Fungicide Tank-Mixes and Incompatibilities

Common Fungicides Used for Fruit Disease Management

Their Compatibilities and Incompatibilities 

·       Topsin M (thiophanate-methyl, FRAC 1)

o   Do not tank mix with highly alkaline materials such as Bordeaux or lime sulfur

o   Do not tank mix with copper

·       Inspire Super (difenoconazole + cyprodinil, FRAC 3 & 9)

o   Do not tank-mix with surfactants or foliar fertilizers

·       Rally (myclobutanil, FRAC 3)

o   Compatible with oil

o   Stable at a wide range of pH

·       Revus Top (mandipropamid + difenoconazole, FRAC 3 & 40)

o   Do not tank-mix with surfactants or foliar fertilizers

·       Topguard (flutriafol, FRAC 3)

o   Compatible with surfactants

·       Fontelis (penthiopyrad, FRAC 7)

o   Compatible with surfactants and oil

·       Pristine (pyraclostrobin + boscalid, FRAC 7 & 11)

o   Compatible with oil (except on pear)

o   Do not use Pristine + oil on pear

o   Do not use surfactants when applying by air (hops)

·       Scala (pyrimethanil, FRAC 9)

o   Not compatible with captan

·       Vangard (cyprodinil, FRAC 9)

o   Compatible with most tank additives

o   Adjust pH to 5.0 – 7.0 when tank-mixed with Rovral (stone fruit, small fruit)

·       Cabrio (pyraclostrobin, FRAC 11)

o   Compatible with most additives or adjuvants

·       Flint (trifloxystrobin, FRAC 11)

o   Compatible with most insecticides, fungicides, and foliar nutrients

·       Sovran (Kresoxim-methyl, FRAC 11)

o   Can be tank-mixed with most recommended insecticides, fungicides, plant growth regulators, adjuvants, or additives

 ·       Captan (FRAC M)

o   Do not mix with oil or within 4 days of an oil application

o   Do not mix with strongly alkaline materials (reduces fungicidal activity) such as   Bordeaux mixture or lime

o   Phytotoxic to apple when mixed with sulfur

·       Copper (FRAC M)

o   Not compatible with Topsin M

o   Do not apply under cool, slow-drying conditions

o   Do not tank-mix with phosphorus acids

o   Tank-mixing with mancozeb may cause phytotoxicity under wet or cool conditions. Spot check before use.

o   Many Bacillus products are incompatible with copper. Read label and use caution.

·       Dithane (mancozeb, FRAC M)

o   Compatible with most insecticides, fungicides, or growth regulators

·       Polyram (metiram, FRAC M)

o   Spray oils may be needed to achieve consistent control

·       Sulfur (FRAC M)

o   Do not mix with oil or use within 2 weeks of each other

o   Do not mix with Bt

o   Phytotoxic to apple when mixed with captan

o   Do not apply to sensitive crop cultivars

o   Do not use at temperatures above 80˚F

·       Syllit (dodine, FRAC M)

o   Do not mix with Bordeaux or lime

·       Ziram (FRAC M)

o   Compatible with most commonly used adjuvants

 

Above comments and compatibilities are per label recommendations, thus terminology and language may vary from one product to another.

Untangling the Web of Copper Fungicides

Fire blight season is approaching, and delayed dormant applications of copper fungicides are commonly recommended for management of various tree fruit diseases.  But there are so many...

Below is a summary of copper formulations, their characteristics, and their limitations. 

Copper Fungicides

·       Fixed Copper

o   Safer for plant tissue than “bluestone” copper (see below)

o   May be used throughout growing season, but may cause fruit russetting

o   Low solubility in water, lower risk for phytotoxicity

o   Release copper ions slowly (with water/rain), longer residual

o   Slow drying time (rainy conditions) increases solubility, ion release, and phytotoxicity

o   Acidic conditions/additives increase solubility, ion release, and phytotoxicity

§  Adjuvants, phosphorus acid fungicides, and mancozeb lower pH

o   Use high rates during dormancy for fire blight management (until ½” green)

o   Lower rates during growing season for management of other diseases, may add lime

o   Common forms of fixed copper fungicides

§  Basic copper sulfate – Cuprofix, Basicop, Phyton, Agristar

§  Copper Hydroxide – Kocide, Champ, Badge, NuCop, CuPro

§  Copper oxychloride sulfate – C-O-C-S

§  Cuprous oxide – Nordox, ChemCopp

·       Copper sulfate pentahydrate – bluestone

o   Dormant spray, only

o   CuSO₄.5H₂O

o   Highly soluble ions, phytotoxic

o   Often combined with lime to help tie up copper ions

o   No residual activity, rapid release of copper ions

o   Common brands of copper sulfate

§  Mastercop, Magna Bon, Aquavet, Delcup

  

Tree fruit diseases managed with copper fungicides:

•                 Fire blight (spray guide recommendations: dormant – label: silver tip to green tip)
•                  Apple scab (dormant to pink)
•               Bacterial canker (after harvest and late dormant)
•                Bacterial spot (dormant/budswell, pink, and petal fall)
•                Peach leaf curl (dormant)
•                Cherry leaf spot (after petal fall)
•                Black knot (dormant)

Copper is an antimicrobial; it is not selective.  Kills any exposed plant cells, bacteria, and fungi

Large numbers of copper ions (rapid release of ions) are phytotoxic to plant tissue, especially leaf tissue

Copper fungicides are not systemic and wash off with rain.  Fixed coppers have more residual activity due to slow release of copper ions.

Metallic copper equivalent is the amount of copper available for fungicidal activity (different from active ingredient).  Basic copper sulfate usually contains the highest metallic copper equivalent.

Copper can accumulate in soils, inhibit plant growth, and is toxic to microorganisms and earthworms

More on fire blight at http://nicolewarduk.blogspot.com/2013/04/fire-blight-infections-occur-during.html

 

Black Rot Common on Grape

Black rot is the most common disease of grape in Kentucky.  If left unprotected, vineyards can suffer high economic losses. 

Infection occurs early in the season, usually before bloom, at temperatures as low as 50˚F.  Early symptoms develop as spots on leaves 1 to 2 weeks after infection (Fig 1).  Tan spots with darker margins often contain black fruiting structures (pycnidia) in centers (Fig.2).  Spores (conidia) from these structures cause secondary infections throughout the season.  As leaves mature, they become resistant, but newly developing leaves can become infected anytime during the season.

Fig 1.  Leaf lesions have light tan centers and darker brown margins.

Fruit infections occur early in the spring, as well.  Grapes are susceptible from flowering until 3 to 4 weeks after bloom.  Early fruit symptoms appear as light brown spots (Fig. 3).  Soon, entire berries turn dark brown and shrivel (Fig 4).  These raisin-like fruit develop black fruiting structures (pycnidia) that overwinter on the “mummies.” 

Fig 2.  Fruiting structures (pycnidia) produce spores that cause secondary infections.  They can be seen with a magnifying glass, and often with the naked eye.

Both cultural practices and fungicides are critical for control of black rot.  Fruit mummies must be removed from vineyards to eliminate sources of overwintering inoculum.  Beginning at pre-bloom, a rigid fungicide regime must be employed.  Strobilurin fungicides (Abound, Pristine, Flint) provide excellent control, but risk for fungicide resistance is high.  Rotate with triazole/SI fungicides (Bayleton, Elite, Rally) and protectant fungicides (Mancozeb, Ziram).

Fig 3.  Fruit infections begin as light brown spots.  Note:  bird’s eye rot (anthracnose) infections on fruit have dark reddish margins with light gray centers.

Commercial growers should refer to the Midwest Small Fruit and Grape spray guide for fungicide and schedule details, while homeowners can use fungicides listed in ID-21 and PPFS-misc-7.  These and other publications can be found at http://www.ca.uky.edu/agcollege/plantpathology/extension/pubs.html#Smallfruit

Fig 4.  Soon after infection, grapes with black rot disease turn dark and shrivel into hard, black mummies.  Fruiting bodies (pycnidia) that develop are the primary source of overwintering for this fungus.