Ink disease sampling and sending procedures

Identification and numbering of samples:

It is essential to be able to link a record to the samples taken. A form number is assigned to each report made. The same number must identify samples taken and sent for the same alert. This number is created at the time of sending and then appears in the history. In the new version of the mobile application, the date and time of sending the form must be associated with your submission.

Soil sampling :

• When to sample?

Phytophthora spp. responsible for ink disease develop and multiply in moist soil. In order to increase the chances of detection, it is preferable to take soil samples after a rainy period, neither too dry nor too wet.

• What to sample?

Each sample should be taken at the foot of a tree showing symptoms of decline.

To get a good representation of the soil at the foot of the tree, it is best to take three samples per tree, at the base of the foliage, at a depth of about 10 cm. Phytophthora spp. infect fine roots, so try to take soil from the area where the roots are growing, so the depth may vary from tree to tree.

• How to sample:

If you have an auger, this tool will allow you to take easily these samples except in very shallow or very stony soils. Otherwise, a spade can be used. In both cases, surface debris must be removed. The three samples per tree are collected in a unique plastic bag to form one sample per tree. After thoroughly homogenising the sample and mixing the three samples, a sample of about 500 g of soil is sufficient for detection.

Taking plant samples:

• When to collect?

To increase the success of Phytophthora spp. detection in plant tissue, it is best to take samples as soon as symptoms are observed, from May to September, before plants or trees die. As Phytophthora spp. are not able to survive in drying samples, it is necessary to ship these samples as soon as possible and/or to keep them cold before shipping.

• What to collect?

When young, dying chestnut plants are observed, it is easiest to collect them with their roots. Dead plants, which are often of no value, should not be harvested and shipped.

If, after removing the corky bark, cortical necrosis are observed at the collar of the trees under black discharge, samples can be taken from the terminal part of the necrosis and from the adjacent non-necrotic tissues.

• How to collect:

To remove the plants, a suitable tool should be used to get as many roots as possible intact. For shipping, it is requested to wrap the plants in newspaper and avoid compacting them too much. To remove necrotic tissue from the crown, a penknife, chisel or axe can be used, depending on the size of the tree and the operator.

In both cases, each sample should be packed in a plastic bag.

Sending:

Samples should be sent to:

Cécile Robin (GEMFor team)

INRAE, UMR BIOGECO

69 route d'Arcachon

33612 Cestas Cedex

FRANCE