First moderate native budworm moth flights detected

Recent pheromone trap results suggest that native budworm activity has increased moderately in the last fortnight.

Native budworm moth (source: cesar)

 

Native budworm (Helicoverpa punctigera) moths are capable of migrating hundreds if not thousands of kilometres in spring. Native budworm attack pulse crops such as field peas, faba beans, lentils, chickpeas, lupins and soybeans, as well as canola, lucerne, medics and clovers. With the help of growers and agronomists, budworm activity is being monitored through a network of traps in eastern Australia. Since monitoring began in early August, Mildura has recorded the largest native budworm catch with 100 and 60 moths trapped between 2^nd-8^th and 9^th-15^th of September, respectively. There has been low moth activity detected in Ouyen, Swan Hill, Kerang, Rupanyup, and south of Horsham in Victoria, and near Wagga Wagga and Forbes in NSW (table 1). 

Table 1. No. of native budworm moths caught in pheromone traps

What does this data tell us? Will moth numbers reflect the grub pressure in each location? It could do, but not necessarily. Moth traps are most useful in showing peaks of activity across time in different regions, but are less useful in predicting relative activity across regions. For example, despite little moth activity detected in Ouyen to date, the first signs of larval activity have been detected in pulse crops in this region. Moreover, experience has shown that despite higher moth catches in the Victorian Mallee than the Riverina, similarly damaging grub numbers can be found across the regions. 

Knowing that moderate flights have descended into the Mildura region of the Victorian Mallee, we can use a predictive model developed by cesar entomologist Garry McDonald, to estimate when eggs laid during peak flights will hatch and reach the 3rd larval instar stage. This is the ideal stage to target budworm larvae if treating with insecticides. In the northern Mallee, eggs laid during flights in early to mid-September will likely reach the 3rd instar larval stage between 1st-11th of October.

Monitoring crops should begin from early podding, particularly after the predicted date for 3^rd instar larvae. The continued migration of moths through spring is probable, and we will keep you updated on moth trap numbers. Monitor pulse and canola crops for larvae regularly using sweep nets; it is important to sample representative parts of the entire paddock prior before making a control decision. Taking an average of larvae caught after multiples of 10 sweeps within at least five locations in a paddock is recommended.

To date, we have not detected any significant Helicoverpa armigera (corn earworm) moth activity in our network of pheromone traps in Victoria or NSW. We will continue to monitor for this species over the coming weeks. 

For more information on management, including economic thresholds see our native budworm PestNote.

 

Thanks to this season’s moth trap operators:

Brad Bennett – AGRIvision (Mallee, VIC)

Jim Cronin – Landmark (Central West Slopes & Plains, NSW)

Bill Gardner – WestVic AgServices (Wimmera, VIC)

Shayn Healy – Crop-Rite Pty. Ltd. (Mallee, VIC)

George Hepburn – Tylers Hardware & Rural Supplies (Wimmera, VIC)

Damian Jones – Irrigated Cropping Council (Kerang, VIC)

Michael Moodie – Moodie Agronomy (Mallee, VIC)

Andrew Rice – ASPIRE agri (Central West Slopes & Plains, NSW)

David White – Delta Agribusiness (Riverina, NSW)

 

Field reports

Andrew McMahen – Landmark (Mallee, VIC)