Impact of weather parameters on Alternaria leaf spot of soybean incited by Alternaria alternata

Abstract

Weather attributes play a crucial role in the infection process and spread of pathogen. Alternaria leaf spot incited by Alternaria alternata is most destructive disease of soybean appeared in southern and eastern parts of Rajasthan as well as India. The effect of various weather parameters along with different date of sowing on the development of Alternaria leaf spot in susceptible soybean cultivar RKS-24 was investigated during Kharif season 2018 and 2019. The various weather factors viz., temperature, relative humidity and rainfall under inoculated conditions and with staggered dates of sowing were taken to observe effect on disease progression and their effect on seed yield. The maximum increase in disease severity (57.82 and 58.22%) and AUDPC (389.45 and 394.42) recorded in crop sown on 18th June (inoculated on 8th July). Lowest disease severity (39.80 and 38.50%) and AUDPC (266.18 and 259.18) were observed during 39–43th standard meteorological week (September, 24–October, 28) in year 2018 and 2019, respectively. Maximum seed yield (1699 kg ha−1) was recorded in plants sown on 9th July, while, lowest seed yield was recorded in plants sown on 18th June with 1441.20 kg ha−1. The trend of disease severity and AUDPC value decreased from early sowing to late sowing (18th June–9th July). Major reasons were fluctuations in temperature, rainfall and relative humidity. It was also observed that the soybean plants for Alternaria leaf spot disease in early sowing were predisposed and so farmers should be advised to practice delayed sowing of soybean crop.

Epidemiological study of Alternaria blight of cabbage in Jorhat district of Assam, India

“…The seed yield per hectare was higher in October and November plantings than in December. According to Fagodiya et al (2022), the severity of Alternaria leaf spot in soybean crops, as measured by the variance of AUDPC, is influenced by both the month of sowing and weather conditions. They found that various weather parameters and sowing dates play a significant role in the onset of the disease, affecting the infection process and pathogen spread.…”

“…In the cluster bean leaf blight, Sharma et al (2020) found the same kind of correlation matrix. Early studies on the various diseases caused by Alternaria also revealed a negative correlation between temperatures (maximum and minimum) and disease severity, while a positive correlation existed between relative humidity and rainfall (Bajaya et al, 2022;Fagodiya et al, 2022). It might be due to the favourable temperature for spore germination of Alternaria is the temperature in the range of 18°C and 24 °C and relative humidity levels above 90% (Nowicki et al, 2012).…”

Occurrence of Diseases and Seed Yield of Early Maturing Soybean Cultivars Grown under the Conditions of Central Europe

“…We can distinguish several factors affecting the occurrence of soybean diseases [11][12][13][14][15][16][17]. The most important factors influencing the severity of plant diseases in European conditions are variable temperature and rainfall conditions.…”

“…Weather conditions can have a positive or negative impact on plant development. Frequent rainfall and high moisture levels are conducive to the development of diseases [11]. Cultivation practices influencing the intensity of fungal diseases include crop sequences and the regionalization of cultivars [17,18].…”

Stress Response to Climate Change and Postharvest Handling in Two Differently Pigmented Lettuce Genotypes: Impact on Alternaria alternata Invasion and Mycotoxin Production

“…It is likely that elevated CO 2 and higher temperatures will increase fungi invasions and toxin production, although the response will be dependent on the host/pathogen combination [ 26 , 27 , 28 ]. In particular, future climatic conditions are expected to change Alternaria incidence and toxin production [ 15 , 29 , 30 , 31 ], because elevated CO 2 alters phytohormone and reactive oxygen signaling, secondary metabolism, and defense-associated development such as stomatal responses in the host [ 32 ], resulting in a higher vulnerability of hosts to phytopathogens such as Alternaria . Possible strategies to limit Alternaria infection include: (1) obtaining resistant cultivars in breeding programs.…”