There has been strong uptake of new alternative fungicides across the almond industry, however careful application has been urged to avoid resistance and maintain their long-term effectiveness.

Customer solutions manager with Elders Scott McKenzie, who supports the South Australian, Victorian and NSW regions, said there had been considerable change in the industry surrounding 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 like 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 says dual active and new mode of action fungicides have become available but needed to be used strategically into the future.

“The more, and newer, fungicide active ingredients and chemistry combinations we can have, the better, but we have to use them strategically.”

“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.”

Newer fungicides 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, 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 says.

“Using good chemistry at this timing to reduce these diseases will carry you well through the season.”

Another big benefit of Solaris, is its low impact on bee populations.

“Bee safety has been at the forefront of a lot of new chemistry developments. It’s important, and growers want to do the right thing by beekeepers and their bees.” Mr McKenzie said..

He said Group 11 fungicides were frequently used in almond disease management programs and using Solaris around bloom  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 says Group 11 and Group 7 fungicide combinations were regularly applied in programs, however ADAMA Australia’s Custodia Forte option combined the strength of azoxystrobin (Group 11) with tebuconazole (Group 3) for improved disease control and resistance management.

“Custodia Forte provides protectant and curative activity and while it is good around the hull rot timing, when growers like to use strong curative sprays to finish the season, some also like to use its systemic and translaminar activity as an early clean-up, especially in higher pressure years.”

“Hull rot can be aggressive in conducive conditions and tough to control, but we are seeing good suppression of it with Custodia Forte, reducing dieback and spur death,” Mr McKenzie said.