Research reports on on the use of chlorpropham (CIPC) for sprout suppression in potatoes
Until its final use in October 2020, CIPC was the most important sprout suppressant used in GB potato stores. Because of its importance, AHDB Potatoes funded a programme of research on CIPC covering the efficiency of application, its uniformity of distribution in stores, residue removal and alternatives to CIPC.
Projects have been categorised according to the topics covered, to allow readers to identify the most relevant report(s).
Click on a project title below to see more information and download the final report
CIPC application and distribution in potato stores
- evaluation of modifications to commercial box stores to improve CIPC residue distribution
- includes studies of the efficacy of CIPC + ethylene for sprout suppression and the effects on fry colours
- characteristics of low temperature box stores influencing CIPC residue distribution
- options to improve the distribution of CIPC in box stores, especially ‘overhead throw’ stores, including modifications to box stacking regimes and application practices (application into plenum chambers and/or low speed recirculation)
- small-scale trials to assess influence of application and storage conditions (temperature, condensation, airflow, solvents) on CIPC particle behaviour
- importance of the timing of initial CIPC application for sprout control efficacy
- CIPC vapour release and movement of vapour through stores
- aspects of north American CIPC application practices evaluated, including continuous recirculation of CIPC fog through the bulk pile with fans operating at low speed
- modification to application equipment to reduce the volume of fog introduced into stores
- application and sprout control efficacies assessed
- sprout control using CIPC vapour and/or small particles of CIPC in stores to improve the uniformity residue distribution
- generation of the data required to create models to predict CIPC distributions in store
- levels of CIPC present in store air and wash water at different times throughout the season
- thermal breakdown of CIPC during the application process
- tested treatments for removing CIPC from store fabric
- following 807/208. Further work on options for reducing the impact of fogging on processing quality, including alternative fuel sources (methanol, LPG) and modification of existing fogging equipment to include a catalytic conversion system
- evaluated use of an ethylene blocker to reduce the deleterious effects on fry colour
- evaluated controlled release technology to use CIPC vapour as a sprout suppressant
- examined the thermal fogging process used in CIPC application and its effect on processing quality, focusing on the influence of ethylene produced during application
- investigated options for minimising the negative effects on fry quality, including ventilation following fogging, use of alternative fogger fuels, reducing the number of CIPC fog applications, and removing ethylene and CO2 from store atmospheres.
- development of methods to quantify the persistence and distribution of CIPC in potato stores
- majority of CIPC residues were found within the top one centimetre of concrete flooring
- potential for cross contamination in buildings where CIPC was applied years previously
Alternative sprout suppressants
The loss of CIPC for the control of sprouting during storage (in 2020) placed greater emphasis on the other tools available to store managers including alternative sprout suppressants, variety choice and store management practices.
- variation in MH residue between tubers
- determine the residue concentration required for control of sprout growth
- comparative efficacy of a range of sprout suppression treatments (with or without prior treatment with maleic hydrazide): ethylene, spearmint oil, orange oil, 1,4-Dimethylnaphthalene (DMN) on a range of pre-pack varieties.
- maleic hydrazide (MH), spearmint oil, ethylene, 1-4 dimethylnaphthalene (DMN)
- sprouting and fry colour assessments