Apple Disease Management Strategies


Apple growers have a variety of products with different chemistries available to them for controlling apple diseases. Each of these different chemistries differs greatly in their activity, retention and re-distribution. Two potential strategies for controlling scab and other diseases in apple orchards are listed below incorporating most of the fungicides available for apples. Each strategy has it's pros and cons, and takes into consideration disease pressure from apple scab and other diseases such as powdery mildew, black rot, cedar apple and quince rust. Your orchard strategy should take into account the history of the orchard, varieties of apples grown, environmental conditions and any restrictions by your buyer. Economics can also play an important role in deciding which products to use, but always remember that cutting corners can cause problems down the line.  

Strategy A

Stage of Development

Fungicide

Target Disease (Pest)

Comments

green tip to 1/2 inch green
 EBDC fungicides or Vangard Apple scab

  • Compatible with oil
  • Economical
  • EBDC good redistribution properties
  • Option to rotate between 2 chemical families
  • Vangard only control apple scab
tight cluster to pink
 Sovran
(2 applications)		 Apple scab Powdery mildew

  • Two applications ,10 apart, shorten interval if rapid growth
  • Marginal control of rusts (apply as a protectant)

Bloom

EBDC

Apple scab

  • If not covered by the Sovran application above

Petal fall to 2nd summer spray

Nova/Nustar +1/2 rate of a protectant EBDC or Captan (Maestro)

Apple scab Powdery mildew Rusts Black rot* Flyspeck and Sooty Blotch

  • Protectant important for control of fruit scab and summer diseases
  • *If 1/2 rate of EBDC used may not control black rot
  • If 1/2 rate of Captan(Maestro) used provides black rot control
  • Captan(Maestro) phytotoxicity to oil in Agrimek and oil applications

Summer

Captan(Maestro) or Sovran

Apple scab Flyspeck and Sooty Blotch* Black Rot* *Sovran not registered for these diseases

  • No more than 4 applications of Sovran a year (30 days to harvest interval)
  • Sovran not to be used as last fungicide of the year

 

Strategy B

Stage of Development

Fungicide

Target Disease (Pest)

Comments

green tip to 1/2 inch green

EBDC fungicides or Vangard

Apple scab

  • Compatible with oil
  • Economical
  • EBDC good redistribution properties
  • Option to rotate between 2 chemical families
  • Vangard only controls apple scab

tight cluster to pink

Nova/Nustar +1/2 rate EBDC or Captan (Maestro)

Apple scab Powdery mildew Cedar apple rust Quince rust

  • Two applications, 7 to 10 days apart , shorten interval if rapid growth

  • Phytotoxicity problems if Captan used too close to oil for mite control

Bloom

EBDC

Apple scab

  • If not covered by the above application

Petal fall to 2nd summer spray

Sovran (2 applications)

 Apple scab Powdery mildew (Although not registered- Rusts Black rot Flyspeck and Sooty Blotch may be controlled)

  • Two applications, 10 days apart, shorten interval if rapid growth
  • No more than two sequential applications then alternate with two applications of fungicide with a different mode of action
  • Marginal control of rusts

Summer

Captan(Maestro) Or Sovran

Apple scab Flyspeck* Sooty Blotch* Black Rot* *( Sovran not registered for these diseases)

  • No more than 4 applications of Sovran a year (30 days to harvest interval)
  • Sovran not to be used as last fungicide of the year
  • Easy on predatory mites

 

 


For more information:
Toll Free: 1-877-424-1300
Local: (519) 826-4047
E-mail: ag.info.omafra@ontario.ca
Author: Kathryn Carter - Pome Fruit IPM Specialist/OMAFRA; Margaret Appleby - IPM Systems Specialist/OMAFRA; Dr. Wendy McFadden Smith - McSmith Agricultural Research Services
Creation Date: 01 May 2003
Last Reviewed: 01 May 2003