Biocontrol Delivery System of <i>Trichoderma harzianum</i> Formulated in Graphite and Silica Nano Particles to Control <i>Rhizoctonia solani</i> on Tomato Plants

Abstract

This paper reports the performance of a graphite and silica nanoparticles-based delivery system forT. harzianumin controlling the in vitro growth ofR. solaniand damping-off disease on tomato plants. The in vitro and in vivo experiments were arranged in the randomized complete block design. The in vitro treatment was a dual culture ofR. solaniandT. harzianumin the various components of formulation on PDA, i.e.,T. harzianum+ 5 wt.% graphite,T. harzianum+ 1wt.% silica NPs.,T. harzianum+ 5 wt.% graphite + 1 wt.% silica nanoparticles,T. harzianum, 5 wt.% graphite, 1 wt.% silica nanoparticles, fungicide (mancozeb), and a control. The in vivo treatment included the application ofT. harzianumin the same compositions as the in vitro treatment, except that there were two controls i.e., inoculated and noninoculated tomato plants withR. solani.T. harzianumby soaking tomato seeds in the formulation suspensions before planting. The results showed that all formulation compositions were able to inhibit the in vitro growth ofR. solani. The inhibitions of the colony growth ofR. solanicaused by formulated and non-formulatedT. harzianumwere the same. This proved that graphite and silica NPs did not resist to the ability ofT. harzianumin controllingR. solani, indicated that the formulation was promising to develop. However, the inhibition of damping-off disease incidence on tomato plants caused by formulatedT. harzianumwas the same as the non-formulated one only on day 7 after treatments. On days 14, 21, and 28, the inhibitions were lower than the non-formulated ones. It was suggested to reapply the formulation ofT. harzianumin the soil at planting and several days after.