The red clover moth, first discovered in Auckland 15 months ago, sparked a nationwide monitoring campaign that initiated the importing of special pheromone traps.
These traps were distributed to growers up and down the county over this summer’s clover growing and flower period.
Foundation for Arable Research seed research manager Richard Chynoweth said the result of the trapping was not what growers wanted to hear.
“The results are not good news for red clover growers with moths being found on farms, roadsides and other areas everywhere from Wairarapa to Southland.
“As it was first identified in Auckland, we can assume they will be found across the North Island as well.”
DAMAGE: Larval feeding damage.
“However, in this case its principal host is red clover,” Chynoweth said.
Adult moths lay eggs on developing red clover flower heads, and once hatched the larvae tunnel into the florets to feed, destroying the growing seed.
As the larvae grow they adhere themselves to a chewed-off floret, using it like a cape or case for protection and camouflage.
Feeding damage to seeds can severely affect crop yields.
Farmers checking their crops for the presence of red clover casebearer should inspect flowers looking for millimetre-sized holes chewed into the base of individual florets and-or distinctive black droppings, also at the base of the florets.
They may also be able to see the casebearing larvae, which look like small red-brown cigars on the flowers.
Chynoweth urged farmers finding evidence of the casebearer moth to discuss management with their crop agrichemical adviser.
