Nozzle Classification for Drift Reduction in Orchard Spraying: Identification of Drift Reduction Class Threshold Nozzles

In fruit growing high values of spray drift are found compared to arable field applications. In arable spraying drift reducing nozzles are certified for use as drift reducing measures. The nozzles which may potentially reduce drift in fruit growing are not jet classified as drift reducing nozzles, although they are available on the market. The development of a nozzle classification system to identify the drift reduction potential of spray nozzles used in fruit crop spraying would open this market. The results of the initial setup of a nozzle classification system for spray drift reduction in orchard spraying based on drop size measurements is described. An evaluation was made of measured drop size characteristics of a series of nozzles in reference to performed field measurements of two characteristic nozzles; Albuz lilac and Lechler ID9001. Based on these anchor points the ranking of the volume fraction of drops smaller than 100 ¿m (V100) of the nozzle to be classified could be scaled to yield a potential drift reduction, assuming a linear relationship between V100 and spray drift deposition. Within this system, the determination of threshold nozzles for the drift reduction classes 50%, 75%, 90% and 95% drift reduction are described. Identified threshold nozzles for these classes are TeeJet DG8002, Albuz AVI 80015, Lechler ID9001 and Albuz TVI80025 all at 7 bar spray pressure, except for the Lechler ID 9001 which is used at 5 bar pressure. These nozzles will be used in field drift measurements to validate the mode

Identification and quantification of point sources of surface water contamination in fruit culture in the Netherlands

Measurements of pesticide concentrations in surface water by the water boards show that they have decreased less than was expected from model calculations. Possibly, the implementation of spray drift reducing techniques is overestimated in the model calculation. The impact of point sources is probably underestimated. A project was initiated for the quantification and qualification of possible point sources in Dutch fruit culture. From a survey it was concluded that the majority of fruit growers do not posses the mandatory equipment regarding filling and cleaning of sprayers. This creates a potential environmental risk for surface water contamination. Further research is focused on: internal and external cleaning of sprayers, environmental impact of the washings, discharge of transport water from fruit sorting installations, and bioremediation systems for processing contaminated water

Development of a Crop Adapted Spray Application (CASA) sprayer for orchards

In the EU-FP6 ISAFRUIT project a Crop Adapted Spray Application system (CASA) for precision crop protection was developed (Doruchowski et al., 2009). The system ensures efficient and safe spray application in orchards according to actual needs and with respect to the environment. The developed CASA system consist of three sub-systems: Crop Health Sensor (CHS) - identifying the health status of fruit crops to apply chemicals only when necessary; Crop Identification System (CIS) - identifying the tree canopy size and density to apply spray precisely at relevant doses; Environmentally Dependent Application Systems (EDAS) - identifying environmental circumstances and navigating the sprayer to adjust application parameters accordingly so that spray drift is minimised and direct water contamination is avoided

Druppelgroottemetingen Teejet, Hardi en Lechler spuitdoppen ter verkrijging van de status driftarm volgens het Lozingenbesluit

In dit rapport worden de resultaten van druppelgroottemetingen aan een serie spuitdoppen gepresenteerd. Aangegeven wordt of op grond van deze metingen de doppen, bij bepaalde drukken, volgens het Lozingenbesluit aangemerkt kunnen worden met de status driftar

No Risk, No Reward: Towards An Automated Measure of Psychological Safety from Online Communication

The data created from virtual communication platforms presents the opportunity to explore automated measures for monitoring team performance. In this work, we explore one important characteristic of successful teams - Psychological Safety - or the belief that a team is safe for interpersonal risk-taking. To move towards an automated measure of this phenomenon, we derive virtual communication characteristics and message keywords related to elements of Psychological Safety from the literature. Using a mixed methods approach, we investigate whether these characteristics are present in the Slack messages from two design teams - one high in Psychological Safety, and one low. We find that some usage characteristics, such as replies, reactions, and user mentions, might be promising metrics to indicate higher levels of Psychological Safety, while simple keyword searches may not be nuanced enough. We present the first step towards the automated detection of this important, yet complex, team characteristic.Comment: Published as an extended abstract in the ACM Conference on Human Factors in Computing Systems (CHI) 202

Ontwikkelingen schurftherkenning fruit

In het EU-FP6 ISAFruit-project wordt een Crop Adapted Spray Application-systeem voor precisiegewasbescherming in de fruitteelt ontwikkeld. Het systeem garandeert een veilige toediening van gewasbeschermingsmiddelen in boomgaarden afgestemd op de grootte van de boom en de geldende weersomstandigheden. Het systeem wordt beschreve

Adaptive latitudinal cline of photoperiodic diapause induction in the parasitoid <i>Nasonia vitripennis</i> in Europe

Living in seasonally changing environments requires adaptation to seasonal cycles. Many insects use the change in day length as a reliable cue for upcoming winter and respond to shortened photoperiod through diapause. In this study, we report the clinal variation in photoperiodic diapause induction in populations of the parasitoid wasp Nasonia vitripennis collected along a latitudinal gradient in Europe. In this species, diapause occurs in the larval stage and is maternally induced. Adult Nasonia females were exposed to different photoperiodic cycles and lifetime production of diapausing offspring was scored. Females switched to the production of diapausing offspring after exposure to a threshold number of photoperiodic cycles. A latitudinal cline was found in the proportion of diapausing offspring, the switch point for diapause induction measured as the maternal age at which the female starts to produce diapausing larvae, and the critical photoperiod for diapause induction. Populations at northern latitudes show an earlier switch point, higher proportions of diapausing individuals and longer critical photoperiods. Since the photoperiodic response was measured under the same laboratory conditions, the observed differences between populations most likely reflect genetic differences in sensitivity to photoperiodic cues, resulting from local adaptation to environmental cycles. The observed variability in diapause response combined with the availability of genomic tools for N. vitripennis represent a good opportunity to further investigate the genetic basis of this adaptive trait.