Brought to you by Tolsma Grisnich
Germ inhibition without CIPC does not happen by itself
The potato storage season started last autumn without the trusted chlorpropham. Although new products are available, most growers do not yet have extensive experience with them. Halfway through the storage season, we make an interim balance and look ahead to the rest of the storage season.
It was not easy to quickly dry batches of potatoes that were stored late and cold. Without heaters it was even impossible. Germination inhibition is usually started immediately after drying. Also because a large number of lots quickly showed germ growth. It soon became apparent that there was still a lot to learn. In terms of the resources themselves, but also of the application technology and how this interacts with the ventilation and cooling technology in storage. In addition, the frost period at the beginning of February also taught us that a cold room and condensation do not go well with the new generation of products.
Evaluation of the first experiences
- Dry product before starting treatment
Provide a dry product that is free from condensation. This also applies to the fans, semicircular steel ducts and the cooling installation. With the sprout inhibitors 1,4SIGHT, Biox-m and Argos, the combination of moisture and sprout inhibitor can cause undesired reactions to a number of materials. This means that internal ventilation must be carried out beforehand in order to distribute any free moisture throughout the batch. Do this at 100% speed so that the same air is well distributed everywhere in contact with the potatoes.
- Drain the moisture from the cooling system
Also drain the moisture on the fins of the air cooler, in the drip tray and in the pipes of the condensate drain. To do this, turn off the cooling and run the air cooler fans 24 hours in advance so that the fins are dry. Then give the system time to allow the condensation water to drain away. Check that the drip tray and drain are clean so that the water can drain quickly.
Moisture also evaporates faster if a stove is turned on briefly to warm up the room. Keep in mind that water and CO2 are also released from gas and oil heaters. Circulation fans and heat bars can also be used to warm up the room for this purpose. As a result, the materials in storage also heat up, reducing the risk of the precipitation of sprout inhibitors.
- Don't over-refresh
An extreme refresh prior to application in order to bridge the long period without refreshing is not recommended. It can cause extreme breathing in combination with the administration of 1,4 SIGHT. As a result, the CO2 content rises faster during treatment.
- Ventilate during application
Leave the mechanical cooling off before, during and after application. There are many known examples of damage to condensate drains due to the crystallization of agents on the cold and wet plastic materials. Before actual application, the airflow must always be started.
Block the possibility of external ventilation and mechanical cooling. This airflow does not have to be at full capacity because then the agent has less time to adhere. So find a balance 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 slatted floor. With 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 chance, especially between the ventilation ducts, that the sprout inhibitor does not end up in every spot.
- Ventilate after application
Most germ inhibitors require the area to be closed for 48 hours after application. Then ventilate internally again as normal. After that, the air must be refreshed (doors on automatic) to avoid a negative influence of CO2 on the baking color. Particularly after treatment with sprout inhibitors, the potato can become more active, causing the CO2 content to rise more quickly. 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.
Other points of interest
- 1,4SIGHT can precipitate through openings into 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 the temperature and RH sensors are clear of the potatoes. Argos can settle on the cables and cause potatoes to rot underneath. Hang the cables so that they are free so that they do not come into contact with potatoes.
- Do not leave machines near potatoes in storage. There are known reactions of the agents with the paint coatings.
- Nebulize the agents at a sufficiently high temperature. Argos in particular can cause violent combustion reactions on the product in droplet form.
- Administering via the outside wall (as before with CIPC) is not possible with all new agents. Concentrations are then too high there. The agent must be given time to be properly absorbed into the airflow. This is only possible when it is absorbed into the airflow above the product. Always read the label carefully to see which method of application the storage area is most suitable for.
- Observe the safety instructions on the label. Also when, for example, technicians have to work on the storage installation shortly after administration. Ensure that there is sufficient external ventilation beforehand.
