Addition of Trichoderma consortia to Chilean endemic flora compost teas strongly enhances in vitro and in vivo biocontrol of phytopathogenic fungi.

AIM: To evaluate the in vitro and in vivo antifungal capability of diverse compost teas of endemic Chilean flora inoculated with a consortium of fungal strains of Trichoderma spp. (biocontrol agent) against three important phytopathogens: Botrytis cinerea, Fusarium oxysporum, andLasiodiplodia theobromae. METHODS AND RESULTS: Compost teas were obtained from the endemic flora of Chile (Azara celastrina, Citronella mucronate, Cryptocarya alba, Peumus boldus, and Quillaja saponaria). Eleven Trichoderma strains were isolated, and antagonism tests were performed to develop fungal consortiums with biocontrol properties. The biocontrol effect of compost teas inoculated with Trichoderma consortia was also analyzed. The results showed that the teas possess antifungal activity against B. cinerea and F. oxysporum and, to a lower degree, against L. theobromae. In vitro tests showed that Trichoderma consortiums improved the suppressive effect against B. cinerea (94-97%), F. oxysporum (89-92%), and L. theobromae (51-73%). Peumus boldus tea showed the highest suppressive effect against the plant pathogen L. theobromae. In addition, the in vivo assay showed that tomato plants treated only with Trichoderma or compost tea did not show differences in height with regard to control plants. However, when these two treatments were combined, the best performance in plant height and protection against pathogens was observed. CONCLUSIONS: This study indicates that the addition of a consortium of Trichoderma strains with intra- and interspecific incompatibilities significantly improves the inhibitory effect of compost teas in in vitro tests against the plant pathogenic fungi, while in vivo it enhances tomato plant growth and reduces plant disease symptoms.

Absolute joint-angle estimation of Generalised N-Trailer vehicles equipped with incremental encoders using moving horizon estimation.

The Generalised N-Trailer (GNT) vehicle is a tool for field operations that optimises harvesting and transportation tasks, offering a highly scalable payload using only one tractor. Precise knowledge of the position and attitude of each segment in the chained vehicle is crucial for the controller's success during operation. In this study, we propose the use of a Nonlinear Moving Horizon Estimator (NMHE) to estimate the system's state when the GNT vehicle is equipped with incremental encoders on its joints. A first NMHE serves as a virtual calibration procedure, estimating initial joint angle values and the system's state using noisy and biased measurements of the joints and the tractor pose. This calibration is performed while the chained vehicle travels along a straight path, whose length is determined by the number of trailers and their geometrical properties. Subsequently, a second NMHE, with fewer optimisation variables and constraints replace the first to effectively reduce the computational burden. Moreover, it treats the incremental encoder measurements as if they were absolute encoders after the initial joint angles have been estimated by the first NMHE. The proposed method is compared against the Extended Kalman Filter (EKF) and validated through simulated and practical real-time experiments, showcasing its effectiveness in achieving precise control and enhancing operational efficiency.