Mummy berry forecast for April 17th

Tuesday, April 17, 2012

The following observations were made at the test site at Tim Strong’s in Kings County on the morning of April 17th:

1. Mature apothecia cups were found at the site,
2. Varieties varied from 0 to 50% F2 (susceptible) stage for mummy berry infection.

In Nova Scotia, we manage the primary phase of mummy berry disease and the conditions necessary for primary infection include 1) inoculum presence, 2) susceptible bud development stage, and 3) suitable weather conditions. At this time, in Kings County, we have met conditions one and two (for early varieties); however, we have not yet had suitable weather conditions for infection.

The decision to spray for mummy berry disease depends almost entirely on the past history of the disease in a particular field. If growers have experienced a problem in the past, they should apply controls.

A ‘fixed spray schedule’ may be used to manage the disease whereby the first fungicide spray should be applied when 40-50% of the flower buds have reached the F2 stage (flower bud scales separating). One or more additional sprays may be required on a 7-10 day schedule.

Alternatively, a ‘weather based spray schedule’ may be employed. This strategy uses temperature and leaf wetness duration to determine if an infection period has occurred. If an infection period occurs and mature apothecia are present, and flower buds are at 40-50% F2, then the grower has up to 72 hours after the start of the wet period to apply Funginex, Mission, or Topas. An additional spray(s) may be required, depending on weather conditions, 7-10 days later.

If you choose to employ the fixed spray schedule, a first spray to early flowering varieties can be applied anytime in Kings County. If you choose to wait for suitable weather conditions for infection, I will be monitoring and reporting as they occur at the station in Kings County. At this time we have not had suitable conditions for infection. Keep in mind that weather conditions can vary greatly across the Province and that bud development stages can vary considerably from location to location. The station in Kings County is a guide only for spray decisions in other areas.