Research Article Severity of rust infection in soybean genotypes with partial resistance as a function of temperature and leaf wetness duration

Leaf wetness duration (LWD) is a key parameter in agrometeorology because it is related to plant disease occurrence. As LWD is seldomly measured in a standard weather station it must be estimated to run warning systems for schedule chemical disease control. The objective of the present study was to estimate LWD over turfgrass considering different models with data from a standard weather station, and to evaluate the correlation between estimated LWD over turfgrass and LWD measured in a 'Niagara Rosada' vineyard, cultivated in a hedgerow training system, in Jundiaí, São Paulo State, Brazil. The wetness sensors inside the vineyard were located at the top of the plants, deployed at an inclination angle of 45º and oriented southwest, with three replications. The methods used to estimate LWD were: number of hours with relative humidity above 90% (NHRH > 90%), dew point depression (DPD), classification and regression tree (CART) and Penman-Monteith (PM). The CART model had the best performance to estimate LWD over turfgrass, with a good precision (R² = 0.82) and a high accuracy (d = 0.94), resulting in a good confidence index (c = 0.85). The results from this model also presented a good correlation with measured LWD inside the vineyard, with a good precision (R² = 0.87) and a high accuracy (d = 0.96), resulting in a high confidence index (c = 0.93), showing that LWD in a 'Niagara Rosada' vineyard can be estimated with data from a standard weather station.

Download Full-text

Leaf wetness duration estimation and its influence on a soybean rust warning system

Australasian Plant Pathology ◽

10.1007/s13313-019-00641-3 ◽

2019 ◽

Vol 48 (4) ◽

pp. 395-408 ◽

Cited By ~ 4

Author(s):

Gustavo Castilho Beruski ◽

Mark Lawrence Gleason ◽

Paulo Cesar Sentelhas ◽

André Belmont Pereira

Keyword(s):

Warning System ◽

Soybean Rust ◽

Leaf Wetness ◽

Leaf Wetness Duration ◽

Duration Estimation

Download Full-text

Influence of Temperature and Leaf Wetness Duration on Infection of Strawberry Leaves by Mycosphaerella fragariae

Phytopathology ◽

10.1094/phyto.2000.90.10.1120 ◽

2000 ◽

Vol 90 (10) ◽

pp. 1120-1125 ◽

Cited By ~ 32

Author(s):

O. Carisse ◽

G. Bourgeois ◽

J. A. Duthie

Keyword(s):

Leaf Surface ◽

Leaf Wetness ◽

Infection Model ◽

Controlled Environment ◽

Conidial Suspension ◽

Precise Description ◽

Leaf Wetness Duration ◽

Influence Of Temperature ◽

Mycosphaerella Fragariae ◽

Weibull Equation

In controlled environment studies, the influence of temperature and wetness duration on infection of strawberry leaves by Mycosphaerella fragariae was quantified by inoculating plants with a conidial suspension and incubating them at various combinations of temperature (5 to 35°C) and leaf wetness duration (0 to 96 h). Infection was expressed as the number of lesions per square centimeter of leaf surface and relative infection was used to develop an infection model. Younger leaves were more susceptible to infection. Regardless of temperature and duration of leaf wetness, only few lesions developed on the oldest (19 to 21 days old) and intermediate leaves (12 to 15 days old), respectively (maximum of 1.7 and 2.3 lesions per cm2) as compared to the youngest leaves (5 to 7 days old; maximum of 12.6 lesions per cm2). On the youngest leaves, lesions developed at all temperatures except at 35°C, and the number of lesions, for all leaf wetness durations, increased gradually from 5 to 25°C and decreased sharply from 25 to 30°C. For temperatures of 15 and 20°C, the number of lesions increased gradually when leaf wetness duration increased from 12 to 96 h. At 25°C, the number of lesions increased with increasing leaf wetness from 12 to 48 h and then at a higher rate from 48 to 96 h. The optimal temperature for infection was 25°C. For most temperatures, a minimum of 12 h of leaf wetness was necessary for infection (more than 1 lesion per cm2). Relative infection was modeled as a function of both temperature and wetness duration using a modified version of the Weibull equation (R 2 = 0.98). The resulting equations provided a precise description of the response of M. fragariae to temperature. The model was sufficiently flexible to account for most characteristics of the response of M. fragariae to wetness duration. The model was used to construct a risk chart that can be used to estimate the potential risk for infection based on observed or forecasted temperature and leaf wetness duration.

Download Full-text

Influence of Leaf Wetness Duration and Temperature on Infection of Grape Leaves by Elsinoë ampelina under Controlled and Vineyard Conditions

Plant Disease ◽

10.1094/pdis-02-20-0262-re ◽

2020 ◽

Vol 104 (11) ◽

pp. 2817-2822

Author(s):

Odile Carisse ◽

Audrey Levasseur ◽

Caroline Provost

Keyword(s):

Leaf Area ◽

Weather Conditions ◽

Leaf Wetness ◽

Predictive Capacity ◽

Leaf Wetness Duration ◽

Infection Period ◽

Richards Model ◽

Elsinoe Ampelina ◽

Independent Observations ◽

The Relationship

On susceptible varieties, indirect damage to vines infected by Elsinoë ampelina range from reduced vigor to complete defoliation while, on berries, damage ranges from reduced quality to complete yield loss. Limited knowledge about the relationship between weather conditions and infection makes anthracnose management difficult and favors routine application of fungicides. The influence of leaf wetness duration and temperature on infection of grape leaves by E. ampelina was studied under both controlled and vineyard conditions. For the controlled conditions experiments, the five youngest leaves of potted vines (Vidal) were inoculated with a conidia suspension and exposed to combinations of six leaf wetness durations (from 0 to 24 h) and six constant temperatures (from 5 to 30°C). A week after each preset infection period, the percent leaf area diseased (PLAD) was assessed. At 5°C, regardless of the leaf wetness duration, no disease developed. At 10 and at 15 to 30°C, the minimum leaf wetness durations were 4 and 6 h, respectively. Above the minimum wetness duration, at temperatures from 10 to 30°C, PLAD increased linearly, with increasing leaf wetness up to 12 h, and then at a lower rate from 12 to 24 h. The optimal temperature for infection was 25°C. Relative infection was modeled as a function of both temperature and wetness duration using a Richards model (R2 = 0.93). The predictive capacity of the model was evaluated with data collected in experimental vineyard plots exposed to natural wetness durations or artificial wetness durations created using sprinklers. In total, 264 vineyard infection events were used to validate the controlled experiments model. There was a linear relationship between the risk of infection estimated with the model and the observed severity of anthracnose (R2 = 90); however, the model underestimated disease severity. A risk chart was constructed using the model corrected for vineyard observations and three levels of risk, with light, moderate, and severe risks corresponding to ≤5, >5% to ≤25, and >25% leaf area diseased, respectively. Overall, 93.9% of 132 independent observations were correctly classified, with 100, 29.4, and 9.4% of the light, moderate, and severe risks, respectively.

Download Full-text

Optimization of a leaf wetness duration model

Agricultural and Forest Meteorology ◽

10.1016/j.agrformet.2020.108087 ◽

2020 ◽

Vol 291 ◽

pp. 108087

Author(s):

S. Zito ◽

T. Castel ◽

Y. Richard ◽

M. Rega ◽

B. Bois

Keyword(s):

Leaf Wetness ◽

Duration Model ◽

Leaf Wetness Duration

Download Full-text

Comparison of Penman–Monteith and non-linear energy balance approaches for estimating leaf wetness duration and apple scab infection

Agricultural and Forest Meteorology ◽

10.1016/j.agrformet.2011.04.010 ◽

2011 ◽

Vol 151 (8) ◽

pp. 1158-1162 ◽

Cited By ~ 9

Author(s):

Alexandre Leca ◽

Luciana Parisi ◽

André Lacointe ◽

Marc Saudreau

Keyword(s):

Energy Balance ◽

Apple Scab ◽

Leaf Wetness ◽

Leaf Wetness Duration ◽

Non Linear

Download Full-text

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

Plant Disease ◽

10.1094/pdis-05-14-0548-re ◽

2015 ◽

Vol 99 (7) ◽

pp. 1010-1019 ◽

Cited By ~ 11

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.

Download Full-text