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Native budworm

As mentioned in the last edition of PestFacts, the Victorian Department of Primary Industries (Victoria DPI) is presently monitoring native budworm (Helicoverpa punctigera) numbers caught in pheromone traps in various regions across Victoria. The pheromone traps attract male moths once they arrive into a crop and provide an indication of the pest risk potential.

Native budworm moths migrate into agricultural areas in eastern Australia in late winter and early spring, when over-wintering pupae in the soil emerge. 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 from pastoral regions. The arrival of moths means that their eggs are likely to be laid onto crops and the resulting caterpillars can cause serious damage to pods if left uncontrolled. 

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. Eggs are approximately 0.5 mm in diameter and white when laid, but darken before hatching. They are most commonly laid on the top third of the plant and growing points.

Native budworm larvae can be 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. Newly hatched larvae (approximately 1.5mm in length) are light in colour with dark brown heads and spots, and as they develop they become darker in colour.

Native budworm is a major pest of all pulses, lucerne, sub clover and annual medic seed crops. They also attack canola and all cereal crops. Larvae can be typically seen higher up on host plants where they feed on buds, flowers, fruits and seeds. The most notable damage by native budworm is on the pods and seeds.

Remember, moth numbers, and the subsequent generation of grubs, will vary between regions and paddocks, so monitoring remains the best way to determine the risk they pose to individual crops. Crops should be monitored using a sweep net from early flowering and throughout podding in pulse crops. Pod inspections are also essential in order to detect small grubs and accurately determine numbers.

The following information has kindly been provided by Victoria DPI. For further information about the native budworm pheromone trapping project, contact Michelle Pardy (Victoria DPI) on 03 5871 0600 or by email: michelle.pardy@dpi.vic.gov.au.

Region

Trap Sites

Moth count

Aug 21-29

Moth count

Aug 28-Sept 4

Crop &

Growth Stage

Comments

Aug 28-Sep 4

Mallee

Ultima

Walpeup

Berriwillock

Werrimul

-

27

-

59

2

0

23

36

Lentils

 Field peas

Lentils

Vetch

0.4-4mm rain across the Mallee. Recent warm temperatures

Wimmera

Nhill

-

12

Faba beans - flowering

4mm rain

North Central

Kerang

-

10

Faba beans

Field peas

-

Trap monitoring began two weeks ago, and while not all traps are operational, reports to date indicate low levels of native budworm moth activity across the Mallee, Wimmera and North Central regions. These counts are well below threshold levels. The low level of trapping suggests that there has not yet been a major in-flight of budworm from central Australia.

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