SOUTH Australia is expected to harvest a winter crop of around 9 million tonnes (Mt), according to the latest Department of Primary Industries and Regions (PIRSA) Crop and Pasture Report released today.

The figure is up slightly from 8.8Mt forecast in its August report, but is down 30 percent from the record SA 2022-23 crop of 12.8Mt.

“Below-average rainfall has been received in significant areas of South Australia during July and August, which may limit crop potential after a promising start during autumn and early winter,” report author and PIRSA senior industry adviser Tamara Rohrlach said.

Based on the season to September 14, the report said development was progressing well, with cereals, canola and pulses at or past flowering, and pasture growth has been good, with high amounts of quality feed available.

“The rainfall and temperature outlook for spring remains a concern to growers.”

The crop mix prediction for 2023-24 season has been adjusted due to an increase in lentil area being observed, predominantly on Eyre Peninsula at the expense of pasture area.

The predicted area of other crop types remains relatively unchanged.

SA’s winter crops are expected to yield close to the 10-year average.

“It should be noted that at this stage of the season, grain crops are highly sensitive to extreme temperatures, and the occurrence of frost and hot winds can significantly impact yield.

“Rainfall through spring will also be critical for the crops to reach their full potential.”

As of mid-September, most early sown cereal crops were at head emergence to flowering, canola crops were well into flowering, and pulse crops were flowering and commencing pod set.

“Crops that were later sown or resown due to waterlogging have a long way to go.”

The report says limited availability of urea during July and August contributed to application delays, and these applications have now largely been completed.

“The season is now at a critical point.

“In the next few weeks, further spring rainfall will see crops on track for average to above average yields.

“If rainfall events cease, or if heat or frost events occur during flowering and grain fill, yield potential will reduce to below average.”

Frost is a key concern over the next few weeks as crops enter flowering and grain fill.

“Some frost damage has already been reported on Eyre Peninsula.

“Growers in frost-prone areas are nervously waiting to assess the outcome of the widespread frost event experienced on September 9.”

Some pest, disease pressure

Wet and windy conditions during June and July have resulted in limited days suitable for spraying operations.

Delays in weed control have led to higher levels of ryegrass in a number of paddocks.

High mouse numbers have prompted some producers to undertake aerial baiting in areas of the Eyre Peninsula.

Crop damage is limited at present, however the prospect of a resurgence of mouse populations as the weather warms up in spring has growers concerned.

The first signs of stripe rust in wheat and leaf rust in barley have occurred in the past month,  prompting foliar fungicide applications to protect crop yield potential.

Powdery mildew in wheat has some growers concerned across an increasing geographic spread since 2022.

With drying spring conditions forecast, yield impacts from the disease are not expected to be as significant as in 2022.

Field slugs have impacted the establishment of significant areas of crops in the South East and higher- rainfall areas of the Mid North.

Baiting programs have mostly addressed the issue.

Aphid numbers are on the rise in many areas as the weather warms, with reports of cereal aphids in wheat and barley, and cowpea aphids in pulses.

Some armyworm damage has been reported in cereals.

Source: PIRSA