Ascochyta emerging in lentils
GroundCover™ Supplement Issue: 102 | Author: Janet Paterson
Intense lentil cropping on the Yorke Peninsula in South Australia over the past decade has caused a rise in ascochyta inoculum loads and a possible breakdown in blight resistance in a popular and previously resistant variety, Nipper.
SA Research and Development Institute (SARDI) pulse pathologist Jenny Davidson is monitoring a suspected breakdown in lentil resistance to the ascochyta fungus.
During a severe outbreak of ascochyta in 2010, Nipper lentils needed fungicide sprays during podding ahead of rain fronts to prevent pod and seed infection. Such infection levels had not been seen before and could indicate that the fungus has broken the variety’s resistance.
SARDI research funded by the GRDC and the SA Grains Industry Trust identified isolates of Ascochyta lentis collected from Yorke Peninsula in 2010 that can separately overcome each of three sources of resistance used in the lentil breeding program.
Under high selection pressure, such as occurs on Yorke Peninsula, these might develop a single resistance type capable of overcoming all three sources of plant resistance.
It is important that growers monitor all lentil crops for ascochyta infection.
Preliminary research indicates that ascochyta can survive in lentil paddocks much longer than previously thought, with 2012 surveys showing inoculum persists for at least three years. This may mean a broader rotation is required to adequately control serious inoculum levels.
Ms Davidson says a seed fungicide dressing is critical to controlling springtime levels of the disease.
Jenny Davidson, senior pulse pathologist, SARDI,
08 8303 9389,
GRDC Project Code DAS00099