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Lesser budworm

Lesser budworm (Heliothis punctifera) larvae have been identified for consultant, Greg Paul (IMAG consulting), from a sample collected near Forbes in the Central West Slopes and Plains district of New South Wales. They were found in a flowering crop of chickpeas and some damage to the foliage was evident, however Greg says there was very little damage to the pods, especially given the high numbers which were present. The majority of caterpillars were found on the ground rather than on the crop plants, and may have been migrating towards an adjacent wheat crop. Some medics and grasses among the chickpeas were also damaged, and Greg says the caterpillars appeared to be favoring these over the crop itself.

Lesser budworm is closely related and similar in appearance to the native budworm (see below), although they are rarely seen in the agricultural areas of south-eastern Australia. Early larval instars of these two species are very difficult to tell apart. Lesser budworm larvae are usually dark in colour while native budworm varies from black to green to light brown in colour. Both have a light coloured strip down each side of the body. For older larvae (>20 mm in length), lesser budworm have white hairs on the collar (segment behind the head) and the body, while native budworm have black hairs on the collar and black to blackish-brown body hairs. A hand lens or microscope is required to observe the difference in hair colour.

Outbreaks of lesser budworm are a rare event as a unique combination of biological and climatic conditions are required. They normally occur in outback Australia where they feed on desert daisies. Conditions that may favor outbreaks in south-eastern Australia are significant inland summer rains which trigger growth bursts of vegetation, enabling moth numbers to build up, followed by favorable winds that enable long distance flights into agricultural and pastoral districts. The potential damage this species can cause is unclear as the full host range is unknown, however like most noctuid moths they are generalist feeders and do not target specific crops.

Click here for images of the lesser budworm.

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