Morning All,
After the first decent week of chill, the significance of data monitoring can be seen. Swan Hill and Griffith are much cooler than the previous 2 years as is Mildura while the Riverland is marginally ahead of last year. I have been asked what is happening in some other regions and have included some areas in the Goulburn Valley for comparative purposes. One of the real values of monitoring chill at a regional level is that it enables dormancy breaking products to be applied to chill hours and not a calendar date and also schedule pruning programs against varietal chill requirements. Pruning can act as a bud stimulator especially with some of the lower chill varieties.
Looking at the 7-day forecast and the snap that we have had is being replaced with mild weather but more importantly nights above 12C indicating that chill accumulation will not occur until the 18th of May. I would expect to not see a lot of movement in chill accumulation over the next week.
For comparative purposes:
From monitoring over the past 24 years, this earlier burst of chill accumulation should result in easier leaf drop than we have seen in the warmer seasons. We are around a week ahead of the average for the commencement of chill accumulation, but May is generally a resetting of the season and data can be quite variable at this time. The important task for this time of the year is getting trees into the resting phase so that they time in dormancy as dormancy is not just the number of hours, but the hours collected over time.
If you look at the graphs below and these follow long term trends in that moving east chill increases and the difference between the main horticultural regions is quite stark.
Regards,
Shane Phillips | Head Chemist - Research & Development
E: shane.phillips@biocentral-labs.com
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