Insect pest management in capsicum and tomato crops is heavily reliant on chemical insecticide applications. A reduction in the amount of chemical insecticides is both a desirable and achievable goal. This project aimed to increase the available tools to growers for the management of the key pest of capsicums and tomatoes, heliothis moth.

Aspects of companion planting were investigated along with the responses of heliothis to biologically diverse environments. Companion planting benefits have long been recognised in home garden situations. The same types of benefits of this increase in biodiversity may be seen in cropping situations.

The key findings of this project were:

• While sorghum companion plants acted as a trap crop in a small scale experiment, this effect was not seen in an experiment in a commercial capsicum crop. In fact, sorghum actually increased the numbers of heliothis eggs on near by capsicum plants.
• Marigolds proved to be highly attractive to heliothis moths in glasshouse experiments and may be a suitable trap crop for capsicums.
• Heliothis moths did not display any learning behaviour in relation to host selection in the field
• None of the reputedly pest repellent herbs tested (tansy, catnip, basil and coriander) were found to be repellent to heliothis moths. Tansy was found to increase the numbers of eggs on their tomato companions.
• Assassin bugs proved to be successful predators of heliothis larvae in capsicum crops. The optimal release rate was 3 bugs/m.

Further investigation of the suitability of marigolds as a trap crop for capsicums is necessary. The use of trap crops in general requires more work to determine if they actually result in a reduction in heliothis pressure within a crop. The use of assassin bugs as predators in capsicums looks promising but further research is required to determine their efficiency and to refine release rates. Assassin bugs should soon be commercially available.

This project has been funded by Hort Innovation, using the research and development levies listed below and contributions from the Australian Government. Hort Innovation is the grower-owned, not-for-profit research and development corporation for Australian horticulture.

• Vegetable Fund