F.A.Q.

What matters most is that sampling is performed between dew formation and the solar zenith. Dew triggers sporulation, while UV rays can render spores non-viable. At any point between these two events—meaning in the morning—is the ideal time to collect samples. 

Since sampling cannot be performed when it rains, it may happen in certain situations that the sampling must be done in the afternoon. Our team always prioritizes completing three samples per week, even when rain is forecast throughout the week. If morning sampling is impossible for several consecutive days and the sky is overcast, we may decide to conduct sampling in the afternoon in order to maintain the three-samples-per-week objective.

We use a volumetric air-sampling system precisely to address situations where there is little to no wind. Our system includes a calibrated pump that provides a constant minimum airflow rate. This ensures that spores of interest are collected regardless of wind conditions. Therefore, even without wind, spores will still be captured. 

Unfortunately, there is no magical number. There is no specific threshold that clearly indicates a problematic situation. Result interpretation must take multiple factors into account, including wind speed, relative humidity, rainfall, vegetation density, UV radiation, crop variety, growth stage, and recent fungicide treatments, among others. 

The only exception concerns Phytophthora infestans, commonly known as late blight. Because of the severe impact of this disease, the detection of even a single spore warrants intervention. 

It is important to understand that our report contains two independent types of information. First, you will see the number of spores detected. Then, you will see the risk index.

The risk index is based on weather conditions over the past few days. If conditions were favorable for disease development, the risk index will be high. It is not linked to the number of spores detected.

This means you may have a high risk index due to weather, while only a small number of spores are present in the air. The opposite is also possible—weather may have been unfavorable, yet spores may still be detected. The highest-risk scenario occurs when both spore levels are high and the weather-based risk index is elevated.

Several elements should be evaluated.

It is recommended to choose a field that accurately represents the surrounding fields. While detection cannot be guaranteed beyond 50 acres, selecting a field with characteristics similar to neighboring fields provides a useful overview of the general situation. For example, if most surrounding fields use variety X, it is less relevant to sample a field with variety Y. 

You should also consider the field’s surrounding geography. For instance, a road adjacent to the field may generate dust and overload the sample cassette. If too many non-fungal particles accumulate on the cassette, the spore count may be underestimated. 

It is also recommended to choose a field that remains accessible, even in very muddy conditions, so our team can sample consistently. 

The risk index is calculated using weather data collected by our on-site weather station. It considers the specific environmental conditions required for each disease to develop. For example, if a pathogen requires at least 90% relative humidity for several consecutive hours, that criterion must be met for the risk level to move from low to high. Many such conditions are evaluated to determine the overall risk index.

Sampling cannot be performed when it is raining for two reasons. 

First, raindrops wash spores down to the ground and disrupt their normal dispersal. 
Second, the sample cassettes contain a transparent gel that allows us to visually identify spores under the microscope. If the gel comes into contact with water, it becomes opaque and the analysis becomes impossible. 

Because of these two factors, sampling during rainfall is not possible. However, sampling between two periods of rain is recommended—the humidity shift at that time is ideal for triggering sporulation. 

There are two important limitations to understand:

• Area limitation : 
  Our program covers up to 50 acres. We can certainly sample smaller fields, but detection cannot be guaranteed over areas larger than 50 acres.
• Detection limit :
  The detection limit of our method is 4 fungal particles per cubic meter. 
  This means that if we find 1 spore on the cassette, once converted to particles per cubic meter, the reported value will be 4 particles. It is therefore impossible to report “1 particle per cubic meter”—the minimum reported value will always be 4.