Endophytic Association ofTrichoderma asperellumwithinTheobroma cacaoSuppresses Vascular Streak Dieback Incidence and Promotes Side Graft Growth

Abstract

Trichoderma species are able to persist on living sapwood and leaves of cacao (Theobroma cacao) in an endophytic relationship. In this research, we evaluated the ability of Trichodema asperellum introduced at the incision site in the bark for side grafting with the concentration of 4 g/10 mL, 4 g/100 mL, and 4 g/1,000 mL (suspended in water) in suppressing vascular streak dieback (VSD) incidence and promoting growth of side grafts in the field. The incidence of VSD in two local clones of cacao, MCC1 and M04, without application of T. asperellum was 71.2% and 70.1% at 21 wk after grafting, respectively. However, when the two clones were treated with a concentration of 4 g/10 mL T. asperellum, the incidence was 20.6% and 21.7%, respectively, compared to 29.1% and 20.9% at 4 g/100 mL and 18.2% and 15.6% at 4 g/1,000 mL. By comparing to the control, the treatment with the same concentrations of T. asperellum listed above, the total number of stomata in MCC1 decreased by 41.9%, 30.2%, and 14.0% and in M04 by 30.5%, 21.9%, and -2.5% (exception), respectively. Otherwise, the total area of stomata opening increased by 91.4%, 99.7%, and 28.6% in MCC1 and by 203.8%, 253.5%, and 35.9% in M04, respectively. Furthermore, the number of buds and branches treated with a mixture concentration on the the two clones increased by 90.7% and 21.7%, respectively. These data showed that the application of T. asperellum to cacao scions while grafting can decrease VSD incidence in side grafts and increase growth of grafts in addition to decreasing total number of stomata, increasing total area of opened stomata, and increasing number of buds and branches.

Dynamic of Vascular Streak Dieback Disease Incidence on Susceptible Cacao Treated with Composted Plant Residues and Trichoderma asperellum in Field

“…We do not know what supports this phenomenon, but Trichoderma is capable of growing and developing in composted plant residues [18], probably increasing the likelihood of penetrating and deploying in cacao tissues, and on the other hand, Trichoderma can degrade the compost making it available to root systems. Therefore, our results offer new insight to the application of the biological agent T. asperellum in combination with composted residues through soil amendment, because, since its discovery in the early 2000s in South Sulawesi [3], there has been no method capable of controlling the VSD disease effectively. An unpublished trial of flutriafol fungicide with the same clone used in this experiment resulted in a small impact on the reduction of VSD incidence.…”

Plant performance of enhancing licorice with dual inoculating dark septate endophytes and Trichoderma viride mediated via effects on root development

“…They discovered that all four Trichoderma harzianum and T. viride inoculum densities increased tomato plant growth especially at the maximum density of 10 10 spores g − 1 soil. Rosmana et al [43] found that treatment with various concentrations of Trichoderma asperellum increased the numbers of Theobroma cacao buds and branches by 90.7 and 21.7%, respectively, relative to the control. Earlier research demonstrated inconsistent results for the effects of T. harzianum and T. viride on tomato plant growth [44].…”

Shallot Basal Bulb Rot Management through Integration of Trichoderma asperellum, Composted Plant Residues and Natural Mulch

“…For inoculum preparation, a sterilized plastic bag containing around 100 g of rice grain medium was inoculated by the fungus of 7-day culture in PDA medium origin. Then, after seven days incubation at a temperature of 26°C-28°C and humidity of 80%-90%, Trichoderma was harvested, dried, and milled to form a smooth powder (Rosmana et al, 2016).…”