Apples Diseases Insects Pest Management

Apple Update: May 17, 2016

Crop Stages

Apple buds are at king bloom to full bloom in Chatham-Kent, Middlesex, Essex, Lambton, Elgin and Norfolk counties  and Niagara Region; full pink to first bloom in the GTA and Simcoe county; tight cluster to pink in Grey County and east of Toronto to Ottawa. There is 1.5 inches of growth on the terminal shoot in Essex County.


Pruning and tree planting is wrapping up in orchards. With 1.5 inches of growth on the terminal shoot in Essex County, some growers will be applying Apogee. Temperatures dropped between 0 and 1 degree over the weekend in areas of Norfolk, Chatham-Kent and Niagara.  Rainfall ranged between 15 to 35 mm across Ontario’s apple growing areas last week. Eastern Ontario continues to be very dry. Essex County has been receiving plenty of rain over the last two weeks.


The risk of fire blight infection was high to exceptional in Essex, Lambton, Waterloo, Wellington, Durham, Northumberland, Quinte and Ottawa regions over the weekend. Growers in southern regions of the province that had open blossoms were applying antibiotics (Streptomycin, Kasumin) in preparation for a potential infection period. The fire blight prediction maps indicate a relatively low risk of infection occurring for the remainder of the week. However, the possibility increases if weather becomes warmer and wetter in regions with open blossoms. Growers are encouraged to monitor conditions over the next few days and be prepared to take action should blossoms open and risk of fire blight infection increases. The fire blight prediction maps will be updated again Wednesday and Friday of this week.

Many regions experienced a long scab infection period at the end of last week and into the weekend. Depending on when protectant fungicides were applied and how much rain occurred (expect reduced efficacy with 2+ inches of rain), some may have found themselves without adequate coverage by the end of the wetting period. Rapid ascospore maturation is on-going in most of the province at this time which means scab infection risk is high.

Foliage is growing rapidly now. Tight cluster to petal fall is a critical time to apply systemic fungicides, such as Group 3, 7 and/or 11 for scab and powdery mildew control. For good resistance management and improved protection against fruit scab, these products should be tank-mixed with a protectant fungicide.

Frog-eye leaf spot (black rot) has been observed on leaves in some orchards with infected branches and mummified fruit. Pruning out diseased material and dead wood is important to reduce the inoculum source within the orchard.


The oriental fruit moth biofix has been set in most of the southern regions of the province. Degree days are being accumulated to determine the appropriate spray timing window.

Codling moth and European apple sawfly traps have gone up in orchards.

Apple leafcurling midge has been caught in all regions monitoring for this pest. Eggs have been observed and leafrolling has begun in early regions. Some growers have applied a pre-bloom insecticide.

Spring feeding caterpillar, mullein bug, aphid and mite activity continues.

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