scholarly journals Monitoring litter interception of rainfall using leaf wetness sensor under controlled and field conditions

2016 ◽  
Vol 31 (1) ◽  
pp. 240-249 ◽  
Author(s):  
Bharat Sharma Acharya ◽  
Elaine Stebler ◽  
Chris B. Zou
Keyword(s):  
Field Conditions ◽  
Leaf Wetness ◽  
Litter Interception

scholarly journals Bremia lactucae Infection Efficiency in Lettuce is Modulated by Temperature and Leaf Wetness Duration Under Quebec Field Conditions

Plant Disease ◽  
2015 ◽  
Vol 99 (7) ◽  
pp. 1010-1019 ◽  
Author(s):  
M. L. Fall ◽  
H. Van der Heyden ◽  
C. Beaulieu ◽  
O. Carisse
Keyword(s):  
Downy Mildew ◽  
Field Experiments ◽  
Field Conditions ◽  
Risk Indicators ◽  
Growth Chamber ◽  
Leaf Wetness ◽  
Risk Indicator ◽  
Bremia Lactucae ◽  
Infection Efficiency ◽  
Leaf Wetness Duration

More than 80% of Canadian lettuce production is located in the province of Quebec. Yet most of our knowledge on the epidemiology of lettuce downy mildew (Bremia lactucae) is derived from controlled-condition experiments or field experiments conducted in subtropical climates and, thus, cannot readily be applied to Quebec lettuce production. The influence of temperature and leaf wetness duration on the infection efficiency (IE) of B. lactucae was studied for 4 years (2003, 2004, 2012, and 2013) under field and growth-chamber conditions. IE was defined as the ratio of the number of lesions/leaf to the airborne conidia concentration (ACC). B. lactucae ACC was measured with rotating-arm samplers three times/week. In addition, 72 lettuce trap plants/sampling day were exposed to the potential airborne B. lactucae inoculum and disease intensity was assessed after 7 days of incubation in greenhouse. Under growth-chamber conditions, an ACC of 1 conidium/m3 was sufficient to cause 1 lesion/leaf, and IE ranged from 0.25 to 1.00. Under field conditions, an ACC of 10 to 14 conidia/m3 was required to cause 1 lesion/leaf, and IE ranged from 0.02 to 0.10, except in 2004, when IE ranged from 0.03 to 1.00. IE increased with increasing leaf wetness duration but decreased with increasing temperature. Also, considering an observed average temperature range from 10 to 20°C in the area of Quebec, 2 h of leaf wetness was sufficient for infection by B. lactucae. Therefore, under Quebec lettuce production conditions, a leaf wetness period of 2 h and an ACC of 10 to 14 conidia/m3 can be used as risk indicators to facilitate disease management decisions. Also, under typical Quebec weather conditions, measuring both morning and evening leaf wetness events could be used to improve the reliability of leaf wetness duration as a downy mildew risk indicator. Further research is needed to validate these risk indicators for integration into management strategies.

Potential for biological control of Cercosporidium personatum leafspot of peanuts by Dicyma pulvinata

1987 ◽  
Vol 65 (11) ◽  
pp. 2263-2269 ◽  
Author(s):  
James K. Mitchell ◽  
Donald H. Smith ◽  
Ruth A. Taber
Keyword(s):  
Biological Control ◽  
Environmental Conditions ◽  
Field Conditions ◽  
Leaf Wetness ◽  
Wild Type ◽  
Cercosporidium Personatum ◽  
Type Isolate ◽  
65 H

The biology of Dicyma pulvinata (Berk. & Curt.) v. Arx, a mycoparasite of Cercosporidium personatum (Berk. & Curt.) Deighton, was investigated under both laboratory and field conditions. At 26 °C, conidia of D. pulvinata close to both hyphae and conidia of C. personatum germinated within 11–17 h. Visible signs of colonization of lesions of C. personatum by D. pulvinata appeared within 58–65 h (21–31.5 h leaf wetness). Dicyma pulvinata was an effective protectant when plants were exposed to continuous leaf wetness at 26 °C for 5 days. In field microplot studies, lesions of C. personatum were visibly colonized by both mutant and wild-type isolates of D. pulvinata within 4 days after applying their conidial suspensions. Environmental conditions during this 4-day period were 40 h leaf wetness, 60 h of 23–28 °C (optimal temperatures for growth of the wild-type isolate), and 17.31 cm rainfall.

EFFECTS OF CULTIVAR RESISTANCE, LEAF WETNESS DURATION AND TEMPERATURE ON RATE OF DEVELOPMENT OF POTATO EARLY BLIGHT

1985 ◽  
Vol 65 (1) ◽  
pp. 179-184 ◽  
Author(s):  
J. D. HOLLEY ◽  
R. HALL ◽  
G. HOFSTRA
Keyword(s):  
Infection Rate ◽  
Early Blight ◽  
Alternaria Solani ◽  
Field Conditions ◽  
Leaf Wetness ◽  
Regression Equations ◽  
Cultivar Resistance ◽  
Leaf Wetness Duration ◽  
Apparent Infection Rate ◽  
Highly Correlated

Regression models were developed from field observations over three seasons in Ontario, to relate apparent infection rate (Y) of early blight, caused by Alternaria solani Sorauer, on three potato cultivars, Kennebec, Chieftain, and Norchip, to leaf wetness duration (W) and air temperature (T). Among regression equations of the form Y = a + bW + cT + dWT or Y = a + bW, cultivar-specific equations accounted for more variability in Y than equations derived from all cultivars. In all-cultivar equations and cultivar-specific equations, W accounted for 85%–89% of the variability in Y. Therefore, cultivar resistance and the average daily duration of leaf wetness were identified as important factors determining apparent infection rate under field conditions. Temperature, either singly or in combination with leaf wetness, accounted for less than 10% of the variability in Y and was negatively correlated with Y and W. The product of temperature and wetness was highly correlated with Y but, under field conditions, an increase in temperature tended to decrease the duration of leaf wetness, and therefore the value of Y as well. It is suggested that cultivar resistance and duration of leaf wetness will be important factors to be considered in the prediction of apparent infection rate and in the development of a practical weather-timed spray program for early blight of potato.Key words: Alternaria solani, Solanum tuberosum, disease control, weather-timed spray

Ichthyotoxicity of the microalga Pseudochattonella farcimen under laboratory and field conditions in Danish waters

2015 ◽  
Vol 116 (3) ◽  
pp. 165-172 ◽  
Author(s):  
NG Andersen ◽  
PJ Hansen ◽  
K Engell-Sørensen ◽  
LH Nørremark ◽  
P Andersen ◽  
...  
Keyword(s):  
Field Conditions

Immobilization of Radionuclides on Iron Canister Material at Simulated Near-field Conditions

2008 ◽  
Author(s):  
Daqing Cui ◽  
Ylva Ranebo ◽  
Jeanett Low ◽  
Vincenzo Rondinella ◽  
Jinshan Pan ◽  
...  
Keyword(s):  
Near Field ◽  
Field Conditions
Sign in / Sign up

Export Citation Format

Share Document