scholarly journals Botrytis cinerea in raspberry in Serbia II: Growth rate and virulence of isolates

2015 ◽  
Vol 30 (1) ◽  
pp. 9-16 ◽  
Author(s):  
Brankica Tanovic ◽  
Jovana Hrustic ◽  
Milica Mihajlovic ◽  
Mila Grahovac ◽  
Goran Delibasic

Growth rate and virulence of 130 isolates of Botrytis cinerea, derived from raspberry fruit originating from six commercial fields in a raspberry growing region of Serbia and classified in two morphological and four genetic groups were studied. The results showed significant differences in mycelial growth rate among the isolates. The highest and lowest recorded growth rates were 24.5 mm/day and 8.4 mm/day, respectively, while the growth rate of most isolates ranged from 15.8 to 21.8 mm/day. The growth rate of isolates that belong to different morphological and genetic subgroups varied similarly. Furthermore, growth rate intervals of all subgroups overlapped, suggesting that the groups cannot be distinguished based on growth rates of the isolates contained. The studied B. cinerea isolates exibited different levels of virulence towards vine, sunflower and raspberry leaves, while an analysis of variance revealed that both the isolates and the inoculated host species were significant sources of variation (P<0.01). Sunflower and raspberry leaves were significantly more sensitive than vine leaves. However, correlation between isolate virulence and different hosts was not found.

2020 ◽  
pp. 2411-2418
Author(s):  
Renata Mori Thomé ◽  
Luiz Vitor Barbosa de Oliveira ◽  
Ciro Hideki Sumida ◽  
Maria Isabel Balbi-Peña

Gray mold in grapes (caused by Botrytis cinerea) and blue mold in citrus (caused by Penicillium italicum) are post-harvest diseases that cause major losses in these crops. The control of these diseases is based on the use of synthetic chemical fungicides. The increase in regulatory policies and demand to reduce the application of pesticides, due to harmful effects on the environment and humans, have led to the search for more ecofriendly alternatives, such as biological control agents. Thus, the present work aims to verify the antagonistic potential of four yeast strains, Pichia caribbica (CCMA 0759), Hanseniaspora opuntiae (CCMA 0760), Pichia manshurica (CCMA 0762), and Lachancea thermotolerans (CCMA 0763), against of B cinerea and P. italicum. To assess the antagonism of volatile compounds, Petri plates with two divisions containing potato-dextrose-agar (PDA) were used by placing a fungal mycelial disc and yeast suspension (3.0 × 106 cells mL-1) on opposite sides of the plate. The colony diameter and mycelial growth rate index of the fungi were evaluated via comparisons with the control plate without yeast. For the evaluation of the antagonism of diffusible substances in the medium, yeasts were striated 3 cm from the center of the plates containing PDA. After 48 h, a mycelial disc of each phytopathogen was placed in the center of the plates. The colony growth, inhibition halo, and mycelial growth rate index were evaluated via comparisons with the control plate. All yeast strains showed an antagonistic effect on the mycelial growth of B. cinerea in both tests. In the volatile compounds test, H. opuntiae, L. thermotolerans, P. caribbica, and P. manshurica inhibited mycelial growth by approximately 82%, 75%, 72%, and 50%, respectively. In the antagonism test of the diffusible substances in the medium, P. caribbica and P. manshurica inhibited mycelial growth by 58% and 33%, respectively. However, these yeast strains did not show an antagonistic effect against P. italicum. Thus, all isolates demonstrated potential to be tested as biocontrol agents of gray mold in post-harvest grape fruits.


Plant Disease ◽  
2012 ◽  
Vol 96 (9) ◽  
pp. 1286-1290 ◽  
Author(s):  
Stylianos Samuel ◽  
Thomas Veloukas ◽  
Antonios Papavasileiou ◽  
George S. Karaoglanidis

This study was conducted primarily to investigate the presence and frequency distribution of the transposable elements Boty and Flipper in populations of the necrotroph plant pathogen Botrytis cinerea in Greece. In total, 334 isolates were collected from diseased grape, strawberry, tomato, cucumber, kiwifruit, and apple fruit during 2009. The presence of the two transposable elements was based on polymerase chain reaction detection. Results showed that all the sampled hosts occurred in sympatry, with four possible different genotypes (transposa type carrying both transposable elements, Boty type carrying only the Boty element, Flipper type carrying only the Flipper element, and vacuma type carrying neither transposable element). Marked differences in genotype frequencies among populations were observed. In tomato, cucumber, grape, and strawberry, transposa isolates carrying both elements were predominant in the populations whereas, in kiwifruit and apple fruit populations, the vacuma isolates were prevailing. Furthermore, in kiwi and apple fruit populations, high frequencies of Flipper-type isolates were observed. In an attempt to explain the observed predominance of vacuma isolates in kiwifruit populations, the mycelial growth rate of a set of vacuma isolates was compared with the mycelial growth rate of a set of transposa isolates at three different temperatures (0, 10, and 20°C). The same set of isolates was used to compare pathogenicity of isolates on wound-inoculated kiwifruit incubated at two different temperatures (0 and 20°C), in terms of disease incidence and disease severity. In addition, the selected isolates were used to compare their ability in causing latent infections on kiwifruit in the field. The results showed that vacuma and transposa isolates had similar mycelial growth rates at the limiting temperatures of 0 and 10°C, while vacuma isolates grew faster at the optimum temperature of 20°C. Similarly, there was no significant difference regarding pathogenicity on kiwifruit between transposa and vacuma isolates. However, artificial inoculations conducted on blossoms in the field showed that vacuma isolates caused significantly higher incidence of latent infections.


2014 ◽  
Vol 45 (3) ◽  
pp. 861-872 ◽  
Author(s):  
P.C. Guadarrama-Mendoza ◽  
G. Valencia del Toro ◽  
R. Ramírez-Carrillo ◽  
F. Robles-Martínez ◽  
J. Yáñez-Fernández ◽  
...  

1984 ◽  
Vol 103 (1) ◽  
pp. 137-153 ◽  
Author(s):  
J. E. Frisch ◽  
T. E. Vercoe

SummaryCalves from three breeds, Brahman, Hereford × Shorthorn (HS) and Brahman × HS (BX), were divided equally into two groups, one of which was treated every 3 weeks from birth onwards to control ticks and gastrointestinal helminths, and one of which was untreated. Mortalities, growth rates and levels of resistance to environmental stresses that affected both mortality and growth under grazing conditions were recorded for all animals up to weaning (6 months) and for all males up to 15 months of age. The Brahmans were the most and the HS were the least resistant to environmental stresses, each of which was shown to depress growth in proportion to its magnitude and to contribute to the high mortalities of the HS. All breeds responded positively to parasite control with the greatest response in both survival and growth in the HS breed and the least response in the Brahman breed.Samples of males from the various breed-treatment groups were taken into pens where they were protected from environmental stresses and fed both low-quality pasture hay and high-quality lucerne hay ad libitum. Measurements were made of fasting metabolism, maintenance requirement, voluntary food intake and gain, variables related to the growth potential of each animal. The HS animals had the highest whilst the Brahmans had the lowest values for each variable.However, despite their low growth potential, the Brahmans had the highest growtli rate, and the HS, despite their high growth potential, had the lowest growth rate, when growth was measured in the presence of all environmental stresses. When parasites were controlled, growth rates were highest for the BX, the breed with intermediate growtli potential, and did not differ between the HS and Brahmans. These interactions arose because of the different contributions of resistance to environmental stresses and growth potential to growth rate measured at the different levels of environmental stresses. The relevance of these interactions to breed evaluation and cross-breeding is considered.Growth potential and resistance to environmental stresses were negatively correlated both between and within breeds, though the latter was biased by the effects of compensation. The influence of these relationships on the likely outcome of selection for increased growth rate, both between and within breeds, is discussed.


2021 ◽  
Vol 13 (4) ◽  
pp. 120
Author(s):  
Karla Danielle Nogueira Cardoso ◽  
Maria Josiane Martins ◽  
Thaisa Aparecida Neres de Souza ◽  
Isabelle Carolyne Cardoso ◽  
Patrícia Nirlane da Costa Souza ◽  
...  

Phomopsis sojae and Sclerotinia sclerotiorum are responsible for stem and pod dryness and white mold in soybean. These pathologies directly affect the quality of seeds/grains and compromise the entire plant. The use of extracts from different plants has been the subject of research for the control of several phytopathogens. Calotropis procera is among botanical species that synthesize efficient compounds for biocontrol. In this context, the aim of this study was to evaluate the in vitro effect of C. procera aqueous extract on P. sojae and S. sclerotiorum. The experiment was carried out in completely randomized blocks in a 2 &times; 5 factorial scheme (two fungi and five extract concentrations 0%, 5%, 10%, 15% and 20%) with 4 replicates. C. procera aqueous extract concentrations were added to Petri dishes containing PDA. After 48 hours, the mycelial growth rate was evaluated. After seven days of incubation, the fungal colony area, sporulation, and germination of P. sojae and S. sclerotiorum were evaluated. There was significant interaction between fungi &times; extract concentrations (p &lt; 0.05) for all variables analyzed. The mycelial growth rate of P. sojae was lower than that of S. sclerotiorum. The diameter of the P. sojae fungal colony was smaller than that of S. sclerotiorum when concentrations of 5%, 10% and 15% were used. As the extract concentration increased, fungi sporulation and germination reduced.


Author(s):  
Anaid Talavera-Ortiz ◽  
Priscila Chaverri ◽  
Gerardo Diaz-Godinez ◽  
Ma de Lourdes Acosta-Urdapilleta ◽  
Elba Villegas ◽  
...  

Abstract:Background and Aims: The production of edible fungi is affected by bacterial, fungal and viral diseases, which very often cause large losses. In the productionof mushrooms of the genus Pleurotus, the fungi of Trichoderma spp. represent a serious problem of contamination and although there are some chemical compoundsthat control the infection, they are not entirely safe for human consumption. As a consequence, alternatives are being searched for through biotechnology,such as the one presented in this paper.Methods: Strains of fungi of the genus Trichoderma were isolated from the substrate where Pleurotus ostreatus was being cultivated. These were identifiedmorphologically and molecularly, followed by tests to inhibit the growth of Trichoderma strains in both agar and wheat straw, using a cetonic extract of thedehydrated fruiting body of Pycnoporus sp.Key results: Two strains of Trichoderma (T. pleuroti and T. atrobrunneum, belonging to the clade of T. harzianum) were isolated from infected substrate obtainedin production modules of Pleurotus ostreatus located in Tlaquitenango and Cuernavaca, in the state of Morelos, Mexico. The effect of a cetonic extract of thefruiting body of Pycnoporus sp. on the mycelial growth of the isolated strains of Trichoderma was also evaluated, observing decrease in mycelial growth rate inPetri dish up to 72% and on lignocellulosic substrate both mycelial growth and sporulation were delayed up to 10 days.Conclusions: The extract of Pycnoporus sp. could be an alternative to control the infection by Trichoderma spp. in mushroom cultures of the genus Pleurotus.Key words: disease control, edible mushrooms, lignocellulosic substrate. 


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