Effect of Trichoderma harzianum and Botanical Extracts on Pre-harvest Parameters of Garlic

Garlic (Allium sativum L.) is an important spice and medicinal crop in India, valued for its nutritional and therapeutic properties, yet its productivity is often constrained by suboptimal growth and disease incidence. The present study was conducted during the Rabi seasons of 2020–21 and 2021–22 at SHUATS, Prayagraj, to evaluate the integrated effects of Trichoderma harzianum and different botanical extracts on growth and yield parameters of garlic under field conditions. The experiment was laid out in a Randomized Block Design (RBD) with eight treatments, including untreated control and chemical check (Mancozeb), each replicated thrice, using the variety ‘Bhimomkara’. Observations on plant height, number of leaves, and bulb yield were recorded and analyzed statistically. Results revealed that the combined application of T. harzianum and neem leaf extract (T1) significantly enhanced vegetative growth and yield performance compared to other botanical treatments and the control. T1 recorded a pooled mean plant height of 46.82 cm, number of leaves per plant of 8.36, and bulb yield of 6.88 t ha⁻¹, which was statistically at par with the chemical check Mancozeb (8.48 t ha⁻¹). Other treatments, particularly eucalyptus leaf extract (6.52 t ha⁻¹) and T2-T. harzianum (6.14 t ha⁻¹), also showed improved performance over the untreated control (3.61 t ha⁻¹). The growth-promoting effects were attributed to the synergistic action of T. harzianum in enhancing nutrient uptake, root proliferation, and hormone production, along with the bioactive compounds of neem that suppress pathogens and improve plant vigor.