Producers urged to inspect lucerne for cowpea aphids

District Veterinarian for Local Land Services in the Monaro region, Lachlan Considine, said current aphid numbers, combined with the dry seasonal outlook and lack of other green feed, mean this could become a genuine issue for producers. 

"Cowpea aphids are associated with photosensitisation, a severe sunburn-like condition in sheep, horses and broken coloured cattle grazing on moisture-stressed lucerne," Lachie said. 

"Affected animals can develop painful lesions on exposed areas such as the teats, muzzle and around the eyes, which makes them reluctant to graze or suckle. This can lead to a sudden loss in body condition and even death from lack of feed intake. Lambs are most at risk." 

Producers are encouraged to physically inspect lucerne before grazing and monitor stock regularly for signs of reddened, crusted or peeling skin. When inspecting lucerne, focus on stems and upper parts of the plant, looking for clusters of small (1-3mm), black (adult) and grey (immature) aphids. Infested plants often appear wilted or yellowed, with a honeydew-like residue on leaves and stunted growth. 

"The Monaro district experienced a major outbreak of cowpea aphids in 2020, which caused significant animal welfare and production losses," Lachie said. 

"Our aim is to raise awareness this season to prevent another large-scale photosensitisation event." 

If stock show signs of severe sunburn or lesions, remove them from infested paddocks and provide shade until recovery. Severely affected animals may need veterinary care. 

Producers are also encouraged to speak with their local agronomist about management options and control strategies for cowpea aphids. 

For more information on cowpea aphids, their effects on lucerne, and images of affected stock, visit Cowpea Aphids on Local Land Services website. 

Media Contact 
For more information, please contact Chris Finley on chris.finley@lls.nsw.gov.au.