scholarly journals Inoculum production and evaluation of temperature and leaf wetness for Passalora sojina inoculation in soybean

2018 ◽  
Vol 44 (2) ◽  
pp. 122-126
Author(s):  
Juliane Nicolodi Camera ◽  
Carolina Cardoso Deuner ◽  
Valéria Cecília Ghissi ◽  
Erlei Melo Reis ◽  
Jana Koefender
Keyword(s):  
Culture Medium ◽  
Culture Media ◽  
Leaf Wetness ◽  
Infant Food ◽  
Optimum Temperature ◽  
Light Regimes ◽  
Inoculum Production ◽  
Wetness Period ◽  
Potato Sucrose Agar ◽  
Leaf Wetness Period

ABSTRACT The objective of this study was to develop a methodology for inoculum production and inoculation of Passalora sojina in soybean to assess the reaction to frogeye leaf spot. Thus, sporulation of fungal races was quantified in five substrates under two light regimes. The temperature and the leaf wetness period that resulted in greater infection efficiency were also determined. Petri dishes containing the culture media Oat Flour Agar (OFA), Tomato Juice (FTJ), V8 agar juice (V8), Infant Food (IF) and Potato Sucrose Agar (PSA) plus isolates of P. sojina races 23, 24 and 25 were subjected to 12-h photoperiod and 24-h continuous dark. Inoculated plants were incubated at temperatures of 15, 20, 25, 30 and 35 ºC and leaf wetness periods of 12, 24, 36, 48 and 72 hours. Experimental design was completely randomized with five replicates. There was interaction among isolate, culture medium and photoperiod. The highest sporulation (conidia/cm2) was obtained in the culture media FTJ (race 23) and V8 (races 24 and 25) under 12-h photoperiod. The optimum temperature for the disease development was 27oC under 72 hours of continuous leaf wetness.

scholarly journals Culture Medium, Light Regime and Temperature Affect the Development of Sirosporium diffusum

2018 ◽  
Vol 10 (6) ◽  
pp. 310
Author(s):  
Tales Poletto ◽  
Marlove F. B. Muniz ◽  
Vinícius S. Fantinel ◽  
Renata F. Favaretto ◽  
Igor Poletto ◽  
...  
Keyword(s):  
Culture Medium ◽  
Culture Media ◽  
Fungal Species ◽  
Light Regime ◽  
Leaf Spot Disease ◽  
Light Regimes ◽  
Physical Conditions ◽  
Randomized Design ◽  
Brown Leaf Spot ◽  
Brown Leaf

Sirosporium diffusum is the causal agent of the brown leaf spot disease on pecan trees that seriously damages the foliage of adult plants and seedlings. This fungal species is difficult to grow satisfactorily in a culture medium. Therefore, the aim of this study was to evaluate the effects of different physical conditions on the development of S. diffusum. In the first assay, eight culture media and five light regimes were combined, while in the second, the three treatments that promoted highest sporulation were combined with three temperatures. The trials were conducted in a two-factorial arrangement in a fully randomized design with six replicates. V8, V8CaCO3, and CA media under a 24-h photoperiod produced the highest respective sporulations: 29 × 104, 35 × 104, and 41 × 104 conidia ml-1. The best temperature for sporulation was 20±1 °C for all culture media, especially V8CaCO3 and CA. The best artificial conditions for obtaining good mycelial growth and sporulation consisted of a photoperiod of 24 h, temperature of 20±1 °C and V8CaCO3 or CA culture medium.

scholarly journals Influence of Temperature and Wetness Periods on the Development of Stemphylium Blight on Lentil

Plant Disease ◽  
2010 ◽  
Vol 94 (10) ◽  
pp. 1219-1224 ◽  
Author(s):  
E. Mwakutuya ◽  
S. Banniza
Keyword(s):  
Leaf Wetness ◽  
Linear Quadratic ◽  
Canadian Prairies ◽  
Linear Temperature ◽  
Glass Slides ◽  
Wetness Period ◽  
Stemphylium Blight ◽  
Simple Logistic ◽  
Germ Tubes ◽  
Leaf Wetness Period

Stemphylium blight of lentil (Lens culinaris subsp. culinaris) caused by Stemphylium botryosum has become more prevalent in the Canadian prairies. Germination of conidia, appressorium formation, and infection of lentil plants were evaluated under controlled conditions at temperatures from 5 to 30°C and increasing incubation periods under wet conditions to elucidate the epidemiology of this disease. On glass slides, conidial germination increased steadily with temperature up to 25 and 30°C, and reached more than 80% after 20 h at these temperatures, compared with around 30% at 5°C. The response of germination on glass slides to temperature was nonlinear, as evident in significant linear, quadratic single factor, and linear, quadratic, and cubic cross factor temperature effects in the model. On lentil leaves, 18% of conidia had germinated after 2 h of incubation at 25°C, and a few germ tubes penetrated into the tissue through stomata. Germination reached 89% after 12 h, and 12% of germ tubes had penetrated into the leaves. Stemphylium blight severity reached more than 80% at 25 and 30°C with leaf wetness periods of 48 h. A simple logistic model with linear temperature, leaf wetness period, and cross factor effects described disease development on lentil plants.

scholarly journals Temperature and Leaf Wetness Requirements for Pathogen Establishment, Incubation Period, and Sporulation of Phytophthora infestans on Petunia × hybrida

Plant Disease ◽  
2005 ◽  
Vol 89 (9) ◽  
pp. 975-979 ◽  
Author(s):  
M. C. Becktell ◽  
M. L. Daughtrey ◽  
W. E. Fry
Keyword(s):  
Phytophthora Infestans ◽  
Incubation Period ◽  
Petunia Hybrida ◽  
Environmental Parameters ◽  
Leaf Wetness ◽  
Lesion Area ◽  
Time Period ◽  
Wetness Period ◽  
Time Required ◽  
Leaf Wetness Period

The temperature and leaf wetness requirements for pathogen establishment (germination, infection, and colonization) and the temperature effects on incubation period and sporulation of Phytophthora infestans on petunia were compared with those on tomato. The responses to environmental parameters were found to be similar on petunia and tomato and agreed with those previously reported for late blight development on tomato and potato. In the current study, temperatures ranging from 13 to 23°C generally were conducive to establishment. Very little establishment occurred at 28°C. The minimum leaf wetness period that enabled pathogen establishment was 2 h, whereas most establishment occurred within 6 h of inoculation. The incubation period (time period from inoculation to lesion development) and the time required for development of sporangia after lesions were formed were shortest at 23 and 28°C, respectively. Production of sporangia was greatest (per square centimeter) at 18°C and was nearly absent at 28°C on both petunia and tomato. The sporulation density at 18°C was only slightly less on petunia compared with tomato (20,000 and 24,000 sporangia/cm2, respectively); however, the total lesion area on petunia was only 20% of that on tomato.

scholarly journals Modification of the TOMCAST Model with Aerobiological Data for Management of Potato Early Blight

Agronomy ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1872
Author(s):  
Laura Meno ◽  
Olga Escuredo ◽  
Maria Shantal Rodríguez-Flores ◽  
Maria Carmen Seijo
Keyword(s):  
Early Blight ◽  
Meteorological Data ◽  
Mean Value ◽  
Leaf Wetness ◽  
Weather Variables ◽  
Growing Seasons ◽  
Mean Temperature ◽  
Wetness Period ◽  
Potato Crops ◽  
Leaf Wetness Period

The present study focuses on establishing thresholds of weather variables for predict early blight in potato crops. For this, the TOMCAST model was adjusted using weather variables and Alternaria conidia levels (mainly A. solani and A. alternata) during six growing seasons in A Limia (Northwest Spain). TOMCAST for the effective management of early blight considers leaf wetness and air temperature to calculate daily severity values (DSVs). Spearman correlations between temperature (minimum and average), mean temperature during leaf wetness period and Alternaria concentration showed the highest positive significant coefficients (0.386, 0.230 and 0.372, respectively; p < 0.01). Specifically, Alternaria levels higher than 50 spores/m3 were found the days with air mean temperature above 18 °C, more than 7 h of leaf wetness. Leaf wetness was decisive to estimate the concentration of Alternaria, resulting in a significant linear regression model (R2 = 0.41; p < 0.001). TOMCAST was adapted to the area, considering 10 °C the minimum threshold for the mean value of temperature during the wet period and 10–15 accumulated disease severity values (DSV). Using TOMCAST, it was possible to predict the first Alternaria peak in most of potato growing seasons. Combining aerobiological and meteorological data to control fungal diseases during crops are a useful tool for sustainable agriculture.

scholarly journals Biological Potencial of Colletotrichum typhae H.C Greene mycoherbicide for Typha domingensis Pers

2018 ◽  
Author(s):  
Cláudio Belmino Maia ◽  
Paulo Alexandre Fernandes Rodrigues de Melo ◽  
Robert Weingart Barreto ◽  
Luiz Antônio Maffia ◽  
Kedma Maria Silva Pinto ◽  
...  
Keyword(s):  
Fungal Species ◽  
Effect Of Temperature ◽  
Leaf Wetness ◽  
Hydroelectric Power ◽  
Specificity Test ◽  
Influence Of Temperature On ◽  
Wetness Period ◽  
Severity Of The Disease ◽  
Leaf Wetness Period

The anthropic interference in aquatic ecosystems, favors the disordered colonization of T. domingensis, damaging the production of hydroelectric power and river traffic. Thus, the objective of this study was to evaluate the potential of C. typhae as a mycoherbicide in the control of T. domingensis, in vitro and in greenhouse. 107 samples of symptomatic T. domingensis leaves were collected in flooded areas of rivers in Brazil, with identification and isolation of the collected fungal species. The concentration of inoculum was determined to evaluate the incidence and severity of the disease, the influence of temperature on mycelial growth and conidia germination, the effect of temperature and leaf wetness period on T. domingensis infection by C. typhae and the host range test. The growth of the colonies of C. typhae was higher at 25 to 30 ºC, there was no interference of the photoperiod on germination of the spores, but the highest percentage of germination occurred at 17.39 ºC. The influence of environmental conditions on infection of inoculated leaves of T. dominguensis indicated that at 15 ºC and the period of leaf wetness of 48 hours promoted the highest incidence of the disease, as well as the severity for the same period of leaf wetness. The specificity test showed that C. typhae is specific and pathogenic to T. domingensis. Being this the first report of the occurrence of this pathogen in aquatic macrophytes of this species and in T. domingensis in Brazil.

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