industrial chicory in Chile.

Vaccinium corymbosum L. is the most cultivated blueberry species in Chile. Chilean fruits typically take up to 50 days to reach oversea markets; therefore, controlling post-harvest pathogens is of outmost importance to maintain international food safety and quality standards. In February 2019, the Microbial Genetic Resources Bank at INIA received fruits of V. corymbosum cv. 'Brigitta Blue' from Mariquina (-39.567869, -72.992461), located in the southern Chilean blueberry production zone, for post-harvest disease diagnosis. Asymptomatic fruits were incubated in moist-chambers at 25 °C with light/darkness cycles of 12 h. After 5 d, some fruits showed sunken areas and small surface wounds that exudated orange masses of conidia; under the epidermis, gray acervuli were also detected. After 15d, these fruits became dehydrated, mummified, and covered by mycelia, all characteristic symptoms of anthracnose (Wharton and Schilder 2008). In Chile, Colletotrichum gloeosporioides has, thus far, been the only causal agent of anthracnose reported in blueberry (Lara et al. 2003). Conidia exudated from the diseased fruit were inoculated on potato-dextrose agar (PDA) and incubated at 25 °C for 7 d. The resulting colony was predominantly cottony with gray aerial mycelium, displaying masses of pale orange conidia; on the reverse side, the colony was a pink-reddish color. Under a microscope, conidia were hyaline, fusiform to elliptic in shape, and displaying guttulate of 12.2±1.2 × 4.17±0.3 μm (n=30), characteristics coinciding with those described for Colletotrichum fioriniae (Pennycook 2017; Shivas and Tan 2009) (Supplementary Figure 1). The isolate was deposited in the Chilean Collection of Microbial Genetic Resources (CChRGM) as RGM 3330. Genomic DNA extraction of RGM 3330 and phylogenetic analyses were carried out according to Cisterna-Oyarce et al. (2022). A multi-locus sequencing analysis was carried out using five genetic markers. The internal transcribed spacer (ITS), glyceraldehyde 3-phosphate dehydrogenase (gapdh), actin (act), and chitin synthase 1 (chs-1) were PCR-amplified following Damm et al. (2012) and beta-tubulin (tub) following Glass and Donaldson (1995). Sequences were deposited in GenBank (ON364141 for ITS and ON369167-70 for tub, act, chs-1, and gapdh, respectively) (Sayers et al. 2021). A BLAST analysis carried out in SequenceServer (Priyam et al. 2019), using a custom database of sequences retrieved from Damm et al. (2012) and Liu et al. (2020), showed that all genetic markers were 100% identical to those of C. fioriniae CBS 128517T (ITS (540/540 identities), gapdh (249/249), act (245/245), and chs-1 (274/274)), except for tub, which shared 99.8% of its identities (416/417) with this species. Maximum likelihood phylogenetic estimation clustered RGM 3330 with C. fioriniae strains CBS 128517T and CBS 126526 with 100% bootstrap support (Supplementary Figure 1). Koch’s postulates were carried out with asymptomatic fruits of V. corymbosum cv. 'Brigitta Blue'. Prior to inoculation, fruits were surface-sterilized for 10 s in 70% ethanol, 3 s in 1% NaOCl, 10 s in 70% ethanol, rinsed three times with sterile distilled water, and subsequently placed in moist-chambers. Two groups of three repetitions of 20 fruits each were sprayed with 9 × 106 conidia/mL of RGM 3330 for the first group and with sterile distilled water for the control. After 5 d at 25 °C with light/darkness cycles of 12 h, only fruits sprayed with the conidial solution developed symptoms of anthracnose and the re-isolated fungi were identical in morphology to RGM 3330. This is the first report of C. fioriniae in blueberry in Chile. References: Cisterna-Oyarce, V., Carrasco-Fernández, J., Castro, J. 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