Australia: CQ growers urged to watch for ascochyta blight

Date:07-06-2011

Central Queensland chickpea growers are urged to be on the lookout for ascochyta blight and be ready to apply a fungicide in order to prevent yield loss or seed damage for next year’s planting.

Julie Ferguson, Department of Employment, Economic Development and Innovation (DEEDI) industry development officer (pulse and grain legumes) says CQ chickpeas are more at risk from ascochyta infection this season than ever before and growers should keep a close eye on their crops right up until harvest.

“Because of the wet season last year, CQ had more reported cases of ascochyta blight than ever before,” Ms Ferguson said.

“That means ascochyta blight is more widespread than it’s ever been in CQ and we want people to be more vigilant than they’ve ever been about looking out for it.”

While CQ’s predominantly dry winters make it a lower-risk environment for ascochyta than southern regions, all current CQ varieties are susceptible to the fungus and each rainfall or overhead irrigation event represents a possible infection cycle during the growing or harvest period.

“CQ is divided into high and low-risk areas in terms of ascochyta, and crops in both those must be inspected regularly for signs of the disease, particularly 10 to 14 days after rain or overhead irrigation.

“If ascochyta is found, a registered fungicide should be applied to the crop just before each predicted rainfall event.”

High risk crops require a preventative spray before the first predicted post-emergent rainfall event, three weeks after emergence or at the three leaf stage, whichever occurs first.

While ascochyta has not been found north of Emerald, it has made its way into chickpea crops scattered throughout CQ’s southern growing areas, and Ms Ferguson says a wet end to the growing season could see ascochyta appear in crops as late as at harvest, rendering seed unusable for planting the following year.

Ms Ferguson said some growers may not be aware they are growing a crop from seed infected with ascochyta.

Even if they are in a district without any reported cases of the disease, ascochyta may appear if seed was sourced from outside CQ or was not treated with a registered dressing containing thiram.

Ascochyta spores are spread by wind or rain splash, so paddocks that contained crops with ascochyta and also neighbouring paddocks and those within 500 metres of infected paddocks are considered high risk, and a one in four-year rotation for chickpeas is recommended to minimise the risk of re-infection.

Areas where recent flooding has deposited chickpea crop residues are also considered to be high risk.