Pesticide dose adjustment in fruit and grapevine orchards by DOSA3D: Fundamentals of the system and on-farm validation

LiDAR Is Effective in Characterizing Vine Growth and Detecting Associated Genetic Loci

The strong societal demand to reduce pesticide use and adaptation to climate change challenges the capacities of phenotyping new varieties in the vineyard. High-throughput phenotyping is a way to obtain meaningful and reliable information on hundreds of genotypes in a limited period. We evaluated traits related to growth in 209 genotypes from an interspecific grapevine biparental cross, between IJ119, a local genitor, and Divona, both in summer and in winter, using several methods: fresh pruning wood weight, exposed leaf area calculated from digital images, leaf chlorophyll concentration, and LiDAR-derived apparent volumes. Using high-density genetic information obtained by the genotyping by sequencing technology (GBS), we detected 6 regions of the grapevine genome [quantitative trait loci (QTL)] associated with the variations of the traits in the progeny. The detection of statistically significant QTLs, as well as correlations (R2) with traditional methods above 0.46, shows that LiDAR technology is effective in characterizing the growth features of the grapevine. Heritabilities calculated with LiDAR-derived total canopy and pruning wood volumes were high, above 0.66, and stable between growing seasons. These variables provided genetic models explaining up to 47% of the phenotypic variance, which were better than models obtained with the exposed leaf area estimated from images and the destructive pruning weight measurements. Our results highlight the relevance of LiDAR-derived traits for characterizing genetically induced differences in grapevine growth and open new perspectives for high-throughput phenotyping of grapevines in the vineyard.

Ozone-Induced Biochemical and Molecular Changes in Vitis vinifera Leaves and Responses to Botrytis cinerea Infections

To investigate how plants cope with multi-stress conditions, we analyzed the biochemical and molecular changes of Vitis vinifera leaves subjected to single or sequential double stresses (infection by Botrytis cinerea (Bc) and ozone (O₃, 100 ppb for 3 h) treatment). In Bc⁺/O₃^- leaves, the hydrogen peroxide (H₂O₂) induction (observed at 12 and 24 h from the end of treatment (FET)) triggered a production of ethylene (Et; +35% compared with Bc^-/O₃^- leaves), which was preceded by an increase of salicylic acid (SA; +45%). This result confirms a crosstalk between SA- and Et-related signaling pathways in lesion spread. The ozone induced an early synthesis of Et followed by jasmonic acid (JA) and SA production (about 2-fold higher), where Et and SA signaling triggered reactive oxygen species production by establishing a feedback loop, and JA attenuated this cycle by reducing Et biosynthesis. In Bc⁺ + O₃⁺ leaves, Et peaked at 6 and 12 h FET, before SA confirmed a crosstalk between Et- and SA-related signaling pathways in lesion propagation. In O₃⁺ + Bc⁺ leaves, the H₂O₂ induction triggered an accumulation of JA and Et, demonstrating a synergistic action in the regulation of defence reactions. The divergence in these profiles suggests a rather complex network of events in the transcriptional regulation of genes involved in the systemic acquired resistance.

Snails as Temporal Biomonitors of the Occurrence and Distribution of Pesticides in an Apple Orchard

The intensive use of pesticides in agricultural areas and the resulting effects have created a need to develop monitoring programs for their active assessment at low cost. This research entails a biomonitoring study of the pesticides in an apple orchard, using juvenile Cornu aspersum (O. F. Müller, 1774) snails exposed in field microcosms. The snails were deployed at three different locations in the orchard area and were used to assess the temporal biomonitoring of 100 different semi-volatile and non-volatile pesticides. The study was performed over an 18-week period and targeted the center, the border, and the outside of the orchard. Results showed that greater levels of pesticides were detected at the center of the orchard as compared to the other sites. The type and level of the applied pesticide influenced its environmental dissipation, as significantly greater levels of semi-volatile pesticides were accumulated by the caged snails in comparison to non-volatile pesticides. The presence of semi-volatile pesticides in the snails outside the orchard revealed the usefulness of these species in the biomonitoring of off-site pesticide emissions. The findings of this study showed that C. aspersum can serve as a reliable and effective model organism for the active biomonitoring of pesticide emissions in agricultural sites.

Spray performance evaluation of a six-rotor unmanned aerial vehicle sprayer for pesticide application using an orchard operation mode in apple orchards

BACKGROUND

In the last decade, unmanned aerial vehicle (UAV) sprayers have been growing rapidly worldwide as a new method for pesticide application, especially in Asian countries. More and more manufacturers and service providers are currently aiming at UAV spraying operation for fruit trees with higher economic value. We evaluated the spray performance of an electric six-rotor UAV sprayer using an orchard operation mode (different application volumes and flight patterns) in a hilly apple orchard with small and sparse trees (SS) and a plain orchard with tall-spindle trees (TS).

RESULTS

Application volume (APV) had a significant influence on the spray coverage parameters in both orchards, while flight pattern, intra-row, inter-row and verti-row, had a relatively limited influence at 60 0 and 85 7 L/ha. The UAV's downwash airflow produced a good spray penetration in the isolated SS trees, but not for the conjoined TS trees. It is better to fly along and above rows at 63.5 L/ha or higher for SS trees. The excessively low underside coverage is the main drawback of UAV orchard pesticide application and the underside droplet size was generally less than 200 μm.

CONCLUSION

Spray performance is closely related to tree shape, planting pattern, UAV payload, application volume, spray droplet size and downwash airflow field. The results provide data support for the best operational practice development and the decision model for the application volume of UAV sprayer orchard operations. The underside spray performance requires further improvement by several effective measures. © 2022 Society of Chemical Industry.