Stem rot of groundnut (Arachis hypogaea L.) caused by Scelrotium rolfsii is the main threat to groundnut production, causing significant economic losses. The present study aims to provide an overview of the potentiality of Trichoderma viride (Tv), Trichoderma harzianum (Th), Pseudomonas fluorescens (Pf), and Bacillus subtilis (Bs), applied either individually or in mixed combination, against Sclerotium rolfsii (isolate SrBKN). The treatment with T. harzianum and P. fluorescens resulted in the highest mycelial growth inhibition (79.61, 83.51, and 86.77%), followed by T. viride and P. fluorescens (75.74, 79.63, and 83.14%). Under in vitro conditions, the combination of bio-agents at 5% culture filtrate proved to be superior against the test pathogen. Seed treatment and soil application of T. harzianum and Pf at 10 (5 + 5) g kg⁻¹ + 10 (5 + 5) kg ha⁻¹, followed by seed treatment and soil application of T. viride and Pf at 10 (5 + 5) g kg⁻¹ + 10 (5 + 5) kg ha⁻¹, resulted in the lowest disease incidence (7.40 and 8.0%), highest disease control (69.37 and 66.88%), maximum dry weight (151 and 147 g plant⁻¹), highest increase in dry weight (75.58 and 70.93), highest pod yield (2665 and 2498 kg ha⁻¹), and highest increase in pod yield (96.38 and 84.08%) under in vivo conditions. We present an effective bio-control-based management module from the lab to the field for the successful control of groundnut stem rot caused by S. rolfsii. Based on the results, it is concluded that the dual formulation of T. harzianum and P. fluorescens, followed by T. viride and P. fluorescens, were the most effective BCAs in suppressing the S. rolfsii. Therefore, an integrated disease management module with these BCAs needs to be developed and validated with a farmers’ participatory mode under field conditions.

Groundnut (Arachis hypogaea L.) is an oilseed crop largely grown throughout the world. Ten isolates of S. rolfsii collected from groundnut grown areas were investigated for their morphological and genetic variability study. Based on morphological variability study, all isolates were divided in six groups based on sclerotia distribution pattern. Isolates produced number of sclerotia in range of 115–375 in light dark brown to dark brown colour while weight of hundred sclerotia and sizes of sclerotia was in range of 85.54–145.13 mg and 0.32–0.68 mm. Genetic diversity was studied through ITS amplification that produced rDNA amplicon size of 650–700 bp which confirmed that all isolates belong to Sclerotium rolfsii. RAPD primers confirmed genetic variation among the isolates. Highest numbers of amplicons (13) were observed in the OPA-9 primer. 102 polymorphic and 3 monomorphic bands were produced by RAPD primers. Isolates SrA-SrH (0.575), SrBKN-SrA (0.384) and SrBKN-SrBKL (0.330) exhibited highest similarity coefficient. Based on dendrogram generated by UPGMA, SrBKN, SrA, SrH, SrJPF, SrJPP and SrT isolates were considered in Group I. SrBKL showed highest (51%) diversity in Group II while Churu (SrC) isolate showed 49% diversity in Group III. Dendrogram and cluster analysis cleared that Group I was more genetically diverse among the isolates. Morphological and molecular diagnosis of the pathogen has a pivotal role in the implementation of chemical (fungicide) and biological (bio-agents) methods.

Kinnow mandarin (Citrus reticulata Blanco) is a valuable fruit crop mainly grown in the North Indian states of India due to its high-quality juice content. Psylla (Diaphorina citri Kuwayama), whitefly (Dialoeurodes citri Ashmead), sooty mould (Capnodium citri) and dieback (Colletotrichum gloeosporioides) pests are the most important biotic constraints affecting its fruit yield up to 70 percent. To manage these pests, farmers often use mixture of non-label claim pesticides (quinalphos 25%EC, lambda-cyhalothrin 2.5%EC, diafenthiuron 50%WP, chlorantraniliprole 18.5 %, cymoxanil 8 % + mancozeb 64 % WP, etc.) without achieving the desired effect. Hence, area-wide implementation of the Integrated Pest Management (IPM) strategy in Kinnow mandarin was implemented during 2021–2023 covering 5 villages at Hisar, Haryana. Among the IPM strategy, installing yellow sticky traps @ 20/ha, neem seed kernel extract spray @ 5 %, and imidacloprid 17.8SL @ 0.3 % reduced the whitefly and psylla populations. The spray of 1 % starch and dipping infected fruits in a bleaching solution @ 0.1 % reduced the severity of sooty mould disease. Pruning and destruction of dead twigs followed by a spray of copper oxychloride 50 WP @ 0.3 % were found very effective too. The lowest average population of psylla and whitefly were recorded in T₁-IPM compared to T₂-farmer practice and T₃-control, respectively. Minimum average disease severity of sooty mould and dieback was noticed in T₁-IPM compared to T₂-farmer practice while the highest disease severity was recorded in T₃-control. Population dynamics of psylla, whitefly and sooty mould, dieback severity, and Area Under Diseases Progress Curve (AUDPC) were found to vary during 11th to 52nd standard meteorological week (SMW). They were observed to be highest in T₃-control treatment, followed by T₂-farmer practice and T₁-IPM. The highest natural enemy's populations (Coccinellid, Chrysoperla, and spider) were recorded in T₃-control followed by T₁-IPM, and then in T₂-farmer practice treatment. The highest average fruit yield and B: C ratio was recorded in T₁-IPM compared to T₂-farmer practice and T₃-control treatment. The validated IPM strategies can be adopted by Kinnow mandarin growing farmers as an economically viable option for the management of psylla, whitefly, sooty mould, and dieback pests.