Hail recovery a long term prospect
Minimising secondary damage will be the key task facing orchardists in eastern growing areas, after devastating hail storms in October.
Queensland Department of Agriculture and Fisheries extension officer Simon Newett said as the storm season continued, it was important for all growers to be prepared for potential hail damage.
“Physical damage to trees lays them open to attack by fungi and insects that take advantage of the wounds, and the loss of canopy exposes the branches to severe sunburn damage,” Mr Newett said.
“In the case of insects, tree wounds release chemicals such as ethylene that appear to act as magnets to some opportunistic insects such as borers.”
For this reason, Mr Newett said it was a good idea to apply a fungicide and insecticide treatment.
“A registered avocado fungicide such as one of the coppers is suitable. The insects most likely to be attracted are borers of various types such as the auger beetle (Xylopsocus gibbicollis) and other ambrosia or pinhole borers.”
The advice from Department of Agriculture and Fisheries (QDAF) Mareeba’s Ian Newton and NSW Department of Primary Industries entomologists Craig Maddox and Ruth Huwer is to consider the registered insecticide chlorpyrifos, which is effective against beetles, or trichlorfon which will also be effective and treat spotting bug at the same time if you have fruit present.
“Once the borers are inside the tree it is too late so an application within a few days then a follow up perhaps a week or two later is suggested,” Mr Newett said.
“The advice is to try and avoid using pyrethroids at this early stage of the season for their potential to result in a build-up of other insects such as scale.
“An azoxystrobin fungicide could be used instead of copper but shouldn’t be applied at the same time as chlorpyrifos because of incompatibility.
“The other thing to take action on as soon as possible is sunburn protection. With branches exposed as a result of the loss of leaf cover some sort of sunblock such as white acrylic paint or a proprietary sunburn protection product should be applied to newly exposed branches especially on the northern and western aspects.”
Mr Newett said these products could often be applied in diluted form through orchard sprayers but multiple applications may be necessary to get enough protection. To speed up the canopy re-growth you may also want to apply some extra nitrogen.
“With the loss of crop it does present an opportunity carry out some canopy management, just remember to protect the newly exposed branches and trunks from sunburn before the fast approaching hot weather arrives,” he said.
If you have any queries or want to discuss your particular situation, please contact Simon Newett on 07 5381 1326, 0400 565 784 or firstname.lastname@example.org.
For an updated version of this article (2019), click here.
Thanks to Chris Searle, Ian Newton (QDAF entomologist at Mareeba) and the NSW DPI entomologists Craig Maddox and Ruth Huwer for their advice.
More information on financial assistance
**Note this is time-limited. Please check to see if this assistance is still available.
The Queensland Rural and Industry Development Authority now has financial assistance available via the Natural Disaster Relief and Recovery Arrangements, for those affected by the Wide Bay-Burnett Severe Storms between 11-14 October 2018. Financial assistance has been activated for primary producers to access low-interest Natural Disaster Assistance and Essential Working Capital Loans. Visit www.qrida.qld.gov.au/current-programs/Disaster-recovery or call 1800 623 946. Those affected directly by the storms may be eligible for low interest loans of up to $100,000 or $250,000, depending on the assistance pool.
This article was produced for the Spring 2018 edition of Talking Avocados, and appeared in the 26 October 2018 edition of Guacamole.
Date Published: 26/10/2018