Limestone Barrens



Insect Pest Research

In the 2002 Long’s Braya and Fernald’s Braya Recovery Plan and the 2005 Low Northern Rockcress Recovery Plan the diamondback moth (Plutella xylostella) was identified as a significant threat.

Diamondback Moth on Braya
Diamondback Moth on Braya

The diamondback moth is not native to the island of Newfoundland. It arrives on the Great Northern Peninsula each year in late spring or early summer, on southwesterly wind currents from overwintering sites in the United States. It is an agricultural pest of mustard crops (Family Brassicaceae), such as cabbage. Such crops are relatively uncommon on the Great Northern Peninsula.

Each year since 1998 diamondback moth eggs have been documented on Long’s Braya and Fernald’s Braya, and a few times on Low Northern Rockcress. Infestation by the diamondback moth can significantly reduce braya seed output because the moth larvae eat the plant's leaves, flowers, and fruit.

Diamondback moth infestation rates were monitored very closely between 2002 and 2007, using pheromone traps and detailed observational surveys. During that time the diamondback moth laid eggs on an average of 30% of the Long’s Braya and 16% of the Fernald’s Braya population.

Larval feeding reduced the mean seed output of infested Long’s Braya by 60% and damaged 26% of leaves. Such damage increases during warm years when the insect can reproduce for a second time, after reaching Newfoundland, resulting in multiple infestations.

Since 2007 the impact of this agricultural pest has been recorded as part of the long-term monitoring program and in effort to manage the pest in ongoing.

Monitoring pheromone trap.

Completing insect survey.


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