Spatial-Spectral Analysis of Hyperspectral Images Reveals Early Detection of Downy Mildew on Grapevine Leaves.

Downy mildew is a highly destructive disease of grapevine. Currently, monitoring for its symptoms is time-consuming and requires specialist staff. Therefore, an automated non-destructive method to detect the pathogen before the visible symptoms appear would be beneficial for early targeted treatments. The aim of this study was to detect the disease early in a controlled environment, and to monitor the disease severity evolution in time and space. We used a hyperspectral image database following the development from 0 to 9 days post inoculation (dpi) of three strains of Plasmopara viticola inoculated on grapevine leaves and developed an automatic detection tool based on a Support Vector Machine (SVM) classifier. The SVM obtained promising validation average accuracy scores of 0.96, a test accuracy score of 0.99, and it did not output false positives on the control leaves and detected downy mildew at 2 dpi, 2 days before the clear onset of visual symptoms at 4 dpi. Moreover, the disease area detected over time was higher than that when visually assessed, providing a better evaluation of disease severity. To our knowledge, this is the first study using hyperspectral imaging to automatically detect and show the spatial distribution of downy mildew on grapevine leaves early over time.

LAMP for in-field quantitative assessments of airborne grapevine downy mildew inoculum.

AIMS: Cheap, rapid tools for measuring emissions of Plasmopara viticola sporangia directly in the field are required to protect grapevines efficiently and sustainably against downy mildew. To this end, we adapted an existing loop-mediated isothermal amplification (LAMP) protocol based on ITS2 sequences, coupled with a rotating-arm sampler and simple cell lysis, for the in-field measurement of airborne sporangia of P. viticola. METHODS AND RESULTS: We estimated the sensitivity and specificity of the molecular reaction with an unpurified DNA template in controlled conditions, using the droplet digital PCR (ddPCR) as a reference. We show that the LAMP lower limit of quantification is 3.3 sporangia.m-3 air sampled. Cell lysis in KOH solution was less efficient than CTAB for DNA extraction, but the repeatability of the method was good. We tested this protocol directly in a plot at Chateau Dillon (Blanquefort, France) in which we monitored P. viticola sporangia concentrations from March to October 2020 (88 samples which revealed concentrations ranging from 0 to 243 sporangia.m-3 ). There was a significant quantitative correlation (R2  = 0.52) between ddPCR and LAMP results. CONCLUSION: LAMP analysis of an unpurified DNA matrix is a simple and reliable method for in-field estimations of the concentration of airborne P. viticola sporangia. SIGNIFICANCE AND IMPACT OF THE STUDY: This study constitutes a first step towards the development of a regional grapevine downy mildew monitoring network in the vineyards of Bordeaux.

Delaying the first grapevine fungicide application reduces exposure on operators by half.

Downy mildew is a severe disease of grapevines treated by repeated fungicide applications during the growing season. The impact of these treatments on human health is currently under scrutiny. Fungicide application long before disease onset is not thought to be greatly beneficial for grape production, but the first fungicide treatment is applied at least six weeks before disease onset in more than 50% of the vineyards in the Bordeaux region, a major French vine-growing area. We estimate that applying one fungicide every two weeks at disease onset would reduce fungicide applications against downy mildew by 56% (95%IC = [51.0%, 61.3%]), on average, relative to current levels. This decrease is slightly greater than the level of exposure reduction resulting from the random suppression of one out of every two fungicide treatments (i.e. 50%). The reduction is lower when treatments are sprayed weekly but still reaches at least 12.4% (95%IC = [4.3%, 20.8%]) in this case. We show that this and other strategies reducing the number of treatments would decrease operator exposure to pesticides as effectively as the use of various types of personal protective equipments in the Bordeaux region. The implementation of this strategy would significantly decrease fungicide use, health risks, and adverse environmental impacts of vineyards.

Forecasting severe grape downy mildew attacks using machine learning.

Grape downy mildew (GDM) is a major disease of grapevine that has an impact on both the yields of the vines and the quality of the harvested fruits. The disease is currently controlled by repetitive fungicide treatments throughout the season, especially in the Bordeaux vineyards where the average number of fungicide treatments against GDM was equal to 10.1 in 2013. Reducing the number of treatments is a major issue from both an environmental and a public health point of view. One solution would be to identify vineyards that are likely to be heavily attacked in spring and then apply fungicidal treatments only to these situations. In this perspective, we use here a dataset including 9 years of GDM observations to develop and compare several generalized linear models and machine learning algorithms predicting the probability of high incidence and severity in the Bordeaux region. The algorithms tested use the date of disease onset and/or average monthly temperatures and precipitation as input variables. The accuracy of the tested models and algorithms is assessed by year-by-year cross validation. LASSO, random forest and gradient boosting algorithms show better performance than generalized linear models. The date of onset of the disease has a greater influence on the accuracy of forecasts than weather inputs and, among weather inputs, precipitation has a greater influence than temperature. The best performing algorithm was selected to evaluate the impact of contrasted climate scenarios on GDM risk levels. Results show that risk of GDM at bunch closure decreases with reduced rainfall and increased temperatures in April-May. Our results also show that the use of fungicide treatment decision rules that take into account local characteristics would reduce the number of treatments against GDM in the Bordeaux vineyards compared to current practices by at least 50%.

Timing of Grape Downy Mildew Onset in Bordeaux Vineyards.

Grapevine downy mildew (GDM) is a severe disease of grapevines. Because of the lack of reliable information about the dates of GDM symptom onset, many vine growers begin fungicide treatments early in the season. We evaluate the extent to which such preventive treatments are justified. Observational data for 266 untreated sites for the years between 2010 and 2017 were used to estimate the timing of GDM onset on vines and bunches of grapes in South West France (Bordeaux region) through survival analyses. The onset of GDM was not apparent on vines and bunches before early to mid-May, and the rate of GDM symptom appearance was highly variable across years. Depending on the year, 50% of the plots displayed symptoms between mid-May and late June for vines. For several years, our statistical analysis revealed that the proportion of plots with no symptoms was high in early August on vines (27.5 and 43.7% in 2013 and 2016) and on bunches (between 23 and 79% in 2011, 2013, and 2016). We found a significant effect of the amount of rainfall in spring on the date of symptom appearance. These results indicate that preventive fungicide application is unjustified in many vineyards, and that regional disease surveys should be used to adjust fungicide treatment dates according to local characteristics, in particular according to rainfall conditions in spring.

How your ears can tell what is hidden in your heart: wild-type transthyretin amyloidosis as potential cause of sensorineural hearing loss inelderly-AmyloDEAFNESS pilot study.

BACKGROUND: Wild-type transthyretin amyloidosis (ATTRwt) is an age-related life-threatening condition. Prognosis is mainly dependent on cardiac involvement. Other organs and tissues may be affected. Their early recognition may increase awareness of physicians and positively affects the prognosis. Presbycusis is another age-related disorder. Whether this disease is associated to ATTRwt amyloidosis is unknown. METHODS: Sixteen consecutive patients with confirmed diagnosis of ATTRwt amyloidosis at the Mondor Amyloidosis Network, France, underwent otoscopy and audiological tests including pure tone audiometry, speech reception threshold and speech discrimination score. RESULTS: The mean age was 79 ± 5 years. All were male with an NYHA average of 2.5 ± 0.8. All the patients had sensorineural hearing loss that seemed to preexist to cardiac disorder with greater severity than expected for their age. For speech discrimination test, the mean speech reception threshold was 28 ± 15 dB and the mean speech discrimination score was 68 ± 16 at 40 dB. Ten patients (62.5%) failed to recognize 100% of the words. Compared to age-related expectations according to statistical distribution (ISO), hearing loss included all frequencies and was more severe in patients with ATTRwt amyloidosis. CONCLUSIONS: These findings suggest that amyloid deposits could infiltrate the various anatomical structures of the inner ear. Description of specific audiologic pattern of ATTRwt amyloidosis might be proposed as a "red flag" and could help for early identification of patients who may be at high risk of ATTRwt amyloidosis as specific treatments are available.

Specific activation of operculum 3 (OP3) brain region during provoked tinnitus-related phantom auditory perceptions in humans.

The phantom sound perception mechanism by which a sound perception occurs without any external sound source is still enigmatic. According to our previous fMRI study, a small region in the parietal operculum 3 was hyperactivated as a function of tinnitus periodicity in subjects with acoustic trauma tinnitus sequelae. This region was localized in the vicinity of neural correlates of middle-ear tympano-ossicular chain movements due to pressure variations. Disturbed proprioceptors are known to trigger illusory perceptions; therefore, we hypothesized that a disturbance of middle-ear proprioceptors may originate phantom sound perceptions. We designed an fMRI study that aimed to stimulate middle-ear proprioceptors by repetitive vibrations using various rates of click trains. In this study, we report that exposure to specific rates of stimuli for a few minutes at comfortable intensity level in healthy subjects distinctly triggered transient tinnitus-like aftereffects. The fMRI neural correlates of the aftereffects were unequivocally localized in the same parietal region as in acoustic trauma tinnitus sufferers. Our results strongly suggest that a middle-ear kinesthetic/proprioceptive illusion exists at the origin of acoustic trauma tinnitus via a somatosensory pathway encompassing the trigeminal system.

First detection of the presence of naturally occurring grapevine downy mildew in the field by a fluorescence-based method.

Early detection of fungal pathogen presence in the field would help to better time or avoid some of the fungicide treatments used to prevent crop production losses. We recently introduced a new phytoalexin-based method for a non-invasive detection of crop diseases using their fluorescence. The causal agent of grapevine downy mildew, Plasmopara viticola, induces the synthesis of stilbenoid phytoalexins by the host, Vitis vinifera, early upon infection. These stilbenoids emit violet-blue fluorescence under UV light. A hand-held solid-state UV-LED-based field fluorimeter, named Multiplex 330, was used to measure stilbenoid phytoalexins in a vineyard. It allowed us to non-destructively detect and monitor the naturally occurring downy mildew infections on leaves in the field.

Vestibular schwannoma and fitness to fly.

INTRODUCTION: When a pilot is referred for vestibular schwannoma (VS), his or her fitness to fly may be questioned. The objective of this retrospective study was to describe a series of VS cases in a pilot population and to discuss their fitness to fly options. METHODS: Between September 2002 and March 2010, the ENT/Head and Neck Surgery Department of the National Pilot Expertise Center conducted nearly 120,000 expert consultations for 40,000 pilots. We examined the files of 10 pilots who were referred to our 2 national experts for VS. RESULTS: At the time of the expert consultation, hypoacusis was present in nine cases (four with total deafness), tinnitus in one case, and vertigo in nine cases. In our series, only 2 of the 10 pilots experienced a negative impact on their fitness to fly. DISCUSSION: Decisions on fitness to fly were based on several factors: minimally disturbed audition, i.e., less than a 35-dB hearing loss with a good speech discrimination score; good balance, i.e., no reported difficulties; no spontaneous nystagmus recorded on videonystagmography (VNG); no postural deviation; and a normal head-shaking test. The delay and the VS's evolution between diagnosis and expert consultation are important because the selection of a treatment to control VS is critical in minimizing the possible associated complications. When a pilot is referred for VS, his or her fitness to fly is determined by the size of the tumor, balance, auditory status, and the follow-up results of these findings. The complications that may arise from VS treatments must also be considered.

Susceptibility to tinnitus revealed at 2 kHz range by bilateral lower DPOAEs in normal hearing subjects with noise exposure.

We investigated potential markers of susceptibility to tinnitus in a group of normal hearing young pilots aged 25-35 years and with 8 +/- 5 years of aircraft noise exposure. 316 pilots were interviewed about their tinnitus status and were tested for hearing thresholds (audiograms) and distortion products otoacoustic emissions (DPOAE-grams). There was no subject with permanent tinnitus. 23% reported having occasionally perceived tinnitus after flight missions and 77% reported never having experienced tinnitus after flight missions. General discomfort in the ears to noise was higher in the occasional tinnitus group (15 vs. 6%). The major finding was that difference of susceptibility to tinnitus in normal hearing subjects exposed to noise on a daily basis seemed to be clearly related to lower DPOAEs, bilaterally, in the 1500- to 2800-kHz range. However, no difference could be observed between groups on audiograms at the 2-kHz frequency range. This study provided evidence of outer hair cell dysfunctions in normal hearing subjects exposed to noise and susceptible to tinnitus. Hypersensitivity to noise and decreased DPOAEs in a non-noise-specific frequency range support the idea of another alteration mechanism than noise itself. This point was discussed in the light of recent publications.

Hearing in military pilots: one-time audiometry in pilots of fighters, transports, and helicopters.

INTRODUCTION: Pilots are exposed to potentially harmful levels of noise, the actual consequences of which are still poorly documented. We have determined the audiometric profiles of pilots as a function of age and type of aircraft (i.e., fighter, transport, helicopter) and have searched for risk factors of deafness other than noise in a pilot population. METHODS: We examined 521 French military pilots ages 20-40 yr during their annual medical check-ups. Pilots were interviewed using a standardized questionnaire and data from tonal audiograms of both ears were collected. Hearing levels were compared between groups of age and aircraft category. RESULTS: Abnormal hearing levels in pilots were found essentially at high frequencies with a marked notch on audiograms at 6 kHz. Left ears had a significantly poorer performance compared with right ears. At a given age, transport pilots had, on average, better hearing at 8 kHz than other pilots, despite a higher number of flying hours. In addition to the 6 kHz notch, helicopter pilots showed a significant hearing loss at 3 kHz. Such an enlargement of the impaired frequency range can disturb speech communication. Prevalence of otitis media in childhood was significantly higher in pilots with abnormal hearing. DISCUSSION: Pilots flying fighter and helicopter aircraft are at a higher risk of hearing loss compared with pilots flying transport aircraft. Improvements in ear protection seem particularly needed for the left ear. Hearing losses can potentially compromise speech communication in helicopter pilots.