Native budworm

Native budworm (Helicoverpa punctigera) are a major pest of a variety of crops during spring to early summer. They feed on buds, flowers, fruiting parts and seeds. They attack field pea, faba bean, lentil, chickpea, lupin and canola crops, as well as pasture seed crops of lucerne, annual medic and clover.

Adult moths are approximately 30-35 mm long, light brown to red-brown, with numerous dark spots and blotches. The hind wings are pale with a dark band along the lower edge. They can live for approximately 2-4 weeks and within this period females can lay over 1000 eggs. Larvae are up to 40 mm long with substantial colour variation (shades of brown, green and orange), usually with darkish strips along the body and bumpy skin with sparse stiff black hairs.

Click here for images of native budworm.

Native budworm moths migrate into agricultural areas in eastern Australia in late winter and early spring. The numbers and timing of these migratory flights are mostly unpredictable as the moths often travel hundreds of kilometres, carried on high altitude wind currents. Upon the arrival of moths, eggs are laid onto crops and the resulting caterpillars can cause serious damage to pods if left uncontrolled. 

The Victorian Department of Primary Industries (DPI Victoria) are monitoring native budworm activity across Victoria. Samples are collected with traps that work by attracting male H. punctigera moths using baits that mimic the female moth sex pheromone. The traps are very specific to native budworm, and as such, provide a good indication of the timing of moth flights from central Australia and how these compare with previous years.

The following pheromone trapping information has been provided by DPI Victoria for September 29^th – October 6^th.

Region	Trap Sites	Moth count 7 days	Moth count 10 days*	Crop & Growth Stage
Mallee	Beulah Culgoa Dumosa Walpeup	60 4 1 10	86 6 1 14	Lentils, flowering Peas, podding Peas, dying Lupins, podding
Wimmera	Brim Warracknabeal	25 5	36 7	Faba beans, podding Faba beans, finished flowering
North Central	Katamatite Kerang	84 36	120 51	Peas, flowering Faba beans, flowering
South West	Willuara	0	0	Faba beans, flowering

*10 day counts are projected; based on 7 day counts.

The dry warm conditions across many regions means growers should carefully consider the yield and economic potential of the crop before spraying. Sampling of crops to determine the abundance of caterpillars is essential. The quickest and easiest method to sample most crops is to sweep using an insect net. Listed below are some tips for effective sweep-netting:

• Take sets of 10 sweeps.  Repeat a minimum of 5 times across the paddock.
• Each set of 10 sweeps should be taken from different representative areas of the crop. 
• After each set of 10 sweeps, count the number of larvae collected and record their size and after the 5 sets of sweeps calculate the average number and size of larvae.
• Use the average estimates to determine if spraying is necessary or not.
• If crops are podding, determine if grubs are burrowing into pods or not. Collect 20 pods as you sweep, split these and check for damage.