Effect of Inoculation Timing and Weather Parameters on the Development of Pokkah Boeng Disease Caused by Fusarium proliferatum in Sugarcane Varieties

Abstract

An experiment was conducted to identify the inoculation period associated with maximum pokkah boeng development in sugarcane under the subtropical conditions of North Bihar. Four susceptible sugarcane varieties, Co 0238, CoV 92102, CoSe 95422 and CoLk 94184, were inoculated on 15 April, 25 April and 5 May. Disease incidence varied significantly with inoculation timing. Across all varieties, inoculation on 25 April resulted in the highest disease incidence, followed by 5 May, whereas the lowest incidence was recorded on 15 April. Co 0238 was the most affected variety, with 21.61% incidence on 25 April, followed by CoV 92102 (19.24%), CoSe 95422 (13.61%) and CoLk 94184 (8.73%). Conditions around 25 April therefore favoured infection and colonisation by Fusarium proliferatum. Weekly disease monitoring from March to August 2022 showed that incidence peaked at 19.6% in the last week of April, when the maximum and minimum temperatures were 35.6 °C and 21.7 °C, morning relative humidity was 80%, and no rainfall was recorded. Correlation analysis showed a positive association between minimum temperature and disease incidence (r = 0.65) and a negative association with relative humidity at 07:00 h (r = -0.41). Multiple linear regression indicated that the measured weather parameters explained 53.30% of the variation in disease incidence. Under the tested conditions, late April was the most favourable period for pokkah boeng development, while minimum temperature and relative humidity were associated with disease progression.