Seeding rate important for early canopy closure in chickpeas
Date: 13 May 2013
- Northern chickpea growers are advised to sow at optimal seeding rates, irrespective of sowing date, to ensure early canopy closure and minimise the risk of viruses.
- Plant on time according to the local environment and minimise the impact of aphid flights.
- Retain standing stubble as this deters aphids from landing on the crop.
- Sow between standing cereal rows, use precision agriculture techniques to sow between the stubble rows. This assists generating a uniform crop canopy which makes the crop less attractive to aphids.
- Ensure adequate nutrition – supplying adequate crop nutrition will assist in generating dense uniform canopies which deter aphids.
Seeding rate is proving important for ensuring early canopy closure and minimising the spread of viruses in northern chickpea crops.
Dr Andrew Verrell, NSW Department of Primary Industries (NSW DPI) research agronomist says recent research supported by the Grains Research and Development Corporation (GRDC) shows growers should sow chickpeas at optimal seeding rates – irrespective of sowing date.
Dr Verrell says varieties surveyed showed no significant difference in terms of plants with virus symptoms but there was a highly significant effect with plant density as very low plant density exhibited the highest incidence of virus symptoms.
“It is important to research the best seeding rate and to plant on time to suit your environment and minimise the impact of aphid flights,” Dr Verrell said.
“We also recommend retaining standing stubble as this deters aphids from landing on the crop.
“Growers can use precision agriculture techniques to sow between standing cereal rows.
This assists generating a uniform crop canopy which makes the crop less attractive to aphids.
“Another strategy is to ensure adequate crop nutrition as this will assist in generating dense uniform canopies which deter aphids.”Dr Verrell says there are more than 14 species of virus that naturally infect chickpeas and are spread by airborne insects, particularly aphids.
“The aphids that fly in to crops do not stay long and do not normally colonise plants,” he said.
“Typical virus symptoms are bunching, reddening, yellowing, death of shoot tips and early death of whole plants. However, it should be remembered that none of these are diagnostic for virus.”
The occurrence of virus in chickpeas is episodic and changes dramatically from season to season and location, he says.
“Clovers, medics, canola/mustard, weeds, and other pulses can host viruses that infect chickpea.”
Dr Verrell says the best control strategies to reduce risk of viruses are agronomic and foliar insecticides are not recommended for chickpea viruses.
A recent survey of 17 chickpea crops in northern NSW led by Dr Kevin Moore found a high incidence of Beet western yellows virus (BWYV) and lower incidences of Alfalfa mosaic virus (AMV) and Cucumber mosaic virus (CMV).
“The survey suggests three major infections with the first flight of aphids in the first week of September,” Dr Verrell says.
“Chickpea trials at NSW DPI’s Tamworth Agricultural Institute (TAI) had a high incidence of plants with virus symptoms.”
The trials were within 300 metres of lucerne and approximately 500m of canola paddocks.
Three trials including sowing date, plant density and nutrient omission were selected and plants exhibiting virus symptoms were counted in spring.
Photo Caption: Planting rate can affect a chickpea crop’s susceptibility to viruses (click on image above for high res version).
Dr Andrew Verrell
NSW Department of Primary Industries
0429 422 150
Rachel Bowman, Senior Consultant, Cox Inall Communications
07 3846 4380 0412 290 673
GRDC Project Code Interim funded project – Pulse agronomy in northern NSW