7th Blight Update and Seasonal Outlook for Nova Scotia- May 13, 2022

Friday, May 13, 2022

In this update, I like to mention a couple of things: GDD and Crop Development Update, Insect Monitoring Traps and Monilinia Blight Infection Update.

I know many growers are busy with spraying today and Saturday to get ahead of the rain events. Good luck and have a great weekend!

GDD and Crop Development Update

GDD accumulation from all stations has now exceeded 200 GDD (Figure 1. GDD summary, May 12). 

                                                            Figure 1. GDD Summary, May 12

 Plant emergence in sprout fields already started in many areas as we are getting close to the important thresholds of plant emergence based on the wild blueberry GDD model (270 GDD- plant emergence start; 290 GDD- 10% plant emergence). Again, if you haven’t applied your spring herbicides (spartan, chikara, ignite and velpar), you should do it as soon as possible. But, at this point, for many fields in the central area, it is too late to apply chikara and ignite. Please check your fields if you are still going to apply those herbicides. Damage will occur when those herbicides are in contact with blueberry plants!

The next threshold we will be watching is 390 GDD (stems with open flowers start). Early flower stage (pre-bloom) and leaf shoot expansion were observed in many fields I visited (Figures 2&3).

Figure 2&3


Insect Monitoring Traps


Some of you might start thinking about getting insect monitoring traps early due to supply chain delays. WBPANS carries traps in the office, so please give them a call and check if you can get the things you need (902-662-3284; info@nswildblueberries.com).

Great Lakes IMP (https://www.greatlakesipm.com/) also has great selections of monitoring tools.


Monilinia Blight Infection Update

Most areas in mainland NS are now well above the 40% F2 stage. For the Cape Breton area, I got a message this morning and it is getting close to the 40% F2 point. Growers in those late areas should check closely at their fields.

On sites I visit weekly, they were all above 80% F2 now. With the warm and dry weather we had last and this week, this might help to dry those mature cups but we are still in the susceptible infection period (Figure 4).

Figure 4. Wild blueberry susceptible stages to monilinia blight infection


The current forecast is calling for a long-wet period from May 15 to May 17 (Table 1). When I talked to many growers, most guys are planning Friday and Saturday to get their first or second applications on before this potential infection period.

Table 1. Weather Forecast for Potential Wetness and Monilinia Infection Periods

Weather Station and Location

Potential Wetness and Monilinia Infection Periods

*ONLY when your field is at or above 40%!!!

*Predict period: May 13-19; reported date: May 13



Glenholme (NSW001)

May 15-17

Murray Siding (NSW002)

May 15-17

Upper Kemptown (NSW022)

May 14-15

Kavanaugh Mills (NSW023)

May 15-18

Debert (NSW036)

May 15-17

Belmont (NSW037)

May 15-17

Staples Brook (NSW038)

May 15-17





Wyvern (NSW003)

May 15-17

Oxford (NSW005)

May 16-17

Halfway River (NSW039)

May 14-17





Blue Mountain (NSW017)

May 15-17

Sunny Brae (NSW018)

May 15-17

New Gairloch (NSW019)

May 15-17

Keble (NSW020)

May 15-18

Four Mile Brook (NSW021)

May 15-17

College Grant (NSW040)

May 15-16



*Weather source: weather stations in wild blueberry fields (http://www.novascotiawildblueberryblog.com/p/weather.html)