Pest and disease control

Thrips, leafhoppers and aphids can infest emerging seedlings, while fruit fly and heliothus can attack fruit, and leaves and fruit respectively. Systemic insecticides give good protection against thrips, leafhoppers, aphids and fruit fly. BT sprays are effective against heliothis. All chemicals used should be labelled and licensed for capsicums.

Common diseases of capsicums include Phytophthora root-rot, Verticillium wilt, Rhizoctonia root-rot, and bacterial leaf spot. Seed fungicide treatments are effective against the three fungal soil-borne diseases (Phytophthora, Verticillium, and Rhizoctonia). Rotations help control of these diseases, so growing paprika after cereals (but not sorghum) or legumes is recommended, only repeating paprika after three or four years. Tomato crops also have a similar range of diseases and pests, so growth after tomatoes should be avoided.

Viruses are likely to be important, with curly-top virus, tomato spotted wilt virus, lucerne mosaic virus, and capsicum mottle virus know to occur. Control of the insect vectors of the virus will reduce the incidence of infection, as will rotations, and control of solanaceous weeds in the area.

Fruit can be harvested fresh like vegetable capsicums and sold as fresh sweet chillies in markets.

However, for the industrial purposes of producing condiment paprika and oleoresin, mechanical harvesting will be vital for the economics of the industry.

There is at present little experience with this. It can be that processing tomato or green bean harvesters can be modified to harvest paprika.

One of the breeding aims of the RIRDC-supported program at the University of Sydney is synchronous early ripening, which will facilitate mechanical harvesting. Ethephon® can be used to stop flowering, hasten fruit maturity and defoliate the plants before mechanical harvesting, and fruit can be left on the plants to partially dry before harvest.

The harvest must then be dried (without overheating), slightly crushed and the calyx removed (half-product), and then milled to produce condiment paprika. The machinery and processes for these steps are still under development.

Oleoresin production is a specialised process unlikely to be undertaken by producers.

About the author

Peter Sharp is the Director of the Plant Breeding Institute at the University of Sydney. He is an expert in the area of cereal molecular genetics, but has in the last few years collaborated with Nickolas Derera AM in developing paprika cultivars, with funding from RIRDC.

A RIRDC-supported PhD student is also developing a hybrid seed production system for paprika under his supervision.

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