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.

scholarly journals Potential of Colletotrichum typhae H.C Greene mycoherbicide for bio-control of Southern cattail (Typha domingensis Pers.) plants

2020 ◽  
pp. 278-285
Author(s):  
Cláudio Belmino Maia ◽  
Paulo Alexandre Fernandes Rodrigues de Melo ◽  
Robert Weingart Barreto ◽  
Luiz Antônio Maffia ◽  
O correto é Kedma Maria Silva Pinto ◽  
...  
Keyword(s):  
Fungal Species ◽  
Effect Of Temperature ◽  
Leaf Wetness ◽  
Aquatic Weed ◽  
Hydroelectric Power ◽  
Specificity Test ◽  
Influence Of Temperature On ◽  
Wetness Period ◽  
Severity Of The Disease

The anthropic interference in aquatic ecosystems favors the disordered colonization of T. domingensis, damaging the production of hydroelectric power and river traffic. Because of this, studies report the efficacy of fungal mycoherbicides, with control rates reaching as high as 90%. Thus, the objective of this study was to evaluate the potential of C. typhae as a mycoherbicide in bio control of T. domingensis, at in vitro and greenhouse conditions. 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 in vitro. 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 was occurred at 20 ºC. The influence of environmental conditions on infection of inoculated leaves of T. dominguensis revealed that at 15 ºC and the period of leaf wetness of 48 hours the highest incidence of the disease was observed, as well as the severity for the same period of leaf wetness. The specificity test showed that C. typhae is specifically pathogenic to T. domingensis. This the first report of the occurrence of this pathogen in aquatic macrophytes of this species and in T. domingensis, a potential mycoherbicide for the control of this aquatic weed.

scholarly journals Temperature, Leaf Wetness, and Isolate Effects on Infection of Minneola Tangelo Leaves by Alternaria sp.

Plant Disease ◽  
1999 ◽  
Vol 83 (5) ◽  
pp. 429-433 ◽  
Author(s):  
Y. Canihos ◽  
T. L. Peever ◽  
L. W. Timmer
Keyword(s):  
Polynomial Equation ◽  
Brown Spot ◽  
Effect Of Temperature ◽  
Leaf Wetness ◽  
Significant Difference ◽  
Alternaria Brown Spot ◽  
Detached Leaves ◽  
Alternaria Sp ◽  
Response To Temperature

Alternaria brown spot causes necrotic lesions on immature leaves, twigs, and fruit of tangerines and their hybrids, reducing yield and fruit quality. The effect of temperature, leaf wetness, and isolate was evaluated in an in vitro system using immature detached leaves of Minneola tangelo Infection was greatest at 27°C, decreased gradually as the temperature declined to 24, 20, and 17°C, and dropped sharply at 32°C. Levels of infection were low at 4 and 8 h of leaf wetness and continued to increase with longer wetting periods up to 36 h. A polynomial equation was developed that provided a good fit for the data (adjusted R2 = 0.93). Isolates differed in aggressiveness, but there was no significant difference among isolates in their response to temperature and leaf wetness duration.

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 Effects of Light, Temperature, and Leaf Wetness Duration on Daylily Rust

Plant Disease ◽  
2003 ◽  
Vol 87 (4) ◽  
pp. 442-445 ◽  
Author(s):  
D. S. Mueller ◽  
J. W. Buck
Keyword(s):  
Light Intensity ◽  
Effect Of Temperature ◽  
Leaf Wetness ◽  
Disease Development ◽  
Lesion Development ◽  
Leaf Wetness Duration ◽  
Different Temperatures ◽  
Controlled Environments ◽  
Incubation Temperatures

Experiments in controlled environments were completed to determine the influence of light intensity, temperature, and leaf wetness duration on daylily rust caused by Puccinia hemerocallidis. As light intensity increased, there was a significant decrease in urediniospore germination (R2 = 0.88 and Y = 96 - 0.6x). Urediniospores germinated in vitro between 7 and 34°C with an optimal temperature of 22 to 24°C. To test the effect of temperature on infection efficiency, plants were inoculated with urediniospores, incubated under high relative humidity at 4, 10, 22, 30, or 36°C, and then transferred to a greenhouse at 23°C for 15 days. Plants incubated at 22°C had an average of 13 lesions cm leaf-1. Incubation temperatures of 4, 10, 30, or 36°C resulted in less than 1.5 lesions cm leaf-1. Plants were inoculated, incubated at 22°C for 24 h, and then incubated at different temperatures for 15 days to test the effect of temperature on disease development. There were no significant differences in disease development at 22 and 30°C; however, there were significantly fewer lesions at 10°C and no lesions developed at 36°C within 15 days. Five to six h of leaf wetness were required for lesion development and as the duration of leaf wetness increased, there was a significant increase in the number of lesions that developed. These studies indicate that for disease development of P. hemerocallidis on daylily, temperatures around 22°C and 5 h of leaf wetness are required during infection. However, once a daylily is infected, disease development is not as sensitive to environmental conditions.

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 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 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.

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