Image from this weeks scouting |
Developing buds become ‘susceptible’ when about 5 mm of green tissue is exposed in vegetative buds and when bud scales are separating in flower buds (F2 stage). The first fungicide spray should be applied when 40-50% of the flower buds have reached the F2 stage. A second spray may be required 7-10 days later.
After that point you need to treat if there is an infection period. Remember, the conditions necessary for primary infection include:
1. inoculum presence (history of monilinia blight in that field)
2. susceptible bud development stage (F2 stage), and
3. suitable weather conditions.
Infection periods are a combination of wetness duration and temperature. The warmer the temperature, the shorter the wet period needs to be to cause an infection period. For more information on this disease, check out Management of Mummy Berry Disease in Highbush Blueberry
A list of products are available in the Highbush Blueberry Insect & Disease Management Schedule for NS 2017.
As we move into May and there is a significant infection period forecasted and fruit bud development is well advanced, a pre-infection application might be well advised.