Almond growers in the Sunraysia, Riverland and Riverina districts are urged to prepare now to act quickly to control key pests during the critical hull split period between December and January.

Sumitomo Chemical Australia regional manager Victoria and Riverina, Frank Galluccio said growers could risk up to 50 per cent of their crop being unmarketable for the lucrative export market if they did not get on the front foot with the main pests, carpophilus beetle and carob moth during hull split.

He said the best defence against these pests was Sumitomo’s insecticide Samurai which treated both pests, stopping them in their tracks as soon as early numbers appeared, usually about three months from the summer-autumn harvest.

“The carpophilus beetle bores holes in the nut and the carob moth chews the nut. They often appear together when almonds start opening up. This is when growers should act. They have a window of a couple of weeks to get ahead of the pests,” he said.

Hull split is a crucial step in almond crop development and occurs when the outer layer of the almond opens to reveal the shell and the kernel as the nut ripens and dries.

Timing can vary depending on weather conditions and variety.

“Growers who fail to act will have lower yields as almonds will be slightly eaten and not suitable for sale, jeopardising grades and returns. Instead of sending nuts to market, what’s left of their crop will go to the domestic market.”

He said Samurai best practice was to apply initial spray as a foliar application at the start of hull split and again at 40 per cent hull split, approximately four to five weeks apart and then two to three weeks before harvest.

Samurai is also effective in the control of mealybug, woolly aphid and codling moth in tree crops such as apples and pears, green peach aphid and oriental fruit moth in peaches and nectarines and mealybug in persimmon, pome fruit and stone fruit.

Mr Galluccio said several mite species – bryobia and two-spotted mites – also targeted almonds in all growing regions and were treatable with insect growth regulator (IGR) ParaMite from the Sumitomo range.

“Mites can occur when growers shut down their irrigation practices to encourage maturity or during a very hot, dry season.

“This puts plants under stress and leaves them vulnerable to mites. Bryobia can start appearing around October and can defoliate trees.

“Two-spotted mites generally occur around December-January,” he said.

“The challenge for growers is which of the mites to tackle with ParaMite as it is best used only once to avoid resistance. A second application can contribute to mite flare-up.

“As Bryobia is the worst of the mites, affected growers should use it against Bryobia at the first sign of activity and when they are in small numbers.

“If two-spotted mites later appear and growers have already used ParaMite, they should use a knockdown product from another chemical group.

“If they have no Bryobia infestation and two-spotted mites later appear, they should use it against two-spotted mites.”

He said growers had one to three weeks to act with ParaMite, depending on the extent of the mite pressure.

“ParaMite is best suited to early application before nymphs turn into adults. Correct timing requires careful monitoring and its use should be rotated with products from different chemical groups. As a translaminar, ParaMite travels through the leaves and controls mites hiding on the underside of the leaf.”

In tree crops, ParaMite is also effective in the control of mites in bananas, citrus, pome and stone fruit.

Mr Galluccio said both Samurai and ParaMite could be used in conjunction if all pests were present.

“Our main message to almond growers is be prepared, check for hot spots – where activity has been present year after year – monitor for pests and pre-warn their chemical dealer of volumes needed in plenty of time,” he said.

Australian almonds are produced from the Riverina region to Sunraysia, Riverland, Northern Adelaide Plains and the Swan region in Western Australia.

Ideal production requires winter chill, and hot, dry harvest conditions anywhere from January to April, depending on the region.