Fungal root endophyte Piriformospora indica mitigates the residues of systemic fungicide in vegetable cowpea

Anthracnose, caused by Colletotrichum gloeosporioides, is a major fungal disease of vegetable cowpea that affects the leaves, stems, petioles, flowers, and pods, leading to considerable yield loss. Modern fungicides, including strobilurins and triazoles, are frequently used to control this disease. Additionally, Piriformospora indica, a beneficial root endophytic fungus, is commonly utilized in plants of varied genera for its disease-suppressing effects and its capacity to enhance plant growth. The present study investigated the application of P. indica-compatible fungicides (trifloxystrobin + tebuconazole and carbendazim) on colonized plants to assess their combined effect on anthracnose management under pot culture conditions. Additionally, fungicide residue on the leaves was analyzed using the QuEChERS-LC-MS/MS method, and degradation percentages were calculated to determine whether P. indica contributes to the reduction of residue buildup. P. indica-colonization, along with spraying of trifloxystrobin 25 % + tebuconazole 18.3 % SC and carbendazim 50 % WP brought down the anthracnose infection by 86.67 and 84.56 per cent in vegetable cowpea seedlings. Residue analysis in P. indica colonised plants showed a higher degradation of 84.83%, 88.25%, and 89.32% with respect to tebuconazole, trifloxystrobin, and carbendazim, and 68.35%, 75.14%, and 76.64% in controls, respectively. The initial deposition of fungicides was lesser in colonized plants. P. indica colonisation also reduced the half-life to 7.57, 7.12, and 7.19 days in response to 12.35, 10.05, and 9.63 days in control plants. Therefore, it was inferred that P. indica reduces the residue build-up in vegetable cowpea by enhancing the degradation percentage.