Newer almond fungicides show strength amid product restrictions
Growing restrictions on the use of some traditional fungicides is shining a light on newer fungicides that also provide benefits around handling and compatibility with other products, as well as for management of beneficial insect species.
Horticulture agronomist Steve Lehmann, who has spent most of his life in South Australia’s Riverland region based at Loxton, including the last 14 years with Elders, said propiconazole and mancozeb,( the latter which had been part of the staple fungicide diet against diseases from October to December) were some of the latest products to come under further restrictions.
As a result, two products increasingly finding a home in growers’ fungicide programs for the major diseases of almond crops are Custodia® and Solaris® fungicides, from ADAMA Australia.
Andrew Wardle, ADAMA Australia commercial manager South Australia said the fact that Custodia and Solaris were both easy-to-use liquid fungicides also meant growers were pleased to avoid the dust and smell issues associated with mancozeb.
Andrew said the wider product restrictions and excellent disease control results had sparked a dramatic rise in sales of Custodia fungicide in the almond industry, while similar results with Solaris and its significantly improved affordability also had generated a sales spike for that product.
He said blossom blight previously was one of the major diseases to target in almonds, however newer fungicides had provided improved control and hull rot had since become “enemy number one’’ for growers. Shot-hole and rust diseases also needed to be kept in-check.
Steve, who for many years also has worked closely with Matt Ward, from Elders Barmera said growers had to combat all diseases during most seasons.
Custodia, an easy-to-use suspension concentrate formulation, combines the strength of both azoxystrobin (Group 11) and tebuconazole (Group 3) for improved, broad spectrum disease control and resistance management.
It offers excellent protectant and eradicant activity, providing a broader window of application to control brown rot/blossom blight, rust and shot-hole, as well as suppress hull rot in a single application.
Highly compatible with other common fungicides and insecticides, Custodia’s systemic and translaminar activity rapidly penetrates leaf tissue to reach the site of infection and/or protect new growth after application.
Solaris, an easy-to-handle emulsifiable concentrate formulation, contains cyprodinil (Group 9), the only mode of action of its kind for use in almonds that assists with resistance management. Cyprodinil is a systemic compound that is taken up into the cuticle and waxy layers of leaves and fruit and is locally redistributed.
Andrew said the fungicides were suited to different spray timings within almond disease management programs, with Solaris applied around flowering and after flowering, while Custodia was generally applied later in programs, also to help combat hull rot.
He said trial results and encouraging grower experiences had underpinned Custodia’s increased use against almond diseases.
“Its uptake has been increasing, it’s a pretty compatible product for mixing in other foliar sprays and with both actives in the one drum, it’s a way better product to put out. Both actives by themselves are good, but mixed together, you get a better chance to control these diseases.’’
Steve said he generally recommended application of Solaris from bloom to petal fall, with its unique Group 9 chemistry also providing an important management tool for resistance.
“We don’t want to use all the good chemistry upfront.’’
He said a typical fungicide program in almonds throughout the region could include winter oil and copper before pink bud and copper applied again at pink bud, and then, when foliage commences, an application of Solaris to target shot-hole and brown rot/blossom blight, followed by Luna* Sensation and then Custodia, targeting similar diseases, and then a hull rot spray at hull split.
Andrew said the integrated pest management (IPM) profile of both Custodia and Solaris fungicides, particularly their soft activity on bee populations, was a major plus.
“Almonds require pollination from bees to produce and corporate growers have arranged contracts with beekeepers to have hives nearby, so they don’t want to knock them around,’’ he said.
“There have been populations that have been completely wiped out by products that get used in other crops.’’
Steve said growers had to be aware of the effects of different fungicides on bee populations if they were planning early sprays while trees were still flowering.
“I even like to see lady beetles in almonds. We often see green peach aphid and if the lady beetles are in high enough numbers, they can help to control them.’’
Article written by ADAMA for Seasons magazine.