Biological Insights into Microbial Biofertilizers for Sustainable Wheat Cultivation and the Management of Haplothrips tritici (Kurdjumov)

The current study presents laboratory and field experiments aimed at applying beneficial microorganisms to improve the biological parameters of wheat and to manage the wheat thrip, Haplothrips tritici . Plant growth-promoting rhizobacteria, including Bacillus subtilis and Pseudomonas fluorescens , were thus assessed both separately and in combination, as were plant growth-promoting fungi, such as Arbuscular mycorrhizae and Trichoderma harzianum , both individually and in conjunction. The in vitro inoculation of P. fluorescens strains resulted in a significant improvement in root and shoot development, measuring 15.49 cm and 11.49 cm, respectively, compared to the control, which recorded 9.0 cm and 9.36 cm. Among the microbial biofertilizers, seed treatments with the synergistic relationship of P. fluorescens and B. subtilis strains exhibited the most significant enhancement in all growth indices under the field experiment, including number of grains/spike (43.40), number of spikes/plant (12.5), Plant height (101.33cm), weight of root/plant (0.39g), and chlorophyl content (39.21) associated with a lowest numbers in the population of wheat thrips/spike (6.20) and severity of wheat infestation (20%) followed by either arbuscular mycorrhizal fungi or P. fluorescens alone. On the other hand, the negative control (untreated seeds) demonstrated the lowest values across all growth indicators, followed by seed treatment with the positive control (chemical insecticides), or both fungal biofertilizers in combination. Microorganism-based fertilizers can be employed as part of integrated pest management strategies to promote wheat health and improved wheat yields in terms of both quality and quantity, which supports sustainable agriculture by decreasing the use of conventional insecticides.