Bushfires are known to cause smoke taint in wine grape production, but the smoke can also have a significant effect on fruit growth rates for all species.
The smoke reduces the sunlight, thereby reducing photosynthesis and reducing fruit growth. This phenomenon is difficult to quantify, except if the fruit has an accurate fruit size sensor installed before, during and after the smoke haze was present.
Phytech have more than 5,000 plant sensors, including at least 500 fruit size sensors, installed across Australian regions affected by smoke from the recent bushfires.
The attached example is from a citrus orchard near Griffith, more than 200km (120mi) from the nearest bushfire. It’s clear to see that fruit growth was severely hampered for the two days where the smoke haze was most severe.
The grower has effectively lost those two days of fruit production (0.6-1.0mm), they can’t regain that lost growth. The Riverina region around Griffith accounts for 30% of Australian citrus production.
The only consolation was a reduction in the water demand of the trees allowing precious irrigation water to be saved. The photo was taken on the road near the orchard on Sunday.