Native budworm actively feeding on cereals has not been an issue for growers or industry in the past, and considering the recent detections, growers and western region industry networks have voiced that they would like support on this issue, especially regarding sampling techniques and spray thresholds. To achieve this, we investigated this new behavioural trend and the population numbers required to cause economic yield losses to determine if and when management is required in non-traditional cereal hosts.

Through pheromone-based moth trapping, crop inspections, glasshouse trials and a field cage trial, we investigated the behaviour of H. punctigera moths and larvae on, and potential economic damage to, wheat in the northern grainbelt of Western Australia. 

• Native budworm moths frequently fly into wheat crops, but they are deterred from laying eggs on wheat plants.
• Native budworm moths prefer to lay eggs on wild radish and (volunteer) lupins in wheat crops so weed control is a critical part of preventing damage to wheat.
• Larvae prefer to feed on wild radish over vegetative (tillering) wheat but prefer to feed on wheat heads in advanced wheat over wild radish.
• Larvae either starve to death or have reduced performance and smaller pupae when forced to feed on wheat, indicating that wheat is not a preferred host.
• Thresholds for native budworm larvae in wheat are likely to be higher than 50 per 10 sweeps or 5 per square metre. 
• At a density of 5 per square metre, larvae account for a yield loss of $1.71 per ha loss given a 2 tonne/ha crop valued at $360/tonne.
• Field inspections of wheat crops during 2022 showed presence of both native budworm and armyworm, so it is important to identify species in the field.

Wheat sown according to local agronomic practices then ten field cages installed to contain native budworm larvae.