Frosts occur in sugarcane growing areas south of Mackay but more significant frost induced losses occur in South Qld and Northern NSW because of the greater frequency and severity of frosting events. Frost damage occurs when freezing ruptures plant cells. The most significant type of damage to the plant is death of the growing point. Other types of damage are leaf burn and death of the eyes down the cane stalk. Death of the growing points occurs at temperatures below -2.0° C. The extent of death will be affected by the minimum temperature reached, the length of time at frosting temperatures and the previous hardening of the crop by exposure to mild frosts. Research by Weaich, Neilsen and Hughes (1995) showed that for the Broadwater mill area based on 29 years of temperature records from frost prone sites that:

• In 20% of years there were no frost problems (minimum temperature > -2.0°C)
• In 60% of years crop management and variety determined frost damage (temperatures from -2.0° to -3.4°C) and
• In 20% of years farmers may have experienced frost damage beyond their control (temps < -3.4°C), which can only be alleviated by breeding cultivars with improved frost resistance.

A fact sheet on the early frost research in NSW is available from the link below:

 Fact Sheet - Frost damage in sugarcane

Managing frost damage - SRA Fact Sheet

Frost testing project

This project established trials to test whether artificial freeze testing of cane seedlings could be used to identify cane varieties that would perform well under field frosting conditions. Trials aimed to ascertain if subjecting seedlings to cold room freezing would produce a similar reaction of damage to that observed in the field and determine an appropriate testing regime of temperature and duration. Varieties were placed in a cold room chamber for 2 hours at a temperature of -3ºC to simulate field frosting conditions. In the 2009 trials, varieties were assessed by slicing the growing point to determine the degree of damage. For the 2010 trials a non-destructive assessment process was utilised and plants assessed over a period of 27 to 106 days after treatment. Some differentiation was identified between varieties through artificial freeze testing. However the degree of differentiation between the good, average and poor categories was very small and the majority of individual trials failed to show any statistical significance. The trials have shown that it is difficult to clearly correlate ratings derived by artificial freeze testing of seedlings with known field reaction of more mature cane plants.

A full report on the project is available from the link below:

Better frost tolerant varieties for NSW - Final report

How cold has it been this winter?

A network of loggers at all mills provide an early indication of how severe a frost event might be. At Broadwater loggers are located at Broadwater mill, Kilgin, East Coraki, Swan Bay, Codrington, Greenridge and Main Camp. At Harwood loggers are located at Woodford Island, Lawrence and Ulmarra. At Condong loggers are located at Dulguigan, Murwillumbah and Mullumbimby.

 Click here for a chart of minimum temps for the Broadwater frost loggers in the 2016 winter