Effect of Trichoderma harzianum (Bio Inoculants), Wheat Straw Mulching and Groundnut Genotypes on Groundnut Early Leaf Spot Disease (GELSD) Management at Rama Northern Ethiopia

Groundnut (Arachis hypogaea L.) is the 13th and fourth most important food and oilseed crop of the world respectively. kernel contains 40-50% oil, 20-50% proteins and 10-20% carbohydrates. However, lack of appropriate management practices of early leaf spot diseases becomes extremely serious production problems in Rama. Trichoderma harzianum could suppress disease causal pathogenic species due to its antagonistic nature. Wheat straw mulches could increase the soil moisture retaining capacity to overcome terminal drought stress and decrease soil temperature. Therefore, a field experiment was conducted in Rama, Central Zone of Tigray, northern Ethiopia, from in 2016 G.C to evaluate the integrated management of groundnut early leaf spot diseases of groundnut of ICGV00308, ICIAR19BT, Werer-961 and Rama local. The treatments were arranged in a factorial randomized complete block design (RCBD) with three replications. The interaction effect of genotypes * T. harzianum at 56 DAP and genotypes * wheat straw mulching at 63 DAP showed significant (p≤0.05) difference on GELS incidence. At the final assessment date 63 DAP, the highest (96.90%) percentage mean incidence occurred in the treatment combination of Rama local without application of wheat straw mulching, followed by 96.10, 93.68 and 89.59% for the treatment combinations of ICIAR19BT*ML0, ICGV00308*ML0 and ICGV00308*ML1, respectively. The lowest values of 52.22 and 51.73% ELSD incidence at the final assessment were recorded for Werer-961 and Rama local genotypes treated by wheat straw mulching, respectively. Application of wheat straw mulching significantly reduced GELS incidence by 45.17 and 27.80% in Rama local and Werer-961, respectively, as compared to the non-mulched plots of the respective genotype. Mulch highly and significantly (p≤0.01) decreased ELSD severity during the final 77 DAP assessment as compared to the non-mulched plots with the highest disease severity of 21.91% as compared to the lowest severity of 18.15% in straw mulched plots. As a recommendation application of wheat straw mulch and T. harzianum on groundnut genotypes showed significant reduction at (P≤ 0.05) on ELSD diseases severity and incidence and producer have to use locally available mulching materials and bio inoculants having diseases suppression characteristics.