Integrated Management of Foliar Diseases in Vegetable Crops
The overall aim of the project was to develop integrated pest management strategies based largely on the use of fungicide alternatives to manage the following key foliar diseases of vegetable crops: powdery mildew on pumpkins and zucchinis; downy mildew on lettuce, cucumbers and squash; anthracnose on cucumbers; and white blister on broccoli, cauliflower and Chinese cabbages. The key areas of research were on – Downy mildew, powdery mildew, and anthracnose management on cucurbits Production of cucurbits in Australia is affected by three fungal foliar diseases: powdery mildew, downy mildew, and anthracnose. These fungal diseases are particularly important in Queensland, where production value of cucurbits is 50% of the total value of cucurbit production in the country. Field trials were conducted in Ayr, Bowen, and Gatton in Queensland to screen zucchini, squash, cucumber, and pumpkin cultivars for low reaction to the diseases and to evaluate the efficacy of alternative spray products on disease control. Commercial cultivars with moderate resistance to the diseases were identified as well as potential alternative spray products with acceptable efficacy. In field-grown zucchini, selected alternative products evaluated as part of spray programs and in combination with the use of cultivars with moderate resistance to the diseases performed equally to a conventional fungicide spray program. The information obtained with this research work can be used to develop integrated disease management programs. Downy mildew and anthracnose management on lettuce Downy mildew and anthracnose are two main fungal diseases of lettuce, often resulting in significant losses in cool and wet conditions. Growth room and field trials were undertaken to evaluate the relative susceptibility of commonly used lettuce cultivars to both diseases, and to evaluate the level of control provided by the application of new fungicides and environment friendly fungicide alternatives. White blister rust management on brassicas White blister rust is a major threat to production of Brassica vegetables (e.g. broccoli, pak choi, cabbages, Brussels sprouts, cauliflower, and cabbage) in Victoria and Tasmania. The disease is commonly controlled with conventional fungicides. Commercial cultivars with some disease resistance have been developed and used as a disease control measure in these crops. Some of these cultivars became susceptible to pathogen populations. New fungicides as well as products alternative to fungicides need be evaluated in order to mitigate resistance development by pathogen populations to the few available systemic fungicides. The research carried out in Victoria and Tasmania aimed to identify alternatives to conventional fungicides and potential new fungicides to control white blister rust in Brassica crops.