THERE has been strong uptake of new alternative fungicides across the almond industry, however careful application has been urged to avoid resistance and to maintain their long-term effectiveness.
Elders customer solutions manager Scott McKenzie, who covers Sunraysia, said there had been considerable change in the industry about fungicide use in recent years.
“Due to restrictions, including strict MRLs (maximum residue limits) into international markets, a lot of our previous staple chemistries have and are looking to be phased out,” Mr McKenzie said.
“Fungicides such as mancozeb and chlorothalonil are still great products and are being used in various cases, but they are unfortunately on the watchlist.
“There is a trend to using newer, safer broad-spectrum fungicides.”
He said dual-active and new mode-of-action fungicides had become available to the almond industry, but they still needed to be used strategically into the future.
“The more new fungicide active ingredients and chemistry combinations we can have, the better, but we have to use them strategically,” he said.
“Some of the new dual active ingredient fungicides work well, but they can be prone to resistance if overused.
“We have seen in other countries that when fungicides are abused, resistance comes into play – and once it’s in, it’s hard to eliminate.
“Knowing your chemical groups and the best timings for fungicide applications helps and should form the basis of programs.
“Introducing and developing new fungicide options involves a lot of work by companies and it can be hard to introduce them into Australia, so we need to treat them properly. We don’t want to lose them.”
Two newer fungicides becoming more widely used against almond diseases with good effectiveness include Solaris and Custodia Forte, both of which are easy-to-use, highly compatible liquid products developed by ADAMA Australia.
Solaris introduced the use of Group 9 fungicide, cyprodinil, to the almond industry, adding a major new tool to assist resistance management.
A systemic compound taken up into the cuticle and waxy layers of leaves and fruit, and which is locally redistributed, cyprodinil is highly active against brown rot, blossom blight, rust and shot hole.
“The Group 9 chemistry puts it in a field of its own, and its best timing is around bloom, targeting shot hole as well as brown rot and blossom blight, the latter of which can be associated with hull rot disease,” Mr McKenzie said.
“Using good chemistry at this timing to reduce these diseases will carry you well through the season.”
Another big benefit with Solaris, and one growers are highly conscious of, is bee safety, with its low impact on bee populations.
“Bee safety has been at the forefront of a lot of new chemistry developments,” Mr McKenzie said.
“It’s important, and growers want to do the right thing by beekeepers and their bees.
He said Group 11 fungicides were frequently used in almond disease management programs and, importantly, the use of Solaris around bloom also would “free up’’ these fungicides to assist their use later in seasons.
“In high-pressure years, there can be eight to 10 fungicide applications required, but you can only have three Group 11 sprays, and no more than two consecutive.
“You can only have two Group 9 applications, so it can be tough in wet seasons and the more options we have the better.”
He said Group 11 and Group 7 fungicide combinations were regularly applied in programs, however Custodia Forte combined the strength of azoxystrobin (Group 11) with tebuconazole (Group 3) for improved disease control and resistance management.
