The EU ban on the use of chlorprofam as an anti-sprouting agent for potatoes has been in effect since last year. In this situation, European experts say the most reasonable solution is maintaining the optimal temperature and humidity conditions in the storage facility.
A potato tuber is a living organism in which certain physiological and biochemical processes take place. Improper storage conditions lead to serious loss of tuber mass. Consider in which environment the tubers are dormant for the longest time.
Potatoes should be sorted immediately after harvesting to remove soil and infected tubers, which are a potential source of bacterial and fungal diseases.
Then, about 1-2 weeks after being stored, the potatoes go through a period of preparation for a dormant state, during which intense respiration and evaporation are still occurring, which leads to a loss of some starch, water and vitamins. The epidermis is covered with a cork, and mechanical damage caused during harvesting heals. For this process to work properly, it is necessary to maintain a temperature of 10-18 ° C and a relative humidity of 90-95%.
Another phase that tubers enter during storage is refrigeration, the main purpose of which is to prepare the tubers for dormancy. Cooling lasts about three weeks and consists in lowering the air temperature to 2-10 ° C (depending on the type of potato and the direction of its use) and maintaining the air humidity at a level similar to the previous stage.
Only after almost a month after the tubers are placed in the potato storage, they enter a phase of full dormancy. For table varieties, the optimum storage temperature is 4-6 ° C, seed potatoes: 2-4 ° C, food-grade potatoes: 6-8 ° C, and tubers for industrial processing are best stored at 2- 4 ° C. Recommended air humidity 85-90%. Dormancy is genetic and varies from cultivar, but tubers can be stored for up to eight months under recommended storage conditions.
Maintaining proper storage conditions is critical to maintaining the quality of raw materials. When the air humidity is lower than the recommended one, the tubers quickly lose moisture, wither, and at a higher humidity, rotting processes begin.
The air temperature has a significant effect on the rate of respiration of tubers - if the temperature is too high, they breathe more intensively, which leads to a loss of tubers mass. Also, high temperatures contribute to the development of fungal diseases.
Too low a temperature is extremely unfavorable, since it leads to a deterioration in taste and an increase in the content of reducing sugars in the tubers.
Many European potato growers may have storage problems this year due to the abandonment of chlorprofam preparations. Instead, plant protection manufacturers offer other naturally occurring inhibitors such as maleic hydrazide in the form of choline salt, peppermint oil, orange oil or 1,4-dimethylnaphthalene.
Orange oil is of particular interest as it prevents germination for up to three weeks (a very long time for a natural inhibitor). Potatoes can be sold immediately after application of the product, they do not have a waiting period. The recommended dose is 100 ml / 1000 kg of potato tubers. The manufacturer recommends using the drug immediately after the first shoots appear. The procedures should be carried out at intervals of 21 days.
Another noteworthy drug is 1,4-dimethylnaphthalene, a hormone that prolongs the natural dormancy of tubers. The maximum dose of the drug is 20 ml per 1 ton of potato tubers, and it can be used immediately after placing the tubers in storage. The manufacturer recommends performing procedures with an interval of at least 28 days with a maximum number of treatments - 6 during the entire storage period. Unlike orange oil, this substance has a 30-day waiting period. Both formulations are used with aerosol generators in ventilated storage facilities.