A new fungicide for management of apple diseases, called Aprovia, is now available for use by commercial growers. Due to its recent release, this product was not included in the latest 2016 publication of the New Jersey Commercial Tree Fruit Production Guide. Thus, below is a discussion of its attributes and suggested usage for disease control.
Aprovia fungicide, manufactured by Syngenta, is currently labeled for use on pome fruit, grapes, blueberries, and some other small vining fruits. Within the pome fruit group, Aprovia can be used on a wide variety of crops, including apple, crabapple, pear, and Asian pear. The labeled pome fruit rate range is 5.5 to 7.0 oz/A with a preharvest interval (PHI) of 30 days and a restricted-entry interval (REI) of 12 hours.
The active ingredient in Aprovia is benzovindiflupyr, which is classified as an SDHI fungicide or FRAC group 7. In efficacy studies to date on apple, Approvia has provided excellent control of apple scab and good control of rust and mildew. In contrast, the only other registered fungicide with a single SDHI active ingredient, Fontelis, provides similar scab but somewhat less (fair) control of rust and mildew. Other SDHI fungicides are available, but are sold as pre-mixes with other chemistries. These dual-active materials are Luna Sensation, Merivon, and Pristine (SDHI + QoI), and Luna Tranquility (SDHI + AP).
Apple scab resistance to the DMI fungicides (e.g., Indar, Rally, Topguard) and QoI fungicides (Flint, Sovran) has become problematic in many eastern U.S. orchards. Thus, the arrival of the SDHI fungicides has provided another tool to be used along with AP fungicides (Scala, Vangard) for disease management in these orchards. However, the SDHI fungicides are classified as having a medium to high risk of resistance development, and the AP materials have a medium risk. Thus, protectant fungicides should always be used in conjunction with these at-risk materials.
For apple orchards with DMI and QoI resistance, an early-season program (following a dormant copper spray) can consist of an AP + mancozeb (Vangard or Scala + Manzate), SDHI + mancozeb (e.g. Aprovia or Fontelis + Manzate), dodine + mancozeb (Syllit + Manzate), and SDHI + AP (Luna Tranquility) sprays. Since DMI resistance can be overcome to some extent using high rates, a spray consisting of the maximum rate of Inspire Super (DMI + AP) with thorough coverage (100 gpa) can also be a consideration for the early season program. The summer program then switches to an SDHI + QoI and captan program, which provides a fairly broad spectrum disease control for the rots and sooty blotch / fly speck.
Since most fungicides today are site-specific at-risk materials developed over time, resistance development often occurs in recent introductions before new chemistries arrive. However, for orchards with no known resistance, it is highly recommended that as many different at-risk fungicide chemistries (four or five) as possible be utilized along with protectant fungicides. Such an approach just may be sustainable.