Dry root rot caused by Rhizoctonia bataticola (Taub.) Butler is one of the most important and widespread and destructive diseases of chickpea (Cicer arietinum L.), causing responsible quantitative and qualitative losses. The survey study revealed that the disease is prevalent in chickpea plants and is widespread in all the three agro-climatic zones of Marathwada region studied. The prevalence/incidence of the disease was more severe in Rabi, 2022-2023 season than in Rabi, 2021-22 season. Almost all chickpea grown in this region were found to be more or less susceptible to dry root disease. The disease was found to be more severe in the Scarcity zone (29.87%), followed by the Assured rainfall zone (25.01%) and the moderate rainfall zone (18.06%).

Rhizoctonia bataticola, incidence, dry root rot, agro-climatic zones.

Chickpea (Cicer arietinum L.) is the only cultivated species of the genus Cicer and is a self-pollinated diploid (2n=2x=16) crop. It is a cool season legume grown as a food crop worldwide. The seed is the most important edible part of the plant. It is also called garbanzo gram or Bengal gram. Chickpea is a predatory crop that is preferably sown in September-November and harvested in February. Depending on the variety, the harvest is ready in about 90-120 days. Areas with low to moderate rainfall and medium cold weather are most suitable for growth, a moderate amount of precipitation of 60-90 cm per year is recommended. It has an indeterminate growth habit, meaning that the growth cycle continues as long as moisture is available.

India is a major producer of chickpea in 2021-22 and this crop was cultivated in an area of ​​98.96 lakh ha with an annual production of 107.37 lakh tonnes and a productivity of 1086 kg/ha, while Maharashtra has an area of ​​19.80 million hectares with a total production of 19.17 lakh tons corresponding to a productivity of 968 kg/ha (FW (DA and FW), Government of India; Annual Report, 2021-2022), while in Marathwada region it was grown in an area of ​​22.31 lakh hectares with production and productivity of 23. 96 lakh tons and 1192 kg/ha (Anonymous, 2022c).

So far, 55 pathogens have been reported in chickpea from early seedling stage to maturity and several of them are economically important. Among several soilborne fungal diseases, dry root rot caused by R. bataticola (Taub.) Butler is the most important disease of chickpea, especially in the central and southern zones, where the crop grows mainly under rain-fed conditions during the harvesting season.

The disease manifests itself mainly in the flowering and ear/podding stages. The first symptom is yellowing of plants and sudden drying. The taproot becomes dark brown, quite brittle in dry soil, and has extensive rot, causing loss of lateral roots. The lower part of the taproot often remains in the soil when the plant is pulled up by the roots. Dry root rot has caused 10-25% yield loss in major chickpea growing states of India (Lakhran and Ahir 2018a). An average incidence of 16.12% was also observed in Marathwada district of Maharashtra state (Kadam et al., 2018). Survey and surveillance recording the incidence and severity of crop diseases are essential for planning appropriate plant protection measures and timely introduction of control measures. Therefore, this study was conducted to estimate the prevalence/incidence of dry root rot disease of chickpea in Marathwada district of Maharashtra state.

Survey. A random survey of chickpea fields of selected farmers covering three agro-climatic zones viz., Scarcity Zone (SZ), Assured Rainfall Zone (ARZ) and Moderate Rainfall Zone (MRZ) of Marathwada region of the Maharashtra state were undertaken, during Rabi, 2021-22 and Rabi, 2022-23, dry root rot disease incidence was assessed and simultaneously collected the dry root rot disease samples. In the selected chickpea crop fields, a 10 m2 area, randomly selected and in that counted total number of chickpea plants and number of plants showing typical dry root rot symptoms was recorded and calculated per cent dry root rot disease incidence by using following formula

Occurrence and distribution of chickpea dry root rot. The random survey of chickpea field was conducted during the Rabi seasons of 2021-22 (Plate 1) and 2022-23 (Plate 2). Survey was conducted in 109 and 138 chickpea crop fields of 08 districts, distributed under three agro-climatic zones viz., Scarcity zone (06), Assured Rainfall zone (07) and Moderate rainfall zone (08) of Marathwada region of the Maharashtra state respectively during 2021-22 and 2022-23.

The results obtained on dry root rot incidence, tahsil-wise (Table 1), district-wise (Table 2 and Fig. 1) and agro-climatic zone-wise (Table 3 and Fig. 2 and 3) are being interpreted herein under following sub-heads. 

Tahsil-wise incidence of dry root rot of chickpea. The results (Table 1) indicated a widespread prevalence of chickpea dry root rot, during both the years of survey and it was ranged from 14.35 (Nanded) to 35.80 (Vaijapur) and 15.23 (Ardhapur) to 36.50 (Vaijapur) per cent, during Rabi, 2021-22 and 2022-23 seasons, respectively. However, mean maximum dry root rot incidence was observed in Vaijapur tahsil (35.80 and 36.50 %), respectively during Rabi, 2021-22 and 2022-23 seasons, followed by Jalna tahsil (33.10 and 35.00 %) and Kalamb tahsil (30.69 and 36.43 %). Whereas in rest of the tahsils dry root rot incidence was observed in the range of 15.20 (Bhokar) to 29.33 (Pathri) per cent and 17.58 (Paithan) to 34.89 (Hingoli) per cent, during Rabi, 2021-22 and 2022-23 seasons, respectively. However, the mean minimum dry root rot disease incidence was observed in Nanded tahsil (14.35 and 21.11 %), during Rabi, 2021-22 and 2022-23 seasons, respectively, followed by Bhokar tahsil (15.20 and 18.77 %) and Paithan tahsil (15.60 and 17.58 %).

Table 1: Tahsil-wise Chickpea dry root rot incidence, during Rabi, 2021- 22 and 2022-23.

District-wise incidence of dry root rot of chickpea. Results (Table 2, Fig. 1) showed that the mean maximum chickpea dry root rot incidence was observed in Jalna district (25.04% and 30.33%, during Rabi 2021-22 and 2022-23 respectively, with maximum pooled incidence of 27.68 per cent, followed by Parbhani (23.89, 29.01 and 26.45%), Osmanabad (24.39, 27.41 and 25.90 %), Aurangabad (23.29, 24.96 and 24.12%), Latur (22.23, 22.95 and 22.59%), Beed (20.03, 24.62 and 22.32%), Hingoli (19.86, 24.74 and 22.30%) and Nanded (16.78, 21.18 and 18.98%). Overall average dry root rot incidence was maximum during Rabi, 2022-23 which was (25.65 %) and it was comparatively minimum (21.93 %) during Rabi, 2021-22. 

Table 2: District-wise prevalence of chickpea dry root rot, during Rabi, 2021- 22  and 2022-23.

Agro-climatic zone-wise incidence of dry root rot of chickpea, during Rabi, 2021-22 and 2022-23. Results (Table 3, Fig. 2 and 3) showed that out of three agro-climatic zones surveyed such as, Scarcity zone (SZ), Assured rainfall zone (ARZ) and Moderate rainfall zone (MRZ), the maximum av. chickpea dry root rot incidence was observed which was 26.99 per cent during Rabi 2021-22 and 32.76 per cent, during Rabi 2022-23, with maximum pooled mean disease incidence of 29.87 per cent in Scarcity zone, followed by Assured rainfall zone (24.07 %, 25.95 % and 25.01%) and Moderate rainfall zone (16.26 %, 19.86 % and 18.06%). In order of merit whereas, maximum average chickpea root rot incidence was observed during Rabi, 2022-23 (26.19%) as compared to the incidence during Rabi, 2021-22 which was 22.44 per cent.

Fig. 1. District-wise dry root rot of chickpea incidence, during Rabi, 2021- 22  and 2022-23.

Fig. 2. Agro-climatic zone-wise dry root rot of chickpea incidence, during Rabi, 2021-22 and 2022-23.

Fig. 3. Pooled mean Agro-climatic zone-wise dry root rot of chickpea incidence,  during Rabi, 2021-22 and 2022-23.

Table 3: Agro-climatic zone-wise chickpea dry root rot incidence, during Rabi,  2021-22 and 2022-23.