Venturia inaequalis

Females are attracted by apple fruits and insert eggs under the apple skin. Larvae will spend up to 30 days to develop until they are in the third instar stage of development. The larvae will leave the fruit, burrow into the soil, moult to the pupal stage soon to overwinter, and remain dormant for some years (Agriculture and Agri-Food Canada, 2013). Their egg and pupal stages are resistant to pesticides, while the highly vulnerable stages appear when the mature apple maggots leave the fruit before pupating and when they newly emerge (BC Ministry of Agriculture, n.d.b; Nechols, 1995). As a result, control options could be applied to the two vulnerable stages to have better suppression. Diseases (Apple Scab) Apple scab, caused by the Venturia inaequalis is one of the most destructive fungal diseases of apple in BC and is even more serious in the Fraser Valley. It can cause significant lost of yield and income for apple growers (BC Ministry of Agriculture, 2016a). Up to 100% yield losses could occur (Agriculture and Agri-Food Canada, 2013). When the apple crops are infected severely, leaves will show brown to black spots (Fig 7) and will ultimately become cracked and drop (Agriculture and Agri-Food Canada, 2013). Moreover, the young fruit is more likely to be infected, which can lead to fruit malformation (Fig 6) (BC Ministry of Agriculture, 2016a). There are two stages of infections. The primary infection often occurs on new leaves in the spring from the overwintered apple…