BIBLIOTECA HORTICULTURA

BIBLIOTECA HORTICULTURA

Tips to prevent potato sprouting without the use of ChlorprophamTips to prevent potato sprouting without the use of Chlorpropham

Tips to prevent potato sprouting without the use of Chlorpropham

Tolsma helps us with the storage technique

A lot of experience has now been gained in Europe with the new germination inhibitors in the first storage season without chlorpropham. Halfway through the ‘20/’21 storage season, it is now time to draw up an interim balance and look ahead to the rest of the storage season

Some batches of potatoes were stored late and cold and it was not easy to dry these batches quickly. Drying has proved almost impossible without the use of heaters.

After the batches had dried, the application of the various inhibitors was often started quickly, also because sprout growth could soon be seen on a large number of batches. After that it turned out that there was still a lot to learn. In terms of the inhibitors themselves, but also of the application technology and how this interacts with the ventilation and cooling technology in the storage.

In addition, the frost period at the beginning of February has also shown that a cold room and the formation of condensation do not go well with the new generation of products.

Below TOLSMA-GRISNICH give some tips on how the storage technique should be used for a good end result:

Drying the product and cooling installation before the start of the treatment
Provide a product that is dry and free from condensation. This also applies to the fans, half steel air ducts and the cooling installation. With the sprout inhibitors 1,4Sight, Biox-m and Argos, the combination of moisture and sprout inhibitor can cause undesirable reactions on a number of materials. This means that internal ventilation must take place beforehand to distribute any free moisture throughout the batch. Do this at 100% speed so that the same air comes into contact with the potatoes evenly distributed everywhere.

It is also important to drain the moisture on the lamellas of the air cooler, in the drip tray and in the pipes of the condensate drain. This can be done first by turning off the cooling prior to treatment and running the air cooler fans 24 hours beforehand so that the lamellas are dry. Then give the system time to drain the condensation water. Checking that the drip tray and drain are clean beforehand helps to get rid of the moisture quickly.

Briefly turning on a heater  to warm up the room can also help evaporate moisture. Remember that gas and oil heaters also release water and CO2. Circulation fans and heatstabs can also be used to heat up the room for this purpose. As a result, the materials in the storage also heat up, reducing the risks of germination inhibitors precipitating.

It is not advisable to refresh extremely prior to application in order to bridge the long period without refreshing. In combination with the administration of 1.4 Sight, this can cause extreme respiration, causing the CO2 content to increase even more during the treatment. 

Ventilate during application
Leave mechanical cooling switched off before, during and for a period after application. Too many examples are known of damage to condensate drains due to the crystallization of inhibitors on the cold and wet plastic materials. The air flow must always be started for the actual application. The possibility of external ventilation and mechanical cooling must be disabled/blocked. This air flow does not have to be at full capacity because then the inhibitor has less time to attach to the sprouts.

A balance will have to be found between good air distribution and a lower air speed. In practice, this means that the fans must run at a minimum of 65% with a grid floor. For a ventilation wall (drying wall and airbags) and (above-ground) ventilation ducts, 80% is the minimum for good air distribution. If the air distribution is not good, there is a risk, especially between the ventilation ducts, that the sprout inhibitor will not end up in every place.

Ventilate after application
After application, the area should remain closed for 48 hours for most sprout inhibitors. Then ventilate internally again as normal. Then remember that refreshing is also started again (hatches on automatic) in order not to have a negative influence of CO2 on the frying color. Especially after a treatment with sprout inhibitors, the potato can become more active, causing the CO2 content to rise faster than normal. The cooling can also be switched on again after this period. If it is switched on earlier, condensation will form again, in combination with temperatures below 5°C from the air coolers, this gives a chance of precipitation of 1,4Sight in particular.

A few other points of interest are:

- At 1.4Sight there is a risk of agent precipitating through openings in an adjacent cell. Make sure that all openings (cable trays, doors, hatches, pipes) are properly sealed .
- When using Argos, make sure that the cables of temperature and RH sensors are free from the potatoes. There are known examples of Argos settling on the cables and potatoes rotting underneath. Hang the cables so that they are free so that they do not come into contact with potatoes.
- It is wise not to leave machines in the storage with the potatoes. There are now known reactions of the inhibitors with the paint coatings.
- Make sure that the inhibitors are nebulized at a sufficiently high temperature. Even when the application is carried out in contract work. Argos in particular, in drop form, can give violent combustion reactions to the product.
- Application via the outside wall as before with CIPC is not possible with all new inhibitors. There are then too high concentrations there. The inhibitor must be given time to be properly absorbed into the air flow. This is only possible when it is included in the air flow above the product. Always read the label carefully to determine for which application method the storage location is most suitable.
- Observe the safety instructions of the label. Even when, for example, technicians must work on the storage installation shortly after application. Make sure there is sufficient external ventilation beforehand.