Helping the Western Australian potato industry capture winter production opportunities in the Mid West
For the WA potato industry to expand it needs to move into new areas outside traditional potato growing areas near and south of Perth. The Mid West area is a promising new area for winter production of potatoes. Factors limiting yield were assessed by monitoring insects and diseases in crops and providing support for agronomic decisions such as irrigation and fertiliser management on three commercial properties in Dandaragan in 2011 and 2012. Whilst improvements in agronomic management were identified the main area of improvement needed was in seed quality. In this respect both the sanitary (pest and disease level) and physiological quality (physiological age) of the seed was important Mid West area growers are both purchasers and growers of seed. The usual supplies of seed from the South West are too physiologically young (immature) for autumn sowings so the Mid West area growers bulk seed for one generation (G4 to G5) and harvest in spring so it is of the right age for the following autumn plantings. Insect monitoring showed aphid numbers in the Mid West area to be higher than in traditional summer growing seed areas in the South West. Virus monitoring showed the aphid borne potato leafroll virus was often found in crops where aphid control was excellent. In other instances there were high levels of other viruses such as potato virus S in crops grown from seed that was assumed to have very low level of viruses. Growers learnt the importance of obtaining generation four seed of the highest quality such as WA certified seed from the WA scheme for their seed crops and to manage these crops so the resulting generation five was of high quality. So high quality source seed and vigilant seed crop management is vital. Growers were advised to purchase rating 1 certified seed as this has a 100 times lower tolerance for diseases than rating 3 seed. Areas north of Perth from Mullewa to Carnarvon were identified as potentially more productive and profitable than areas further to the south for winter potato production. These areas were identified using the LINTUL-POTATO model which simulates potential yield based on temperature and the potato crop’s light-use-efficiency for producing tubers. The model showed that an area with a climate like Carnarvon might produce a 63 percent higher yield for a 15 June planting date than Dandaragan. More work is needed to validate these predictions with yield data from crops in the field in these locations.