Pests and diseases
Brown spot of jujube, caused by the fungal pathogen Nothophoma quercina was recently detected in WA. No other significant diseases have been found in jujubes to date.
Pests include rabbits, kangaroos and birds but these can be controlled by fencing or netting the orchard. The jujube is susceptible to Mediterranean fruit fly (Medfly) so a baiting program may be required. Three main control strategies are recommended:
- cover spraying
- bait or spot spraying
- lure and kill devices.
The effectiveness of these control techniques should be monitored with traps. Medfly not only affects crop production, but limits access to interstate and overseas markets.
In China some 86 pests and 10 diseases have been reported to be harmful to jujubes. Of the pests, peach fruit moth and Lygus pratensis are most common and serious. Among diseases and disorders, witches broom, fruit splitting and rust are the most serious.
Fruit splitting is an issue for jujubes in Western Australia. It is a water-related physiological disorder and can ruin a large percentage of the crop in some years. The severity depends on water management throughout the growing season, rain around fruit maturation, and cultivar resistance. Maintaining soil moisture during the growing season will help reduce splitting but resistant varieties are the best option.
Parrots are the most damaging pest to small and/or relatively isolated orchards. The rainbow lorikeet has also become a serious pest in some growing areas where it can pose an even greater threat to crops than the twenty-eight and red cap parrots.
Bird control methods include:
- Exclusion netting: Although expensive (approximately $30 000/ha) this method will also alleviate the effects of extreme weather events such as hail storms and hot temperatures (sunburn). When assessing the advantage of netting as a means of bird control, the percentage of crop loss as well as the time spent controlling birds by other methods must be taken into account.
- Bird scaring devices: Birds generally become accustomed to scaring devices and noise generators in the orchard and their effectiveness is quickly lost. Varying degrees of control can be obtained by swapping from one device to another and altering their location in the orchard.
- Culling: Unless many hours are spent each week keeping pressure on birds by shooting, they will continuously invade the orchard and ruin a large percentage of your crop.
Contact your local Department of Biodiversity, Conservation and Attractions - Parks and Wildlife Service office prior to scaring, or culling birds on your property as permits may be required for some species.
Without netting, bird control is time consuming and requires a constant commitment to prevent crop damage.