Articles
FORECASTING OF POWDERY MILDEW DISEASE INCIDENCE ON BER (ZIZIPHUS MAURITIANA LAM.) BASED ON WEATHER
Article number
840_63
Pages
447 – 454
Language
English
Abstract
Ber, a drought tolerant hardy arid fruit crop cultivated in the northern dry zone of Karnataka, It suffers severe yield losses due to infection of powdery mildew disease.
Field experiments were carried out during 1998-2001 on two ber cultivars, namely, Umran and Kadaka, to understand the role of weather on the disease incidence.
Different growing environments were provided by pruning the trees on different dates between mid April and mid May.
The results indicated that, cv.
Umran was more susceptible than cv.
Kadaka to the disease.
The disease incidence was significantly high on early pruned (Mid-April) ber trees compared to the later pruned ones.
The forecastability of the disease was evaluated by using the meteorological data of the antecedent lead times of one to four weeks.
For disease incidence in September, November and December months, maximum temperature and afternoon relative humidity are important, whereas rainfall showed dominating influence for forecast of the disease.
Further, the analysis revealed that, the lead-time for the forecast of disease in September was three to four weeks, whereas it was three weeks in October, one week in November and three weeks in December.
Again, the dependent meteorological variables were afternoon relative humidity, rainfall, maximum temperature and morning relative humidity.
Importance of the rainfall pattern during the canopy/disease growth is ascribed as the main reason for importance of different sensitive variables in different months.
Graphical presentations are made to indicate the limits of maximum temperature and afternoon relative humidity to detect the sensitive limits of the two parameters for high incidence (>60%) of powdery mildew disease on ber during the four months.
Appropriate regression models were developed to forecast disease incidence in different months.
Field experiments were carried out during 1998-2001 on two ber cultivars, namely, Umran and Kadaka, to understand the role of weather on the disease incidence.
Different growing environments were provided by pruning the trees on different dates between mid April and mid May.
The results indicated that, cv.
Umran was more susceptible than cv.
Kadaka to the disease.
The disease incidence was significantly high on early pruned (Mid-April) ber trees compared to the later pruned ones.
The forecastability of the disease was evaluated by using the meteorological data of the antecedent lead times of one to four weeks.
For disease incidence in September, November and December months, maximum temperature and afternoon relative humidity are important, whereas rainfall showed dominating influence for forecast of the disease.
Further, the analysis revealed that, the lead-time for the forecast of disease in September was three to four weeks, whereas it was three weeks in October, one week in November and three weeks in December.
Again, the dependent meteorological variables were afternoon relative humidity, rainfall, maximum temperature and morning relative humidity.
Importance of the rainfall pattern during the canopy/disease growth is ascribed as the main reason for importance of different sensitive variables in different months.
Graphical presentations are made to indicate the limits of maximum temperature and afternoon relative humidity to detect the sensitive limits of the two parameters for high incidence (>60%) of powdery mildew disease on ber during the four months.
Appropriate regression models were developed to forecast disease incidence in different months.
Publication
Authors
M.M. Jamadar, H. Venkatesh, R.A. Balikai, D.R. Patil
Keywords
ber, powdery mildew, pruning periods, weather, forecasting
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